Assessment of Clinicopathological Response to Neoadjuvant Chemotherapy in Patients Diagnosed With Locally Advanced Breast Carcinoma.

Introduction Globally, breast carcinoma is the most prevalent carcinoma and the primary cause of cancer-related deaths in women. Neoadjuvant chemotherapy (NACT) is a widely used treatment approach for patients with locally advanced breast carcinoma (LABC), as it reduces the size of the tumor, making previously inoperable tumors operable. Studies suggest that patients with LABC achieve a high response rate following NACT. Still, no such research has been done to date in central India. So, this study was designed to evaluate the clinical and pathological response to NACT in patients diagnosed with LABC who presented at a tertiary care institute in central India. The primary outcome of our study was the clinical and pathological response following NACT in patients diagnosed with LABC. The secondary outcome was the comparison of the response to NACT in different molecular receptor subtypes of LABC. Methods After approval from the IEC (2044/IEC-AIIMSRPR/2021, dated 30/11/2021) and written informed consent from the patients, this study was carried out at All India Institute of Medical Sciences, Raipur, from January 2022 to January 2023. Fifty-six women, aged 18 years and above, diagnosed with LABC, were included in this study. Patients who were lost to follow-up, did not give consent, underwent previous cancer treatment in any form, had unknown immunohistochemistry (IHC) status, had inconclusive pathological reports, had fungating/ulcerative breast lesions, were pregnant or lactating, and desired to be pregnant shortly were excluded. Demographic details of the patients and baseline tumor characteristics were noted. Patients diagnosed with LABC were administered NACT using a standard regimen. After three months, the clinical and pathological response of the tumor to NACT was assessed. Patients who responded to chemotherapy underwent surgery, while those with static or progressive disease were continued on chemotherapy for an additional three cycles and then reassessed. Based on the histopathological report of the postoperative specimen, the subtype and grading of the tumor were done, and an assessment of the clinical and pathological response of the tumor to NACT in various subtypes was made. Results Fifty-six patients receiving NACT for LABC were studied. Post-NACT, significant improvement in tumor characteristics, including size, hardness, and fixity to the skin or muscle, was noted (P<0.05), and the number of patients with axillary and supraclavicular lymphadenopathy decreased significantly (P<0.05). A significant rise in the number of patients belonging to T0-T2 and N0-N1 stages, along with a decline in the number of participants belonging to T3-T4 and N2-N3 stages, was noted, suggesting a remarkable downstaging of the tumor (P=0.001) post-NACT. A remarkable improvement in the grading of the tumor was noted (P=0.001). Out of 56 patients, in 12 (21.4%) patients, a complete pathological response (cPR) of the tumor was noted, while in the remaining 44 patients, there was no change in the ER/PR and HER2-neu receptor status. Triple-negative breast cancer (TNBC) had a maximum cPR rate of 12.5%. Conclusion Post-NACT, a significant downstaging and downgrading of the tumor and downstaging of lymph nodes were noted. We conclude that NACT has a definitive role in patients diagnosed with LABC as far as the clinical and pathological response of the tumor is concerned. Also, the TNBC subtype responds maximally to NACT and carries a better prognosis.