Prognostic analysis and expression patterns of programmed cell death ligand 1 and BRAF V600E in esophageal neuroendocrine carcinoma.

Esophageal neuroendocrine carcinoma (ENEC) is a rare and highly aggressive malignancy. The present study investigated the expression of BRAF V600E and programmed death ligand 1 (PD-L1) and analyzed prognostic factors affecting patient outcomes. A total of 56 patients diagnosed with ENEC at the Affiliated Hospital of North Sichuan Medical College between January 2019, and September 2024 were retrospectively analyzed. Among them, 39 patients received surgery and were tested for BRAF V600E and PD-L1 expression using immunohistochemistry. Survival outcomes were estimated using the Kaplan-Meier method, and prognostic factors were assessed using Cox regression models. BRAF V600E mutations were identified in 12.8% (5/39) of cases, and PD-L1 expression was positive in 15.4% (6/39). In the mixed neuroendocrine carcinoma and squamous cell carcinoma (MiNEC-SCC), the positivity rates for both BRAF V600E and PD-L1 were 33.3% (3/9). Across the entire cohort, the 1-year overall survival (OS) and progression-free survival (PFS) rates were 79.7 and 43.1%, respectively, while the 3-year OS and PFS rates were 49.5 and 25.1%, respectively. Clinical lymph node stage and surgery were notably associated with both OS and PFS. Patients with tumor thickness >1 cm and length >3 cm had markedly worse PFS. Multivariate analysis identified surgery as an independent predictor of improved PFS (P=0.015). Among patients who underwent surgery, postoperative adjuvant therapy was independently associated with improved PFS (P=0.026). In conclusion, BRAF V600E and PD-L1 were more frequently expressed in the MiNEC-SCC compared with small cell neuroendocrine carcinoma. Surgery and postoperative adjuvant therapy were notably associated with improved PFS.