Curative Management After Endoscopic Resection for Esophageal Squamous Cell Carcinoma Invading Muscularis Mucosa or Shallow Submucosal Layer-Multicenter Real-World Survey in Japan

INTRODUCTION: Curative management after endoscopic resection (ER) for esophageal squamous cell carcinoma (ESCC), which invades the muscularis mucosa (pMM-ESCC) or shallow submucosal layer (pSM1-ESCC), has been controversial.METHODS: We identified patients with pMM-ESCC and pSM1-ESCC treated by ER. Outcomes were the predictive factors for regional lymph node and distant recurrence, and survival data were based on the depth of invasion, lymphovascular invasion (LVI), and additional treatment immediately after ER.RESULTS: A total of 992 patients with pMM-ESCC (n = 749) and pSM1-ESCC (n = 243) were registered. According to the multivariate Cox proportional hazards analysis, pSM1-ESCC (hazard ratio = 1.88, 95% confidence interval 1.15-3.07, P = 0.012) and LVI (hazard ratio = 6.92, 95% confidence interval 4.09-11.7, P < 0.0001) were associated with a risk of regional lymph node and distant recurrence. In the median follow-up period of 58.6 months (range 1-233), among patients with risk factors (pMM-ESCC with LVI or pSM1-ESCC), the 5-year overall survival rates, relapse-free survival rates, and cause-specific survival rates of patients with additional treatment were significantly better than those of patients without additional treatment; 85.4% vs 61.5% (P < 0.0001), 80.5% vs 53.3% (P < 0.0001), and 98.5% vs 93.1% (P = 0.004), respectively. There was no difference in survival rate between the chemoradiotherapy and surgery groups.DISCUSSION: pSM1 and LVI were risk factors for metastasis after ER for ESCC. To improve the survival, additional treatment immediately after ER, such as chemoradiotherapy or surgery, is effective in patients with these risk factors.