Ramping up physical activity may slow prostate cancer progression
More exercise may reduce risk of cardiovascular disease
Many older men have prostate cancer. In 2018, 31,488 American men died of prostate cancer. But sometimes the cure is worse than the illness. Recent research suggests that prostate cancer is over-treated via highly invasive procedures, such as biopsy and prostate removal, which can have major adverse effects. Downsides include sexual impotence, urinary incontinence, and bowel malfunction. It’s important to remember that while high levels of prostate-specific antigen (PSA) predict increased risk of prostate cancer, high levels do not conclusively document the presence of prostate cancer. Plus, current technology cannot determine if prostate cancer will change from indolent (inactive) to active. Based on the above factors, increasing numbers of men diagnosed with prostate cancer choose to make lifestyle changes and employ “watchful waiting” rather than pursue traditional, invasive therapies. Might healthy lifestyle choices reduce the risk of indolent prostate cancer becoming active?
An unusual situation provided an opportunity to create a randomized, clinical trial to determine if lifestyle changes inhibited the progression of prostate cancer. Ninety-three men, all of whom had confirmed prostate cancer (by biopsy) elected not to pursue conventional treatment. The 93 men were randomized to either an intervention group or a control group. Members of the intervention group received an intensive lifestyle change program, focused on improved diet, increased physical exercise, and reduced stress for one year. Members of the control group received usual care.
Diet, exercise, stress management, and group support improved for the intervention participants. Prostate-specific antigen levels in the intervention group declined, while they increased in the control group. Changes in the percent of a line of prostate cancer cells stimulated by the patient’s serum at baseline and after one year showed a far greater decline for the intervention group than the control group. In addition, seven of ten metabolic markers commonly used to evaluate risk of cardiovascular disease declined for the intervention group compared to the control group. Thus, intensive lifestyle changes may slow the progression of early-stage prostate cancer plus reduce the risk of cardiovascular disease.
The first published evidence of a link between level of physical activity following diagnosis of non-metastatic prostate cancer and risk of cancer-specific mortality appeared in 2011. A subsequent study used data from 1,455 men with diagnosed prostate cancer to extend the link of increased physical activity to risk of prostate cancer progression. After 22 months of follow-up, men who walked at a brisk pace for more than three hours per week had significant 52 percent lower risk of prostate cancer progression compared to men who walked at an easy pace for less than 3 hours per week. Total non-vigorous activity and walking duration did not predict significantly reduced risk of progression.
Danish researchers conducted a 2-year home-based endurance training program for clinic out-patients with either biochemical recurrence of prostate cancer following radical prostatectomy or cancer managed with active surveillance. Twenty-five patients participated in either a 24-month, (3 times/week) home-based endurance training or usual care. Response variables includes aerobic fitness, body composition, insulin sensitivity, and biomarkers. Monthly PSA measurements provided data to calculate prostate-specific antigen doubling time. Longer doubling time predicts slower cancer progression. Doubling time increased significantly for patients in the endurance training group. Members of the training group showed improvements in aerobic capacity (VO2 max), body composition (less fat mass), and several health biomarkers (plasma triglycerides, adiponectin, IGF-1, IGFBP-1, and fasting glucose levels). Improvements in physical fitness predicted increased PSA doubling time, suggesting a link between physical fitness and prostate cancer progression.
Men diagnosed with prostate cancer increasingly choose active surveillance over radical therapy, such as prostate removal. In addition, men with prostate cancer are three times more likely to die of cardiovascular disease than from prostate cancer. Evidence suggests that increased physical activity might slow the progression of inactive to active prostate cancer. Researchers at the University of Alberta in Canada recruited 52 men (average age 63) with prostate cancer under active surveillance for a clinical trial pitting twelve weeks of supervised high-intensity interval training (HIIT) against usual care.
Unsurprisingly, compared to men in the usual care group, men in the HIIT group showed significantly greater cardiorespiratory fitness (measured as VO2 max), upper body strength, and lower body flexibility. Also, compared to men in the usual care group, men in the HIIT group showed significantly greater decreases in PSA levels and greater decreases in a line of prostate cancer cells (under laboratory conditions). Finally, men in the HIIT group had statistically non-significant increases in doubling-time of PSA levels. These results cited here provide compelling reasons for men who choose active surveillance of their prostate cancer to increase their physical activity and keep their prostate cancer inactive, not to mention reduced risk of cardiovascular disease.