Oral Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2022

Understanding the association between excess body weight and prognosis in triple-negative breast cancer: a meta-analysis (#49)

Larissa Vaz Goncalves 1 , Melinda M Protani 1 , Jodi M Saunus 2 , Graham A Colditz 3 , Marina M Reeves 1
  1. School of Public Health, The University of Queensland, Brisbane, Queensland, Australia
  2. Mater Research Institute, The University of Queensland, Brisbane, Queensland, Australia
  3. Division of Public Health Sciences, Department of Surgery, Washington University School of Medicine, St Louis, MO, USA

Aims: The association between obesity and triple-negative breast cancer (TNBC) prognosis has been equivocal, with considerable heterogeneity between and within studies. Recent meta-analyses report adverse associations with overall survival (OS) and disease-free survival (DFS) in TNBC. This meta-analysis aimed to update the previous meta-analyses and provide a broader examination of potential sources of heterogeneity in the association between excess body weight and survival in TNBC, including disease and study-specific characteristics.

Methods: A systematic search through PubMed, Embase, CINAHL, and Web of Science databases was conducted until January 14, 2022. Random-effects meta-analyses were used to pool hazard ratios (HR) for OS, DFS, and breast cancer-specific mortality (BCSM). Subgroup analyses examined the impact of sources of study heterogeneity. Methodological quality and risk of bias of included studies were evaluated using the Newcastle-Ottawa Scale.

Results: In meta-analyses of included studies (n=33), significant associations were observed between excess body weight and worse OS (n=24; HR=1.17 [95%CI: 1.05 to 1.31]) and DFS (n=26; HR=1.12 [1.02 to 1.24]) but not BCSM (n=10; HR=1.09 [0.94 to 1.27]). In subgroup meta-analyses, significant inter-study survival differences were observed for exposure/comparison body mass index cut-points (OS, p=0.040), menopausal status (OS, p=0.026), and study location (OS, p<0.001; DFS, p=0.001). Asian and European studies reported significant associations with OS (HR=1.31 [1.11 to 1.54] and HR=1.46 [1.04 to 2.04], respectively) and DFS (HR=1.28 [1.07 to 1.54] and HR=1.44 [1.13 to 1.84], respectively), however no association was observed between obesity and TNBC prognosis in North American studies (OS: HR=1.02 [0.89 to 1.17]; DFS: HR=1.01 [0.91 to 1.12]). These subgroup differences remained robust after excluding poor quality studies.

Conclusions: Ethnic differences in the association between excess body weight and TNBC appear to exist. Further exploration of study heterogeneity is needed to properly understand populations most at risk.