Role of chemotherapy after curative esophagectomy in squamous cell carcinoma of the thoracic esophagus: A propensity score‐matched analysis

BACKGROUND: The efficacy of postoperative treatment of squamous cell carcinoma of the esophagus has not yet been determined. In this retrospective study, we investigated whether postoperative adjuvant chemotherapy (POCT) confers a survival benefit on patients who undergo curative esophagectomy. METHODS: A total of 782 patients were enrolled in our study. The patients were divided into surgery alone (S) and surgery plus postoperative chemotherapy (S + POCT) groups. Propensity score matching (PSM) was used to eliminate the differences in baseline characteristics. The primary endpoint was overall survival (OS), which was calculated by the Kaplan–Meier method and compared with the log‐rank test. A Cox proportional hazards model was used to identify factors influencing the prognosis. RESULTS: Of 782 patients, 343 (43.9%) underwent S alone, and 439 (56.1%) underwent S + POCT before PSM. The five‐year OS rates were 42.3% and 47.8% in the S and S + POCT groups (p = 0.080), respectively. After PSM (296 patients per group), the five‐year OS rates were 48.7% and 56.2% in the S and S + POCT groups (p = 0.025), respectively. For different cycles of POCT, patients with more than three cycles had a better survival than those with less than three cycles. The significant predictive factors for OS were pN stage (HR = 1.861, 95% CI: 1.310–2.645, p = 0.001), number of dissected nodes (HR = 0.621, 95% CI: 0.494–0.781, p < 0.001) and POCT received (HR = 0.699, 95% CI: 0.559–0.875, p = 0.002), which were identified by multivariate Cox regression analyses in the matched samples. CONCLUSIONS: POCT appears to improve the OS rate of patients with ESCC after resection, and at least four chemotherapy cycles are necessary. These conclusions warrant further confirmation in large‐scale multicenter randomized controlled trials.