Outcome of rare types of breast cancer in Hispanic woman.

Abstract

96 Background: Rarer histological types of breast cancer represent less than 5% of all cases. The identification might be of value in assessing prognosis and predicting response to therapy in a Hispanic population. Methods: A total of 1,400 consecutive woman diagnosed with any type of breast cancer between 1991 and 2010 were identified. Histological types were classified according to World Health Organization criteria and the Armed Forces. Ductal, lobular and mixed ductal/lobular carcinomas and women with missing data were excluded, leaving a total of 60 patients. Tumor grade, vascular invasion, hormonal receptor status, ki-67 labeling index, HER2 overexpression, tumor size and nodal status were recorded and analyzed by histologic type. Survival curves were calculated by histology. Results: A total of 60 patients were classified according histology in order of frequency as mucinous (36.7%), medullary (10%), papillary (8.3%), metaplastic (8.3%), tubulo-lobular (6.7%), tubular (5.0%), metaplastic with epidermoid differentiation (3.3%), signet cell adenocarcinoma (3.3%), apocrine (3.3%), neuroendocrine (3.3%), acinary (1.7%), histiocytoid (1.7%), leiomyosarcome (1.7%), phyllodes (1.7%), high grade sarcoma (1.7%), and mucinous papillary (1.7%). Women with leiomysarcome type had the youngest mean age at diagnosis (27y) followed by mucinous (32y), and high grade sarcoma was the oldest mean age (76yrs). Most of histologists (82%) presented as stage I and II at diagnosis. Only mucinous, medullary and metaplastic presented with advanced disease (4%). With respect to ER/PR status, 36% of mucinous cases and 60% of papillary cases were ER+/PR+, while 50% of medullary cases and 60% of metaplastic cases were ER−/PR−. Only 13% had overexpression of HER2. Compared with OS reported for ductal and lobular carcinoma, median survival was significantly longer 54 months (40.4–67.5) and DFS median 66.1 months (48-82 months). Conclusions: Rare breast carcinomas are a heterogeneous group with more favorable prognosis compared to ductal carcinoma. Though many of these histologic subtypes are quite rare, an accurate and reliable histopathology assessment is crucial in order to determinate treatment, principally to the need for systemic treatment.