Cancer is a common cause of death worldwide and its incidence is on the rise together with the global aging population. Surgery, irradiation, and chemotherapy are the usual treatment options, immunotherapy is now becoming more common. In particular radiotherapy (RT) can be used prior to surgery as neoadjuvant or after surgery as adjuvant. It represents a treatment option for various cancers at different stages, even in advanced disease RT can be used as palliative therapy to reduce tumour burden and relieve pain. For people with different comorbidities that cannot undergo chemotherapy or that refuse systemic treatment, RT may be the only option. RT may cause symptoms due to circulating cell destruction byproducts such as nausea, fever, loss of appetite, and weight loss. Patients may experience also cancer-related fatigue (CRF) which encompasses physical, emotional, and cognitive fatigue or exhaustion associated with cancer or its treatment. This complex picture of disease and treatment-related symptoms can lead to reduced physical activity, physical performance, and quality of life (QoL) in these patients. Physical activity is one of the modifiable risk factors for cancer as it was demonstrated that physical inactivity correlates with many cancer types, and exercise together with standard cancer treatment was associated with increased survival rate, decrease in recurrence and better management of side effects of treatment and cancer itself. The protective effect of exercise was explained through the influence on sex hormones and insulin-like growth factor and for its immunomodulatory action increasing the number of anti-inflammatory molecules such as interleukin-10 (IL-10). Furthermore, exercise may normalise the tumour microenvironment, helping systemic therapies to reach the cancer site. Exercise is also beneficial for other comorbidities such as diabetes, hypertension, cardiovascular diseases, obesity, etc. Today there is no review to address the effects of exercise on in people with cancer who undergo RT alone. This review investigated whether exercise together with usual care was helpful and safe compared to usual care alone in people undergoing RT only for cancer treatment.
This review is important for
People with cancer of different types and at different stages who may receive RT as single therapy due to comorbidities or who do not want to receive a systemic treatment. It may be beneficial also for their loved ones/caregivers, health professionals caring for this population, general practitioners, researchers, and policymakers.
Outcomes of this review
This is a new Cochrane Systematic Review (CSR) published in 2023. The outcomes analysed were fatigue, quality of life, physical performance, psychosocial effects; overall survival, return to work, anthropometric measurements and adverse events. The CSR included three two-arm RCT trials published and/or registered up to 26 October 2022, with 130 participants. Results showed that exercise may improve fatigue and may have little or no effect on quality of life. It is uncertain if it improves physical performance or phycological effects. Two studies reported no adverse events. No studies reported on other outcomes of interest. It remains unclear at what point in time the benefits of exercise interventions are detectable.
These results must be interpreted with caution because (i) only three trials met the inclusion criteria with a (ii) small number of participants. (iii) The participants have different baselines, which reduces the comparability of the results. (iv) Duration of follow-up was very limited in all three studies, so no long-term effects were measured. (v) Only one study reported adverse events during the intervention period. (vi) All three studies excluded severe pre-existing medical conditions; thus results are not applicable to this population. (vii) Randomization process was unclear and information on study design was superficial, no data on baseline activity was collected. (viii) There were inconsistencies in some reported data. (ix) Overall, the studies had poor documentation resulting in uncertainties in the assessment of the systematic error. (x) The risk of blinding bias was unclear or high for most of the studies.
Author’s conclusion of the review
The overall quality of evidence was very low to low. Even if the single studies reported benefits of exercise in all the outcomes the analysis of this review did not consistently support these results. In fact, there was low-certainty evidence that exercise improved fatigue and it is uncertain whether exercise improved physical performance, quality of life or psychosocial effects. In conclusion, exercise may be beneficial in people with cancer who are receiving RT alone, but the evidence is of low certainty, therefore the authors could not make solid conclusions to support recommendations for clinical practice.
Future recommendations
The authors recommended that large-scale, multi-center studies are needed, particularly to strengthen the evidence for improved fatigue, physical performance and other outcomes, to report survival rates and short- and long-term adverse events, examining whether they occur with any specific exercise programme and which types of cancer. Future trials may assess whether exercise could worsen or reduce RT-induced adverse events. In particular breast cancer studies should report RT-induced adverse events affecting lung function, which may in turn affect exercise performance and program completion.
by Robin Kuruvila Sentinella