Blanchard et al., 2003a). The effectiveness of behavioral interventions to modify physical activity behaviors among cancer survivors was the subject of a 2004 Agency for Healthcare Research and Quality (AHRQ) evidence report (Holtzman et al., 2004).37 According to this review, controlled trials of behavioral interventions to increase physical activity among cancer survivors show positive and consistent effects of physical activity on the following outcomes:
Vigor and vitality
Quality of life
Similar findings come from a recent systematic review of randomized controlled clinical trials (Knols et al., 2005; Pinto et al., 2005). The exercise prescription associated with these positive outcomes in cancer survivors was generally moderate- to vigorous-intensity aerobic activity on 3 or more days per week, for 10 to 60 minutes per session. The findings for many of these outcomes parallel the results in generally healthy populations. The effect of physical activity on cancer recurrence or survival is unknown, but physical activity might improve prognosis through beneficial effects on cardiovascular disease (McTiernan, 2004) or through hormonal mechanisms (Holmes et al., 2005). Resistance training has beneficial effects on muscle and bone and may counteract some of the side effects of cancer treatment (e.g., bone and muscle loss) and help improve survivors’ physical function and quality of life (Galvao and Newton, 2005).
For physical activity to be recommended for cancer survivors, it must be safe and not associated with adverse outcomes. The results of the studies reviewed by AHRQ generally indicate that it is safe for cancer survivors to be physically active. Questions about the safety of physical activity remain, however. For example, one concern is that exercise by breast cancer survivors could induce or exacerbate lymphedema. Most studies have reported no adverse effects of upper body exercise on breast cancer survivors at risk for lymphedema. However, current clinical guidelines from multiple sources
This section of the report is based almost entirely on the AHRQ evidence review (AHRQ, 2004). Additional randomized trials of exercise among survivors have been published that were not included in the AHRQ review. Their results are consistent with the review’s findings of beneficial effects of exercise on cardiovascular fitness and/or quality of life (Courneya et al., 2003a,b; Thorsen et al., 2005).