Cystic Duct Carcinoma: A New Classification System and the Clinicopathological Features of 62 Patients.

Lingxi Nan,Dexiang Zhang,Xiaobo Bo,Shulong Zhang,Jie Wang,Yajie Dai,Yueqi Wang,Changcheng Wang,Houbao Liu

doi:10.3389/fonc.2021.696714

Abstract

BackgroundCystic duct carcinoma (CDC) is a rare biliary malignancy with a low incidence and poor prognosis. However, the clinical landscape of the disease has not been clarified and no widely applicable classification system has been developed.MethodsSixty-two patients with CDC were included in this retrospective study, and a new classification system was established using imaging data. Blood indices, radiological characteristics, pathological features, surgical procedures, and overall survival data were collected. The efficacy of the new classification in predicting resectability was evaluated using receiver operating characteristic (ROC) curves, and K-means clustering and t-distributed stochastic neighbor embedding were applied to verify the conclusion.ResultsThe pT stage of patients with type II CDC was significantly worse than that of type I. Patients with type II CDC were more likely to experience distant metastasis and invasion of the nervous system, vascular system, and liver. The resectability of patients with type II CDC was significantly worse than that of patients with type I CDC. Patients with type II CDC had worse prognoses. ROC curve analysis and K-means clustering revealed that the new classification could better categorize patients with CDC than currently available systems.ConclusionPatients with type II CDC have significantly worse clinicopathological outcomes. The new classification system has better accuracy in grouping patients with CDC.

Highlights

Cystic duct carcinoma (CDC) is an extremely rare malignancy in the biliary tract
receiver operating characteristic (ROC) curve analysis and K-means clustering revealed that the new classification could better categorize patients with CDC than currently available systems
In 1951, Farrar [1] proposed the following criteria for this rare disease: growth must be restricted to the cystic duct; there can be no neoplastic process in the gallbladder, hepatic, or common bile ducts; and histological examination of the tumor must confirm the presence of carcinoma cells

Summary

Introduction

Cystic duct carcinoma (CDC) is an extremely rare malignancy in the biliary tract. In 2003, Ozden [3] further modified the definition of CDC as a malignant gallbladder lesion that is centered in the cystic duct. We found that CDC appears to be commonly associated with hilar involvement, and the extent of tumor invasion in the porta hepatis significantly affects resectability and patient prognosis. Only Yokoyama’s classification defines CDC involving the porta hepatis as the hepatic hilum (HH) type, which still lacks a subdivision based on the extent of invasion [7]. We believe that further subdivision of CDC that invades the porta hepatis is necessary to improve the current classification systems. Cystic duct carcinoma (CDC) is a rare biliary malignancy with a low incidence and poor prognosis. The clinical landscape of the disease has not been clarified and no widely applicable classification system has been developed

Methods

Results

Conclusion