Prognostic Factors for Primary Localized Gastrointestinal Stromal Tumors After Radical Resection: Shandong Gastrointestinal Surgery Study Group, Study 1201.

BACKGROUND: Most previous risk-prediction models for gastrointestinal stromal tumors (GISTs) were based on Western populations. In the current study, we collected data from 23 hospitals in Shandong Province, China, and used the data to examine prognostic factors in Chinese patients and establish a new recurrence-free survival (RFS) prediction model. METHODS: Records were analyzed for 5285 GIST patients. Independent prognostic factors were identified using Cox models. Receiver operating characteristic curve analysis was used to compare a novel RFS prediction model with current risk-prediction models. RESULTS: Overall, 4216 patients met the inclusion criteria and 3363 completed follow-up. One-, 3-, and 5-year RFS was 94.6% (95% confidence interval [CI] 93.8-95.4), 85.9% (95% CI 84.7-87.1), and 78.8% (95% CI 77.0-80.6), respectively. Sex, tumor location, size, mitotic count, and rupture were independent prognostic factors. A new prognostic index (PI) was developed: PI = 0.000 (if female) + 0.270 (if male) + 0.000 (if gastric GIST) + 0.350 (if non-gastric GIST) + 0.000 (if no tumor rupture) + 1.259 (if tumor rupture) + 0.000 (tumor mitotic count < 6 per 50 high-power fields [HPFs]) + 1.442 (tumor mitotic count between 6 and 10 per 50 HPFs) + 2.026 (tumor mitotic count > 10 per 50 HPFs) + 0.096 × tumor size (cm). Model-predicted 1-, 3-, and 5-year RFS was S(12, X) = 0.9926exp(PI), S(36, X) = 0.9739exp(PI) and S(60, X) = 0.9471exp(PI), respectively. CONCLUSIONS: Sex, tumor location, size, mitotic count, and rupture were independently prognostic for GIST recurrence. Our RFS prediction model is effective for Chinese GIST patients.

[Analysis of gastric gastrointestinal stromal tumors in Shandong Province: a midterm report of multicenter GISSG1201 study].

OBJECTIVE: To summarize the treatment status of gastric gastrointestinal stromal tumor (GIST) in Shandong province,by analyzing the clinicopathological features and prognostic factors. METHODS: Clinicopathological and follow-up data of 1 165 patients with gastric GIST between January 2000 and December 2013 from 23 tertiary referral hospitals in Shandong Province were collected to establish a database. The risk stratification of all cases was performed according to the National Institutes of Health(NIH) criteria proposed in 2008. Kaplan-Meier method was used to calculate the survival rate. Log-rank test and Cox regression model were used for univariate and multivariate prognostic analyses. RESULTS: Among 1 165 cases of gastric GIST, 557 were male and 608 were female. The median age of onset was 60 (range 15-89) years. Primary tumors were located in the gastric fundus and cardia in 623 cases(53.5%), gastric body in 346 cases(29.7%), gastric antrum in 196 cases(16.8%). All the cases underwent resection of tumors, including endoscopic resection (n=106), local resection (n=589), subtotal gastrectomy(n=399), and total gastrectomy(n=72). Based on the NIH risk stratification, there were 256 cases (22.0%) at very low risk, 435 (37.3%) at low risk, 251 cases (21.5%) at intermediate risk, and 223 cases (19.1%) at high risk. A total of 1 116 cases(95.8%) were followed up and the median follow-up period was 40 (range, 1-60) months. During the period, 337 patients relapsed and the median time to recurrence was 34 (range 1-60) months. The 1-, 3-, and 5-year survival rates were 98.6%, 86.1% and 73.4%, respectively. The 5-year survival rates of patients at very low, low, intermediate, and high risk were 93.1%, 85.8%, 63.0% and 42.3% respectively, with a statistically significant difference (P=0.000). Multivariate analysis showed that primary tumor site (RR=0.580, 95%CI:0.402-0.835), tumor size (RR=0.450, 95%CI:0.266-0.760), intraoperative tumor rupture(RR=0.557, 95%CI:0.336-0.924), risk classification (RR=0.309, 95%CI:0.164-0.580) and the use of imatinib after surgery (RR=1.993, 95%CI:1.350-2.922) were independent prognostic factors. CONCLUSIONS: The choice of surgical procedure for gastric GIST patients should be based on tumor size. All the routine procedures including endoscopic resection, local excision, subtotal gastrectomy and total gastrectomy can obtain satisfactory curative outcomes. NIH classification has a high value for the prediction of prognosis. Primary tumor site, tumor size, intraoperative tumor rupture, risk stratification and postoperative use of imatinib are independent prognostic factors in gastric GIST patients.