Optimized Lymphadenectomy for Early Gastric Cancer Based on the Analysis of 1141 Cases from a Single Institution

Background: According to the treatment guidelines for gastric cancer in Japan (3rd edition), D1 lymphadenectomy is recommended for T1a cancer (out of indication for endoscopic resection) and a group of T1b cancer (differentiated type, not larger than 1.5cm and clinically N0). D1+ lymphadenectomy is recommended for T1b cancer other than above group. D2 lymphadenectomy is for clinically N+ early gastric cancer (EGC). Methods: Consecutive 1141 resected EGC cases in our institution from January 1991 to December 2013 were analyzed. The size, depth of wall invasion, presence of ulcer, histological type and distribution of metastasis positive lymph node were evaluated. Results: There were 678 T1a and 463 T1b cancers. Lymph node metastasis positive T1a were 11 cases. All of them were undifferentiated type and the metastasis positive lymph nodes were all confined to the D1 area. Lymph node metastasis positive T1b cancer was 82 cases. Among them, 70 cases were within D1 area, 77 cases were within D1+ area and 79 cases were within D2 area. The other 3 cases had metastasis positive lymph node in beyond the D2 area. Conclusion: D1 lymphadenectomy is enough for T1a EGC that is out of indication of endoscopic resection and D1+ lymphadenectomy is reasonable for T1b EGC. These cases are good indication of laparoscopic surgery. D2 lymphadenectomy is required for T1b undifferentiated cancers which size is larger than 4 cm.