VIENNA, Austria—Infection with hepatitis C virus (HCV) is known to increase the risk of liver cancer, but a study presented here at the International Liver Congress shows that the risk is also increased for other cancers as well. Overall, the crude risk of developing any cancer among patients with HCV infection was 2.33 times that of getting cancer if a person did not have the infection, reported Anders H. Nyberg, MD, a hepatologist at Kaiser Permanente Southern California in San Diego.
If hepatocellular cancer patients are taken out of the equation, the risk of all forms of cancer remains elevated—an 84 percent increased risk, the data showed. Not surprisingly, the risk of liver cancer is greatest—68 times higher among those with HCV infection—compared with those who do not have chronic infection, he said at a news conference. The meeting is sponsored by the European Association for the Study of the Liver
Specifically, the following increased rates were found for these cancers in people with HCV compared with those without the infection, Nyberg reported:
- Non-Hodgkin lymphoma: 3.59 times greater risk;
- Myeloma: 3.41 times greater risk;
- Renal cancer: 3.05 times greater risk;
- Stomach cancer: 3.03 times greater risk;
- Pancreatic cancer: 2.79 times greater risk;
- Head and neck cancer: 2.56 times greater risk;
- Esophagus cancer: 2.51 times greater risk;
- Lung cancer: 2.44 times greater risk;
- Prostate cancer: 2.05 times greater risk; and
- Colorectal cancer: 1.88 times greater risk.
The HCV cohort of patients had a higher rate of alcohol abuse, tobacco use, cirrhosis, and diabetes, and after stratification for alcohol abuse, tobacco use, body mass index, and diabetes, the increased cancer rates remained significant for total cancer sites, liver cancer, and non-Hodgkin lymphoma, he said.
“In the absence of alcohol abuse, tobacco use, and diabetes there was an increase in the rate of many cancer types among those with HCV. However, in the presence of those variables HCV had a more moderate effect on the cancer rates,” because of the overarching impact those risk factors have on cancer in general.
He said that when he analyzed each of the three areas that remained significant even with the risk factors, he was able to determine that tobacco use, alcohol abuse, and the presence of diabetes are significant risk factors for liver cancer in patients with HCV infection.
Tobacco, body mass index, and diabetes appear to be risk factors for all cancers, he said, but alcohol abuse did not appear to significantly influence cancer when looking at all sites of the disease.
Tobacco and diabetes appeared to significantly increase the risk of non-Hodgkin lymphoma in patients with HCV infection.
Possible Mechanisms of Action
Nyberg suggested several possible mechanisms by which cancer rates would be higher in patients with HCV infection, particularly the effects of chronic inflammation and its effects on oncogenes and tumor suppression genes: “We do not have any data that would suggest that patients who clear HCV would reduce their risk of cancer,” he told OT. “We think it probably would lower risk, but we don't know that. We could wait for those studies, but my preference would be to try to clear HCV now and not wait.”
The moderator of the news conference, Laurent Castera, MD, Vice-secretary of the European Association for the Study of the Liver and Professor of Hepatology at Hospital Beaujon of the University of Paris VII, commented: “This data adds to the evidence bank linking hepatitis C with an increased risk of cancer, and highlights that there is still a long way to go in order to fully understand this complex and devastating disease. If you smoke, if you drink, and if you are overweight you have a greater risk of developing cancer.”
Nyberg suggested that caution be used in interpreting the results. He said that the study strengths were the use of a large database in a real world population, but the retrospective nature of the study makes it difficult to establish a cause-and-effect relationship. Confounders may not be accurately recorded, and especially tobacco and alcohol use may be under-recorded.
“The take-home message from this study is that we need to work with our patients on lifestyle changes.”
The retrospective cross-sectional study, which was sponsored by Gilead Sciences, accessed data from Kaiser Permanente Southern California, a large health maintenance organization that includes about three million members. The researchers cross-linked the Kaiser database with the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) cancer registry to identify new cancer cases.
The study included adults with a diagnosis of chronic HCV by ICD-9 code or positive HCV RNA test between January 2008 and December 2012. Those with HIV and those with a history of organ or bone marrow transplantation were excluded.
The researchers identified 1,831 patients with chronic HCV infection who were also diagnosed with cancer. There were 33,881 patients with HCV infection who did not have cancer. There were also 5,297,191 patients in the study who did not have HCV infection.
The mean age of the HCV patients with cancer was 62.6; the mean age of chronic HCV patients without cancer was 59.4; and the average age of the non-HCV population was 71.9.
Men were more likely to have HCV and cancer—62.9 percent of that group were males; 59.3 percent of the patients with HCV but without a cancer diagnosis were men; and 49.1 percent of the non-HCV patient population were men.
About 47.6 percent of the patients with HCV and cancer were white; 23.2 percent were Hispanic; 19.6 percent were black. About 41.4 percent of the patients with HCV infection but no cancer were white; 28.5 percent were Hispanic, and 12.5 percent were black. In the general non-HCV population, those rates were 29.1, 35.2, and 7.8 percent, respectively.
“The people with HCV who develop cancer smoke and drink way more than the people who do not have cancer,” Nyberg noted.
Tobacco use was reported in 74.2 percent of the patients with HCV and cancer; 66.3 percent of the patients with HCV but no cancer, and 29.7 percent of the general non-HCV population studied.
About 18.3 percent of the patients with HCV and cancer said they had a history of alcohol abuse, as did 13.3 percent of the patients with HCV but no cancer, and 2.1 percent of the non-HCV infected population.
About 31.1 percent of the patients with HCV and cancer also had diabetes, as did 20.4 percent of the group with HCV but no cancer, and 7.4 percent of the group without HCV infection.
Cirrhosis was diagnosed in 71.7 percent of the patients with HCV infection and cancer; 34.7 percent of the patients with HCV but no cancer; and 6.7 percent of the population without HCV infection.