Obesity may not be related to pathologic response in locally advanced rectal cancer following neoadjuvant chemoradiotherapy

Quoc Riccardo Bao; Filippo Crimì; Giovanni Valotto; Valentina Chiminazzo; Francesca Bergamo; Alessandra Anna Prete; Sara Galuppo; Badr El Khouzai; Emilio Quaia; Salvatore Pucciarelli; Emanuele Damiano Luca Urso

doi:10.3389/fonc.2022.994444

Obesity may not be related to pathologic response in locally advanced rectal cancer following neoadjuvant chemoradiotherapy

Front Oncol. 2022 Sep 29:12:994444. doi: 10.3389/fonc.2022.994444. eCollection 2022.

Affiliations

¹ General Surgery 3, Department of Surgical- Oncological and Gastroenterological Sciences DiSCOG, University of Padova, Padova, Italy.
² Institute of Radiology - Department of Medicine, University of Padova, Padova, Italy.
³ Unit of Biostatistics, Epidemiology and Public Health, Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Padova, Italy.
⁴ Unit of Medical Oncology 1, Veneto Institute of Oncology IOV - IRCCS, Padova, Italy.
⁵ Radiotherapy Unit, Veneto Institute of Oncology IOV - IRCCS, Padova, Italy.

Abstract

Background: The aim of this study is to evaluate the correlation between body mass index (BMI) and body fat composition (measured with radiological fat parameters (RFP)) and pathological response after neoadjuvant chemoradiotherapy for locally advanced rectal cancer patients. The secondary aim of the study was to assess the role of BMI and RFP on major surgical complications, overall survival (OS), and disease-free survival (DFS).

Methods: All patients who underwent surgical resection following nCRT between 2005 and 2017 for mid-low rectal cancer were retrospectively collected. Visceral fat area (VFA), superficial fat area (SFA), visceral/superficial fat area ratio (V/S), perinephric fat thickness (PNF), and waist circumference (WC) were estimated by baseline CT scan. Predictors of pathologic response and postoperative complications were investigated using logistic regression analysis. The correlations between BMI and radiologic fat parameters and survival were investigated using the Kaplan-Meier method and log-rank test.

Results: Out of 144 patients included, a complete (TRG1) and major (TRG1+2) pathologic response was reported in 32 (22%) and 60 (45.5%) cases, respectively. A statistically significant correlation between BMI and all the RFP was found. At a median follow-up of 60 (35-103) months, no differences in terms of OS and DFS were found considering BMI and radiologic fat parameters. At univariable analysis, neither BMI nor radiologic fat parameters were predictors of complete or major pathologic response; nevertheless, VFA, V/S>1, and BMI were predictors of postoperative major complications.

Conclusions: We found no associations between BMI and body fat composition and pathological response to nCRT, although VFA, V/S, and BMI were predictors of major complications. BMI and RFP are not related to worse long-term OS and DFS.

Keywords: BMI; neoadjuvant chemoradiotherapy; obesity; pathological response; radiologic fat parameters and rectal cancer outcomes rectal cancer; visceral fat.