The patient populations from the two clinics studied here were clearly quite different. Not only did demographic and tumor characteristics vary, but also the indications for choice of therapy and the radicality of surgical intervention performed varied. Despite these differences, established independent prognostic factors for gastric carcinoma, such as depth of tumor infiltration, extent of lymph node metastasis, and presence of distant metastasis, as well as R0 resection, were reconfirmed by our results. The importance of these prognostic factors for the comparison between nations has already been reported in studies comparing Japan and Western industrialized nations [5
]. Depth of tumor infiltration and the extent of metastasis, as well as the possibility for an R0 resection selected from suitable surgical procedures, are clinical features that patients possess before entering a clinic. This applies also for the age of the patient. In contrast are the frequency of successful R0 resections and the extent of lymphadenectomies performed, which are determined at least partially by the operating surgeon.
In terms of patient-related factors, there were more women in Gdansk than in Cologne who were subjected to surgery for gastric carcinoma. It is possible that this represents a selection bias, because the incidence of gastric carcinoma in women in the two countries does not differ. Age and comorbidity also affect prognosis [16
]. Although the age distribution at the two clinics did not differ, presentation of the illness later in life does decrease life expectancy. Age also correlates with the severity of comorbidities, a fact that could explain why more severe comorbidity appears to have no prognostic relevance [17
]. Furthermore, the parameter chosen here, the ASA classification, is a nonspecific measure to estimate prognosis [18
The main difference in clinicopathological features was seen in the depth of tumor invasion into the gastric wall. Early gastric cancer was more prevalent in Cologne than in Gdansk. This correlates with data published by the Polish Gastric Cancer Study Group and the “German Gastric Cancer Study, for Gdansk and Cologne, respectively [19
]. We believe that the observed differences in tumor stage frequency are secondary to varying schools of thought in German society and Polish society, as well as differences in national health policies. There is probably less access to gastroscopy in Poland than in Germany, and perhaps Polish patients do not immediately visit general practitioners with the first symptoms of gastric disease. Although there were differences between the clinics in the tumor stage assessed at time of operation, the tumor stage distribution among our patients was nothing like that observed in Japan, where 56–65% of all gastric cancers are stage I [22
]. This suggests that all European Union countries must take more care to achieve earlier diagnosis.
Surgeon-dependent factors include the selection of surgical therapy and the radicality of the tumor resection performed. In Germany, clear guidelines for the therapeutic approach to gastric cancer exist [10
]. As a consequence, different indications were used by the two clinics to determine the types of resection and lymphadenectomy performed and the need for splenectomy, as well as the number of resected lymph nodes.
One of the most important prognostic factors was the number of resected lymph nodes. Each additional resected lymph node improved the probability of survival. These results correspond to other reports in the literature [22
]. Peyre et al. [23
] found similar results for patients with adenocarcinoma of the esophagus or gastric cardia in an international study assessing the impact of the extent of surgical resection.
Controversy regarding the optimal extent of lymph node dissection continues worldwide [24
]. An extended lymph node dissection is thought to provide more appropriate pathological staging and better regional disease control, as well as possible survival advantages compared to limited lymph node dissection [25
]. Two recent prospective, randomized European trials (in The Netherlands and the United Kingdom) were designed to evaluate whether extended lymphadenectomy improves overall survival. Neither study identified a difference in survival rates. However, the results of both studies were influenced by increased postoperative morbidity/mortality rates associated with increased rates of splenectomy and pancreatectomy in patients undergoing D2-dissection [26
]. In a review study, McCulloch et al. concluded that the question of extended versus limited lymph node dissection has not yet been decided [30
The fact that 57% of Gdansk patients had splenectomy performed during gastrectomy came out as an unanticipated observation. It was related to the conviction that removal of the lymph nodes located in the splenic hilum may be a prognostic marker. Several studies have concluded that the disadvantages of splenectomy outweigh the prognostic benefits for patients with gastric cancer [22
]. The results of our analysis convinced the Gdansk surgical team to change the strategy of management and to improve the surgical quality [33
]. Currently, the rate of splenectomies in Gdansk does not exceed 20%.