Chronic Hepatitis C Linked to Increased Risk of Kidney Cancer

SUMMARY: People with chronic hepatitis C virus (HCV) infection have double the risk of developing renal cell carcinoma, or kidney cancer, according to a study published in the April 2010 issue of Cancer Epidemiology, Biomarkers and Prevention. While the reason for this link remains unclear, the researchers recommended that clinicians should carefully monitor and follow up on signs of kidney problems in hepatitis C patients, and people newly diagnosed with kidney cancer should be tested for HCV.

By Liz Highleyman

Chronic hepatitis C is primarily a disease of the liver, but it can also contribute to problems elsewhere in the body. HCV infection has been linked to kidney disease in the past. Stuart Gordon from Henry Ford Hospital and Wayne State University School of Medicine and colleagues aimed to determined whether this was true specifically for renal cell carcinoma (RCC).

The investigators analyzed data from the large racially/ethnically diverse Henry Ford healthcare system in Detroit The study cohort included 67,063 participants who were tested for HCV between 1997 and 2006, and followed to monitor development of RCC until April 2008; about 5% were HCV positive. The researchers used the health system's cancer registry to identify patients diagnosed with kidney cancer.

Results

• 0.6% of HCV positive patients (17 out of 3057) developed renal cell carcinoma during follow-up, compared with 0.3% of HCV negative participants (177 out of 64,006).
• The RCC cases in HCV positive patients included 8 clear cell cancers, 6 papillary cancers, 2 mixed clear cell/papillary, and 1 undifferentiated.
• Among participants diagnosed with RCC, HCV positive patients were of a significantly younger average age than HCV negative patients (54 vs 63 years; P < 0.001).
• In a univariate analysis, the hazard ratio for developing RCC among HCV positive patients was 2.20.
• In a multivariate analysis that adjusted for other known kidney cancer risk factors including older age, male sex, black race, and chronic kidney disease, the hazard ratio for hepatitis C patients was 1.77, or a 77% increase in risk.
• Men were 2.4 more likely to develop RCC than women.
• African-Americans had about a 40% higher risk of developing RCC than other racial/ethnic groups.
• Each additional year of age increased kidney cancer risk by about 3%.
• Based on these findings, the study authors concluded, "Chronic HCV infection confers a risk for the development of RCC."

"The results of this study would suggest a more careful surveillance of newly diagnosed RCCs for the presence of HCV infection," they advised. "It is premature to recommend more comprehensive screening of HCV positive patients for this relatively uncommon neoplasm. However, a heightened awareness of an increased kidney cancer risk should dictate more careful follow-up of incidental renal defects when detected on imaging procedures in patients with chronic hepatitis C."

"These results add to growing literature that shows that the hepatitis C virus causes disease that extends beyond the liver, and in fact most of our HCV-infected kidney cancer patients had only minimal liver damage," Dr. Gordon said in a press release issued by Henry Ford Hospital.

Investigator affiliations: Division of Gastroenterology and Hepatology, and Departments of Urology and Biostatistics and Research Epidemiology, Henry Ford Hospital, Detroit, MI; Wayne State University School of Medicine, Detroit, MI.

7/6/10

Reference
SC Gordon, D Moonka, KA Brown, and others. Risk for renal cell carcinoma in chronic hepatitis C infection. Cancer Epidemiology, Biomarkers and Prevention 19(4): 1066-1073 (Abstract). April 2010.

Other Source
Henry Ford Health System. Hepatitis C Infection Doubles Risk for Kidney Cancer. Press release. April 6, 2010.

Source