A meta-analysis on surgery with or without postoperative radiotherapy to treat squamous cell esophageal carcinoma

Esophageal cancer (EC) is the sixth most common cause of cancer-related mortality in the world. Currently, surgery is the recommended treatment modality when possible. The outcomes of surgery alone are poor, and postoperative radiotherapy (PORT) has been used to patients with esophageal squamous cell carcinoma (ESCC) for years. However, the value of PORT for patients with ESCC after curative resection remains controversial. To assess the benefits and harms of postoperative radiotherapy compared with surgery alone for patients with ESCC we performed in this meta-analysis.

A comprehensive electronic literature search was performed via the Cochrane Library, MEDLINE and EMBASE from January 1st, 1990 to October 1st, 2018 for relevant trials. The primary outcomes of interest are overall survival (OS) and disease-free survival (DFS). A meta-analysis was performed to calculate the hazard ratio (HR) with 95% confidence interval (CI).

Three randomized controlled trials (RCTs) and seven retrospective studies (RS) were included, for a total of 5640 patients with 1774 in the PORT group and 3866 in the surgery alone group respectively. Meta-analysis showed there were significant increases both for OS (HR 0.86, 95%CI 0.79-0.93, p = 0.0004) and DFS (HR 0.74, 95%CI 0.63-0.87, p = 0.004) for patients administered PORT compared with surgery alone. Regarding the postoperative recurrence, PORT can significantly reduce the local recurrence rate (OR 0.34, 95%CI 0.29-0.40, p < 0.00001), while it showed no difference in distant metastasis (OR 1.09, 95%CI 0.91-1.30, p = 0.37). Subgroup analysis demonstrated PORT can improve the OS for patients with positive lymph node (N+, HR 0.73, 95%CI 0.59-0.90, p < 0.00001), curative resection (R0 resection, HR 0.81, 95%CI 0.73-0.90, p < 0.0001) and T3 stage (HR 0.84, 95%CI 0.80-1.0, p = 0.05).

PORT improved the OS and DFS for patients with ESCC compared with surgery alone, and significantly reduced the local recurrence. PORT showed survival benefits for specific subgroups such as patients with positive lymph node, R0 resection margin and T3 stage.