Epidemiologic Study of Triple-Negative Breast Cancer

This study enrolled patients in the Surveillance, Epidemiology, and End Results (SEER) database diagnosed with triple-negative breast cancer between 2010 and 2019 [the International Classification of Diseases for Oncology (ICD-O-3) site recode: “Breast” and morphology code: “8500/3” with negative receptor status for estrogen receptor (ER) status, progesterone receptor (PR) status, human epidermal growth factor receptor 2 (Her 2)] (https://seer.cancer.gov/). Before using this database, we signed the SEER Research Data Use Agreement and the Best Practices Assurance and accessed the data via login 11578-Nov2021. So, the institutional ethics committee exempted the study from ethical review.
The 53,253 patients recruited were selected on the basis of the following exclusion criteria (1): Distant metastasis or metastatic status unknown; (2) Unconfirmed by positive histopathology; (3) Not the first primary malignancy; (4) Age <18 years old; (5) required variables were unknown; (6) The follow-up time was 0 months. The AJCC 7th and 8th editions of breast cancer used in this study were consistent and could therefore be combined. The final selected patients were divided into training and validation groups according to the ratio of 7:3. Age at diagnosis, marital status, race, tumor stage, histological grade, and treatment may be related to the prognosis of TNBC and were used in this study.