Early gastric cancer with signet-ring cell histologic type: risk factors of lymph node metastasis and indications of endoscopic surgery.

BACKGROUND To clarify the biologic behavior of the early signet-ring cell cancers (SRCs) by comparing the clinicopathologic features and the incidence of lymph node metastasis between different histologic types of early gastric cancer (EGC) and to propose the indications of endoscopic surgery for SRCs. METHODS Clinicopathologic features and the incidence of lymph node metastasis of 422 EGCs were retrospectively reviewed and compared according to the histologic type. RESULTS Clinicopathologic features, incidence of node metastasis, prognosis, as well as the incidence of recurrence for SRCs, were similar to those of differentiated cancers (DCs), however, significantly different from those of undifferentiated cancers (UDCs). Tumor size, histologic type, lymphatic and/or blood vessel invasion (LBVI), and depth of invasion were independent factors predicting node metastasis for EGCs. For DCs and SRCs with mucosal invasion and ≤ 2 cm in diameter without LBVI, no metastatic lymph node was detected (95% CI, 0-5.0). Also, for DCs and SRCs with mucosal invasion and >2 cm in diameter without LBVI, or with submucosal invasion and ≤ 2 cm in diameter without LBVI, no metastatic lymph node was detected (95% CI, 0-3.0). CONCLUSION Clinicopathologic features of SRCs were similar with DCs, but different from other UDCs. Consequently, the treatment strategy for SRCs might be similar with that for DCs. According to the incidence of node metastasis, we propose SRCs with mucosal invasion without LBVI, or with submucosal invasion and ≤2 cm in diameter without LBVI, might be suitable for endoscopic surgery.