Aspirin use is associated with a reduced risk of cholangiocarcinoma: a systematic review and meta-analysis

Current Therapeutics in Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is an orphan, cholestatic liver disease that is characterized by inflammatory biliary strictures with variable progression to end-stage liver disease. Its pathophysiology is poorly understood. Chronic biliary inflammation is likely driven by immune dysregulation, gut dysbiosis, and environmental exposures resulting in gut-liver crosstalk and bile acid metabolism disturbances. There is no proven medical therapy that alters disease progression in PSC, with the commonly prescribed ursodeoxycholic acid being shown to improve liver biochemistry at low-moderate doses (15-23 mg/kg/day) but not alter transplant-free survival or liver-related outcomes. Liver transplantation is the only option for patients who develop end-stage liver disease or refractory complications of PSC. Immunosuppressive and antifibrotic agents have not proven to be effective, but there is promise for manipulation of the gut microbiome with fecal microbiota transplantation and antibiotics. Bile acid manipulation via alternate synthetic bile acids such as norursodeoxycholic acid, or interaction at a transcriptional level via nuclear receptor agonists and fibrates have shown potential in phase II trials in PSC with several leading to larger phase III trials. In view of the enhanced malignancy risk, statins, and aspirin show potential for reducing the risk of colorectal cancer and cholangiocarcinoma in PSC patients. For patients who develop clinically relevant strictures with cholestatic symptoms and worsening liver function, balloon dilatation is safer compared with biliary stent insertion with equivalent clinical efficacy.

Statins associate with lower risk of biliary tract cancers: A systematic review and meta-analysis

BACKGROUND

Biliary tract cancers (BTCs), encompassing cholangiocarcinoma (CCA), gallbladder (GBC), and ampulla of Vater cancers (AVC), are common hepatobiliary cancer after hepatocellular carcinoma with a high mortality rate. As there is no effective chemopreventive agent to prevent BTCs, this study aimed to explore the role of statins on the risk of BTCs.

METHODS

PubMed, Embase, and Cochrane Library from inception until 24 April 2020 were searched according to the Meta-Analyses of Observational Studies in Epidemiology (MOOSE) guidelines. The adjusted risk ratios (aRRs) of BTCs and individual cancer were pooled using a random-effects model.

RESULTS

Eight observational studies (3 cohort and 5 case-control studies) were included with 10,485,231 patients. The median age was 68.0 years (IQR: 67.0-71.5) and 48.3% were male. Statins were associated with a lower risk of all BTCs (aRR: 0.67; 95% CI: 0.51-0.87). The pooled aRR for CCA was 0.60 (95% CI: 0.38-0.94) and GBC was 0.78 (95% CI: 0.68-0.90). There was only one study on AVC with aRR of 0.96 (95% CI: 0.66-1.41). The pooled aRR for lipophilic and hydrophilic statins was 0.78 (95% CI: 0.69-0.88) and 0.70 (95% CI: 0.61-0.80), respectively. The effects were attenuated in studies that adjusted for aspirin and/or non-steroidal anti-inflammatory drugs (aRR: 0.80, 95% CI: 0.72-0.89) and metformin (aRR: 0.80, 95% CI: 0.72-0.90).

CONCLUSIONS

Statins, both lipophilic and hydrophobic, were associated with a lower risk of BTCs, particularly CCA and GBC.

Association Between Proton Pump Inhibitor Use and Biliary Tract Cancer Risk: A Swedish Population-Based Cohort Study

BACKGROUND AND AIMS

Biliary tract cancer is a group of highly aggressive malignant disorders, yet risk factors are poorly understood. In this study, we aim to assess whether prolonged use of proton pump inhibitors (PPIs) increases the risk of incident biliary tract carcinoma in a nation-wide population-based cohort in Sweden.

APPROACH AND RESULTS

Using nation-wide registries, we identified all adults who received maintenance PPIs (≥180 days) according to the Swedish Prescribed Drug Register from 2005 through 2012. Data on incident biliary tract cancer were retrieved from the Swedish Cancer, Death and Outpatient Registers. Risk of biliary tract cancer in persons who received PPI treatment was compared with the general population of the corresponding age, sex, and calendar year yielding standardized incidence ratios (SIRs) with 95% CIs. Of 738,881 PPI users (median follow-up of 5.3 years), 206 (0.03%) developed gallbladder cancer and 265 (0.04%) extrahepatic and 131 (0.02%) intrahepatic bile duct cancer corresponding to SIRs of 1.58 (95% CI, 1.37-1.81), 1.77 (95% CI, 1.56-2.00), and 1.88 (95% CI, 1.57-2.23), respectively. In sensitivity analyses restricted to persons without a history of gallstones or chronic liver or pancreatic diseases, SIRs were 1.36 (95% CI, 1.17-1.57) and 1.47 (95% CI, 1.19-1.80) for extra- and intrahepatic duct cancer, respectively. The risk remained higher than the corresponding general population with ≥5 years of PPIs use, ruling out confounding by indication.

CONCLUSIONS

In this study, long-term use of PPIs was associated with an increased risk of gallbladder, intrahepatic, and extrahepatic bile duct cancer compared with the general population.

A potential role for aspirin in the prevention and treatment of cholangiocarcinoma

Cholangiocarcinoma is the second most common primary hepatic cancer, with a rising incidence worldwide. Owing to late diagnosis and limited treatment options, the prognosis for cholangiocarcinoma remains dismal, compelling a search for new treatments. As aspirin exhibits a well-supported chemopreventive effect on common cancers, researchers have proposed using aspirin as a potential preventive and adjuvant agent for cholangiocarcinoma. In the present review of the literature, we provide a background on cholangiocarcinoma and potential mechanisms of action underlying the anticancer effect of aspirin. Although the exact mode of action remains unclear, multiple downstream effects of aspirin may interfere with cholangiocarcinogenesis, tumour growth and metastasis-including inhibiting the COX-2 pathway, preventing platelet aggregation and modulating certain proteins and signalling. This review also summarises evidence to support the chemopreventive effects of aspirin on common cancers, particularly colorectal cancer and discusses studies that report a positive outcome of aspirin in cholangiocarcinoma. Regular use of aspirin is associated with a reduced incidence of colorectal cancers as well as cholangiocarcinomas, and improved survival. Aspirin thus appears to play a role in the primary prevention and treatment of cholangiocarcinoma. However, further studies are needed to confirm these benefits and to establish a cause-and-effect relationship.

Cholangiocarcinoma 2020: the next horizon in mechanisms and management

Cholangiocarcinoma (CCA) includes a cluster of highly heterogeneous biliary malignant tumours that can arise at any point of the biliary tree. Their incidence is increasing globally, currently accounting for ~15% of all primary liver cancers and ~3% of gastrointestinal malignancies. The silent presentation of these tumours combined with their highly aggressive nature and refractoriness to chemotherapy contribute to their alarming mortality, representing ~2% of all cancer-related deaths worldwide yearly. The current diagnosis of CCA by non-invasive approaches is not accurate enough, and histological confirmation is necessary. Furthermore, the high heterogeneity of CCAs at the genomic, epigenetic and molecular levels severely compromises the efficacy of the available therapies. In the past decade, increasing efforts have been made to understand the complexity of these tumours and to develop new diagnostic tools and therapies that might help to improve patient outcomes. In this expert Consensus Statement, which is endorsed by the European Network for the Study of Cholangiocarcinoma, we aim to summarize and critically discuss the latest advances in CCA, mostly focusing on classification, cells of origin, genetic and epigenetic abnormalities, molecular alterations, biomarker discovery and treatments. Furthermore, the horizon of CCA for the next decade from 2020 onwards is highlighted.