Efficacy of Positron Emission Tomography in Evaluating Neoadjuvant Chemotherapy Response and Factors Affecting Pathological Response in Breast Cancer

Abstract

Objective: Pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) is associated with higher disease-free survival and overall survival (OS). Posttreatment clin- ical response (cR) should be evaluated, and the associated factors should be identified. Our aim was to define the efficacy of positron emission tomography (PET) in cR evaluation and possible factors affecting pCR. Methods: The medical records of patients who were operated on for breast cancer be- tween January 2015 and December 2020 were evaluated. Preoperative cRs were investigated with PET. College of American Pathologists (CAP) 2019 scoring system was used in the eval- uation of pathological response. The factors affecting the clinical and pathological response were investigated by examining the menopausal status of the patients, the stage at the time of diagnosis, PET findings before and after NAC, histopathological type of the tumor, molec- ular subtype, and KI-67 level. Results: The data of 234 female patients were examined. The mean age was 52.5±12.1 years. The pCR (CAP=0) was observed in 28% of the patients, while the pCR was observed in 40 (72.7%) of 55 (24%) patients with cCR. KI-67 increase and HER2 positivity were fac- tors that positively affected the pathological response (p