Exercise Linked to Improved Outcomes in Cancer Patients Across Multiple Cancer Types
New research demonstrates that physical activity after cancer diagnosis reduces mortality risk in less common cancers and enhances circadian clock function in tumor tissue, supporting exercise as a therapeutic intervention.
Higher levels of moderate/vigorous physical activity (MVPA) after cancer diagnosis had a significant association with a lower risk of cancer mortality, according to pooled data from six large cohort studies. The analysis focused on seven cancers not normally included in studies of physical activity and showed variable effects on cancer mortality, depending on the type of cancer and level of activity.
Low levels of MVPA (>0 to <7.5 metabolic equivalent of task [MET]-hr/wk) were associated with reduced mortality risk for bladder, endometrial, and lung cancers, with point estimates ranging from 0.56 to 0.67. Survivors of ovarian, oral, and rectal cancers had nonsignificant improvement, but achieved statistically significant improvement with higher levels of MVPA. Survivors of kidney cancer had a nonsignificant reduction in cancer mortality risk across the range of MET-defined activity levels.
Survivors of lung or rectal cancer who were inactive before diagnosis nonetheless had a lower cancer mortality risk if they met guideline recommendations (7.5 to <15.0 MET-hr/wk) for MVPA after diagnosis. The study represents the largest effort to date to pool data from major U.S. cohorts, providing a larger sample size to evaluate associations of MVPA with cancer mortality among survivors of less commonly studied cancer types. The availability of repeated physical activity assessments across all six cohorts overcomes a key limitation of prior studies that relied on single time-point measures after diagnosis and provides valuable insights into the impact of long-term habitual physical activity.
Current guidelines recommend that patients with a history of cancer get 150-300 minutes of moderate-intensity or 75-150 minutes of vigorous physical activity a week (7.5 to 15.0 MET-hr/wk). However, the recommendations are based in large part on studies of mortality outcomes in breast, prostate, and colon cancer.
In prostate cancer specifically, a systematic review and Bayesian network meta-analysis of fifty-four randomized controlled trials involving 3,522 participants assessed the effects of diverse exercise interventions on physical and quality-of-life outcomes. Exercise interventions significantly improved muscle strength, body composition, fatigue, aerobic capacity, and quality of life compared to usual care. Resistance training (RT) may be the most beneficial intervention for enhancing muscle strength and aerobic capacity, aerobic training (AT) for reducing body fat, combined aerobic–resistance training (AT_RT) for alleviating fatigue, and high-intensity interval training (HIIT) for improving quality of life. All exercise modalities demonstrated good safety and feasibility, with no major adverse events reported.
Although standard treatments for prostate cancer, including surgery, androgen deprivation therapy (ADT), and radiotherapy, enhance survival, they frequently induce adverse effects such as muscle wasting, increased body fat mass, fatigue, and diminished quality of life.
Research in male C57BL/6J mice bearing Lewis lung carcinoma (LLC) investigated whether the timing of exercise modulates circadian gene expression and tumor growth. Mice were subjected to treadmill moderate intensity continuous training (55%-65% of maximum speed) at either a fixed (ZT2) or alternating Zeitgeber times (ZTAlt) for 3 weeks. Scheduled exercise at ZT2 significantly increased the amplitude of Per2, Per3, and Rev-Erbα expression rhythms in tumor tissue. No rhythmic enhancement was observed in the ZTAlt group. TNF-α acrophase was shifted in the ZT2 group, indicating a temporal immunomodulatory effect. Consistently performing exercise at the same time of day enhances tumor circadian clock genes rhythmicity, supporting chrono-exercise as a potential non-pharmacological adjuvant in cancer treatment.
Alterations in circadian timing mechanisms are increasingly recognized as contributing to tumor initiation and progression. Moreover, evidence indicates that malignant cells can interfere with the expression and synchronization of core clock genes.