Metaplastic carcinoma of the breast, an unusual disease with worse prognosis : the experience of the European Institute of Oncology and review of the literature

Background: Metaplastic carcinoma of the breast is a rare form of breast cancer and has an uncertain prognostic significance. The purpose of the present study was to compare the clinical course, and prognosis, between this type of tumor and poorly differentiated ductal carcinoma. Patients and methods: We analyzed 37 cases of metaplastic carcinoma of the breast treated at our institution (European Institute of Oncology in Milan, Italy) between 1997 and 2004, comparing them with 72 cases (control group) of poorly differentiated ductal carcinoma. All 109 patients had negative receptors and were G3 at final histology. The control cases were matched according to year of surgery, pT (pT1 vs. pT2/3/4), and pN (absent vs. present). Results: Of the 37 patients, eleven died from disease progression, eight developed metastatic disease and two experienced local recurrence. In the control group (72 patients) we observed three deaths due to disease progression, 13 distant metastases, and two local recurrences. Conclusion: The overall survival in the metaplastic carcinoma group was significantly worse than in the control group. As regards to disease-free survival, there was no statistically significant difference between the two groups.