A Randomized, Double-Blind Trial of Succinylated Gelatin Submucosal Injection for Endoscopic Resection of Large Sessile Polyps of the Colon

OBJECTIVES: Succinylated gelatin (SG) is an inexpensive, safe, colloidal solution. It was superior to normal saline (NS) in a porcine colon endoscopic resection (ER) model. Our aim was to compare the efficacy, efficiency, and safety of ER with SG vs. NS. METHODS: A randomized double-blind trial of submucosal injection with SG vs. NS was conducted for patients undergoing colonoscopy and ER for sessile lesions >= 20 mm in size at an Australian academic hospital endoscopy unit. The primary end point was the "Sydney Resection Quotient" (SRQ), defined as "lesion size in mm divided by the number of pieces to resect." This allows a comparison of technical outcomes for lesions of various sizes. A large lesion removed in fewer pieces gives a greater value. RESULTS: Eighty patients (45 men, mean age 69) with lesions sized 20-100 mm were randomized. A total of 41 SG subjects were well matched to 39 NS subjects, with median (interquartile range) lesion size 40 mm (25-45) vs. 35 mm (30-50), respectively (P=0.382). Complete single-session lesion excision was 90% in both groups. There were no adverse events attributable to SG. The SRQ (median (interquartile range)) was SG 10.0 (7.5-20.0) vs. NS 5.9 (4.4-11.7), P=0.004. Other end points (median (interquartile range)) included fewer resections per lesion in the SG group: 3.0 (1.0-6.0) vs. NS 5.5 (3.0-10.0), P=0.028; fewer injections per lesion with SG: 2.0 (1.0-3.0) vs. NS 3.0 (2.0-11.0), P=0.002; lower injection volume: 14.5 ml (8.5-23.0) vs. NS 20.0 ml (16.0-46.0), P=0.009; and shorter procedure duration with SG: 12.0 min (8.0-28.0) vs. NS 24.5 min (15.0-36.0), P=0.006. CONCLUSIONS: SG significantly improves SRQ by almost halving the number of resections for piecemeal ER. SG also safely halves procedure duration.