Proximal gastrectomy with exclusion of no. 3b lesser curvature lymph node dissection could be indicated for patients with advanced upper-third gastric cancer

Proximal gastrectomy has been introduced for early gastric cancer located in the upper third of the stomach, but expansion of its indication to advanced tumors has not been generally accepted in terms of lesser curvature lymph node dissection. We reviewed the medical records of 385 patients with tumors in the upper third of the stomach, and the incidence of metastasis and the therapeutic index related to the proximal (no. 3a) and distal (no. 3b) lymph nodes of the lesser curvature were analyzed and compared with those of tumors in the middle third (n = 1093) and lower third (n = 922) of the stomach. The no. 3a rate of metastasis from advanced tumors in the upper third of the stomach was significantly higher than that from tumors in the middle third or lower third of the stomach. The no. 3b metastasis rate did not show any significant differences between the three locations, but the therapeutic index of no. 3b lymph nodes in the upper third of the stomach (1.7) was far lower than that in the middle third (7.1) or lower third (7.0). Further, the rate of metastasis from tumors with the distal border ending in the upper third of the stomach (2.2 %) was significantly (P < 0.0001) lower than that from tumors located in the upper third of the stomach but extending to the middle third (19.6 %), as well as from tumors located in middle third (17.1 %) or lower third (19.6 %), with the therapeutic index being only 1.1. The four no.-3b-positive tumors all measured more than 40 mm, and included one T3 tumor and three T4 tumors. Proximal gastrectomy with exclusion of no. 3b lymphadenectomy could be indicated for at least T2 tumors measuring less than 40 mm localized in the upper third of the stomach.