Published online May 15, 2023. doi: 10.4251/wjgo.v15.i5.843
Peer-review started: November 5, 2022
First decision: February 2, 2023
Revised: February 16, 2023
Accepted: March 15, 2023
Article in press: March 15, 2023
Published online: May 15, 2023
Intraductal papillary neoplasm of the bile duct (IPNB) is a rare distinct subtype of precursor lesions of biliary carcinoma. IPNB is considered to originate from luminal biliary epithelial cells, typically displays mucin-hypersecretion or a papillary growth pattern, and results in cystic dilatation. According to the 2010 World Health Organization classification of tumors in the digestive system, IPNB is defined as the biliary counterpart of intraductal papillary mucinous neoplasm of the pancreas (IPMN) and has identical histopathologic pancreaticobiliary, gastric, intestinal, and oncocytic features. There are still several important differences between IPMN and IPNB exist, unlike invasive IPMN and traditional cholangiocarcinoma in the biliary tract, very little is known about the clinicopathological features and prognostic variables of invasive IPNB.
The epidemiology, tumor characteristics, treatment strategy, and long-term results of invasive IPNB are limited because of the relatively low case numbers.
We conducted a Surveillance, Epidemiology, and End Results (SEER) database evaluation of invasive IPNB to address these shortcomings, and to further elucidate the epidemiological and clinical trends to guide treatment decision-making and to identify further clinical and scientific research areas.
Invasive IPNB, IPMN, and traditional cholangiocarcinoma data for affected individuals from 1975 to 2016 were obtained from the SEER database. Annual percentage changes in the incidence and incidence-based (IB) mortality were calculated.
The incidence and IB mortality of invasive IPNB showed sustained decreases. Similar decreases in incidence and IB mortality were seen for invasive IPMN but not for traditional cholangiocarcinoma. Both overall survival (OS) and cancer-specific survival (CSS) for invasive IPNB were better than for invasive IPMN and traditional cholangiocarcinoma. The most common tumor sites were the pancreaticobiliary ampulla (47.9%) and perihilar tract (36.7%), but the mucin-related subtype of invasive IPNB was the main type, intrahepatically (approximately 90%). In the univariate and multivariate Cox regression analysis, age, tumor site, grade and stage, subtype, surgery, and chemotherapy were associated with OS and CSS (P < 0.05).
Current population-based study revealed a gradual decrease in the incidence and IB mortality rates of invasive IPNB in the United States population during 1975-2016. The prognosis of invasive IPNB was not only regarding tumor grade and SEER historic stage, but also for different sites and tumor subtypes. Surgery and chemotherapy are associated with improved invasive IPNB outcomes; individuals who do not undergo surgery have the highest risk of death.
The inspiration of this article is that we found a rare case of hepatic mucoidepidermoid carcinoma (HMEC) in our cancer research center, and found that the malignancy mucinous carcinoma in liver including IPNB, mucinous cystadenocarcinoma and adenosquamous carcinoma. So in our future research direction, we will analyze IPNB cases’ tissues from our center by the next generation sequencing, combined with our published article to analyze the relationship between IPNB and HMEC.