Incidence, clinical features, and outcomes of special types in breast cancer in a single institution population.

The low incidence of special types of breast cancer hinders adequate clinical research efforts. As such, collecting sufficient data to develop well‐established therapy strategies are difficult. The aim of our study was to obtain more data on these special types in order to better understand the different characteristics and optimize therapy strategies. A single‐institution retrospective cohort study from January 2007 until September 2015. One hundred and five patients remained after excluding the patients with invasive ductal and lobular carcinoma. The percentage of these so called special types in this population was 4%. Tubular carcinoma, cribriform carcinoma, carcinoma with medullary features, carcinoma with apocrine differentiation, secretory carcinoma, mucinous carcinoma, and invasive papillary carcinoma had a good or excellent prognosis, while invasive micropapillary carcinoma, adenoid cystic carcinoma, metaplastic carcinoma, and carcinoma with neuroendocrine features had a worse prognosis. Special types of breast cancer form a heterogeneous group. Submitting them all to the same treatment modality may lead to both over‐ and under‐treatment. We need to combine our data to optimize treatment strategies for the different special types. [ABSTRACT FROM AUTHOR]