Significant progress has been made in the field of exercise-oncology research over the past two decades. As the field continues to forge ahead, it is time to reflect on past accomplishments in order to inform and define the critical unanswered questions postulated to have the largest impact on the field and on clinical care. Against this background, we overview the extant literature base together with ongoing/planned studies examining the role of exercise therapy following a cancer diagnosis with a view towards identifying major gaps in the knowledge.
Method: We adapted the Physical Exercise Across the Cancer Experience (PEACE) organizational framework to systematically overview published as well as ongoing studies of exercise therapy across the cancer survivorship continuum [i.e. 1) pretreatment; 2) during treatment; and 3) post-treatment]. To overview ongoing studies, we performed a systematic review of all exercise trials in adult cancer patients registered in Clinical Trials.Gov and the International Standard Randomized Controlled Trial Number Register.
Results: Data from published studies provides relatively strong evidence that exercise therapy is a well-tolerated and safe adjunct therapy that can mitigate several common treatment-related side effects among cancer patients across the PEACE framework. In addition, observational studies suggest that higher levels of exercise may be associated with improved prognosis in patients with solid tumors. Regarding ongoing studies, a total of 82 independent clinical studies were identified. Consistent with prior work, most ongoing studies are being conducted either during or following adjuvant therapy in women with breast cancer with exercise interventions following standard exercise prescription guidelines. Across all studies, there were a total of approximately 51 different primary endpoints; in two-thirds of studies, quality of life, fatigue, or physical functioning was the primary endpoint.
Conclusion: There have been significant leaps in knowledge regarding the role and efficacy of exercise therapy in cancer survivors over the past 25 years. On the platform of this evidence base, it is now time to launch the next generation of research to ensure continued progress in this emergent field. This work will continue to contribute to the ultimate goal of improving both the quantity and quality of life of persons diagnosed with cancer.