Abstract and Introduction
Abstract
Side effects accompanying androgen deprivation therapy (ADT), including sarcopenia, loss of bone mass and reduction in muscle strength, can compromise physical function, particularly in older patients. Exercise, specifically resistance training, may be an effective and cost-efficient strategy to limit or even reverse some of these adverse effects during and following therapy. In this review, we discuss common morphological and physiological ADT-related side effects or 'Androgen Deprivation and Sarcopenia-Related Disorders' and the existing clinical trials incorporating physical exercise in prostate cancer patients receiving active therapy. Further, training concepts and guidelines are provided for prescribing resistance exercise programs for this population.
Introduction
Worldwide prostate cancer is the second most common cancer in men representing 19% of cancers among men in developed countries. With the aging of the population in developed and developing countries, the incidence of all cancers, which are normally higher in those aged >65 years, is predicted to substantially rise, particularly for colon and prostate cancer, which are well established aging-related cancers. Advancing age increases not only the vulnerability to cancer but also the risk for other comorbid conditions (for example, cardiovascular disease, diabetes, osteoporosis, arthritis and sarcopenia) that can compromise physical function and independent living and ultimately result in death.
The introduction of the prostate-specific antigen (PSA) blood test into routine clinical practice in Australia and the USA in the 1990s has led to earlier diagnosis of disease. Men are often minimally symptomatic or completely asymptomatic and can be expected to survive substantially longer than their historical counterparts. Full characterization of toxicity is now seen to be an important priority for research. For example, sarcopenia, which is the age-related loss of muscle mass and strength, can be largely exacerbated in this cancer group owing to the catabolic side effects of some forms of treatment such as androgen deprivation therapy (ADT).
In the non-cancer older population, resistance exercise has been endorsed as a potent countermeasure to sarcopenia and its implementation in clinical and home settings are relatively simple and inexpensive. Additionally, this exercise mode has reliably shown to induce other health benefits by promoting increases in the ability to perform daily tasks and increased physical reserve capacity. Recently, the role of structured exercise as a possible adjuvant therapy during cancer treatment has gained recognition, with most intervention trials incorporating cardiovascular activities. Research into the effects of resistance exercise in prostate cancer patients and survivors are limited with only two studies reported. Although research in this area is still emerging, preliminary findings indicate the beneficial effect of resistance exercise on the musculoskeletal system, reducing levels of fatigue and enhancing quality of life among cancer patients and survivors.
In this review, we discuss (1) common ADT treatment-related side effects relevant to the musculoskeletal system, chronic disease and functional ability; (2) the beneficial effects derived from existing resistance exercise trials in this patient group and (3) guidelines for implementing this exercise mode as a potential treatment strategy.