Validating the prognostic and discriminating value of the TNM-classification for gastric cancer - a critical appraisal.

AIM We investigated the effect of the new tumour-, node-, metastasis- (TNM) classification on predicting and discriminating gastric cancer patient prognosis using the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program. PATIENTS AND METHODS From the SEER-database we retrieved gastric cancer patients with a primary adenocarcinoma, of Caucasian or Asian ethnicity and without distant metastases (M0). The pTNM-stage was determined according to the 7th edition of the union internationale contre le cancer (UICC) guidelines. RESULTS Spanning the period 2004-2010, 6136 patients fulfilled all inclusion criteria including 3424 (55.8%) men, 2712 (44.2%) women, 4629 (75.4%) Caucasian and 1507 (24.6%) Asian patients. 1524 (24.8%) patients underwent total gastrectomy and 4612 (75.2%) non-total gastrectomy. Only in 41.2% of the patients were >15 lymph nodes resected. 1857 (31.0%) patients received radiotherapy. Patient survival depended on ethnicity, type of surgery and radiotherapy. The discriminating value of the UICC-stage grouping could not be validated for Caucasian patients with >15 lymph nodes resected and who had not received radiotherapy: stage groups IIB, IIIA, IIIB and IIIC showed substantial overlap in survival ranges. In addition, the tumour specific survival of the different T-/N-combinations was significantly different in stage groups IIIB and IIIC, respectively. CONCLUSIONS Our retrospective analysis of the SEER-database does not validate the discriminating value of stage grouping of the 7th edition of the UICC-stage grouping. A revision should be considered and more reliable prognostic biomarkers are urgently needed.