It is estimated that there were 19.3 million newly diagnosed cancer cases and almost 10 million cancer-related deaths globally in 2020. Despite the numerous advances in cancer treatment, cancer incidence and mortality have been increasing over the years, thus making cancer one of the greatest health threats to human beings.
In recent decades, the advent of novel therapies in cancer has significantly prolonged the survival of oncological patients, yet many of these individuals are left with residual deficits, particularly motor and neurological, as well as cancer-related fatigue and depression.
Exercise-based cancer rehabilitation is one of the main strategies which has been proved to be an effective way to improve the quality of life of cancer survivors. There are three main types of exercise training included as part of cancer rehabilitation: resistance exercise, aerobic exercise, and the combination of both. Furthermore, cognitive, and psychological support during this period might have a synergistic effect with physical activity.
Although rehabilitation procedures are very well established after cardiovascular and neurological events, such as myocardial infarction or stroke, their role in oncology has only marginally been investigated nor completely accepted by the medical community. Nevertheless, cumulating evidence with clinical experience suggests that physical activity has emerged as an important complementary supportive care for cancer patients and can improve the care of patients with cancer and their quality of life.
General clinical guidelines recommend that cancer rehabilitation begins ideally at the time of cancer diagnosis and continues through and beyond cancer treatment, but this is rarely done in clinical practice.There has been an effort to conduct qualitative studies to evaluate the effects of physical activity on cancer patients, with a particular focus on factors influencing an active lifestyle in cancer patients during or right after conclusion of oncological treatments. Most of these studies have been regrouping patients with a specific cancer type, with a particular focus on breast cancer. Nevertheless, it is relatively difficult to gain evidence from single qualitative studies on it owns, mostly due to the variety of qualitative methodologies employed and the lack of consistent results.
The principal aim of cancer rehabilitation is to help patients regain functioning, promote their independence and to increase their social participation, no matter how long or short the timescale. To evaluate and optimize rehabilitation, it is therefore very important to measure its outcomes in a structured and reproducible way. In recent exercise guidelines, most of the available evidence on the efficacy of oncology rehabilitation is derived from randomized controlled trials (RCTs), which have strengthened the body of proof for the efficacy of exercise in cancer rehabilitation, but on the other side they have been reported to lack generalizability to the clinical setting. In these trials, patients often must meet pre-specified criteria (e.g., diagnosis, disease stage, age) to be eligible for enrolment in RCTs and must give consent to participate. This might bias results toward a healthier, fitter, and more motivated population, which may not be comparable to a broader population of cancer survivors. While RCTs have the most powerful study design to investigate the efficacy of rehabilitation in a specific population under ideal circumstances, observational studies may be more appropriate to evaluate interventions in daily practice and in more heterogeneous populations with complex, chronic diseases such as cancer.
A major determinant of functional capacity is exercise behaviour. The beneficial effects of physical exercise have been shown to improve multiple aspects of health in cancer survivors, including quality of life, fatigue, as well as all cause and cancer specific mortality.
Physical impairments and psychosocial symptoms should be assessed and treated concomitantly, and lifestyle and exercise interventions provided to optimize functioning and quality of life (QoL). Quality of life can be defined as a multidimensional structure that reflects a person's subjective evaluation of their well-being and functioning across multiple life domains, and each of these should be specifically addressed by cancer support services. According to Ferrans, five dimensions of QoL have been described: physical; functional; psychological/emotional; social; and spiritual. Ideally, all these dimensions should be explored in cancer patients in relation to exercise.
Metanalysis across several studies have shown that patients noticed consistent improvements in their physical and psychological functioning and health. Furthermore, many patients have reported that exercise has helped them to better manage the physical consequences of cancer and its treatment, contributing to their overall fitness.