After gastrectomy, endoscopic evaluation of superficial esophageal cancer can be challenging due to refluxed digestive fluids and changed background mucosa, making diagnosis of tumor margin difficult. To clarify factors associated with unclear tumor margin in endoscopic resection (ER) for superficial esophageal cancer after gastrectomy by classifying cases into clear (C) and unclear (U) groups.

A total of 130 patients who underwent ER for superficial esophageal cancer after gastrectomy were retrospectively analyzed. 73 patients were classified into the C group and 57 into the U group. The U group was defined by at least one of the following: requirement of repeat preoperative endoscopy, horizontal margin classified as HMx or HM1 after ER, or piecemeal resection. Clinical variables were compared between groups.

In univariate analysis, the U group showed a significantly lower one-piece complete resection rate (82.5%, p < 0.001). The background mucosa with multiple Lugol-voiding lesions (referred to as LVLs Grade C) (p = 0.010), type of gastrectomy (p = 0.033), and reconstruction method (p = 0.012) were identified as factors associated with unclear tumor margin. In multivariate analysis, LVLs Grade C (p = 0.026) was identified as an independent factor, and the frequency of unclear tumor margin was lower with gastro-gastro anastomosis compared with Billroth-I reconstruction (p ≒ 0.005) as well as with pylorus-preserving gastrectomy (PPG) compared with distal gastrectomy (DG) (p ≒ 0.039).

In superficial esophageal cancer after gastrectomy, the changed background mucosa and gastrectomy procedure and the type of reconstruction may influence tumor margin diagnosis during endoscopic evaluation.