Objective To investigate the application value of digital single-operator peroral cholangioscopy on the preoperative evaluation of extrahepatic cholangiocarcinoma.

Methods The propensity score matching and retrospective cohort study was conducted. The clinicopathological data of 172 patients with extrahepatic cholangiocarcinoma who were admitted to the First Affiliated Hospital of Army Medical University from December 1, 2017 to April 1, 2022 were collected. There were 91 males and 81 females, aged 65(range, 45‒68)years. Of 172 patients, 36 cases undergoing preoperative digital single-operator peroral cholangioscopy examination were allocated into the experimental group, and 136 cases not undergoing preoperative digital single-operator peroral cholangioscopy examination were allocated into the control group. Observation indicators: (1) propensity score matching and comparison of general data of patients between the two groups after matching; (2) surgical conditions. Propensity score matching was done by the 1:1 nearest neighbor matching method and caliper setting as 0.02. Measurement data with normal distribution were expressed as Mean±SD, and t test was used for comparison between groups. Measurement data with skewed distribution were expressed as M(Q₁,Q₃), and the Mann-Whitney U test was used for comparison between groups. Count data were expressed as absolute numbers or percentages, and comparison between groups was analyzed using the chi-square test or Fisher exact probability. The rank sum test was used for comparison of ordinal data.

Results (1) Propensity score matching and comparison of general data of patients between the two groups after matching. Of 172 patients, 60 cases were successfully matched, including 30 cases in the experiment group and 30 cases in the control group, respectively. Before propensity score matching, cases with or without preoperative bile drainage were 27, 9 in the experiment group, versus 62, 74 in the control group, showing a significant difference between the two groups (χ²=9.86, P<0.05). The above indicators were 23, 7 in the experiment group, and 23, 7 in the control group after propensity score matching, showing no significant difference between the two groups (χ²=0.00, P>0.05). The elimination of preoperative bile drainage confounding bias ensured comparability between the two groups. (2) Surgical conditions. After propensity score matching, there were 10 cases and 0 case without surgery in the two groups. Cases undergoing radical operation including R₀, R₁, R₂ resection were 16, 0, 4 in the experiment group, versus 18, 6, 6 in the control group, showing a significant difference between the two groups (χ²=6.85, P<0.05).

Conclusions Preoperative digital single-operator peroral cholangioscopy exami-nation can improve the R₀ resection rate of extrahepatic cholangiocarcinoma.