Mee Joo Kang1, Jiwon Lim2, Sung-Sik Han1, Hyeong Min Park1, Sun-Whe Kim1, Young-Joo Won2,3, Sang-Jae Park1. 1. Center for Liver and Pancreatobiliary Cancer, National Cancer Center, Goyang, Korea. 2. Division of Cancer Registration and Surveillance, National Cancer Center, Goyang, Korea. 3. Department of Cancer Control & Population Health, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Korea.
Abstract
BACKGROUND: Misclassification of Klatskin tumor as intrahepatic rather than extrahepatic bile duct cancer (eBDC) may overestimate the incidence of intrahepatic BDC (iBDC). This study aimed to investigate the impact of misclassified Klatskin tumor on iBDC and eBDC incidences in Korea, where BDC is highly endemic. METHODS: The data of incidence, topography and morphology code of BDC from 1999 to 2017 were obtained from the Korea Central Cancer Registry, which covers the entire 51.6 million Korean population. For misclassification analysis, all Klatskin tumor was reclassified as eBDC. RESULTS: Klatskin tumor accounted for 13.5% of all 81,414 BDC cases. In the registry, an average of 59.7% of Klatskin tumor was classified as iBDC, gradually decreasing from 95.5% to 16.9%. Misclassification led to a 17.3% overestimation of iBDC cases and a 15.0% underestimation of eBDC cases in average. After reclassification, age standardized rate (ASR) of incidence per 100,000 population decreased in iBDC from 3.4 to 2.9 and increased in eBDC from 2.8 to 3.2. Average annual percent change of iBDC and eBDC incidences were 2.0% and 1.2%, respectively, but ASR of iBDC significantly decreased since 2012 (p<0.0001). CONCLUSIONS: Misclassification of Klatskin tumor has remarkable impact on the incidence of iBDC and eBDC in a highly endemic country. This article is protected by copyright. All rights reserved.
BACKGROUND: Misclassification of Klatskin tumor as intrahepatic rather than extrahepatic bile duct cancer (eBDC) may overestimate the incidence of intrahepatic BDC (iBDC). This study aimed to investigate the impact of misclassified Klatskin tumor on iBDC and eBDC incidences in Korea, where BDC is highly endemic. METHODS: The data of incidence, topography and morphology code of BDC from 1999 to 2017 were obtained from the Korea Central Cancer Registry, which covers the entire 51.6 million Korean population. For misclassification analysis, all Klatskin tumor was reclassified as eBDC. RESULTS:Klatskin tumor accounted for 13.5% of all 81,414 BDC cases. In the registry, an average of 59.7% of Klatskin tumor was classified as iBDC, gradually decreasing from 95.5% to 16.9%. Misclassification led to a 17.3% overestimation of iBDC cases and a 15.0% underestimation of eBDC cases in average. After reclassification, age standardized rate (ASR) of incidence per 100,000 population decreased in iBDC from 3.4 to 2.9 and increased in eBDC from 2.8 to 3.2. Average annual percent change of iBDC and eBDC incidences were 2.0% and 1.2%, respectively, but ASR of iBDC significantly decreased since 2012 (p<0.0001). CONCLUSIONS: Misclassification of Klatskin tumor has remarkable impact on the incidence of iBDC and eBDC in a highly endemic country. This article is protected by copyright. All rights reserved.
Entities:
Keywords:
Bile duct neoplasms; Cholangiocarcinoma; Epidemiology; Incidence; Klatskin tumor