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

Background: The 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%).

Objective: To experimentally investigate risk factors associated with perforation in excised CRC specimens.

Design: Experimental study.

Setting: Ex vivo experiment on freshly excised human colon cancer specimens at an academic hospital.

Patients: This study involved 47 patients with strictured CRCs of <15 mm in internal diameter as assessed by a preoperative contrast enema.

Intervention: Immediately 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 Measurements: Correlations between macroscopic perforation and 20 items, including morphological and histopathological characteristics.

Results: Perforation 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 > or =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.

Limitations: An uncontrolled study with a small number of patients.

Conclusion: Histopathological 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.