I was surprised by this article - and rather dismayed. I hate posting negative news but I always think it is better to know. Of course, I happen to be a diabetic.....wouldn't you just know?
Diabetes Is Leading Cause of Attributable Cases of Hepatocellular Carcinoma
April 28, 2010 (Washington, DC) — Which risk factor for hepatocellular carcinoma (HCC) is associated with the largest proportion of cases of the disease in the United States?
If you answered hepatitis C (HCV), hepatitis B (HBV), or alcohol-related disease, you would be wrong.
The mistake is understandable. These risk factors have the highest odds ratios for HCC, and therefore put an affected individual at relatively higher risk of developing the disease than other factors, said Katherine McGlynn, PhD, from the National Cancer Institute (NCI), here at the American Association for Cancer Research (AACR) 101st Annual Meeting.
However, more cases of HCC overall are attributable to diabetes than any other risk factor, she said during a meeting press conference, where the results of the study were highlighted.
The impact of well known risk factors for HCC, such as hepatitis, "tends to be misinterpreted" because information on their incidence is not presented, Dr. McGlynn told reporters.
Also, "there is a perception that the majority of cases of the disease are not associated with a known risk factor," she said.
But the new study from Dr. McGlynn and colleagues from the NCI and Baylor College of Medicine in Houston, Texas, sheds light on the risk factors for HCC and their incidence.
They found that diabetes was associated with the greatest percentage of cases (33.5%), followed by alcohol-related disorders (23.9%), HCV infection (20.7%), HBV infection (5.7%), rare metabolic disorders (3.1%), and obesity (2.7%).
The findings conflict with conventional wisdom about HCC and its associated risks, said Dr. McGlynn.
Much of the hepatocellular carcinoma literature now states that HCV is 'the major risk factor.'
"Much of the hepatocellular carcinoma literature now states that HCV is 'the major risk factor for hepatocellular carcinoma in the United States'," she told Medscape Oncology.
Overall, approximately 63% of HCC was associated with 1 or more of these risk factors, indicating that 37% of cases are not explainable by the known risk factors.
Still, the new findings point to an important direction in the prevention of HCC.
"Overall, controlling diabetes might have a greater impact than any other single factor on reducing the incidence of hepatocellular carcinoma in the United States," the study authors conclude in their abstract.
The incidence of HCC has been steadily increasing in the United States, said Dr. McGlynn. The total incidence was about 1.59 per 100,000 person-years in 1975; by 2006, the total incidence reached 4.82 per 100,000 person-years, according to a graphic presented by Dr. McGlynn.
Mining the SEER–Medicare Database
In the study, the investigators reviewed data from the NCI Surveillance, Epidemiology and End Results Program (SEER)–Medicare linked database.
The case population consisted of 5607 people diagnosed with HCC who had at least 3 prediagnostic years of Medicare coverage between 1994 and 2005. The control population was a 5% random sample of people residing in SEER–Medicare locations.
For each HCC risk factor, odds ratios of an individual developing HCC were calculated.
They found that HCV infection was the risk factor with the highest odds ratio (44.26; 95% confidence interval [CI], 39.52 - 49.56). The odds ratio (95% CI) for HBV infection was 13.37 (10.53 - 16.97); for alcohol-related disease was 4.43 (4.14 - 4.74); for rare metabolic disorder was 3.51 (2.96 - 4.15); for diabetes was 2.37 (2.23 - 2.52); and for obesity was 1.53 (1.37 - 1.72).
The risk-factor percentages also varied by racial/ethnic group.
In terms of explainable risk factors, the investigators found that 67.9% of Asians with HCC had 1 or more of the identified risk factors, whereas only 53.5% of blacks had an identifiable risk factor. These 2 groups had the highest and lowest percentages, respectively; Hispanics (64.9%) and whites (62.9%) were in between.
The investigators also used the SEER–Medicare data to calculate the proportion of HCC cases attributable to the risk factors. As noted above, the order of risk factors was very different, with diabetes at the top of the list of attributable cases.
Are clinicians acutely aware that diabetes causes HCC?
"I think so," said Ernest T. Hawk, MD, MPH, vice president of the Division of Cancer Prevention and Population Sciences at the University of Texas M.D. Anderson Cancer Center in Houston. Dr. Hawk moderated the AACR press conference at which Dr. McGlynn spoke.
I suspect that primary care physicians may not know that persons with diabetes are at increased risk.
"It's well known that diabetes and overweight can cause hepatocellular carcinoma. They are in the list of causes in all medical textbooks. But they may be under a name like metabolic syndrome," he told Medscape Oncology.
However, Dr. McGlynn said that, compared with the other causes, diabetes and overweight have been associated with HCC only "more recently."
"I suspect that primary care physicians may not know that persons with diabetes are at increased risk of hepatocellular carcinoma," she said.
The authors have disclosed no relevant financial relationships.
American Association for Cancer Research (AACR) 101st Annual Meeting: Abstract 1816. Presented April 19, 2010.