Read the original paper in Current Oncology here.
Any comprehensive (and arguably introductive) discussion of strategies to optimize cancer survivorship considers the role of exercise. Following a diagnosis, exercise has been shown to improve pre-, peri, and post-treatment physical and psychosocial outcomes in many cancers and their related treatments. The breadth of the existent evidence that describes these benefits continues to grow at an unmatched rate in the field of complimentary therapies in oncology. As such, reviews of the literature have been published multiple times per year over the past few years. Certainly, one would assume that with this rapidly expanding volume of evidence, a movement towards clinical integration of exercise in oncology would follow in haste. Unfortunately, this has not been the case as community-based or clinically-integrated cancer exercise programs remain the exception rather than the norm, even amongst larger tertiary care institutions. However, there are signs that we are on the cusp of a new era in survivorship where exercise is considered an essential adjunct therapy and is recommended to a majority of patients with some facilitation of a safe and effective exercise prescription.
This evolution in cancer care is evident in the variety of emerging publications. First, indications of the maturity of the field are represented by the number of studies reporting on long-term outcomes of exercise interventions. Earlier work in the field was limited to post-intervention follow-ups of 6 months, whereas now, we are beginning to see benefits that are sustained for up to 2 years(1, 2). Second, there is a growing body of research that assesses the exercise preferences for specific cancer survivors. This literature expands on the established efficacy of exercise and pursues the programmatic and individual nuances that facilitate initial participation and long-term adherence. Third, investigations into the role of exercise now include a more liberal definition of ‘exercise’, with a significant amount of research conducted on specific modalities (e.g. aerobic versus resistance training) and intensities (vigorous versus mild). Furthermore, alternative exercise approaches, such as t’ai chi and yoga have also gained a strong reputation for their cancer-specific benefit. Dr. Culos-Reed and colleagues reviewed 25 studies examining the role of yoga for cancer survivors and found numerous clinically relevant benefits(3). Fourth, the development of clinical practice guidelines for exercise in oncology (most notably those of the American College of Sports Medicine to “avoid inactivity” and to try to acquire a minimum of 150 minutes of moderate to vigorous physical activity plus 2-3 sessions per week of strength training(4)) is becoming more refined with specific recommendations for different cancer types and treatments(5). These exercise recommendations incorporate adaptations and additions to the general exercise prescription to address the disease-specific sequelae. Fifth, individualized exercise prescriptions for cancer survivors are supported by evidence-based risk assessment tools to ensure that exercise testing and training can be conducted safely. Burr, Jones, and Shephard (2012) have developed a clinical decision tree to assess the risk of a serious adverse event related to exercise among cancer patients as a guide for clinicians to use when recommending exercise with consideration for the type of supervision needed (6). Sixth, cancer-exercise program evaluation reports are more apparent in the literature suggesting that the availability of these services is expanding. These cancer-exercise programs appear in a variety of settings, including cancer care centres (7, 8), community-based organizations (9, 10), and universities(11). This literature is likely the most direct reflection of knowledge translation in this field and representative of the more widespread clinical integration. Seventh, studies are now starting to incorporate the economic feasibility of their interventions with formal cost-benefit analyses (12). These are likely the missing piece of the literature that will ultimately lead to systemic resource allocation to exercise-based cancer rehabilitation programs, especially in a publicly funded healthcare setting. This is generally considered the catalyst for eventual incorporation of exercise into standard post-cardiac intervention care (13). Finally, clinicians and researchers are more frequently disseminating call to action papers, calling upon their colleagues within oncology and sub-disciplines to respond to the overwhelming and compelling empirical literature with integrated exercise programming for their patients (e.g. (8, 14-16)). These professional pleas for cancer-exercise programs reflect the urgency for which these services are needed and appreciated by patients and their clinicians.
In practice, cancer-exercise services likely fall under the mandate of ‘survivorship’ or ‘rehabilitative’ programming. In this respect, exercise is among a variety of complimentary therapies aimed at reducing the cancer burden post-diagnosis. Such services include lymphedema management, sexual function rehabilitation, and general psychosocial support and counselling. Interestingly, exercise may be considered a core component to each of these distinct programs which is another indicator of expanding clinical integration.
There are areas that remain to be addressed which will ultimately support cancer-exercise programming. At present, we do not know how to effectively maintain the magnitude of benefit over time, largely because exercise behaviour tends to decline following the formal intervention phase. To this end, more research is needed that examines methods of boosting exercise adherence during and, more importantly, after the intervention. Strategies to optimize long-term exercise maintenance may include electronic health coaches or some type of immediate, professional feedback to assist with barriers to exercise as they arise. Similarly, more research is needed to establish what program delivery models (e.g. home-, hospital-, or community-based) are most beneficial, economically efficient, and provide enduring health behaviour changes.
The advancement of exercise as a clinical modality in oncology is apparent and trends in the literature suggest that implementation is becoming more universal. Although much more research is needed to clarify and exploit the positive determinants of exercise in cancer survivors, many have suggested that the literature is sufficient to justify the inclusion of exercise in management of most cancers. The path towards clinical integration has been forged by our colleagues in cardiology that utilize exercise as the foundation for rehabilitative success. Clinicians and researchers in oncology are several years behind but have made great strides towards the ultimate goal exercise as a standard of care for all cancer survivors.
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