Exercise On Metabolic Syndrome In Breast Cancer Survivors: 5-year Follow-up To A Randomized Controlled Trial

Breast cancer survivors experience many treatment-related side effects, including the development of metabolic syndrome which is associated with poor prognosis and higher risk of mortality. We previously reported that a 16-week aerobic and resistance exercise intervention significantly improved metabolic syndrome (MetS) among sedentary, overweight/obese breast cancer survivors. PURPOSE: We sought to determine whether improvements in MetS were maintained 5-years post-intervention among sedentary, overweight/obese breast cancer survivors. METHODS: We conducted a 5-year follow-up study after the completion of a 16-week, two-armed randomized controlled trial comparing a combined supervised aerobic and resistance exercise program to a usual care group. The sample included 84 sedentary breast cancer survivors that were overweight or obese (Body mass index ≥25.0 kg/m2). No intervention was conducted during the follow-up period. Waist circumference, blood pressure, and fasting blood samples were obtained 5 years following the post-intervention timepoint. MetS z-score was calculated by assessing waist circumference, blood pressure, fasting levels of high-density lipoprotein cholesterol (HDL-C), triglycerides, and glucose. A comparison of measurements between post-intervention and follow-up timepoints was performed using linear mixed-model analyses. RESULTS: Participants with follow-up data (N = 84) were aged 58.9 ± 10.2 years old, were mostly obese (52%), and 70% were ethnic minorities. At follow-up, MetS z-score significantly increased in both the exercise group (mean difference 2.4; 95% CI, 0.2 to 3.5; p = 0.02) and usual care group (mean difference 4.8; 95% CI, 0.8 to 6.5; p = 0.01). However, the change in MetS z-score from post-intervention to follow-up was significantly lower among the exercise group compared to the usual care group (mean difference -2.4; 95% CI, -4.7 to -0.5; p = 0.001). CONCLUSIONS: The attenuated increase of MetS z-score in the exercise group compared to the usual care group suggests that exercise might have a beneficial long-term effect on MetS. Therefore, an exercise intervention may be able to attenuate the increased risk of MetS in breast cancer survivors over a 5-year follow-up period.