Cystic duct cancer: Should it be deemed as a type of gallbladder cancer?

Abstract

BACKGROUNDAccording to the latest American Joint Committee on Cancer and Union for International Cancer Control manuals, cystic duct cancer (CC) is categorized as a type of gallbladder cancer (GC), which has the worst prognosis among all types of biliary cancers. We hypothesized that this categorization could be verified by using taxonomic methods.AIMTo investigate the categorization of CC based on population-level data.METHODSCases of biliary cancers were identified from the Surveillance, Epidemiology, and End Results 18 registries database. Together with routinely used statistical methods, three taxonomic methods, including Fisher’s discriminant, binary logistics and artificial neuron network (ANN) models, were used to clarify the categorizing problem of CC.RESULTSThe T staging system of perihilar cholangiocarcinoma [a type of extrahepatic cholangiocarcinoma (EC)] better discriminated CC prognosis than that of GC. After adjusting other covariates, the hazard ratio of CC tended to be closer to that of EC, although not reaching statistical significance. To differentiate EC from GC, three taxonomic models were built and all showed good accuracies. The ANN model had an area under the receiver operating characteristic curve of 0.902. Using the three models, the majority (75.0%-77.8%) of CC cases were categorized as EC.CONCLUSIONOur study suggested that CC should be categorized as a type of EC, not GC. Aggressive surgical attitude might be considered in CC cases, to see whether long-term prognosis could be immensely improved like the situation in EC.

A rare gastric metastasis secondary to residual cystic duct carcinoma: case report and literature review

“…The biological characteristics of residual cystic duct carcinoma are similar to those of gallbladder cancer. The incidence of gallbladder cancer is relatively low, accounting for only 0.6% in all cholecystectomy specimens, and cystic duct cancer is about 0.44% [ 9 , 10 ]. The occurrence of residual cystic duct carcinoma is even more rare.…”

T1b primary remnant cystic duct cancer following cholecystectomy: A case report

“…Cystic duct cancer is a rare entity. Tu-Nan Yu et al reviewed extrahepatic cholangiocarcinoma diagnosed between 2006 and 2015, cystic duct cancer was only accounted 0.44 % [ 2 ]. In 1951, Farrar proposed diagnostic criteria for cystic duct carcinoma.…”

Clinical implication of the geometric location (fundal end versus cystic ductal end) of gallbladder cancer

“…4,12 To the best of our knowledge, there has been no study that focused on the clinical implication of the geometric location (e.g., fundal end, cystic ductal end) of GC. While there are some studies that compared GCs with cystic duct cancers, [13][14][15][16][17][18] they are limited because of the rarity of cystic duct cancers and controversies about the entity of cystic duct cancers. Also, cancers located in the cystic duct show different clinical courses from GCs.…”

“…Also, cancers located in the cystic duct show different clinical courses from GCs. 14,15 Therefore, we hypothesized that there would be different characteristics between GCs located on the fundal end and those located on the cystic ductal end.…”