Background: Breast biphasic metaplastic sarcomatoid carcinoma (MSC) is rare and aggressive. We analyzed 100 patients treated at M. D. Anderson Cancer Center (MDACC) with 213 MSC and 98 carcinosarcoma patients identified through the Surveillance, Epidemiology and End-Results (SEER) database to describe clinical and pathologic characteristics.
Patients and methods: We searched the MDACC (1985-2001) and SEER databases (1988-2001) for breast MSC and carcinosarcoma patients.
Results: We identified 100 MDACC MSC patients: 66% had node-negative disease and 6% distant metastases at presentation. Median recurrence-free survival (RFS) of 94 patients with stages I-III disease was 74 months (range 3-74), with 52% 5-year RFS [95% confidence interval (CI) 0.42-0.63]. Median overall survival in these patients was not reached, with 64% 5-year survival (95% CI 0.54-0.75). The initial stage of the tumor, but not use of adjuvant chemo- or radiotherapy, had a strong association with outcome. The pathologic complete response rate to neoadjuvant chemotherapy was 10%. Median survival from the time of recurrent disease was 14 months (range 1-55). Tumors were usually hormone receptor- and HER2/neu-negative. SEER data were consistent with MDACC findings.
Conclusions: Breast MSC and carcinosarcoma are aggressive, treatment-refractory tumors with shared clinical features and outcome similar to poorly differentiated receptor-negative adenocarcinomas. New therapeutic agents are needed.