Suitability of sentinel node mapping as an index of metastasis in early gastric cancer following endoscopic resection

Background. When pathological diagnosis following endoscopic resection (ER) for early gastric cancer (EGC) suggests probable lymph node metastasis, additional surgery with lymphadenectomy should be performed. The sentinel node (SN) concept has yet to be applied to tumors following ER. The aim of this study was to evaluate the feasibility of SN navigation surgery for such tumors. Methods. Forty patients diagnosed with EGC lesions <4 cm in diameter underwent gastrectomy with SN mapping following ER. A technetium-99 m tin colloid solution and a dye were injected into the submucosal layer around the post-ER scar in all four abdominal quadrants. We then compared the SN distribution and metastases among the patients who underwent ER and controls (n = 192). Results. SNs were identifiable in all patients, and the mean number of SNs per case was 4.9. The location of the SN basin was similar in the patients who underwent ER and the controls. One patient (3 %) whose primary tumor had invaded the submucosal layer had a metastatic SN. The median time from ER to surgery was 73 days. No postoperative recurrence was observed in any patient over a median follow-up of 1,023 days. Conclusions. Our findings suggest that the SN basin is not greatly affected by ER. The SN concept could be suitable for tumors following ER, but conventional gastrectomy with lymphadenectomy involving the SN basin should be used at present.