Survival and Prognostic Nomogram for Primary Gastrointestinal Melanoma (PGIM): A Population-based Study

Primary gastrointestinal mucosal melanoma (PGIM) is an aggressive and rare disease, commonly with poor prognosis. We aimed to determine the clinical risk and prognosis of this rare entity.

Patients (n=962) with PGIM documented in the Surveillance, Epidemiology, and End Results database between 1975-2016 were included. Prognostic factors on overall survival (OS) and cancer-specific survival (CSS) were identified. A nomogram was constructed to predict the OS of PGIM patients.

Primary site, summary stage, and therapeutic method were all independent predictors of OS and CSS, and age was the only factor significantly associated with OS. Independent prognostic factors of OS were selected to develop a predictive nomogram. The Harrell's C-index of the nomogram was 0.712, the area under the curve (AUC) was 0.746, 0.758, 0.810 for the 1-, 3-, and 5-year OS, respectively, and calibration plots were in good agreement.

Several prognostic factors of PGIM were demonstrated and a practical nomogram model was created in this study.