Radiotherapy Improves Survival of Patients with Lymphovascular Invasion in pT1b Esophageal Squamous Cell Cancer after Endoscopic Submucosal Dissection.

Overall, 774 patients were screened, and 161 patients were included. Forty-seven (29.2%) patients received adjuvant radiotherapy following ESD (RT group) and 114 (70.8%) underwent ESD alone (non-RT group). There were no significant differences in overall survival (OS) and disease-free survival (DFS) between the RT and non-RT groups. Lymphovascular invasion (LVI) was the only prognostic factor. In the LVI+ group, adjuvant radiotherapy significantly improved survival (5-year OS: 91.7% vs. 59.5%, P = 0.050; 5-year DFS: 92.9% vs. 42.6%, P = 0.010). In the LVI- group, adjuvant radiotherapy did not improve survival (5-year OS: 83.5% vs. 93.9%, P = 0.148; 5-year DFS: 84.2% vs. 84.7%, P = 0.907). The standardized mortality ratios were 1.52 (95% CI, 0.04-8.54) in LVI+ group with radiotherapy and 0.55 (95% CI, 0.15-1.42) in LVI- group without radiotherapy.Adjuvant radiotherapy could improve survival in pT1b ESCC with LVI+ other than LVI- after ESD. Selective adjuvant radiotherapy based on LVI status achieved survival rates similar to those of the general population.