Abstract C123: Ethnocentric differences in sarcopenic obesity and body composition in response to an aerobic and resistance exercise intervention for breast cancer survivors

Abstract

Abstract Background and Purpose: Hispanic breast cancer survivors (HBCS) have a 1.1-1.5 greater risk of breast cancer mortality when compared to non-Hispanic breast cancer survivors (NHBCS). This disparity may result from modifiable lifestyle factors, as Hispanic women are more apt to be obese and sedentary than matched non-Hispanic counterparts, placing them at risk for obesity-related comorbidities. Also, gains in fat mass with declines in lean mass, known as sarcopenic obesity (SOb), often occur as a side effect of cancer treatment. Thus, participation in physical activity is paramount, as exercise is strongly associated with lowering the risk of cancer recurrence and premature mortality. The purpose of this analysis was to examine ethnicity as a moderator of the effects of a 16-week supervised aerobic and resistance exercise intervention on SOb and body composition (BCM) in overweight/obese breast cancer survivors. Experimental Design: Sedentary, overweight or obese (BMI>25.0 kg/m2) breast cancer survivors (Stage I-III; n=100) were randomized to exercise (n=50) or usual care (n=50). The exercise intervention promoted supervised, progressive moderate-vigorous (65-85% maximum heart rate [MHR]) aerobic and resistance exercise thrice weekly for 16 weeks. Markers of SOB and BCM, including appendicular skeletal muscle index (ASMI), BMI, % body fat and truncal fat were measured at baseline and post-intervention (4 months). Differences in mean changes for outcomes by ethnicity were evaluated using linear mixed-models to assess effect modification. Summary of Results: The study enrolled 57 HBCS and 43 NHBCS with an average age of 53.5±10.4 years and BMI of 33.5±5.5 kg/m2. HBCS were diagnosed with more advanced cancers, were significantly more obese and less physically active compared to NHBCS (p<0.001); 96% of the HBCS and 92% of the NHBCS presented with SOb. Post-intervention, SOb and BCM indices were significantly improved in the exercise arm (both HBCS and NHBCS) as compared to baseline (p 0.01) and usual care (p<0.001). However, HBCS exhibited more favorable improvements compared to NHBCS, including an increase in ASMI (mean difference, -2.1; 95% confidence interval (95% CI), 0.4 to 5.1; p<0.001) and truncal fat (-4.4; 95% CI, -9.1 to -0.8; p<0.001). Ethnicity was found to moderate the effect of the exercise intervention on fat mass (P for interaction=0.09) and % body fat (P for interaction=0.09). Conclusions: HBCS may achieve better outcomes with exercise in attenuating disparities related to SOb and BCM. To our knowledge, this is the first study to investigate ethnocentric differences between HBCS and NHBCS as they pertain to participation in physical activity and high-risk comorbidities related to poorer cancer prognosis and mortality. Exercise presents as a useful lifestyle modifiable intervention to attenuate ethnic health disparities in breast cancer survivors; future studies should aim to enroll diverse populations. Citation Format: Frank C. Sweeney, Wendy Demark-Wahnefried, Kerry S. Courneya, Debu Tripathy, Nathalie Sami, Kyuwan Lee, Thomas A. Buchanan, Darcy Spicer, Leslie Bernstein, Joanne E. Mortimer, Christina M. Dieli-Conwright. Ethnocentric differences in sarcopenic obesity and body composition in response to an aerobic and resistance exercise intervention for breast cancer survivors [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C123.