Pathological Evaluation of Response to Neoadjuvant Chemotherapy in Breast Cancer

Background:Breast cancer is globally known to be the most commonly diagnosed cancer in women. Among various modes of advanced therapies available surgery remains the prime modality aided by chemotherapy, hormonal therapy and radiation. With the increasing use of neoadjuvant chemotherapy for breast conservation, it becomes necessary for a pathologist to have the thorough knowledge of possible changes rendered by the therapy. Aim: To assess the tumor and lymph node response in breast carcinoma after paclitaxel based chemotherapy. Settings and Designs : A Cross sectional study carried out in the Histology section of Pathology department in American International Institute of Medical Sciences, Udaipur. Methods: Study was conducted over the period of 4.5 years from January 2019 to May 2023. Clinical and tumor characteristics of patients with breast carcinoma (n=47) were assessed preoperatively. Post- NACT breast cancer specimens (modied radical mastectomy and breast conservation surgery) received in the histopathology section of our institute were analysed grossly and slides were prepared. The response in tumor and lymph node was graded into pathological complete response (pCR), pathological partial response (pPR), and pathological no response (pNR). Statistical Analysis: Statistical analysis was done using Pearson's Chi square test. Results: Our studies showed a pCR of 23.4% , pPR of 70.2% and pNR of 6.4%. Clinically small sized tumors (2–5 cms) showed a pCR of 6.0% (p value 0.001). Mean age at presentation was 49.9 yrs. 97.8 % of cases were invasive ductal carcinoma NOS of which 23.9% cases showed complete response (p value <0.001) . Only 2.1% of the cases were mucinous carcinoma and all of them showed partial response. Ductal carcinoma in situ and lymphovascular invasion were found to be resistant to chemotherapy (p value 0.015). Conclusion: The study concludes that histopathology is a gold standard method to assess the chemotherapeutic tumor response. Tumor grades can be downgraded after neoadjuvant chemotherapy