Relevant prognostic factors in gastric cancer: ten-year results of the German Gastric Cancer Study.

OBJECTIVE In 1986 a prospective multicenter observation trial in patients with resected gastric cancer was initiated in Germany. An analysis of prognostic factors based on the 10-year survival data is now presented. PATIENTS AND METHODS A total of 1654 patients treated for gastric cancer between 1986 and 1989 at 19 centers in Germany and Austria were included. The resected specimen were evaluated histopathologically according to a standardized protocol. The extent of lymphadenectomy was classified after surgery based on the number of removed lymph nodes on histopathologic assessment (25 or fewer removed nodes, D1 or standard lymphadenectomy; >25 removed nodes, D2 or extended lymphadenectomy). Endpoint of the study was death. Follow-up is complete for 97% of the included patients (median follow-up of the surviving patients is 8.4 years). Prognostic factors were assessed by multivariate analysis. RESULTS A complete macroscopic and microscopic tumor resection (R0 resection according to the UICC 1997) could be achieved in 1182 of the 1654 patients (71.5%). The calculated 10-year survival rate in the entire patient population was 26.3% +/- 4.7%; it was 36.1% +/- 1.6% after an R0 resection. In the total patient population there was an independent prognostic effect of the ratio between invaded and removed lymph nodes, the residual tumor (R) category, the pT category, the presence of postsurgical complications, and the presence of distant metastases. Multivariate analysis in the subgroup of patients who had a UICC R0 resection confirmed the nodal status, the pT category, and the presence of postsurgical complications as the major independent prognostic factors. The extent of lymph node dissection had a significant and independent effect on the 10-year survival rate in patients with stage II tumors. This effect was present in the subgroups with (pT2N1) and without (pT3N0) lymph node metastases on standard histopathologic assessment. The beneficial effect of extended lymph node dissection for stage II tumors persisted when patients with insufficient lymph node dissection (<15 nodes) were excluded from the analysis. There was no difference in the postsurgical morbidity and mortality rates between patients with standard and extended lymph node dissection. CONCLUSIONS Lymph node ratio and lymph node status are the most important prognostic factors in patients with resected gastric cancer. In experienced centers, extended lymph node dissection does not increase the mortality or morbidity rate of resection for gastric cancer but markedly improves long-term survival in patients with stage II tumors. This effect appears to be independent of the phenomenon of stage migration.