dose optimale d'activité physique durant les traitements du cancer du sein

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A meta-analysis showed that one and a half to two hours of physical exercise per week reduces fatigue associated with breast cancer treatment.

A meta-analysis, based on 17 randomized controlled trials and published in the Annals of Oncology journal in 2013 by Carayol and colleagues, assessed the benefits of physical activity during breast cancer treatment (chemotherapy and/or radiotherapy). Following the implementation of a one-and-a-half to two-hour weekly program of physical activity, the results evidenced a reduction in fatigue and depression indices, and an increase in the quality of life index of the participants. The program combined endurance exercise and light muscular strengthening.

The Study Rationale

In certain cases, breast cancer treatment involves chemotherapy and/or radiotherapy. These treatments cause side effects; specifically, fatigue, and, quite often, anxiodepressive symptoms combine to alter the quality of life of patients. As a result, people undergoing treatment tend to remain psychologically idle, and this “forced rest” appears to be detrimental to their overall health and quality of life. Accordingly, researchers are focusing on ways to reduce these symptoms. Though a counter-intuitive solution, moderate and regular exercise may help patients cope successfully with treatment-induced fatigue. This study set to prove this hypothesis and determine the optimal dose of exercise.

The Question

What is the optimal dose of weekly physical exercise to alleviate fatigue, depression and anxiety in, but also to improve the quality of life of breast cancer patients undergoing treatment?

The Protocol

This meta-analysis was based on all the randomized controlled trials available in the international scientific and medical literature. Only 17 studies out of 896 articles were selected. The exclusion of such a large number of studies is due to methodological weaknesses, amalgams of cancer types, lack of specifics on program content or lack of fatigue and quality of life measures, or late (i.e., post treatment) resumption of physical activity. This meta-analysis was the first to assess the effect of dose of physical activity in breast cancer treatment. 748 patients were assigned to “physical activity” groups, and 632 patients were assigned to “control” groups.

Main Results

The results of this meta-analysis evidenced that the “physical activity” groups enjoyed statistically significant benefits from their participation in a program combining endurance training (walking, biking, rowing…) and light muscular strengthening of all body parts (elastics, gymnastics, body-weight, free weights…). Performing 1.5 to 2 hours of medium intensity weekly physical activity substantially reduced fatigue and depression in patients undergoing breast cancer treatment, and significantly improved their quality of life.

What it means for Patients

Performing one and a half to two hours of weekly adapted physical activity combining endurance training and light muscular strengthening reduces fatigue and anxiety in patients undergoing breast cancer treatment. It also improves their quality of life.

What it means for Healthcare Professionals

An adapted physical activity program initiated at the inception of breast cancer treatment and combining 1.5 to 2 hours per week of anaerobic exercise and light muscular training reduces patients’ fatigue and depression. This type of program also improves their quality of life. There is no evidence supporting the effect superiority of any activity over another.

What it means for Researchers

Because of the methodological shortcomings of available studies, this type of meta-analyses still lacks statistical power. These non-pharmacological interventional studies are time-consuming and require a large number of patients. While performing physical activity does reduce the side effects of breast cancer treatments – and particularly fatigue – there is still no evidence that it might lower the risk of cancer recurrence or that it could prolong the life of patients.

What it means for Policymakers

This meta-analysis showed that all types of physical activity do not compare equally in terms of fatigue reduction during breast cancer treatment; the study warned of the risks associated with offering weekly physical activity doses below or above the ones specified in this program.

The reference

Carayol M, Bernard P, Boiché J, Riou F, Mercier B, Cousson-Gélie F, Romain AJ, Delpierre C, Ninot G (2013). Psychological effect of exercise in women with breast cancer. Annals of Oncology, 24(2), 291-300.

To reference this Blog en Sante © article.

Ninot G (2014). Exercise During Cancer Treatments. Blog en Sante, A2.

© Copyright 2014 Grégory Ninot. All rights reserved.

Thanks to Syl Billere for the English Revision.