Clinical evaluation of pN-stage (TNM) in gastric cancer: an analysis of distribution of regional lymph nodes in node-positive patients.

Background: The aims of the present study were to identify the distribution of regional lymph nodes in gastric cancer patients based on the number of nodes and to assess the influence of the examined area of lymph nodes on the determination of node stage according to TNM in node-positive patients with gastric cancer.

Materials And Methods: A total of 346 node-positive patients with primary solitary carcinoma of the stomach (210 males and 136 females; age range, 27 to 84 years; mean, 58.5 years), who underwent curative gastric resection combined with D2 or more extended lymph node dissection, were enrolled in the present study. The anatomical distribution of regional lymph nodes at each station classified according to the JCGC was assessed from pathology records.

Results: The number of first tier and all regional nodes dissected was < 15 in 7 patients (2%) of all patients and <15 in 37 patients (11%), respectively. Metastasis to first tier nodes was found in 2129 nodes (21%) but not in 8199 nodes (79%) and to second tier nodes in 375 nodes (9%) but not in 4028 nodes (91%), representing a significant difference between the two node groups (p<0.0001). No metastasis to first tier nodes was found in 12 patients (5%) out of 229 patients with pN1 tumor. Similarly, the number of metastases to first tier nodes in 15 patients (21%) out of 73 patients with pN2 tumor and in 13 patients (29%) out of 44 patients with pN3 tumor were 1-6 and 7-15, respectively.

Conclusion: The present findings suggest that the extent of lymph node dissection does affect node stage as classified according to TNM and that restriction of the number of dissected regional lymph nodes (> or = 15 lymph nodes) may not be essential for practical staging of TNM.