Clinical features and prognostic factors of esophageal signet ring cell carcinoma: construction and validation of a model based on the SEER database

BACKGROUND: Signet ring cell carcinoma (SRCC) of the esophagus is a rare subtype of esophagus cancer with a poor prognosis. Our study aimed to determine the prognostic factors and establish nomograms to predict overall survival (OS) and cancer-specific survival (CSS) for patients with esophageal SRCC. METHODS: A total of 401 esophageal SRCC patients were identified from Surveillance Epidemiology and End Results (SEER) database and randomly divided into training and validation groups. We integrated the significant prognostic factors identified by multivariate cox analysis and construct nomograms to predict 2- and 5-year OS and CSS. Then, we evaluated the performance of the nomograms through concordance index (C-index), calibration curve, and the area under the curve (AUC) of the receiver operating characteristic curve. RESULTS: Multivariate Cox analysis revealed that American Joint Committee on Cancer (AJCC) stage, chemotherapy and surgery were associated with both OS and CSS. The C-indexes for OS and CSS predicted nomograms were 0.773 and 0.806, respectively. The calibration curves demonstrated good agreement between the actual observation and the nomogram prediction. Furthermore, the novel nomograms displayed higher AUC values in predicting OS and CSS compared to the 7th Tumor-Node-Metastasis (TNM) staging system. CONCLUSIONS: AJCC stage, chemotherapy and surgery were independent prognostic factors in esophageal SRCC patients. The proposed three-factor nomogram can assist clinicians predict the accurate prognosis of esophageal SRCC, thus contributing to individualized clinical practice.