Obesity and survival in the neoadjuvant breast cancer setting: role of tumor subtype in an ethnically diverse population

• Published in: Breast cancer research and treatment 2018-01, Vol.167 (1), p.277-288
• Main Authors: Liu, Ying L., Saraf, Anurag, Catanese, Benjamin, Lee, Shing M., Zhang, Yuan, Connolly, Eileen P., Kalinsky, Kevin
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aromatase; Associations; Body Mass Index; Breast cancer; Breast Neoplasms - complications; Breast Neoplasms - drug therapy; Breast Neoplasms - epidemiology; Breast Neoplasms - pathology; Bridged-Ring Compounds - adverse effects; Bridged-Ring Compounds - therapeutic use; Cancer research; Chemotherapy; Chemotherapy, Adjuvant - adverse effects; Development and progression; Disease-Free Survival; Doxorubicin - adverse effects; Epidemiology; ErbB-2 protein; Ethnicity; Female; Health aspects; Humans; Invasiveness; Kaplan-Meier Estimate; Medical schools; Medicine; Medicine & Public Health; Middle Aged; Minorities; Minority & ethnic groups; Mortality; Neoadjuvant Therapy - adverse effects; Obesity; Obesity - complications; Obesity - drug therapy; Obesity - epidemiology; Obesity - pathology; Oncology; Prognosis; Retrospective Studies; Survival; Tamoxifen; Taxoids - adverse effects; Taxoids - therapeutic use; Triple Negative Breast Neoplasms - complications; Triple Negative Breast Neoplasms - drug therapy; Triple Negative Breast Neoplasms - epidemiology; Triple Negative Breast Neoplasms - pathology
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-017-4507-y

Background Obesity may negatively affect survival in breast cancer (BC), but studies are conflicting, and associations may vary by tumor subtypes and race/ethnicity groups. Methods In a retrospective review, we identified 273 women with invasive BC administered Adriamycin/Taxane-based neoadjuvant chemotherapy from 2004 to 2016 with body mass index (BMI) data at diagnosis. Obesity was defined as BMI ≥30. Associations between obesity and event-free survival (EFS), using STEEP events, and overall survival (OS), using all-cause mortality, were assessed overall and stratified by tumor subtype [[Hormone Receptor Positive (HR+)/HER2−, HER2+, and Triple-Negative Breast Cancer (TNBC])] in our diverse population. Results Median follow-up was 32.6 months (range 5.7–137.8 months). Overall, obesity was associated with worse EFS (HR 1.71, 95% CI 1.03–2.84, p  = 0.04) and a trend towards worse OS ( p  = 0.13). In HR+/HER2− disease ( n  = 135), there was an interaction between obesity and hormonal therapy with respect to OS but not EFS. In those receiving tamoxifen ( n  = 33), obesity was associated with worse OS (HR 9.27, 95% CI 0.96–89.3, p  = 0.05). In those receiving an aromatase inhibitor ( n  = 89), there was no association between obesity and OS. In TNBC ( n  = 44), obesity was associated with worse EFS (HR 2.62, 95% CI 1.03–6.66, p  = 0.04) and a trend towards worse OS ( p  = 0.06). In HER2+ disease (n = 94), obesity was associated with a trend towards worse EFS (HR 3.37, 95% CI 0.97–11.72, p  = 0.06) but not OS. Race/ethnicity was not associated with survival in any subtype, and there were no interactions with obesity on survival. Conclusions Obesity may negatively impact survival, with differences among tumor subtypes.