Background: Gastrointestinal stromal tumors (GISTs) of the stomach are found incidentally during gastric cancer screening in Japan. This study investigated whether the Japanese gastric cancer screening system helps to improve treatment outcomes in gastric GIST based on an analysis of the GIST registry conducted by the Kinki GIST Study Group.
Methods: The registry was designed to collect data on background characteristics, treatment methods, pathologic characteristics, and prognosis of GIST from January 2003 through December 2007 at 40 participating institutions.
Results: The study enrolled 672 GIST patients, 482 of whom had gastric GIST. According to the modified National Institutes of Health consensus criteria, 22.6 % of the patients were classified as high risk for recurrence, 18.5 % as intermediate risk, 35.9 % as low risk, and 13.9 % as very low risk. After exclusion of the patients inevaluable for treatment outcome, the study included 137 symptomatic patients (symptomatic group) and 147 asymptomatic patients (asymptomatic group). The diagnosis of the asymptomatic patients was determined through gastric cancer screening. The median tumor size in the asymptomatic group was significantly smaller than in the symptomatic group (3.5 vs. 5.3 cm; P < 0.0001). The 5-year recurrence-free survival rate in the asymptomatic high-risk patients (72.4 %) was lower than in their symptomatic counterparts (46.3 %) (P = 0.017). More patients in the asymptomatic group underwent laparoscopic surgery (42.2 vs. 27.2 %; P = 0.0081).
Conclusions: By identifying asymptomatic patients, the Japanese gastric cancer screening system contributes to early detection of gastric GIST and favorable treatment outcomes.