Several studies have shown that statin therapy reduces the risk of liver cancer. However, most of these papers come from countries with high incidence of liver cancer (Asian region). Now the relationship has been studied for the United Kingdom, a country with a low rate of disease. The survey should also clarify to what extent it plays a role whether the patient already has chronic liver disease and what influence diabetes might have on the association.
The basis for the case-control study was the United Kingdom’s Clinical Practice Research Datalink (CPRD) registry, from which they identified 1195 individuals with primary hepatocellular carcinoma (HCC) (disease between 1988 and 2011). These patients were matched 4:1 with 4640 matched control subjects without liver cancer.
50 percent risk reduction
About one-quarter each of the registry and control patients had been prescribed two or more statins before the index date. Statin use was associated with an overall statistically significant 45% risk reduction for liver cancer. Patients were considered “current users” if they were still taking statins within the year before the survey. They benefited the most (OR 0.53; 95% CI 0.42-0.66).
The association was shown when established risk factors for HCC such as hepatitis B and C infection, BMI, smoking status, or alcohol abuse were taken into account, and it remained significant even when the two parameters “pre-existing liver disease” and “diabetes” were added. For these two items, a significantly greater risk reduction was found with statin use if chronic liver disease (OR 0.32; 95% CI 0.17-0.57) or diabetes (OR 0.30; 95% CI 0.21-0.42) were present than if they were not (in the order above, OR 0.65 and OR 0.66, respectively). This is interesting because it was previously thought that the reduced risk of liver cancer with statins might also be related to the fact that fewer patients with pre-existing chronic liver disease are receiving statins – after all, statin-associated hepatotoxicities are known, even if such complications are rare overall. Since individuals with liver damage per se have a higher risk of liver cancer, this would have been a purely spurious association (the authors call it “confounding by contraindication”). Such doubts have now been refuted.
Also refuted is the assumption that protection applies only to Asians, in whom HBV infection is a more significant factor than in non-Asian populations.
High-risk patients benefit particularly
The results show that particularly high-risk patients, e.g. those with pre-existing liver disease and diabetes, benefit from statin administration. Here, the probability of HCC was reduced by a remarkable 70%. The exact reasons for this are currently still in the dark. The anticarcinogenic effect of statins could be due to inhibition of angiogenesis or even promotion of apoptosis.
Source: McGlynn KA, et al: Statin Use and Risk for Primary Liver Cancer in the Clinical Practice Research Datalink. J Natl Cancer Inst 2015; 107(4): djv009 doi: 10.1093/jnci/djv009.
InFo ONCOLOGY & HEMATOLOGY 2015; 3(7): 4.
