Clinicopathologic features and prognosis of gastrointestinal stromal tumors: A retrospective study

Abstract ObjectiveGastrointestinal stromal tumors (GISTs) are rare but are the most common mesenchymal tumors of the digestive tract. GISTs represent a spectrum of tumors characterized by variable behaviors and activating mutations in KIT proto-oncogene, receptor tyrosine kinase (KIT) or platelet derived growth factor receptor α (PDGFRA) genes. This study aimed to analyze the histological and molecular characteristics of GISTs and the clinicopathologic features associated with its prognosis.MethodsWe retrospectively analyzed clinical, pathological and prognostic data for 941 patients who underwent GIST surgery at our hospital from 2010 to 2020. Influencing factors associated with GIST gene mutations and clinicopathological features related to patient prognosis were evaluated. The Kaplan-Meier method was used for survival analysis.ResultsGISTs were found to be more common in women than in men, to occur at an older age, and were located mainly in the stomach. GISTs were generally small in size, had a low mitotic index and were more often rated as very low risk/low risk. Immunohistochemistry showed that 96.7% and 98.4% of tumors were positive for CD117 and DOG-1. KIT and PDGFRA mutations were identified in 113 (76.4%) and 4 (4.0%) cases, respectively. Survival analysis showed GIST patient prognosis to be related to sex, age, tumor site, tumor size, mitotic count and the combined with other tumors. Patients with exon 11 mutation in KIT had a better prognosis than those with exon 9 mutation in KIT. Relapse or metastasis occurred in 39 patients during the follow-up period. Most relapsed or metastatic GISTs had concordant pathological and mutational characteristics with the primary tumor; they carried an identical KIT/PDGFRA mutation, and the mitotic index was usually high. But 4 metastatic GISTs carried a different KIT mutation compared to the promary tumor. Furthermore, coexistence of double mutations in KIT was observed in five tumors, with worse prognostic features.ConclusionsClinicopathological features( sex, age, site, tumor size, mitotic count, and the coexisting with other types of tumors) of GISTs, and mutation sites of KIT and PDGFRA were associated with the risk of GIST progression, which may contribute to optimization of individualized adjuvant therapy.