Long‐term outcome of esophagectomy for primary malignant melanoma of the esophagus: a single‐institute retrospective analysis

Primary malignant melanoma of the esophagus (PMME) is a highly malignant tumor with a poor prognosis. Because PMME is an extremely rare disease, therapeutic strategies against the tumor have yet to be established, and the efficacy of esophagectomy remains unclear. The objective of this study was to evaluate the post‐esophagectomy survival of PMME patients. Ten patients who underwent esophagectomy for PMME between March 2005 and April 2013 at the Department of Gastroenterological Surgery, Cancer Institute Hospital, Tokyo, Japan, were identified from the institutional database. We retrospectively retrieved clinical information and data on the long‐term outcomes from the patients' records. Survival rates after esophagectomy were calculated by the Kaplan–Meier method, and the hazard ratios of mortality were determined using the Cox's model. A follow‐up study of the 10 patients revealed 7 cancer recurrences and 5 deaths. Median survival time was 34.5 months, and 5 of 10 patients survived longer than 2 years. The 1‐year disease‐free survival rate was 40%, and the 1‐ and 3‐year overall survival rates were 70% and 60%, respectively. Importantly, all three of the non‐relapsing patients were histologically confirmed as free of lymph node involvement. The four patients with lymph node metastasis relapsed within 1 year. The disease‐free survival was significantly shorter in patients with lymph node involvement than in those without lymph node involvement (univariate hazard ratio = 13.3, 95% confidence interval 1.85–266.4; P = 0.009). In conclusion, esophagectomy might benefit PMME patients with no lymph node metastasis. Further large‐scale cohort studies are needed to establish the treatment strategy for PMME.