Pre-operative Evalution of Gastric Gastrointestinal Stromal Tumors: Endoscopic Ultrasound vs Ct Scan

K B Williams, MD, MS, J F Bradley, MD, B A Wormer, MD, D Banerjee, A L Walters, MS, K T Dacey, MHA, A E Lincourt, PhD, MBA, B T Heniford, MD

Carolinas Medical Center

Introduction
The aim of this study is to compare the preoperative anatomic localization and tumor size measurements of endoscopic ultrasound (EUS) vs abdominal computer topography (CT) in the resection of gastric gastrointestinal stromal tumors (GIST).
Methods and Procedures
Patients undergoing resection of a gastric GIST from 2006 to 2012 in our institution were identified. Only patients who had both pre-operative EUS and CT were included in final analysis. Pre-resection tumor characteristics (anatomic location and size) resulted by EUS and CT were compared to operative location and final pathologic specimen. Pre-operative imaging complications were also examined.
Results
One-hundred thirty-two abdominal GIST resections (42.4% male) were identified. Average patient specifics included: age- 61.6 ± 15.2 years, BMI- 29.4 ± 7.6 kg/m2, tumor size- 5.4 ± 4.2 cm, and LOS- 5.6 ± 3.5 days. Most common presenting symptoms (in order of decreasing frequency) were signs of GI bleeding, abdominal pain, asymptomatic/incidental finding and anemia. Tumors were most commonly located in the greater curve (19.9%), body (15.3%) and fundus (14.5%). Seventy-nine resections were performed laparoscopically, 38 were open, 10 were laparoscopic hand-assisted, 4 were robotic and there was a single conversion of laparoscopic to open procedure.
Pre-operatively, all patients underwent EGD, 84 underwent CT and 48 underwent EUS; 27 patients were identified who underwent both (CT+EUS). Five CT+EUS were given neoadjuvant therapy (imantinib) and therefore were not included in location or size analysis. Anatomic location and tumor size as determined by EUS and CT were compared to operative anatomic location and final pathologic size. Percent agreement comparing anatomic location determined by EUS and CT to operative location were both high (86.4% for EUS, 77.3% for CT) with no statistical difference between the two (p>0.05). Using linear regression analysis, tumor size determined by EUS and CT were both shown to be significantly correlated when compared to final pathologic size (p<0.001); there was no significant difference in deviation between tumor size measurements from either modality (p>0.05).
Spindle cell cytology from EUS-guided fine needle aspiration or cold forceps biopsy was noted in 21 of the 27 EUS+CT patients and all 21 were confirmed GIST by c-kit positive immunostaining. There were 2 incidents of post-procedure hemorrhage after EUS-guided FNA which required intervention for hemostasis (endoscopic clipping or endoscopic Argon electrocautery). There were no complications noted from pre-operative CT imaging.
Conclusions
Pre-operatively, EUS and CT are equivalent for anatomic localization and size determination of gastric GISTs. EUS had a higher rate of complications and does not offer benefits beyond CT other than potential tissue diagnosis, if one is indicated prior to resection of a gastric mass. Masses in the stomach suggestive of a GIST on CT do not require EUS workup prior to surgery.

Session: Podium Presentation

Program Number: S060