Losing bone and muscle mass while gaining fat is a troubling problem for men receiving androgen deprivation therapy for prostate cancer, putting them at risk for heart disease, frailty and broken bones. Depletion of bone in these men is even more rapid than that associated with menopause in women.
But a first-of-its-kind randomized clinical trial is providing evidence that targeted exercise can slow bone loss, reverse muscle weakness, and prevent gains in body fat in men with prostate cancer undergoing androgen deprivation therapy, or ADT.
Kerri Winters-Stone, Ph.D., co-leader of the Knight Cancer Institute’s Cancer Prevention and Control Program, first developed the exercise regimen for women at risk of osteoporosis and related fractures. Called “Prevent Osteoporosis with Impact and Resistance,” it combines functional resistance training with jumping exercises performed wearing a weighted vest. Winters-Stone and colleagues adapted it for older men receiving ADT and enlisted 51 such patients to participate in one year of resistance and impact training or in a placebo program of stretching exercises. Although most of the men were in their 70s and many were physically limited, 84 percent stuck with the exercises for a year and none experienced a training-related injury.
In July, the researchers reported that the training group managed to shed body fat, including central fat depots that are typical with androgen deprivation, while the placebo group gained fat mass. This outcome is particularly notable because excess body fat puts men at risk for heart disease and can create inflammation in the body that undermines blood sugar control and favors cancer progression. The loss of total and central body fat among men in the training group appeared to be the way that exercise helped to lower insulin levels.
Men in the training group also achieved significant gains in lower and upper body strength and they experienced less disability compared with men in the control group, who gained no strength, the researchers first reported in January. Men in the training group also felt that their own functioning had improved, while those in the control group felt theirs had gotten worse.
The evidence that the exercise program stopped bone loss is not as strong as it was for other outcomes, but the data are promising, Winters-Stone says. In a third paper published last August, the researchers reported that the exercise program stopped bone loss at the spine, but not the hip – both common sites of bone fractures related to osteoporosis. “This may be because we were very conservative in the jumping component of the program, which is the exercise believed to strengthen hip bones the most,” Winters-Stone says. “Since men tolerated the jumping well and had no injuries, we may try to beef up this portion of the program in future studies.”
As Winters-Stone and her colleagues work to define the most effective exercise program, there is no need to wait for more evidence to counsel patients on the benefits of strength training, she says. “Providers can work with physical therapists to make sure that patients are physically ready to do strength training, and with exercise physiologists to create a training program that is right for each man with prostate cancer.”
Resistance Exercise Reduces Body Fat and Insulin During Androgen-Deprivation Therapy for Prostate Cancer by Kerri Winters-Stone, Nathan F. Dieckmann, Gianni F. Maddalozzo, Jill A. Bennett, Christopher W. Ryan, and Tomasz M. Beer; Oncol Nurs Forum, July 2015.
Resistance training reduces disability in prostate cancer survivors on androgen deprivation therapy: evidence from a randomized controlled trial by Kerri Winters-Stone, Jessica C. Dobek, Jill A. Bennett, Nathan F. Dieckmann, Gianni F. Maddalozzo, Christopher W. Ryan, and Tomasz M. Beer; Arch Phys Med Rehabil, January 2015.
Skeletal Response to Resistance and Impact Training in Prostate Cancer Survivors by Kerri M. Winters-Stone, Jessica C. Dobek, Jill A. Bennett, Gianni F. Maddalozzo, Christopher W. Ryan, and Tomasz M. Beer; Med Sci Sports Exerc, August 2014.