Vertical margin involvement after endoscopic submucosal dissection for esophageal squamous cell carcinoma: a retrospective single-center study

Indeterminate or positive vertical margins (VMx/VM1) occasionally occur after endoscopic submucosal dissection (ESD) for superficial esophageal squamous cell carcinoma (ESCC), necessitating additional treatment. However, the factors associated with vertical-margin involvement remain unclear. This study aimed to determine the incidence and clinicopathological risk factors for VMx/VM1 after ESD in superficial ESCC. We retrospectively analyzed superficial ESCC lesions treated with ESD at Hiroshima University Hospital between November 2007 and December 2024. In Analysis 1, all lesions with VMx/VM1 were identified among the entire ESD cohort to determine the overall incidence and clinical background of vertical-margin involvement. In Analysis 2, the analysis was restricted to pT1b-SM2 lesions to evaluate whether preoperative endoscopic and endoscopic ultrasonography (EUS) findings were associated with VMx/VM1 in lesions with substantial submucosal invasion. Logistic regression analysis was used to identify factors independently associated with VMx/VM1. Among 1223 lesions treated with ESD, VMx/VM1 occurred in 51 (4.2%). In lesions pathologically diagnosed as T1a or T1b-SM1, vertical-margin involvement was mainly associated with severe submucosal fibrosis, including postoperative anastomotic lesions, post-ESD scars, and residual or recurrent lesions after chemoradiotherapy. In pT1b-SM2 lesions, obscuration of the outermost hyperechoic line on EUS was independently associated with VMx/VM1 (odds ratio, 4.46; 95% confidence interval, 1.36-14.66; p = 0.014), whereas macroscopic type 0-Is morphology showed a trend toward association (odds ratio, 8.92; 95% confidence interval, 0.91-87.16; p = 0.060). Both findings correlated with greater submucosal invasion depth. Vertical-margin involvement after ESD for superficial ESCC was uncommon but clinically relevant. Outermost hyperechoic-line obscuration on EUS may help identify lesions with a higher risk of VMx/VM1 before ESD. Not applicable.