Response of mucinous breast carcinoma to neoadjuvant chemotherapy

Abstract

Background/aim: Mucinous breast carcinoma (MC) is thought to be a favorable-differentiated form of invasive breast cancer and is rarely preferred for neoadjuvant chemotherapy (NAC). The study aimed to define the response of MCs to NAC.Materials and methods: The study reviewed the demographic, clinicopathologic characteristics, management, and follow-up data of 70 patients diagnosed with MC between May 2010 to December 2020 by examining patients’ historical files and oncology records.Results: The median age, tumor size, and follow-up period of patients were respectively 52.9 (range 32 to 87) years, 25.8 (range 8 to 88) mm, and 61.5 (range 18 to 143) months. Out of 70 patients, 45 had conservative surgery, 25 had a mastectomy, and 22 had axillary clearance due to a positive sentinel node biopsy or clinical axilla. Eight patients (11.4%) received NAC. Twenty-one patients (30.0%) received adjuvant chemotherapy whereas almost all patients received hormone therapy. Preoperative core biopsy diagnosis of 4 of 8 patients receiving NAC was unspecified invasive breast carcinoma. NAC was preferred in younger patients, tumors larger in diameter, tumors with initial higher T-stage, especially patients with clinically positive axilla, and tumors with higher Ki-67 index. Despite these preference criteria, both overall mastectomy and axillary clearance rates were significantly higher in these patients. Two local and 5 systemic recurrences were observed in the follow-up period. There was no significant contribution of NAC to survival.Conclusion: The study may conclude that NAC is not sufficiently effective neither in avoiding mastectomy by downsizing the tumor, nor in avoiding axillary clearance in MCs, and no significant benefit on survival could be provided. In addition, the study may emphasize the importance of identifying the subtype of carcinoma, and the significant association between the degree of response to NAC and breast carcinoma subtype.