Analysis of clinicopathological and immunohistochemical parameters and correlation of outcomes in gastrointestinal stromal tumors.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. We analyzed the clinicopathological features, resectability, immunohistochemical markers, and various factors predictive of disease recurrence and survival. Retrospective analysis of prospectively maintained database of GIST patients managed from 2005 to 2016 was done. Size, site, malignant potential, nuclear pleomorphism, histopathological variety, immunohistochemical markers, type of surgery, and adjuvant imatinib therapy were analyzed. Ninety-two patients with GIST were analyzed. Immunohistochemistry showed positivity for c-kit (82.4%), DOG1 (75%), and PDGFR-α (79%). Among 16 patients with c-kit-negative tumors, 10 patients were positive for DOG1, PDGFR-α, or both. The most common primary site was stomach (44, 47.8%) followed by small bowel (17, 18.5%) and duodenum (14, 15.2%). Of 92 patients, 80 (87%) underwent R0 resection with organ sparing resection in 56 (70%) patients. Seventeen (21.3%) patients showed recurrence at a median follow-up of 6 years. Median and 5-year overall survival (OS) was 36 months (12-120) and 75%, respectively, and 5-year RFS was 81.8%. On univariate analysis, size, mitotic activity, malignant potential, and nuclear pleomorphism were predictors of recurrence. However, on multivariate analysis, only nuclear pleomorphism was significant. GISTs had a wide spectrum of presentation, and immunohistopathological features with organ sparing resection were conceivable in maximum. Nuclear pleomorphism may be considered as an important variable to predict recurrence in addition to malignant potential of tumors.