Correlation between breast and axillary pathologic complete response after neoadjuvant chemotherapy in breast cancer

AIM: The aim of this study was to evaluate the correlation of the pathological response in breast tissue and the axilla of patients with breast cancer who underwent surgery following neoadjuvant chemotherapy. Method: This retrospective cohort study included patients with T1-4, N1-3, M0 breast cancer who underwent surgery following neoadjuvant chemotherapy at Gaziosmanpasa Training and Research Hospital between 2013 and 2022. The response of the breast tissue to chemotherapy was evaluated with the Miller-Payne grading system, and the response of the axillary lymph nodes to chemotherapy was evaluated with the Pinder grading system. The patients were grouped histopathologically as luminal A, luminal B, Her-2 enriched, or triple negative breast cancer (TNBC). RESULTS: The study was completed with 140 patients. Pathological complete response (pCR) was seen in the breast in 40 patients and in the axilla in 34. Of the patients with pCR in the breast, pCR was also determined in the axilla in 45%. In the patients with pCR in both the breast and axilla, Her-2 enriched subtype, estrogen receptor negativity, progesterone receptor negativity, Her-2 neu positivity, and Ki-67 level >25% were determined to be effective (p<0.05). Her-2 neu positivity was evaluated as statistically significant in the development of pCR in both the breast and axilla (OR: 4.06, 95% CI:1.2-13.6, p=0.023). CONCLUSION: The development of pCR in the breast, especially in the Her-2 enriched subgroup, can be accepted as a predictive factor for the evaluation of axillary response in patients with breast cancer. The least compatibility was seen in the luminal A subgroup.