Diagnostic Immunostaining and Tumor Markers Predict the Prognosis of Esophageal Neuroendocrine Cell Carcinoma Patients

Background Esophageal neuroendocrine carcinoma (ENEC) has a poor prognosis, and predicting the prognosis by examining various markers may contribute to the determination of treatment strategies. Therefore, a multiple-institution retrospective study was performed to identify biomarkers using diagnostic immunohistochemistry and serum tumor markers that predict the prognosis of patients with ENEC. Methods The results of immunohistochemical examination and serum tumor markers were extracted from the data of 141 ENEC patients at 39 institutions certified by the Japan Esophageal Society. The study then examined correlations between these data and prognosis or treatment effects. Results The ENEC patients with positively for all expression of synaptophysin (Syn), chromogranin A (CgA), and CD56 had a significantly worse prognosis than the patients with other expression patterns. Additionally, surgery and chemoradiotherapy were significantly more effective treatments than chemotherapy for the patients who were not positive for all expressions of Syn, CgA, and CD56. In terms of serum tumor markers, the patients with a high neuron-specific enolase (NSE) value had a significantly worse prognosis than the patients with a normal NSE value, and complete response (CR) cases treated with chemotherapy were significantly fewer in the high-NSE group. The results of multivariate analysis demonstrated that high NSE levels were an independent poor prognostic factor for esophageal endocrine cell carcinoma. Conclusion This study showed that positivity for all expressions of Syn, CgA, and CD56, and a high NSE value were significantly worse prognostic factors for ENEC patients than other expression patterns and may be important prognostic biomarkers of ENEC.