P1718 - Surveillance of Small Gastrointestinal Stromal Tumors With Endoscopic Ultrasound

Rukaiya Bashir Hamidu, MD, Giselle Mahoro, MD, Anthony J. DiMarino, MD, Anthony Infantolino, MD
Thomas Jefferson University Hospital, Philadelphia, PA

Introduction: Given the malignant potential of asymptomatic gastrointestinal stromal tumors (GISTs) with low malignant risk and size < 2 cm, the so-called ‘small’ GISTs, some experts recommend surgical resection. Others recommend surveillance with endoscopic ultrasound (EUS) until the tumors grow or become symptomatic. Robust data to support regular EUS surveillance or the optimal interval is, however, scarce as the natural history of small GISTs, especially their growth rate and metastatic potential is largely understudied. In turn, substantial practice variation exists regarding this approach. This study aims to elucidate the current surveillance practices among endoscopists and examine the progression of small GISTs under EUS surveillance.

Methods: This study involved a retrospective chart review of patients who underwent EUS for GIST from January 2010 to December 2020 at Thomas Jefferson University Hospital. Only patients with small GISTs (maximal tumor diameter < 2 cm) were included in the analyses. Data collected included tumor location, EUS features including maximal diameter and internal echo-pattern, as well as the frequency, duration, and outcomes of surveillance.

Results: Twelve patients were found to have small GISTs (Figure 1), of which eight underwent EUS surveillance (Table 1). The mean follow-up duration was 53.6 months. The frequency of surveillance ranged from every 1 to 3 years. Only 2 patients had tumor progression (Table 1). Tumor size increased from 0.9 cm to 1.5 cm at 56 months in Patient 1 and, from 1.1 cm to 2.0 cm at 21 months in Patient 2. There were no changes in other EUS features and both patients underwent surgical resection of their tumors. Surgical histopathological result from Patient 1 revealed a GIST with very low risk of malignancy given the tumor size and a mitotic rate of 3 mitoses per 50 high-power field. Cytopathological results of a fine-needle aspiration specimen from Patient 2 showed KIT and DOG1 positive spindle cells consistent with a GIST; Surgical pathology was unavailable for review.

Discussion: The results of our study affirm that only a small number of small GISTs progress during long-term follow-up. Thus, substantiating extended follow-up intervals for small GISTs, perhaps every 3 years. With the increased utility of endoscopy and EUS, patients with such tumors may be encountered more frequently. The reduction of visit burden may improve patient adherence, increase the efficiency of the surveillance approach and, would be more cost-effective.




Disclosures:


Rukaiya Bashir Hamidu, MD, Giselle Mahoro, MD, Anthony J. DiMarino, MD, Anthony Infantolino, MD. P1718 - Surveillance of Small Gastrointestinal Stromal Tumors With Endoscopic Ultrasound, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.