Bariatric surgery and incidental gastrointestinal stromal tumors - a single-center study

Introduction: Gastrointestinal stromal tumors (GISTs), originating from Cajal cells, are most commonly located in the stomach; therefore they can be found in the specimens excised during bariatric operations. The global prevalence of GISTs is about 130 cases per million population. Morbidity differs depending on geographical latitude. Although surgery is the treatment of choice for GISTs, 40-50% of patients after radical surgical treatment will have a relapse or metastases. Aim: To analyze the incidence of GISTs in patients undergoing bariatric surgery and to verify whether an operation performed according to the bariatric protocol is oncologically radical in case of GIST. Material and methods: A single-center retrospective study. The study group comprised 1252 obese patients qualified for bariatric procedures, with no upper gastrointestinal tract neoplasms found during preoperative diagnostic examinations. In case of suspicious macroscopic pathologies (n = 81) present during the operation, tissue specimens underwent histopathological examination with further investigation performed if GISTs were found, including tumor size and localization, mitotic index and immunohistochemical analysis. Results: Gastrointestinal stromal tumors were found in 16 cases, and benign tumors of various histological origin in 33 cases. All cases of GIST found came from stomach specimens, 7 from the gastric corpus vs. 9 from the fundus. Fourteen GISTs were found during laparoscopic sleeve gastrectomies (LSGs) vs. 2 during laparoscopic Roux-en-Y gastric bypasses (LRYGBs). Conclusions: In case of incidental findings of GISTs during bariatric surgery, tumor resection with negative margins of incision may be considered as complete oncological treatment if there was very low/low risk stratification of GIST's recurrence after surgery.