Invasive neuroendocrine carcinoma of the breast: a prognostic research of 107 Chinese patients.

Neuroendocrine carcinoma (NEC) of the breast, a distinct type of mammary carcinoma whose terminology was not proposed until 2003, has not been well recognized or studied. The aim of our study is to evaluate the clinicopathological features and outcomes of this type of tumor. We conducted a comparative study on 107 NEC patients and 475 invasive ductal carcinoma, not otherwise specified(IDC, NOS) patients from the Department of Pathology, Huashan Hospital, Fudan University, to determine the demographic, pathological, and clinical features at presentation, along with patient outcomes and prognostic factors. With an older age at presentation, NECs are more likely to be estrogen receptor(ER)/ progesterone receptor (PR) positive and human epidermal growth factor receptor 2 (HER-2) negative, and have a higher propensity for local recurrence and poorer overall survival(OS). Higher T classification, M classification, TNM stage, the expression of Ki67, and the absence of PR expression are prognostically of poorer OS and distant recurrence-free survival(DRFS). Distant metastasis is also a dependent prognostic factor. NEC of the breast is a distinct type of neoplasm with higher malignancy. Novel therapies such as the endocrine therapy should be explored and studies with larger case number and longer follow-up will be needed.