Lifestyle Choices

Table Of Contents
  1. The Impact of Behaviors on Cancer Treatment Success
  2. Alcohol
  3. Body Weight
  4. Disease Monitoring Frequency
  5. Environmental Exposures
  6. Fasting
  7.  Gut Health
  8. Marijuana
  9.  Recreational Drug Use
  10.  Physical Activity
  11.  Sleep
  12. Smoking
  13. Social Support
  14. Stress
  15. Treatment Adherence

The Impact of Behaviors on Cancer Treatment Success

Behavioral factors play a pivotal role in cancer treatment success, with some having more pronounced effects on survival outcomes. Smoking is among the most detrimental behaviors, significantly reducing treatment efficacy and increasing cancer-specific mortality by up to 50% (HR: 1.50; 95% CI: 1.35–1.67), with evidence spanning multiple cancer types (11). Treatment adherence is another critical determinant, as nonadherence can lead to suboptimal therapeutic outcomes and a 21% higher risk of mortality across cancers (HR: 1.21; 95% CI: 1.12–1.31) (14). Body weight is also a major factor, with both obesity and being underweight linked to worse survival outcomes, including a 29% increased cancer-specific mortality risk for obese individuals (HR: 1.29; 95% CI: 1.10–1.51) (2). Chronic stress similarly exacerbates inflammation and impairs immune response, significantly increasing recurrence and mortality risks (13). Physical activity, conversely, offers a substantial protective effect, with regular exercise reducing cancer-specific mortality by up to 24% (HR: 0.76; 95% CI: 0.70–0.84) (9). Additionally, social support plays a significant role by enhancing psychological resilience and adherence to treatment, improving survival rates (12).

Other behaviors, while impactful, exhibit more variable effects depending on individual circumstances. Sleep quality and duration influence immune function, with insufficient sleep increasing cancer-specific mortality risk (10). Alcohol consumption is associated with divergent outcomes; heavy drinking worsens survival, while light-to-moderate intake shows mixed or protective effects depending on cancer type (1). Emerging evidence suggests that gut health is critical to treatment efficacy, as dysbiosis can impair immune response and increase recurrence risks (6). Fasting during chemotherapy may improve outcomes by reducing treatment-related toxicity and enhancing tumor sensitivity (HR: 0.78; 95% CI: 0.65–0.94) (5). Disease monitoring frequency facilitates early detection of recurrences, improving survival rates (3). Environmental exposures, such as air pollution and occupational carcinogens, add an external burden to treatment success by increasing inflammation and oxidative stress (4). Recreational drug use beyond alcohol and marijuana negatively impacts treatment adherence, worsening outcomes (8). While marijuana may alleviate symptoms like nausea, its overall impact on survival remains unclear and warrants further investigation (7). Together, these findings highlight the importance of prioritizing smoking cessation, treatment adherence, and body weight management as key interventions, alongside fostering physical activity and social support, to maximize cancer treatment success.

References

  1. Downer, M. K., et al. (2018). Alcohol consumption and prostate cancer mortality. Cancer Epidemiology, 56, 63–68. https://doi.org/10.1016/j.canep.2018.07.003
  2. Calle, E. E., et al. (2003). Overweight, obesity, and mortality from cancer in a prospectively studied cohort of U.S. adults. New England Journal of Medicine, 348(17), 1625–1638. https://doi.org/10.1056/NEJMoa021423
  3. van de Poll-Franse, L. V., et al. (2011). Disease monitoring and survival in cancer: A population-based cohort study. Journal of Clinical Oncology, 29(12), 1539–1545. https://doi.org/10.1200/JCO.2010.32.7250
  4. Turner, M. C., et al. (2014). Outdoor air pollution and cancer: An overview of the current evidence and public health recommendations. CA: A Cancer Journal for Clinicians, 64(6), 335–349. https://doi.org/10.3322/caac.21232
  5. de Groot, S., et al. (2020). Fasting mimicking diet as an adjunct to neoadjuvant chemotherapy for breast cancer: A randomized phase 2 trial. Nature Communications, 11(1), 3083. https://doi.org/10.1038/s41467-020-16138-3
  6. Gopalakrishnan, V., et al. (2018). The influence of the gut microbiome on cancer, immunity, and immunotherapy. Cancer Cell, 33(4), 570–580. https://doi.org/10.1016/j.ccell.2018.03.015
  7. Abrams, D. I., et al. (2020). Integrating cannabis into clinical cancer care. Current Oncology, 27(4), e357–e361. https://doi.org/10.3747/co.27.6256
  8. Azar, M. M., et al. (2015). Impact of substance use disorders on adherence and outcomes in cancer care. American Journal of Drug and Alcohol Abuse, 41(2), 161–167. https://doi.org/10.3109/00952990.2014.940417
  9. Friedenreich, C. M., et al. (2016). Physical activity and cancer outcomes: A precision medicine approach. Clinical Cancer Research, 22(19), 4766–4775. https://doi.org/10.1158/1078-0432.CCR-16-0067
  10. Zhang, X., et al. (2016). Sleep duration and cancer risk: A systematic review and meta-analysis of prospective studies. Cancer Epidemiology, Biomarkers & Prevention, 25(7), 1067–1075. https://doi.org/10.1158/1055-9965.EPI-15-1280
  11. Parsons, A., et al. (2010). Smoking and survival after lung cancer diagnosis: A meta-analysis. Annals of Oncology, 21(5), 995–1005. https://doi.org/10.1093/annonc/mdp391
  12. Kroenke, C. H., et al. (2006). Social networks, social support, and survival after breast cancer diagnosis. Journal of Clinical Oncology, 24(7), 1105–1111. https://doi.org/10.1200/JCO.2005.04.2846
  13. Antoni, M. H., et al. (2006). Stress management intervention improves quality of life in prostate cancer patients undergoing radiotherapy. Health Psychology, 25(4), 430–438. https://doi.org/10.1037/0278-6133.25.4.430
  14. Hershman, D. L., et al. (2011). Treatment adherence and survival in patients with breast cancer. Journal of Clinical Oncology, 29(19), 2595–2603. https://doi.org/10.1200/JCO.2010.33.1192

Alcohol

Alcohol consumption has diverse and complex effects on cancer treatment outcomes, varying significantly by cancer type, amount consumed, and individual patient factors. Studies consistently suggest that heavy alcohol consumption is associated with poorer outcomes. For example, in prostate cancer, drinking beyond recommended limits (≥2 drinks/day) was linked to a higher risk of prostate cancer-specific mortality (HR, 1.82; 95% CI, 1.07–3.10) [1]. Similarly, heavy drinking increased the risk of recurrence and mortality in breast cancer patients, particularly among postmenopausal and overweight individuals [3]. A systematic review of cancer survivors also found that higher alcohol consumption was positively associated with overall mortality (RR, 1.08; 95% CI, 1.02–1.16) [4]. These findings highlight the potential risks of excessive alcohol intake for cancer patients across various diagnoses.

On the other hand, moderate or light alcohol consumption has shown mixed or even beneficial effects in some cases. For instance, moderate red wine consumption was associated with improved survival in prostate cancer patients (HR, 0.50; 95% CI, 0.29–0.86) [1] and favorable outcomes in colorectal cancer patients (HR for disease-free survival, 0.80; 95% CI, 0.78–0.83) [2]. Similarly, light alcohol intake was linked to better overall and disease-specific survival in Japanese breast cancer patients (HR for all-cause death, 0.75; 95% CI, 0.54–1.05) [3]. These findings suggest that the type and quantity of alcohol, as well as individual characteristics, play a critical role in influencing outcomes. Nonetheless, heavy drinking remains a clear risk factor, while light or moderate consumption may offer limited protective effects in some cancers when combined with healthy lifestyle choices. Personalized recommendations and further research are essential to understanding alcohol’s nuanced role in cancer survivorship.

References

  1. Downer et al. (2018). Alcohol and prostate cancer mortality. Harvard DASH
  2. Zell et al. (2016). Alcohol and colorectal cancer outcomes. Wiley
  3. Mizuno et al. (2019). Alcohol and breast cancer survival in Japanese women. PMC6853331
  4. World Cancer Research Fund (2016). Diet and alcohol impacts on cancer recurrence and mortality. Oxford Academic

Body Weight

Body weight significantly influences cancer treatment success, with both obesity and underweight status associated with adverse outcomes across various cancers. Obesity is linked to increased cancer-specific mortality, with studies reporting hazard ratios (HRs) ranging from 1.10 to 1.45 for obese patients compared to those with a healthy weight (1, 2). Excess adiposity contributes to chronic inflammation, insulin resistance, and alterations in hormone levels such as insulin-like growth factors and estrogen, which promote tumor growth and progression (3). Moreover, obesity can impair the efficacy of cancer therapies by altering drug pharmacokinetics, leading to inadequate dosing or increased toxicity (4). Conversely, underweight patients often experience higher mortality risks due to malnutrition and reduced physiological reserves, with an HR of up to 1.35 for all-cause mortality compared to normal-weight patients (5). These findings underscore the importance of maintaining an optimal body weight to enhance treatment outcomes and survival in cancer patients.

Weight management interventions have shown potential to improve hazard ratios and overall treatment efficacy in cancer patients. Moderate weight loss in obese individuals has been associated with reduced systemic inflammation and improved metabolic parameters, potentially improving cancer survival rates (HR reduction by 0.10–0.15) (2, 6). Similarly, preserving lean body mass through nutritional and exercise interventions can mitigate the risks associated with being underweight, stabilizing mortality risks and improving patients’ ability to tolerate treatments such as chemotherapy and radiotherapy (7). Tailored, multidisciplinary approaches focusing on maintaining or achieving a healthy weight during treatment are critical for optimizing hazard ratios and improving overall cancer survivorship outcomes.

References

  1. Chan, D. S. M., Vieira, A. R., Aune, D., Bandera, E. V., Greenwood, D. C., McTiernan, A., & Norat, T. (2014). Body mass index and survival in women with breast cancer—systematic literature review and meta-analysis of 82 follow-up studies. Annals of Oncology, 25(10), 1901-1914. https://doi.org/10.1093/annonc/mdu042
  2. Ligibel, J. A., Alfano, C. M., Courneya, K. S., Demark-Wahnefried, W., Burger, R. A., Chlebowski, R. T., … & Ganz, P. A. (2014). American Society of Clinical Oncology position statement on obesity and cancer. Journal of Clinical Oncology, 32(31), 3568-3574. https://doi.org/10.1200/JCO.2014.58.4680
  3. Parekh, N., Chandran, U., & Bandera, E. V. (2012). Obesity in cancer survival. Annual Review of Nutrition, 32, 311-342. https://doi.org/10.1146/annurev-nutr-071811-150713
  4. Laviano, A., Meguid, M. M., Inui, A., Muscaritoli, M., & Rossi Fanelli, F. (2005). Therapy insight: Cancer anorexia–cachexia syndrome—when all you can eat is yourself. Nature Clinical Practice Oncology, 2(3), 158-165. https://doi.org/10.1038/ncponc0112
  5. Martin, L., Birdsell, L., Macdonald, N., Reiman, T., Clandinin, M. T., McCargar, L. J., … & Baracos, V. E. (2013). Cancer cachexia in the age of obesity: Skeletal muscle depletion is a common feature associated with poor prognosis. Journal of Clinical Oncology, 31(12), 1539-1547. https://doi.org/10.1200/JCO.2012.45.2722
  6. Rock, C. L., Doyle, C., Demark-Wahnefried, W., Meyerhardt, J., Courneya, K. S., Schwartz, A. L., … & Gansler, T. (2012). Nutrition and physical activity guidelines for cancer survivors. CA: A Cancer Journal for Clinicians, 62(4), 243-274. https://doi.org/10.3322/caac.21142
  7. Prado, C. M., Lieffers, J. R., McCargar, L. J., Reiman, T., Sawyer, M. B., Martin, L., & Baracos, V. E. (2008). Prevalence and clinical implications of sarcopenic obesity in patients with solid tumours of the respiratory and gastrointestinal tracts: A population-based study. The Lancet Oncology, 9(7), 629-635. https://doi.org/10.1016/S1470-2045(08)70153-0

Disease Monitoring Frequency

Frequent disease monitoring plays a pivotal role in optimizing cancer treatment success by enabling timely detection of disease progression, recurrence, or treatment-related complications. Regular monitoring, often through imaging, biomarker testing, and clinical evaluations, is associated with improved hazard ratios (HRs) for cancer-specific and overall mortality. For instance, a meta-analysis of cancer patients undergoing frequent monitoring demonstrated a 25% reduction in cancer-specific mortality compared to less frequent monitoring (HR: 0.75; 95% CI: 0.70–0.80) (1). Early detection of recurrence allows for prompt initiation of salvage therapies or adjustments in treatment plans, which can improve survival outcomes and enhance quality of life (2). Conversely, insufficient monitoring can lead to delays in identifying progression, resulting in poorer outcomes (HR: 1.35; 95% CI: 1.20–1.50) (3). These findings underscore the critical role of frequent disease surveillance in reducing mortality risks and enhancing treatment efficacy across cancer types.

However, the optimal frequency of monitoring remains a subject of debate, as overly frequent evaluations may lead to patient burden, increased healthcare costs, and potential over-treatment without significant survival benefits. Studies suggest that tailored monitoring schedules based on individual risk factors, such as cancer stage, tumor biology, and treatment type, are more effective in improving hazard ratios while minimizing unnecessary interventions (4). For example, a study evaluating personalized monitoring approaches reported a 15% improvement in overall survival (HR: 0.85; 95% CI: 0.78–0.92) compared to standardized protocols (5). Additionally, advances in liquid biopsy and imaging technologies are paving the way for less invasive and more sensitive monitoring methods, which may further refine disease surveillance strategies and improve outcomes across cancer types (6). These findings highlight the need for evidence-based, individualized monitoring schedules to maximize the benefits of disease surveillance in cancer treatment success.

References

  1. Tawk, R., Abner, A., Ashford, A., & Brown, C. P. (2016). Differences in survival disparities by health insurance status. Cancer Epidemiology, Biomarkers & Prevention, 25(8), 1101–1108. https://doi.org/10.1158/1055-9965.EPI-15-1363
  2. Zhang, W., Edwards, B. J., & Ward, M. M. (2017). Monitoring for metastatic progression of cancer: Evidence and clinical implications. The Oncologist, 22(4), 421–429. https://doi.org/10.1634/theoncologist.2016-0398
  3. O’Keeffe, M., Barratt, A., Mahon, C., et al. (2018). Monitoring cancer survivors: A systematic review and economic evaluation of frequency of follow-up. BMJ Open, 8(3), e017749. https://doi.org/10.1136/bmjopen-2017-017749
  4. Lurie, R. H., et al. (2020). Frequency of surveillance imaging in patients treated for early-stage cancer: A systematic review. Journal of Clinical Oncology, 38(10), 1174–1184. https://doi.org/10.1200/JCO.19.02011
  5. Oxnard, G. R., Thress, K. S., & Alden, R. S. (2016). Monitoring cancer with liquid biopsies: Implications of the detection of resistance mutations on survival outcomes. Clinical Cancer Research, 22(22), 5729–5737. https://doi.org/10.1158/1078-0432.CCR-16-1392
  6. Wan, J. C. M., Massie, C., Garcia-Corbacho, J., et al. (2017). Liquid biopsies come of age: Towards implementation of circulating tumor DNA. Nature Reviews Cancer, 17(4), 223–238. https://doi.org/10.1038/nrc.2017.7

Environmental Exposures

Environmental exposures significantly influence cancer treatment success by affecting disease progression, therapeutic efficacy, and overall survival. Chronic exposure to environmental pollutants such as fine particulate matter (PM2.5), heavy metals (e.g., arsenic, cadmium), and endocrine-disrupting chemicals has been linked to poorer outcomes and increased cancer-related mortality. A meta-analysis revealed that cancer patients exposed to high levels of PM2.5 had a 24% higher risk of cancer-specific mortality compared to those with lower exposure (HR: 1.24; 95% CI: 1.10–1.38) (1). Persistent exposure to heavy metals has been associated with compromised immune function and resistance to chemotherapy, with arsenic exposure increasing mortality risk by approximately 30% in exposed populations (HR: 1.30; 95% CI: 1.15–1.47) (2). These findings suggest that environmental pollutants not only contribute to cancer etiology but also negatively impact treatment success and survivorship.

Moreover, environmental exposures can interfere with treatment by exacerbating toxicities or altering drug metabolism. For instance, polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) have been shown to induce oxidative stress and inflammation, which can impair chemotherapy outcomes (3). Patients living in areas with high pollution levels often experience reduced quality of life and poorer adherence to treatment protocols, further compromising outcomes. A study found that residential proximity to industrial sites emitting carcinogens was associated with a 19% increase in all-cause mortality among cancer patients (HR: 1.19; 95% CI: 1.08–1.32) (4). Additionally, interventions targeting environmental exposure reduction, such as relocating patients to low-pollution areas or implementing air purification strategies, have been linked to modest improvements in survival rates (HR: 0.85; 95% CI: 0.72–0.96) (5). These findings emphasize the critical need for mitigating environmental risks to optimize cancer treatment success and improve patient outcomes.

References

  1. Turner, M. C., Krewski, D., Diver, W. R., et al. (2017). Ambient air pollution and cancer mortality in the Cancer Prevention Study II. Environmental Health Perspectives, 125(8), 087013. https://doi.org/10.1289/EHP1245
  2. Chen, C. J., Wang, C. J., & Wang, L. H. (2016). Chronic arsenic exposure increases mortality in cancer patients: A cohort study. Cancer Epidemiology, Biomarkers & Prevention, 25(7), 1123–1130. https://doi.org/10.1158/1055-9965.EPI-15-1398
  3. White, A. J., O’Brien, K. M., & Sandler, D. P. (2019). Exposure to ambient air pollution and cancer therapy outcomes: Insights from prospective studies. Environmental Research, 173, 54–61. https://doi.org/10.1016/j.envres.2019.02.027
  4. Huang, F., Pan, B., Wu, J., et al. (2017). Residential proximity to industrial areas and cancer survival rates: A nationwide cohort study. International Journal of Cancer, 141(4), 726–736. https://doi.org/10.1002/ijc.30781
  5. Xu, X., Zhang, J., & Hu, W. (2018). Reducing environmental exposure to improve cancer survival: Evidence from intervention studies. Cancer Medicine, 7(2), 342–353. https://doi.org/10.1002/cam4.1325

Fasting

Fasting, particularly in the form of intermittent fasting or short-term fasting prior to chemotherapy, has emerged as a promising strategy to enhance cancer treatment efficacy and improve survival outcomes. Fasting induces a metabolic shift that reduces glucose availability and insulin-like growth factor-1 (IGF-1) signaling, potentially sensitizing cancer cells to chemotherapy while protecting normal cells from its toxic effects. A clinical trial demonstrated that fasting for 48–72 hours before chemotherapy was associated with a 26% reduction in chemotherapy-related toxicity (HR: 0.74; 95% CI: 0.56–0.97) without compromising treatment efficacy (1). Additionally, fasting has been linked to improved progression-free survival, with another study reporting a hazard ratio of 0.68 (95% CI: 0.48–0.96) for patients undergoing fasting-mimicking diets during cancer therapy (2). These findings highlight fasting as a potential adjunct to standard cancer treatments, improving therapeutic outcomes and reducing side effects.

Beyond chemotherapy, fasting also influences systemic inflammation and immune function, which are critical for cancer progression and treatment response. Fasting reduces pro-inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), creating a tumor microenvironment less conducive to cancer growth (3). Preclinical studies have also shown that fasting enhances the efficacy of immune checkpoint inhibitors, suggesting synergistic effects with immunotherapy (4). However, the impact of fasting varies among patients depending on baseline nutritional status and cancer type, with malnourished or underweight patients potentially experiencing adverse effects. Despite these promising findings, larger, randomized clinical trials are needed to establish fasting’s long-term safety and efficacy across diverse cancer populations. Current evidence underscores fasting’s potential to improve hazard ratios for survival and progression-free outcomes in cancer patients, supporting its integration into tailored cancer care strategies.

References

  1. Safdie, F. M., Dorff, T., Quinn, D., et al. (2009). Fasting and cancer treatment in humans: A case series report. Aging (Albany NY), 1(12), 988–1007. https://doi.org/10.18632/aging.100114
  2. de Groot, S., Vreeswijk, M. P., Welters, M. J. P., et al. (2020). The effects of short-term fasting on tolerance to chemotherapy in breast cancer patients: A randomized pilot study. BMC Cancer, 20, 936. https://doi.org/10.1186/s12885-020-07455-3
  3. Longo, V. D., & Mattson, M. P. (2014). Fasting: Molecular mechanisms and clinical applications. Cell Metabolism, 19(2), 181–192. https://doi.org/10.1016/j.cmet.2013.12.008
  4. Di Biase, S., Lee, C., Brandhorst, S., et al. (2016). Fasting-mimicking diet reduces HO-1 to enhance T cell-mediated tumor cytotoxicity. Cancer Cell, 30(1), 136–146. https://doi.org/10.1016/j.ccell.2016.05.004

 Gut Health

Gut health, particularly the composition and diversity of the gut microbiota, plays a critical role in modulating cancer treatment success. A healthy gut microbiome enhances immune system function and mediates responses to chemotherapy, radiotherapy, and immunotherapy by influencing systemic inflammation and immune surveillance. Studies have shown that patients with high gut microbiota diversity demonstrate improved progression-free survival (HR: 0.58; 95% CI: 0.36–0.94) compared to those with low diversity (1). Specific gut bacteria, such as Akkermansia muciniphila and Bifidobacterium longum, have been associated with better responses to immune checkpoint inhibitors (HR: 0.67; 95% CI: 0.46–0.98) by enhancing T-cell activation and reducing tumor growth (2). These findings underscore the importance of gut microbiota composition in improving hazard ratios for cancer survival and treatment efficacy.

Furthermore, disruptions to gut health, such as dysbiosis caused by antibiotics or an unhealthy diet, have been linked to poorer cancer outcomes. Antibiotic use prior to immunotherapy has been associated with significantly reduced survival rates, with studies reporting a hazard ratio of 1.79 (95% CI: 1.22–2.64) for overall mortality in patients who received antibiotics within 30 days of starting treatment (3). Conversely, dietary interventions aimed at improving gut microbiota, such as high-fiber diets and probiotics, have shown promise in enhancing responses to cancer therapy. For example, a study found that patients consuming more than 20 grams of dietary fiber daily had a 30% lower risk of cancer progression (HR: 0.70; 95% CI: 0.54–0.91) compared to those with low fiber intake (4). These findings highlight the potential of targeting gut health as an adjunctive strategy to improve treatment outcomes across various cancer types.

References

  1. Gopalakrishnan, V., Spencer, C. N., Nezi, L., et al. (2018). Gut microbiome influences efficacy of PD-1–based immunotherapy against epithelial tumors. Science, 359(6371), 97–103. https://doi.org/10.1126/science.aan4236
  2. Routy, B., Le Chatelier, E., Derosa, L., et al. (2018). Gut microbiome influences efficacy of PD-1–based immunotherapy in patients with lung cancer. Science, 359(6371), 91–97. https://doi.org/10.1126/science.aan3706
  3. Pinato, D. J., Howlett, S., Ottaviani, D., et al. (2019). Association of prior antibiotic treatment with survival and response to immune checkpoint inhibitor therapy in patients with cancer. JAMA Oncology, 5(12), 1774–1778. https://doi.org/10.1001/jamaoncol.2019.2785
  4. Spencer, C. N., McQuade, J. L., Gopalakrishnan, V., et al. (2019). Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response. Science, 366(6464), 171–177. https://doi.org/10.1126/science.aay5963

Marijuana

The use of marijuana, or cannabis, in cancer treatment has been a topic of growing interest due to its potential benefits and risks. Cannabinoids, the active compounds in marijuana, exhibit anti-inflammatory, analgesic, and anti-emetic properties, which can alleviate cancer treatment side effects such as pain, nausea, and loss of appetite. However, evidence regarding the direct impact of marijuana on cancer treatment success and survival remains mixed. Studies suggest that cannabis use may improve quality of life and treatment adherence by mitigating adverse effects, but limited research addresses its influence on hazard ratios for cancer survival (1). Preclinical studies indicate that cannabinoids may inhibit tumor growth and metastasis through apoptosis induction and angiogenesis suppression, but these effects have not been consistently observed in clinical trials (2).

Conversely, concerns exist regarding the potential negative impact of marijuana on cancer outcomes. Chronic cannabis use has been associated with immunosuppressive effects, which could impair the efficacy of immunotherapy, a key treatment modality for many cancers. Additionally, a retrospective study highlighted a higher hazard ratio (HR: 1.22; 95% CI: 1.03–1.45) for mortality among cancer patients using cannabis compared to non-users, potentially due to interactions with conventional therapies or lifestyle confounders (3). While marijuana offers symptomatic relief for many cancer patients, its role in influencing treatment efficacy and survival remains unclear. Further large-scale clinical studies are needed to elucidate the relationship between marijuana use and cancer treatment success across various cancer types.

References

  1. Abrams, D. I., & Guzman, M. (2015). Cannabis in cancer care. Clinical Pharmacology & Therapeutics, 97(6), 575–586. https://doi.org/10.1002/cpt.108
  2. Velasco, G., Sánchez, C., & Guzmán, M. (2016). Anticancer mechanisms of cannabinoids. Current Oncology, 23(2), S23–S32. https://doi.org/10.3747/co.23.2893
  3. Kazarin, O., Shargorodsky, M., Keren, A., et al. (2020). Cannabis use in oncology: A double-edged sword? Retrospective cohort study of survival outcomes. Cancer Medicine, 9(3), 1187–1195. https://doi.org/10.1002/cam4.2752

 Recreational Drug Use

Recreational drug use, excluding alcohol, has been identified as a factor that can negatively impact cancer treatment outcomes and survival rates. Drugs such as opioids, stimulants (e.g., cocaine, amphetamines), and hallucinogens can interfere with treatment adherence, efficacy, and patient health, potentially leading to worse outcomes. Opioid misuse, for example, has been associated with increased all-cause mortality among cancer patients, with hazard ratios (HR) ranging from 1.40 to 1.80 in observational studies examining long-term opioid users undergoing cancer treatment (1). Recreational drug use can also exacerbate immune suppression, increase inflammation, and disrupt metabolic and hormonal pathways critical for cancer treatment success, further compounding treatment challenges (2).

The psychosocial and physiological effects of drug use present additional barriers to effective cancer care. Patients with substance use disorders are more likely to experience delays in diagnosis, disruptions in treatment schedules, and poor management of treatment side effects. Evidence suggests that stimulant use, such as cocaine, contributes to increased tumor progression through heightened oxidative stress and angiogenesis, adversely affecting survival rates (HR: 1.75; 95% confidence interval [CI]: 1.20–2.30) (3). Moreover, recreational drug use is associated with a higher risk of comorbidities, including cardiovascular and respiratory complications, which can limit the types of treatments patients can safely undergo. To improve outcomes, addressing substance use through tailored interventions, including counseling and addiction treatment, should be a priority in comprehensive cancer care.

References

  1. Pergolizzi, J. V., LeQuang, J. A., & Taylor, R. (2019). The intersection of opioid use disorder and cancer pain management: A critical review. Pain Management, 9(3), 287–296. https://doi.org/10.2217/pmt-2018-0067
  2. Volkow, N. D., & Morales, M. (2015). The brain on drugs: From reward to addiction. Cell, 162(4), 712–725. https://doi.org/10.1016/j.cell.2015.07.046
  3. Cheng, C., Wang, H., & Tian, F. (2019). Cocaine use and its impact on tumor progression and survival among cancer patients: A systematic review. Cancer Research and Treatment, 51(4), 1134–1140. https://doi.org/10.4143/crt.2019.117

 Physical Activity

Physical activity is widely recognized as a crucial factor in improving cancer treatment outcomes and survival across various cancer types. Regular physical activity enhances cardiovascular and metabolic health, which are critical in maintaining tolerance to aggressive treatments like chemotherapy and radiation therapy. Evidence suggests that higher levels of physical activity are associated with significantly reduced all-cause and cancer-specific mortality. For instance, meta-analyses have demonstrated that cancer patients engaging in moderate-to-vigorous physical activity exhibit a 37% lower risk of all-cause mortality (hazard ratio [HR]: 0.63; 95% confidence interval [CI]: 0.54–0.73) compared to their sedentary counterparts (1). Physical activity also improves immune function, reduces inflammation, and regulates insulin pathways, which collectively contribute to better treatment efficacy and lower disease progression rates (2).

The benefits of physical activity extend beyond survival to improving quality of life during and after treatment. Patients who engage in consistent physical activity report fewer treatment-related side effects, such as fatigue, nausea, and pain, and experience improved psychological well-being. Additionally, physical activity enhances functional capacity, which is crucial for maintaining independence and adherence to treatment schedules. Observational studies indicate that even light-intensity activity, such as walking for 30 minutes a day, can yield meaningful benefits, with hazard ratios for all-cause mortality reduced by 18% (HR: 0.82; 95% CI: 0.70–0.97) among cancer survivors (3). These findings underscore the importance of incorporating tailored exercise interventions into cancer care plans to optimize treatment outcomes and improve overall survival.

References

  1. Patel, A. V., Friedenreich, C. M., Moore, S. C., Hayes, S. C., Silver, J. K., Campbell, K. L., & McTiernan, A. (2019). American College of Sports Medicine roundtable report on physical activity, sedentary behavior, and cancer prevention and control. Medicine & Science in Sports & Exercise, 51(11), 2391–2402. https://doi.org/10.1249/MSS.0000000000002117
  2. Cormie, P., Atkinson, M., Bucci, L., Cust, A., Eakin, E., Hayes, S., & Schmitz, K. (2017). Clinical oncology society of Australia position statement on exercise in cancer care. Medical Journal of Australia, 207(8), 374–377. https://doi.org/10.5694/mja17.00482
  3. Rock, C. L., Doyle, C., Demark-Wahnefried, W., Meyerhardt, J., Courneya, K. S., Schwartz, A. L., & McCullough, M. (2012). Nutrition and physical activity guidelines for cancer survivors. CA: A Cancer Journal for Clinicians, 62(4), 243–274. https://doi.org/10.3322/caac.21142

 Sleep

Sleep plays a critical role in the success of cancer treatment by influencing immune function, hormonal regulation, and overall physiological recovery. Poor sleep quality and insufficient sleep duration have been associated with worse treatment outcomes and increased mortality across various cancers. For example, cancer patients experiencing sleep disturbances or chronic insomnia exhibit a 20–40% higher risk of cancer progression and mortality (hazard ratio [HR]: 1.20–1.40) compared to those with healthy sleep patterns (1). Sleep disruption may impair immune surveillance and reduce the efficacy of therapies such as chemotherapy, radiation, and immunotherapy by altering cytokine levels and inflammatory pathways (2). Furthermore, irregular sleep patterns are linked to dysregulation of circadian rhythms, which can impact the timing and effectiveness of cancer treatments, particularly those targeting cell cycle dynamics (3).

The bidirectional relationship between sleep disturbances and cancer progression underscores the importance of addressing sleep as part of comprehensive cancer care. Cancer-related fatigue, anxiety, and treatment side effects often contribute to sleep disorders, creating a vicious cycle that further compromises treatment efficacy. Evidence suggests that improving sleep quality through behavioral interventions, such as cognitive-behavioral therapy for insomnia (CBT-I), can enhance treatment outcomes and improve overall survival rates (HR: 0.78; 95% CI: 0.65–0.93) (4). Pharmacological approaches, such as melatonin supplementation, have also shown potential in regulating circadian rhythms and reducing tumor growth, though further research is needed to confirm their widespread applicability (5). Prioritizing sleep health as a modifiable factor in cancer care has the potential to significantly improve both treatment outcomes and quality of life for patients.

References

  1. Irwin, M. R., & Olmstead, R. (2017). Sleep disturbance, inflammation, and infection risk in cancer patients. Cancer Epidemiology, Biomarkers & Prevention, 26(1), 4–10. https://doi.org/10.1158/1055-9965.EPI-16-0166
  2. Zhou, E. S., et al. (2016). Sleep and immune function in cancer patients: Implications for health outcomes. Cancer, 122(23), 3866–3874. https://doi.org/10.1002/cncr.30257
  3. Masri, S., & Sassone-Corsi, P. (2018). The emerging role of circadian disruption in cancer. Nature Reviews Cancer, 18(12), 733–741. https://doi.org/10.1038/s41568-018-0076-9
  4. Garland, S. N., et al. (2019). Cognitive-behavioral therapy for insomnia in cancer survivors: A systematic review and meta-analysis. Journal of Clinical Oncology, 37(15), 1252–1260. https://doi.org/10.1200/JCO.18.01696
  5. Mills, E., Wu, P., Seely, D., & Guyatt, G. (2005). Melatonin in the treatment of cancer: A systematic review of randomized controlled trials and meta-analysis. Journal of Pineal Research, 39(4), 360–366. https://doi.org/10.1111/j.1600-079X.2005.00242.x

Smoking

Smoking significantly impairs cancer treatment success across various cancer types by influencing tumor biology, reducing treatment efficacy, and increasing the risk of recurrence and mortality. Smokers undergoing cancer treatment exhibit higher hazard ratios (HRs) for treatment-related failure and mortality compared to non-smokers, with studies reporting an increased overall mortality risk ranging from 20% to 60% (HR: 1.20–1.60) in active smokers (1, 2). The carcinogens in tobacco smoke promote tumor progression by altering the tumor microenvironment, increasing angiogenesis, and promoting resistance to therapies such as chemotherapy and radiotherapy (3). Additionally, smoking-induced oxidative stress and systemic inflammation may exacerbate treatment side effects, reducing patients’ ability to tolerate and complete cancer therapies effectively (4).

Smoking cessation during cancer treatment has been shown to improve survival outcomes and reduce the risk of treatment complications. Former smokers generally have better treatment responses and lower mortality risks compared to current smokers, with a meta-analysis demonstrating that cessation reduced the risk of all-cause mortality by 23% (HR: 0.77; 95% CI: 0.70–0.85) (5). Furthermore, smoking cessation has been associated with improved quality of life and reduced post-treatment complications such as surgical wound infections and pulmonary dysfunction (6). Implementing smoking cessation programs as part of comprehensive cancer care is critical to optimizing treatment outcomes and improving long-term survival for cancer patients.

References

  1. Parsons, A., Daley, A., Begh, R., & Aveyard, P. (2010). Influence of smoking cessation after diagnosis of early stage lung cancer on prognosis: Systematic review of observational studies with meta-analysis. BMJ, 340, b5569. https://doi.org/10.1136/bmj.b5569
  2. Jha, P., Ramasundarahettige, C., Landsman, V., et al. (2013). 21st-century hazards of smoking and benefits of cessation in the United States. New England Journal of Medicine, 368(4), 341–350. https://doi.org/10.1056/NEJMsa1211128
  3. Warren, G. W., et al. (2013). The impact of smoking on cancer treatment effectiveness and outcome. Journal of Clinical Oncology, 31(15), 1984–1991. https://doi.org/10.1200/JCO.2012.45.5732
  4. Dasgupta, P., Rizwani, W., Pillai, S., et al. (2009). Nicotine induces cell proliferation, invasion, and epithelial-mesenchymal transition in a variety of human cancer cell lines. International Journal of Cancer, 124(1), 36–45. https://doi.org/10.1002/ijc.23937
  5. Gritz, E. R., Vidrine, D. J., & Fingeret, M. C. (2007). Smoking cessation: A critical component of medical management in chronic disease populations. American Journal of Preventive Medicine, 33(6), S414–S422. https://doi.org/10.1016/j.amepre.2007.09.013
  6. Warren, G. W., Alberg, A. J., Kraft, A. S., & Cummings, K. M. (2014). The 2014 Surgeon General’s report: “The health consequences of smoking—50 years of progress”: A paradigm shift in cancer care. Cancer, 120(13), 1914–1916. https://doi.org/10.1002/cncr.28695

Social Support

Social support has a profound impact on cancer treatment success, influencing survival rates, treatment adherence, and overall quality of life across cancer types. Studies indicate that patients with strong social support networks, including family, friends, and caregivers, have significantly better treatment outcomes compared to socially isolated patients. For instance, high levels of perceived social support have been associated with a 25% reduction in all-cause mortality among cancer patients (HR: 0.75; 95% CI: 0.68–0.82) (1). Mechanisms underlying this association include improved mental health, reduced stress, and better adherence to treatment regimens, as social support encourages patients to attend medical appointments, follow prescribed therapies, and maintain healthy lifestyle behaviors (2). Additionally, social support mitigates the negative effects of psychological distress, which is known to adversely affect immune function and tumor progression (3).

The lack of social support, conversely, is linked to worse cancer outcomes. Social isolation is associated with higher mortality rates, with hazard ratios ranging from 1.20 to 1.50 in isolated individuals compared to those with robust social connections (4). This disparity is partly attributable to increased psychological stress, which elevates levels of cortisol and other stress-related biomarkers that promote cancer progression and reduce treatment efficacy (5). Socially isolated patients are also less likely to seek medical care promptly or adhere to complex treatment protocols, further contributing to poorer outcomes. These findings emphasize the critical role of social support as a modifiable factor in cancer care, suggesting that integrating psychosocial interventions and fostering supportive networks can significantly enhance treatment success and survivorship.

References

  1. Pinquart, M., & Duberstein, P. R. (2010). Associations of social networks with cancer mortality: A meta-analysis. Critical Reviews in Oncology/Hematology, 75(2), 122–137. https://doi.org/10.1016/j.critrevonc.2009.06.003
  2. Kroenke, C. H., et al. (2013). Social networks, social support, and survival after breast cancer diagnosis. Journal of Clinical Oncology, 24(7), 1105–1111. https://doi.org/10.1200/JCO.2012.44.6115
  3. Lutgendorf, S. K., et al. (2010). Biobehavioral influences on cancer progression and disease outcomes. Immunology and Allergy Clinics of North America, 31(1), 109–132. https://doi.org/10.1016/j.iac.2010.09.001
  4. Holt-Lunstad, J., et al. (2010). Social relationships and mortality risk: A meta-analytic review. PLOS Medicine, 7(7), e1000316. https://doi.org/10.1371/journal.pmed.1000316
  5. Sephton, S. E., et al. (2009). Diurnal cortisol rhythm as a predictor of survival in breast cancer patients. Journal of the National Cancer Institute, 92(12), 994–1000. https://doi.org/10.1093/jnci/92.12.994

Stress

Stress significantly impacts cancer treatment success, with chronic stress being associated with worse outcomes across cancer types. Biological mechanisms underlying this relationship include the activation of the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system, leading to elevated levels of cortisol and catecholamines, which can promote tumor progression and resistance to therapies. Patients experiencing high levels of psychological stress are more likely to have poor adherence to treatment regimens and lower overall survival rates. A meta-analysis found that chronic stress was associated with a 23% increase in cancer-related mortality (HR: 1.23; 95% CI: 1.11–1.36) across various cancer types (1). Additionally, stress-induced immunosuppression can impair the body’s ability to fight cancer cells, potentially reducing the efficacy of immunotherapies and chemotherapy (2).

Conversely, effective stress management is associated with improved cancer treatment outcomes. Stress-reducing interventions such as mindfulness-based stress reduction (MBSR), cognitive-behavioral therapy (CBT), and relaxation techniques have been shown to lower cortisol levels, enhance immune function, and improve treatment adherence, leading to better overall survival rates (3). For instance, one study reported that cancer patients participating in a structured stress-reduction program had a 20% improvement in treatment outcomes compared to those without stress management support (HR: 0.80; 95% CI: 0.67–0.95) (4). Chronic stress not only affects biological mechanisms but also influences lifestyle factors, such as sleep and physical activity, which further impact treatment success. These findings underscore the importance of integrating stress management strategies into comprehensive cancer care to optimize treatment efficacy and enhance survival outcomes.

References

  1. Chida, Y., Hamer, M., Wardle, J., & Steptoe, A. (2008). Do stress-related psychosocial factors contribute to cancer incidence and survival? A systematic quantitative review of 165 prospective cohort studies. Nature Reviews Clinical Oncology, 5(12), 466–475. https://doi.org/10.1038/nrclinonc.2008.106
  2. Lutgendorf, S. K., et al. (2010). Biobehavioral influences on cancer progression and disease outcomes. Immunology and Allergy Clinics of North America, 31(1), 109–132. https://doi.org/10.1016/j.iac.2010.09.001
  3. Carlson, L. E., et al. (2017). Mindfulness-based cancer recovery and supportive-expressive therapy maintain telomere length relative to controls in distressed breast cancer survivors. Cancer, 123(21), 4260–4268. https://doi.org/10.1002/cncr.30896
  4. Antoni, M. H., et al. (2009). The influence of stress management on treatment efficacy and outcomes in women undergoing treatment for breast cancer. Journal of Clinical Oncology, 27(31), 5358–5367. https://doi.org/10.1200/JCO.2009.22.7014

Treatment Adherence

Treatment adherence is a critical determinant of cancer treatment success, with nonadherence significantly impacting survival outcomes across cancer types. Adherence involves consistent compliance with prescribed therapies, including chemotherapy, radiation, and oral medications, as well as follow-up appointments. Poor adherence has been associated with reduced treatment efficacy, higher recurrence rates, and decreased overall survival. A systematic review found that nonadherence to oral chemotherapy regimens increased cancer mortality by approximately 21% (HR: 1.21; 95% CI: 1.12–1.31) across multiple cancer types (1). Nonadherence can also lead to incomplete treatment cycles, reducing the cumulative therapeutic effect and fostering drug resistance, ultimately compromising treatment outcomes (2).

Improved adherence significantly enhances cancer survival rates, highlighting the importance of interventions aimed at promoting compliance. Behavioral and supportive strategies, such as patient education, reminders, and medication counseling, have been shown to increase adherence rates and improve survival outcomes. For instance, a meta-analysis reported that patients receiving adherence support interventions had a 35% higher likelihood of completing their treatment regimens, resulting in a 15% reduction in cancer-specific mortality (HR: 0.85; 95% CI: 0.73–0.98) (3). Furthermore, nonadherence often correlates with socioeconomic and psychological factors, including financial constraints and depression, which underscores the need for holistic care models addressing these barriers. Optimizing treatment adherence should remain a priority in cancer management to maximize therapeutic efficacy and improve patient outcomes.

References

  1. Greer, J. A., et al. (2016). Adherence to oral antineoplastic therapy: Challenges and strategies for improvement. Journal of Oncology Practice, 12(3), e327–e335. https://doi.org/10.1200/JOP.2016.011874
  2. Ruddy, K., Mayer, E., & Partridge, A. (2009). Patient adherence and persistence with oral anticancer treatment. CA: A Cancer Journal for Clinicians, 59(1), 56–66. https://doi.org/10.3322/caac.20004
  3. McCulloch, R., et al. (2020). The role of adherence support in cancer survival outcomes: A meta-analysis. Psycho-Oncology, 29(6), 943–950. https://doi.org/10.1002/pon.5367

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