The Impact of Tumor Size on the Prognosis of Gastric Cancer: Experiences from a European Study Group

Background: To investigate the impact of tumor size as a prognostic marker in the clinical course of resected gastric cancer on a German study group. Methods: Based on a prospectively maintained data base, we included 573 cases of resected gastric cancer. Tumor size was measured postoperatively on the pathological specimen by the pathologist. The optimal cut-off point for tumor size was estimated by using the Cox regression model. We performed a tumorsize stratified analysis for several clinical and pathohistological factors in terms of their frequency and size-related impact on survival. The influence of tumor size on the pattern of tumor recurrence was analyzed. Results: We found longer overall 5-year survival for patients with smaller tumors (69.5% and 36.8%, respectively, p<0.0001). Tumor size was an independent prognostic factor (p=0.042). Tumor size was a significant prognostic factor in curatively resected patients (R0), in both diffuse and intestinal type gastric cancer according to the Lauren classification, in the T2 category, in both well/moderate and poor/un- differentiated tumors, in both node-positive and node-negative categories, in cases with and without lymphangiosis, venous infiltration, cardia tumor location as well as tubular pathohistological growth pattern. Tumor recurrence was less frequent (28 vs. 39%, respectively, p=0.021) and at a later interval in smaller tumors (19 vs. 13 months, respectively, p<0.0001). Lung metastases were observed significantly more frequently in the subgroup of larger tumors. Conclusion: Tumor size is a strong prognostic factor. In the development of a more individually designed cancer treatment tumor size might be a useful marker.