DOES THE BODY MASS INDEX (BMI) IMPACT THE OVERALL SURVIVAL (OS) OF BRAZILIAN WOMEN WITH BREAST CANCER (BC) WHO HAVE ACHIEVED PATHOLOGICAL COMPLETE RESPONSE (PCR) AFTER NEOADJUVANT CHEMOTHERAPY (NCT)?

Abstract

Objective: This study aimed to evaluate the impact of obesity on the survival of patients with breast cancer (BC) treated
with neoadjuvant chemotherapy (NCT) in two public hospitals in Brazil. Methods: This is a retrospective, multicenter
study that evaluates women with BC at Pérola Byington (HPB) and State Public Servant (HSPE) hospitals between January
2011 and May 2020. Stages I–III, age ≥18 years, and who underwent NCT were included. Patients were categorized by the
World Health Organization definition as follows: body mass index (BMI) <18.5 kg/m2
: malnutrition; 18.5 to <25 kg/m2
: normal; 25 to <30 kg/m2
: overweight; ≥30 kg/m2
: obesity. Pathological complete response (pCR) was defined as the absence
of invasive breast and axillary tumors. T-test or chi-square test was used to individually analyze the association of each
variable between groups with and without pCR. Univariate and multivariate analyses were performed to calculate odds
ratios, 95% confidence intervals of the independent variables BMI, age, and clinical stage, correlated with pCR with p-value
<0.05 as statistically significant. Results: We enrolled 1779 patients, mean age of 50 years, and mean BMI of 28.08 kg/m2
.
Most of them were in stage III (68%) with ductal histological type (95.11%). After NCT, 1435 patients had residual disease
and 344 patients had pCR. The BMI ratio was 1.57% malnutrition, 30.58% normal, 35.13% overweight, and 32.72% obese.
When the pCR was associated with BMI, there was no significance on overall survival (OS) when evaluating separate centers (HPB: p=0.46, HSPE: p=0.49) or together (p=0.83). Disease-free survival was only possible in HPB without significance
(p=0.83) for BMI. Conclusion: This Brazilian study showed no interference of BMI on OS in patients submitted to NCT
with pCR. There were few patients achieving pCR (19.34%) probably because of the initial stage. Despite not having an
impact on survival, most of our women were overweight or obese (72.85%), showing how obesity is common in Brazilian
women and should be understood as a public health problem.