Large sessile colon polyps are usually considered the most technically challenging type of polyp to remove. Injecting submucosal fluid to create a cushion between the lesion and the intestinal wall can reduce complications during endoscopic polypectomy. Prior research comparing injectable submucosal fluids showed that a 50% dextrose solution was superior to a standard saline solution but that it was associated with increased risk for postpolypectomy syndrome.

To test another alternative solution, researchers in Australia recently conducted a randomized, double-blind trial that compared outcomes of endoscopic resection using injection of either normal saline (NS) solution or succinylated gelatin (SG) — a safe, colloidal plasma volume-expanding solution, regularly used to treat hypovolemia. Eighty patients with lateral-spreading tumors (20 mm to 100 mm) were randomized, of which 41 patients in the SG group and 39 patients in the NS group were well matched with regard to lesion size (40 mm vs. 35 mm).

Complete single-session excision of the lesions was achieved in 90% of both groups, without any adverse events attributable to SG. The SG group had fewer resected pieces per polyp than the NS group (median, 3.0 vs. 5.5; P=0.028). The SG group also had fewer injections per lesion (median, 2.0 vs. 3.0; P=0.002), a smaller injection volume (median, 14.5 mL vs. 20 mL; P=0.009), and a shorter procedure duration (median, 12.0 minutes vs. 24.5 minutes; P=0.006).

Comment: This randomized, controlled trial of a polypectomy tool is exactly the type of study that is needed to define optimal polypectomy practice. This trial indicates clear advantages for the colloidal expander material as an improved injection solution compared with saline. Unfortunately, this product is not available in the U.S., but similar products are available for testing.

— Douglas K. Rex, MD

Published in Journal Watch Gastroenterology December 3, 2010