Performance of risk stratification systems for gastrointestinal stromal tumors: A multicenter study

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor type in the gastrointestinal system. Presently, various classification systems to prognosticate GISTs have been proposed.

To evaluate the application value of four different risk stratification systems for GISTs.

Patients who were diagnosed with GISTs and underwent surgical resection at four hospitals from 1998 to 2015 were identified from a database. Risk of recurrence was stratified by the modified National Institute of Health (NIH) criteria, the Armed Forces Institute of Pathology (AFIP) criteria, the Memorial Sloan Kettering Cancer Center (MSKCC) prognostic nomogram, and the contour maps. Receiver operating characteristic (ROC) curves were established to compare the four abovementioned risk stratification systems based on the area under the curve (AUC).

A total of 1303 patients were included in the study. The mean age of the patients was 55.77 ± 13.70 yr; 52.3% of the patients were male. The mean follow-up period was 64.91 ± 35.79 mo. Approximately 67.0% the tumors were located in the stomach, and 59.5% were smaller than 5 cm; 67.3% of the patients had a mitotic count ≤ 5/50 high-power fields (HPFs). Thirty-four tumors ruptured before and during surgery. Univariate analysis demonstrated that tumor size > 5 cm (P < 0.05), mitotic count > 5/50 HPFs (P < 0.05), non-gastric location (P < 0.05), and tumor rupture (P < 0.05) were significantly associated with increased recurrence rates. According to the ROC curve, the AFIP criteria showed the largest AUC (0.754).

According to our data, the AFIP criteria were associated with a larger AUC than the NIH modified criteria, the MSKCC nomogram, and the contour maps, which might indicate that the AFIP criteria have better accuracy to support therapeutic decision-making for patients with GISTs.