(P 196) SURVEILLANCE STRATEGIES AND LONG-TERM OUTCOMES IN LOW-RISK GASTRIC GASTROINTESTINAL STROMAL TUMORS (GGISTS)

Author(s)

NG

Nicole Ghuman, MD

General Surgery Resident
Univeresity of British Columbia
Vancouver, British Columbia, Canada

Co-Author(s)

Rachel J. Livergant, MD, MBT (she/her/hers)

General Surgery Resident
University of British Columbia
Vancouver, British Columbia, Canada
Erika Schmitz, MD, FRCSC (she/her/hers)

Surgical Oncologist
University of British Columbia
Kingston, Ontario, Canada
TH

Trevor D Hamilton, MD, FRCSC, FACS

Surgical Oncologist
University of British Columbia
Vancouver, British Columbia, Canada

Objective: Gastric gastrointestinal stromal tumors (gGISTs) may be stratified based on risk profile for recurrence. International guidelines vary widely in terms of intensity and modalities of recommended surveillance strategies. Given the lack of consensus to inform an optimal surveillance strategy, this study examines recurrence patterns and risk factors of gGISTs.

Methods: This retrospective, population-based study included patients diagnosed with gastric GISTs between 2015 and 2024. GISTs were identified via pathological data, and demographic, surgical, and surveillance data was collected via chart review. Patients were included if the gGIST was discovered incidentally, and patients were excluded if they were metastatic at initial presentation.

Results: Of 134 cases, the median age at diagnosis was 69 years (IQR 60-75), with a slight male predominance (n=74, 55%). Most cases were very low (n=74, 55%) or low risk (n=40, 30%), with a smaller amount of moderate (n=19, 14%) and high risk (n=2, 1%). The majority of patients had low grade tumors (n=122, 90%); median mitoses was 2, IQR 1-3. The majority were resected using minimally invasive techniques (n=115, 85%). gGISTs were typically resected via wedge resection (95%, n=127), with 5% receiving total gastrectomy. Intra-operative endoscopies were performed in 46% (n=63). The median size of the GISTs included in the study was 3.9 cm (IQR 3-5.7). Median follow-up time was 32.5 months (IQR 15, 54). Only 2 recurrences were identified on surveillance; one patient had a moderate risk tumor and the other had a high risk primary tumor. 5-year recurrence was 0.8%, and 8-year recurrence was 9.9%. Overall survival was 86.6% at 5 years and 77.0% at 8-years. There was a large variation in surveillance strategies, including endoscopy, cross-sectional imaging, and no surveillance.

Conclusion: Gastric GIST recurrence risk is low following resection. Larger cohort studies are required to identify specific risk factors for recurrence and determine if surveillance strategies are warranted.