Comparison of outcomes between surgery and chemoradiotherapy after endoscopic resection for pT1a-MM with lymphovascular invasion or pT1b esophageal squamous cell carcinoma: Japanese multicenter propensity score-matched study.

Background: Lymphovascular invasion (LVI) or pT1b is noncurative after endoscopic resection (ER) for esophageal squamous cell carcinoma (ESCC), and therefore surgery or chemoradiotherapy (CRT) is recommended. However, there has been debate regarding which treatment has better outcomes and whether individual risks should be considered.

Methods: This was a multicenter, retrospective study conducted at 65 hospitals in Japan. The inclusion criteria were patients with ESCC who underwent ER between January 2006 and December 2015, with pT1a-muscularis mucosa (MM) with LVI or pT1b, with negative vertical margins, cN0M0, and who underwent surgery or CRT. A 1:1 propensity score-matched analysis was performed between two groups. The primary and secondary end points were overall survival (OS) and relapse-free survival (RFS). OS and RFS were also compared between two subgroups: low risk (pT1a-MM with LVI and pT1b without LVI) and high risk (pT1b with LVI) for metastatic recurrence.

Results: Among 472 patients, 160 patients were selected from each group. The OS and RFS did not differ between surgery and CRT groups (hazard ratio, 0.887; P = .635 and hazard ratio, 1.036; P = .876, respectively). Subgroup analysis showed that CRT had a better prognosis in the low-risk group, and conversely, surgery had a better prognosis in the high-risk group. But these were not significant. The high-risk CRT group had a significant worse prognosis than the low-risk CRT group.

Conclusions: In patients with noncurative ER for ESCC, surgery and CRT showed no difference in long-term outcomes. Indications for CRT in the high-risk group need further investigation because of poor prognosis.