EPIC: Smoking responsible for more incidence of hepatocellular carcinoma than chronic hepatitis

Trichopoulos D. J Natl Cancer Inst. 2011;doi:10.1093/jnci/djr395.

Chronic hepatitis B virus or hepatitis C virus remained the strongest risk factor for hepatocellular carcinoma, but results of a nested case-control study in Europe showed that 47.6% of hepatocellular carcinomas were associated with smoking.

Results from the European Prospective Investigation into Cancer and Nutrition (EPIC) study showed that 13.2% of hepatocellular carcinomas were associated with hepatitis B virus (HBV) while 20.9% were attributed to hepatitis C virus (HCV). Obesity (16.1%) and heavy alcohol intake (10.2%) were also major contributing factors.

"Although chronic infection with HBV and/or HCV was the strongest risk factor for hepatocellular carcinoma, tobacco smoking was responsible for more cases of hepatocellular carcinoma than either or both of these viruses in this population," the researchers said.

Using data collected from 1992 to 2006, representing 4.41 million person-years, researchers identified 125 patients with hepatocellular carcinoma and matched 115 of those patients with 229 control participants.

Seventeen (14.8%) of the patients with hepatocellular carcinoma had HBV compared with six (2.6%) of the control group. Twenty-six (22.6%) of experimental patients were HCV-infected compared with seven (3.1%) of control participants.

Obesity was associated with increased risk, especially among men; 31.3% of men in the study group were obese compared with 15.1% of men in the control group. Researchers did not observe a similar association for men with a BMI between 25 kg/m² and 30 kg/m².

Similarly, high alcohol intake appeared to be positively associated with hepatocellular carcinoma risk. Nearly one-quarter (23.5%) of patients in the study group were heavy drinkers vs. 11.4% of control participants. There was no evidence that moderate alcohol intake, coffee intake, educational level or physical activity were major contributing risk factors.

Writing in an accompanying editorial, Morris Sherman, MD, and Josep M. Llovet, MD, of the Mount Sinai School of Medicine, New York, said it was not surprising that HBV and HCV were significant contributing factors to the development of hepatocellular carcinoma. The unexpected finding was the importance of smoking when it comes to risk.

"What we should take away from this study is that among all patients with previously existing risk factors for hepatocellular carcinoma, smoking is a major contributing cofactor," they wrote. "We should be counseling our patients who have other risk factors for hepatocellular carcinoma to quit smoking. Of course, there are many other health reasons to stop smoking. Here is one more."

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