Endoscopic balloon dilation for obstructive colorectal cancer: a basic study on morphologic and pathologic features associated with perforation

BackgroundThe use of endoscopic dilation and a self-expandable stent for colorectal cancer (CRC) presenting with a stricture or obstruction, either prior to surgery or as a palliative measure (an alternative to colostomy), causes perforation with relative high incidence (1%-17%).ObjectiveTo experimentally investigate risk factors associated with perforation in excised CRC specimens.DesignExperimental study.SettingEx vivo experiment on freshly excised human colon cancer specimens at an academic hospital.PatientsThis study involved 47 patients with strictured CRCs of <15 mm in internal diameter as assessed by a preoperative contrast enema.InterventionImmediately after surgical resection, a balloon with a diameter of 18 mm was placed in the stricture. The balloon was inflated slowly with hydrostatic pressure over 1 minute and kept at the maximum diameter for 1 minute.Main Outcome MeasurementsCorrelations between macroscopic perforation and 20 items, including morphological and histopathological characteristics.ResultsPerforation occurred in 8 of 47 (17.0%) CRC specimens. Four items showed statistically significant (P < .05) correlations with perforation: peritumoral proliferation of collagen fibers (relative area ≥23.9% in the visual field), annularity of the tumor, severe stricture (<7.9 mm), and fewer residual smooth muscle cells in the muscularis propria, reflecting tumor encroachment. The best predictor of perforation was a combination of severe stricture and pronounced peritumoral proliferation of collagen fibers.LimitationsAn uncontrolled study with a small number of patients.ConclusionHistopathological and morphological items associated with a decrease in elastic compliance were more important as predictors of perforation than dilation procedure parameters, such as balloon pressure.