Abstract P2-08-31: Role of body mass index in Brazilian breast cancer patients: Clinical-pathological characteristics and outcome in a single-institution retrospective cohort
Authors: Orlandini Leonardo F , Pimentel Franklin F , Carrara Hélio HA , dos Reis Francisco JC , de Andrade Jurandyr M , Tiezzi Daniel G 
Published: March 2020

Abstract
Background: Despite of several studies described body mass index (BMI) as a poor prognostic factor in breast cancer (BC) patients, the available data are still conflicting and the relation between obesity and BC remains unclear. In this study we evaluated the association of BMI at presentation with BC clinicopathological characteristics and outcomes in a Brazilian public hospital population.
Methods: Retrospective review of all patients diagnosed and treated for breast cancer in a Brazilian public hospital, between 1999 and 2013 was performed. Pathological and clinical characteristics as well as survival was collected in the medical and electronic patients’ records. Bivariate and multivariate analyzes were done using SPSS version 20. It was considered to be obese women with BMI ≥ 30kg/m2.
Results: Of 1,833 women included in this study, 620 (33.8%) was obese at presentation. When comparing age and menopause, obese women were slightly older and more related to postmenopausal status. (table 1).
Correlation between clinicopathological characteristics and body mass index.BMI ≥ 30kg/m2BMI &lt; 30kg/m2p valuen = 620n = 1211BMI, average (SD)35.0 (4.5)25.1 (3.1)0.01Age (years), median (range)56.2 (25.8 - 89.7)54.5 (22.6 - 93.9)0.03Size (mm), median (range)22 (0-154)20 (0-140)0.01n (%)n (%)Postmenopausal412 (66)722 (60)0.01HistologyDuctal531 (86)1007 (84)0.25Lobular26 (4)49 (4)Other57 (9)142 (12)Grade1125 (21)236 (21)2322 (54)623 (55)0.983145 (24)282 (25)Stage (TNM)030 (5)71 (6)I (A+B)110 (18)215 (18)II (A+B)227 (37)483 (40)0.43III (A+B+C)229 (37)399 (33)IV22 (4)42 (3)SubtypeLuminal375 (63)682 (59)Luminal/HER2+79 (13)173 (15)0.34Her2+53 (9)125 (11)Triple negative91 (15)184 (16)Estrogen receptor +459 (75)865 (74)0.23Progesterone receptor +396 (65)717 (60)0.06HER2+134 (22)303 (26)0.09Relapse (%)318/1211 (26,3%)164/620 (26,5%)0.930Time to recurrence (years) (range)2,40 (0,0-17,4)2,30 (0,20-16,6)0.821All cause mortality350/1211 (28,9%)350/1211 (28,9%)0.896Breast cancer specific Mortality273/1211 (22,5%)273/1211 (22,5%)0.752
There was no other significant association between BMI and tumor characteristics, recurrence or overall and specific survival.
Conclusion: In our population, BMI was not a risk factor for more aggressive BC at presentation, neither for worse outcomes. BMI may not be so accurate to measure body fat content and the results of the studies may suffer influence of different populations. Otherwise the effects of obesity may be mitigated by the heterogeneous behavior of breast cancer and the current cancer therapies.
Citation Format: Leonardo F Orlandini, Franklin F Pimentel, Hélio HA Carrara, Francisco JC dos Reis, Jurandyr M de Andrade, Daniel G Tiezzi. Role of body mass index in Brazilian breast cancer patients: Clinical-pathological characteristics and outcome in a single-institution retrospective cohort [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-08-31.