Required esophageal resection length beyond the tumor boundary to ensure a negative proximal margin for gastric cancer with gross esophageal invasion or esophagogastric junction cancer.

Background: To obtain a pathologically negative proximal margin (PM) for gastric cancer with gross esophageal invasion (EI) or esophagogastric junction (EGJ) cancer, we should transect the esophagus beyond the proximal boundary of gross EI with a safety margin because of a discrepancy between the gross and pathological boundaries of cancer. However, recommendations regarding the esophageal resection length for these cancers have not been established.

Methods: Patients who underwent proximal or total gastrectomy for gastric cancer with gross EI or EGJ cancer were enrolled. A parameter ΔPM, which corresponded to the length of a discrepancy between the gross and pathological proximal boundary of the tumor, was evaluated. The maximum ΔPM, which corresponded to the minimum length ensuring a pathologically negative PM, was first determined in all patients. Then subgroup analyses according to factors associated with ΔPM ≥ 10 mm were performed to identify alternative maximum ΔPMs.

Results: A total of 289 patients with gastric cancer with gross EI or EGJ cancer were eligible and analyzed in this study. The maximum ΔPM was 25 mm. Clinical tumor (cTumor) size and growth and pathological types were independently associated with ΔPM ≥ 10 mm. In subgroup analyses, the maximum ΔPM was 15 mm for cTumor size ≤ 40 mm and superficial growth type. Furthermore, the maximum ΔPM was 20 mm in the expansive growth type.

Conclusions: Required esophageal resection lengths to ensure a pathologically negative PM for gastric cancer with gross EI or EGJ cancer are proposed.