Characteristics analyses and tumor staging proposal for primary malignant melanoma of the esophagus: a retrospective study

Primary malignant melanoma of the esophagus (PMME) is a malignant tumor with a poor prognosis. This study aimed to conduct survival analysis for patients with PMME and propose a staging system for PMME. Data from 179 patients were compiled for survival analysis and to propose a staging system for PMME. Survival analysis was conducted using the Kaplan-Meier method, log-rank test, and Cox proportional hazards model. The median OS of the 179 patients with PMME was 20.0 months. The 1-, 3-, and 5-year survival rates were 67.0%, 35.0%, and 17.0%. In the pooled analysis of 179 patients, significant differences in OS were observed between patients with tumors invading the lamina propria or muscularis mucosae (T1a) and deeper layers (T1b, T2, T3, T4) (P < 0.001). Significant differences in OS were observed between patients with no regional lymph node metastasis and those with one or more regional lymph node metastases (P < 0.001). PD-1 inhibitors significantly improved 3-year OS for patients with the pT1b-4 N+ stage (P = 0.020). The proposed staging system for PMME is as follows: (1) Stage I: T1aN0M0 (2) Stage II: T1b-4N0M0 and T1N1M0; Stage III: T2-4N1M0 and TxNxM1(P < 0.001). The lower T-stage and no lymph node metastasis indicated better prognosis. Surgery could be considered an effective treatment for patients with early-stage PMME. The effectiveness of surgery as a treatment for advanced-stage patients remained unclear and required further research. However, PD-1 inhibitors might improve the 3-year OS for advanced-stage patients. Furthermore, the tumor, node, metastasis staging system for PMME was proposed, and could be valuable in guiding prognostic predictions.