Strong link between diabetes and liver cancer

U. ROCHESTER (US) — People with high blood sugar are at greater risk of having advanced liver cancer at the time of diagnosis, which suggests diabetes may promote more invasive tumors.

A number of prior studies have shown various associations between diabetes and cancer in general. The connection makes sense, because of the liver’s regulation of sugars and longtime observations that people prone to liver failure are also are prone to diabetes. Several prior studies have also shown that cancer patients with diabetes often have worse outcomes; but the reasons why are not clear.

A new study published in Cancer Investigation links diabetes to distant metastasis in patients with hepatocellular cancer, a form of liver cancer usually found in people with liver cirrhosis.

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“Although our research is preliminary and based on a retrospective dataset, the findings are very interesting and hypothesis-generating,” says Gregory C. Connolly, senior instructor of medicine at the University of Rochester Medical Center.

“The association we detected suggests that patients with liver cancer and diabetes may have changes in cancer cell signaling that promote tumor invasiveness. The more we understand about the mechanisms at work, the more successful we’ll be at treating patients with both diseases.”

Connolly and colleagues looked at disease trends among 265 primary liver cancer patients diagnosed between 1998 and 2008. Of the total, they found that 34 percent had diabetes at the time of the cancer diagnosis. And among the diabetic group, 33 percent had liver cancer that had already spread to distant organs—compared to 9.7 percent of patients with advanced liver cancer who did not also have diabetes.

Moreover, the diabetic patients who took insulin had the highest rates of advanced cancer, compared to diabetics who managed their blood sugars through diet restriction or oral medications.

In the United States the incidence of diabetes mellitus (high blood sugar) has roughly doubled in the past 20 years. The rate of hepatocellular carcinoma, the most common form of liver cancer, has also risen steadily.

Most primary liver cancer is attributed to hepatitis or chronic alcohol abuse, but the National Cancer Institute reported in 2010 that diabetes is now associated with a greater percentage of liver cancer cases than any other factor.

Survival rates for advanced liver cancer are dismal. In the current study, 85 percent (or 237 people) died during the median follow-up period of 6.5 months. But patients without diabetes had a median survival time of 7.55 months versus 6.04 months for those who also had diabetes.

“Because the incidence of people with glucose intolerance and liver cirrhosis or primary liver cancer is so strong, it is imperative that we better understand the relationship so that these patients can be treated and managed in the best way possible,” says senior author Aram F. Hezel, assistant professor of medicine in hematology/oncology.

Source: University of Rochester