Physical activity correlates with lower levels of insulin, insulin-like growth factor I (IGFI), and inflammatory cytokines. This may inhibit proliferation and promote apoptosis of CaP cells. These investigators hypothesized that brisk walking after a diagnosis of CaP would reduce risk of CaP progression.
The study used the CaPSURE database, which included questionnaires on physical activity and diet. Participants were questioned on frequency, intensity and duration of walking, jogging and other cardiovascular exercises. A metabolic equivalent task (MET) value was assigned to each activity relative to the resting metabolic rate. Vigorous activities required 6 or more METs. Physical activity was then correlated with CaP progression. The study population included 2,134 men enrolled in CaPSURE between 2004 and 2005. Non-localized disease patients were excluded. After other exclusions, 1,455 men were analyzed.
Regarding CaP, they found 117 events; 45 with biochemical progression, 66 patients who required secondary treatments, 3 men with bone metastasis, and 3 CaP deaths. Twenty-four percent of participants withdrew or were lost to followup. Participants who engaged in vigorous activity were younger, leaner, and less likely to be current smokers than the least active men. The active men were more likely to have a PSA >10ng/ml and were more likely to have had radical prostatectomy for treatment. Men who walked at a brisk pace 3 or more times per week had a 57% (statistically significant) reduced rate of CaP progression compared with men who walked 3 hours or less per week at a brisk pace. This was true after adjusting for body mass index. Not enough men participated in vigorous activity to statistically link that to decreased risk of CaP progression. The beneficial oncologic effect of brisk walking 7 or more hours per week was more pronounced in men with Gleason score <7 compared with ≥7.
Richman EL, Kenfield SA, Stampfer MJ, Paciorek A, Carroll PR, Chan JM
Cancer Res. 2011 Jun 1;71(11):3889-95