Background: Several clinical trials have been published in recent years to investigate the probable benefits of physical exercise for women with breast cancer. It is necessary to carry out systematic reviews using a rigorous methodology to ensure that decision-making is based on the best available evidence. However, systematic reviews that were not conducted according to transparent methodology, as recommended by Cochrane, may result in misleading findings about the effects of an intervention.
Objectives: To map and critically assess the methodological quality of systematic reviews on physical activity for patients with breast cancer.
Methods: A meta-epidemiological study including systematic reviews of randomized clinical trials that evaluated the effects of physical exercise in patients with breast cancer. The search strategy was performed in MEDLINE (via PubMed) (July 1, 2022). Study selection was performed by two independent reviewers using the Rayyan platform. Methodological quality was assessed using the AMSTAR-2 tool.
Results: We included 57 systematic reviews published between 2006 and 2021, only randomized clinical trials on the effects of physical activity in patients with breast cancer. The results showed that 58% of the included reviews were classified as low or critically low quality. Only 10% were classified as high methodological quality and 32% as moderate quality. Furthermore, complete search strategies were presented in 54.4% of the reviews, and 59.6% fully described the search date; 61.4% had data and/or language restrictions and 52.6% performed additional manual searches.
Conclusions: The findings of this study showed a methodological weakness of most systematic reviews on the effects of physical exercises for patients with breast cancer. Caution is needed on the part of health professionals, managers and policymakers in health, patients and the population when interpreting the applicability of these results, and it is suggested to conduct systematic reviews of high methodological quality to assist in the decision-making process.
Patient, public and/or healthcare consumer involvement: The low-quality evidence on physical exercises for women with breast cancer could influence the effects of this intervention and impact the clinical practice recommendation.