Consequence of neo-adjuvant chemotherapy on morphology of breast carcinoma: A systematic evaluation.

ABSTRACT

BACKGROUND: Neo‑adjuvant chemotherapy (NAC) in locally advanced breast cancer is the present trend. Following NAC, a considerable alteration of morphology occurs in the tumor. AIMS: To study effects of NAC on morphology of breast carcinoma and to evaluate the pathologic response (PR). MATERIALS AND METHODS: A total of 39 surgically resected mastectomy specimens of patients of invasive locally advanced breast carcinoma who received NAC were evaluated for macroscopic and microscopic (by routine stains and immunohistochemistry) alteration of morphology. RESULTS: Macroscopically well‑defined tumor noted in 25 cases (64.1%) and in the rest (14 cases, 35.9%), only fibrotic areas identified. Microscopic examination identified malignant cells in 29 (74.4%), significant chronic inflammation in 24 (61.5%), hyalinized fibrosed stroma in 25 (64.1%) and necrosis in 11 (28.2%) cases. Immunohistochemistry assisted in differentiating malignant cells from histiocytes. In 15 cases (38.5%), axillary lymph nodes isolated where fibrosis seen in 12 (30.8%) and malignant cell in 8 (20.5%) cases. In 34 cases where the pre‑treatment biopsy were available, complete pathologic response (pCR) and partial pathologic response (pPR) were achieved in 7 (20.6%) and 23 (67.4%) cases respectively. DISCUSSION: Protocol of systematic evaluation of morphological changes is different in cases of a patient treated by NAC. Nature of malignancy was difficult to categorize as morphology of typical breast carcinomas were altered. Sometimes, immunohistochemistry is advantageous as routine H and E stains are not sufficient to isolate malignant cells in fibrotic and necrotic areas. Appropriate morphological evaluation of the mastectomy specimen is absolutely crucial for assessment of PR and subsequent management.