By Robert Preidt
FRIDAY, Jan. 25, 2019 (HealthDay News) -- A large number of U.S. cancer patients with hepatitis B and C don't know they have the virus, which can cause life-threatening complications during some cancer treatments, researchers say.
The findings suggest screening for hepatitis B and C may be appropriate in community cancer clinics, according to investigators from the SWOG Cancer Research Network, an international group funded by the U.S. National Cancer Institute.
The study included more than 3,000 cancer patients across the United States who had a blood test to check for hepatitis and HIV.
The researchers found that 6.5 percent of the patients had past hepatitis B; 0.6 percent had chronic hepatitis B; 2.4 percent had hepatitis C, and 1.1 percent had HIV. That's similar to rates in the general U.S. population.
A large proportion of patients with past (87 percent) and chronic (42 percent) hepatitis B infections were undiagnosed prior to the study, as were as 31 percent of patients with hepatitis C, according to the report.
Rates of undiagnosed HIV were low -- 5.9 percent of patients with HIV were diagnosed through the study.
Many patients had no risk factors, such as injection drug use, for the infections, including: 27 percent with past hepatitis B; 21 percent with chronic hepatitis B; 32 percent with hepatitis C; and about 20 percent with HIV.
"While our results don't suggest that universal HIV screening is necessary for cancer patients, they do provide new evidence to inform a discussion in the oncology community about whether we should require hepatitis screenings," said Dr. Scott Ramsey, a SWOG investigator.
Ramsey is also director of the Hutchinson Institute for Cancer Outcomes Research in Seattle.
He said screening may be especially important in an age of immunotherapies for cancer because the treatments may affect patients' immune systems and alter the course of their viral infections.
"While we don't know much about the impact of immunotherapies on patients with cancer and hepatitis and other viral infections, oncologists should know as much as possible about the overall health of the people they treat," Ramsey said in a SWOG news release.
Joseph Unger, a SWOG biostatistician also based at the Hutchinson Institute, said chronic hepatitis B and C are a significant challenge because they affect millions of Americans, many of them with cancer.
"Testing cancer patients for these diseases could catch a lot of undiagnosed cases and help modify their cancer care to improve outcomes," Unger explained in the news release.
Ramsey is analyzing results of a separate SWOG study to determine whether universal hepatitis and HIV screenings of cancer patients would be cost effective.
The report was published online Jan. 17 in JAMA Oncology.