Accurate lymph node staging is of greater prognostic importance than subclassification of the T2 category for gastric adenocarcinoma.

Background: Examination of 15 or more lymph nodes is necessary for accurate staging of gastric adenocarcinoma. This study examined whether prognostic discrimination is improved by distinguishing between pT2 tumors limited to the muscularis propria (MP) and those extending to subserosa (SS).

Methods: A single-institution, prospectively maintained database for 1985-2000 was reviewed for patients who had had R0 resection of pT2 gastric carcinoma.

Results: There were 161 patients with MP and 201 patients with SS. The prevalence of nodal metastasis was significantly lower with MP than with SS (47% vs. 66%, respectively; P <.001). As compared with MP, SS was associated with a similar prevalence of pN1 (44% vs. 43%) but a significantly higher prevalence of pN2 or pN3 (3% vs. 23%; P <.001). Five-year survival was significantly greater for patients with MP than with SS (64% vs. 49%; P =.005). On multivariate analyses, however, only the pN category and tumor site were independently significant prognostic factors. With accurate nodal staging, patients with MP or SS had similar survival in association with pN0 (90% vs. 86%) or pN1 (56% vs. 44%). pN2 or pN3 were mainly limited to SS tumors and these patients had poor survival (26% and 0%).

Conclusion: For pT2 gastric adenocarcinoma, the depth of mural invasion was not an independently significant prognostic factor.