# Significance of Intraoperative Lavage Cytology in Perihilar Cholangiocarcinoma

## TL;DR

This study examines whether intraoperative lavage cytology helps predict peritoneal metastasis in perihilar cholangiocarcinoma patients, finding limited significance in prognosis.

## Contribution

The study evaluates the clinical utility of intraoperative lavage cytology in perihilar cholangiocarcinoma, a context where its value was previously unclear.

## Key findings

- CY positivity was associated with higher PM recurrence rates, but not statistically significant.
- No significant differences in survival outcomes were observed between CY+ and CY− groups.
- Surgical resection may still be justified for CY+ patients despite non-significant prognostic differences.

## Abstract

Perihilar cholangiocarcinoma (PHC) has a poor prognosis, with frequent early metastatic recurrence after curative resection. Peritoneal metastasis (PM) is particularly difficult to diagnose and predict. While intraoperative lavage cytology (CY) is a standard method to detect PM, its utility remains unclear in PHC. In this study, we investigated the significance of CY in PHC patients.

We retrospectively examined the relationship between CY status and clinicopathological factors in 285 PHC patients and underwent CY for resection between January 1993 and December 2020.

32/285 (11.2%) cases were CY positive. We excluded 61 cases of expiratory laparotomy due to distant metastasis or local extension and nine cases with postoperative hospital mortality. 215 cases were divided into CY positive group (CY+, n = 12) and CY negative group (CY−, n = 203). PM recurrence was higher in the CY+ group (33.3%) than in the CY− group (13.3%), though not statistically significant (p = 0.087). Median recurrence‐free survival was 21.7 months (CY+) versus 30.6 months (CY−) (p = 0.357), and early recurrence (< 6 months) occurred in 16.7% versus 10.3% (p = 0.552). The median survival time was 42.8 months (CY+) and 44.1 months (CY−), with no significant difference (p = 0.678).

CY status was not strongly associated with PM or predictive of PM recurrence. Surgical resection may be justified in CY+ cases, as no statistically significant difference in prognosis was observed; however, these findings are exploratory and require validation in future studies.