Physical activity for cancer patients: clinical risk assessment for exercise clearance and prescription

Cancer is an important cause of both morbidity and mortality, currently accounting for approximately 1 of every 4 deaths in North America.1,2 However, survival rates are continually increasing, as diagnostic and surgical techniques are improved and ever more effective local, regional, and systemic therapies are introduced. Approximately 66% of patients now live for at least 5 years following a first diagnosis of cancer, and more than 14.5 million North Americans live with such a history.1,2 Today's family physician must thus be prepared not only to diagnose cancer, but also to provide appropriate lifestyle advice to manage the long-term consequences of cancer diagnosis and therapy. There are diverse physiologic, psychological, and psychosocial responses to both the diagnosis and the treatment of cancer.3–8 The range of effects calls for a multidisciplinary approach, with physical activity (PA) and exercise training interventions increasingly becoming integral to long-term patient management. Conventional cancer therapies induce adverse symptoms, often with unfavourable lifestyle changes, including a decrease in habitual PA and weight gain.9 These changes have negative effects on patients' quality of life and can limit their ability to undertake the activities of daily living. However, increasing evidence indicates that both of these adverse developments can be attenuated by participation in regular PA.5,6 On the basis of this burgeoning evidence base, several investigators and clinics have started to examine the important contribution of PA and exercise training to supportive care before, during, and following cancer therapy. In general, gains in cardiorespiratory fitness have been accompanied by decreased fatigue and enhanced overall quality of life.3–8 Cancer-specific, evidence-based assessments of the risks and benefits of PA are thus needed by family physicians, qualified exercise professionals, and other members of the allied health team. This article provides an executive summary of findings from a systematic review of the cancer-specific literature,10 undertaken as one in a comprehensive series of analyses examining the risks of PA in patients with various chronic diseases. The information contained in this article forms the foundation for the newly created Physical Activity Readiness Questionnaire (PARQ+) and electronic Physical Activity Readiness Medical Examination (ePARmed-X+).11 We briefly discuss PA risk assessment in patients with cancer based on currently available adverse event–related data, and introduce decision trees that facilitate clinical decision making for the family physician.