The diagnostic accuracy of cholangioscopy-guided sampling has not been rigorously evaluated.

To prospectively evaluate the accuracy of cholangioscopy-guided mini-forceps sampling and compare it with standard cytology brushings and forceps biopsies for the tissue diagnosis of indeterminate biliary lesions.

Prospective, long-term follow-up, paired design cohort study.

Tertiary center.

Patients undergoing cholangioscopy for the evaluation of indeterminate biliary lesions.

Each patient underwent triple sampling with cholangioscopy-guided mini-forceps, cytology brushing, and standard forceps.

Diagnostic accuracy of each sampling method compared with the patient final status (cancer vs no cancer).

A total of 26 patients (17 cancer positive/9 cancer negative) were enrolled. The mean follow-up in the patients with no cancer was 21.78 (SD ±6.78) months. The procedure was technically successful in all cases (100%). Sample quality was adequate in 25 of 26 (96.2%) of the cytology brushings, in 26 of 26 (100%) of the standard forceps biopsies, and in 25 of 26 (96.2%) of the mini-forceps biopsies. The sensitivity, accuracy, and negative predictive values were 5.9%, 38.5%, and 36% for standard cytology brushings; 29.4%, 53.8%, and 42.8% for standard forceps biopsies; and 76.5%, 84.6%, and 69.2% for mini-forceps biopsies, respectively. When comparing the 3 methods of sampling, mini-forceps biopsy provided significantly better sensitivity and overall accuracy compared with standard cytology brushing (P < .0001) and standard forceps biopsy (P = .0215).

Potential for selection bias.

Cholangioscopy-guided biopsies of indeterminate biliary lesions have significantly higher accuracy compared with ERCP-guided cytology brushings and standard forceps biopsies, but negative findings on mini-forceps biopsy cannot rule out malignancy with a high degree of certainty. (

NCT01227382.).