Bidirectional communication between the gut microbiota and the central nervous system.

By 2040, 24% of all cancer survivors will be ages 65–74, 31% will be ages 75–84, and 18% will be 85 and older, but our healthcare system may not be prepared to meet the needs of this growing population of older survivors []. The combined effects of cancer treatment and aging can accelerate the development of comorbidities, disabilities, and fall-related injuries []. Cancer treatment can alter health and functioning in ways similar to aging by causing fatigue, weakness, cognitive decline, dependence, and disability while also causing unique treatment-related toxicities like chemotherapy-induced peripheral neuropathy (CIPN) or vestibular dysfunction [], []. These effects are exacerbated by increasing levels of pain, depressive symptoms, and social isolation that is associated with cancer and cancer treatment, further diminishing quality of life [], [], []. Exercise could provide a low-cost, accessible, and efficacious strategy to improve functioning and quality of life for this growing population[]. However, exercise programs must consider the unique abilities, needs, and preferences of older adults living with and beyond cancer (herein, referred to as older cancer survivors) and the combined complexities of aging and chronic illness. Current exercise guidelines for cancer survivors from the American College of Sports Medicine (ACSM) and the American Society of Clinical Oncology (ASCO) recommend modest levels of exercise (e.g., 30 minutes of moderate-intensity aerobic or resistance exercise three times per week) to improve cancer-related health outcomes, including physical functioning and health-related quality of life [], []. However, a noted limitation of both recommendations was the inability to issue age-specific guidelines for older cancer survivors due to the lack of clinical trial evidence specific to this population. The National Comprehensive Cancer Network also provides exercise guidelines for all cancer survivors, with a few additional recommendations that are relevant to older survivors, such as engaging in balance exercise for lowering fall risk [], []. However, clinical practice remains largely bereft of specific guidance to include exercise in care plans for older cancer survivors, which may contribute to their low engagement in recommended levels of exercise []. While the evidence base matures, development of consensus-based best practice recommendations could fill the practice gap that impedes the implementation of exercise in standard of care for older cancer survivors. The ACES (Advancing Capacity to Integrate Exercise into the Care of Older Cancer Survivors) initiative was funded from a National Cancer Institute-funded effort to build infrastructure in cancer and aging (1R21CA280996) and has an aim to develop consensus-based exercise recommendations for older cancer survivors. The goal of the recommendations is to complement the existing ACSM guidelines on exercise for cancer survivors by adding specificity for older (65+ years) survivors on pre-exercise evaluation and assessment, and exercise prescription, programming, tolerance, and safety. In developing recommendations, ACES followed an evidence-to-decision making framework that included extracting information from the extant literature []. For this purpose, we conducted a scoping review of published controlled exercise oncology trials that were designed for cancer survivors over the age of 65. Our objectives were to describe the consideration of pre-exercise evaluation, participant inclusion/exclusion criteria, exercise prescription, programming and delivery, outcome selection, and safety and tolerance in controlled exercise trials to help inform best practice recommendations.