Diagnostic yield and safety of endoscopic ultrasound-guided trucut [corrected] biopsy in patients with gastric submucosal tumors: a prospective study.

BACKGROUND AND STUDY AIMS: Endoscopic-ultrasound-guided trucut needle biopsy (EUS-TCB) has not been adequately evaluated in patients with submucosal tumors (SMTs). PATIENTS AND METHODS: This prospective, uncontrolled study involving 49 consecutive patients with hypoechoic gastric SMTs (> or = 20 mm) evaluated diagnostic yield and 30-day morbidity of EUS-TCB, factors related to the success of EUS-TCB, and agreement between EUS-TCB and the surgical pathology diagnosis. Seventy-three percent of tumors were gastrointestinal stromal tumors (GIST).
RESULTS: Tumor tissue adequate for diagnosis was obtained by EUS-TCB in 31 patients (63 %; 95 %CI 49 % to 75 %). In the remaining cases, EUS-TCB provided no tissue (n = 11) or an insufficient amount (n = 7). Logistic regression analysis showed that tumor location on the lesser curvature of the stomach was the only independent predictor of obtaining diagnostic material [odds ratio (OR) 7.4; 95 %CI 1.9 to 28; P = 0.004]. The experience of the endosonographer, the size of the tumor, and the location of the tumor relative to the long axis of the stomach were not related to the success of the biopsy. Agreement between EUS-TCB and surgical pathology specimens in respect of the diagnosis and CD117 status was high (0.9, standard error 0.31; and 0.95, standard error 0.16, respectively); however, there was no correlation between the mitotic index as determined on EUS-TCB and that determined on the surgical pathology specimen (correlation coefficient, 0.08). There were two severe septic complications in 52 procedures (3.9 %; 95 %CI 0.3 % to 14 %).
CONCLUSIONS: The diagnostic yield of EUS-TCB in patients with gastric SMTs was moderate. Tissue samples were too small to reliably determine the mitotic index. Antibiotic prophylaxis should be considered because of possible septic complications.