Secretory Carcinoma of Breast: A Population-Based Study.

In this study, it was aimed to evaluate the characteristic features and survival of secretory carcinoma of the breast (SCB), which is one of the rare malignant tumors of the breast. Data of patients with histopathological diagnosis of SCB between 2010 and 2019 were extracted from the SEER database. These patients were evaluated in terms of age, race, molecular subtype, grade, estrogen receptor (ER), progesterone receptor (PR), HER2 receptor, TNM stage, surgical status, chemotherapy and radiotherapy treatment. Overall survival (OS) and breast cancer-specific survival (BCSS) of the whole population and subgroups [in terms of surgery procedure (mastectomy/breast-conserving surgery), and hormone receptor status (positive/negative)] were analyzed. 70 patients were included in the study. The mean age was 57 years (range 2-82). 32.9% of the patients were diagnosed under the age of 50. 97.1% of the patients were female; 2.9% were male. The vast majority of patients were white race (81.4%). Although the rates of localization were higher in the upper outer quadrant (31.4%), centrally located tumors (18.5%) were also quite common. The most frequently detected molecular subtype was hormone positive/HER2 negative. All patients were non-metastatic, 81.4% of patients did not have lymph node metastases, and most of the patients were stage IA. Median follow-up was 37 months (range 0-118 months). Considering all patients, OS was 76.3%, 5-year OS was 91.8%, and BCSS was 88%, 5-year BCSS was 97.8%. There was no statistically significant difference in OS and BCSS according to subgroups ( SCB, a rare histopathologic type, has high OS and BCSS rates.