Some cancer patients need hepatitis B virus screening before therapy

By Will Boggs MD

NEW YORK (Reuters Health) - Cancer patients who have hepatitis B virus (HBV) risk factors or anticipate therapy that could reactivate HBV should undergo HBV screening before their cancer therapy begins, according to an American Society of Clinical Oncology (ASCO) provisional clinical opinion (PCO) update.

"There are various hepatitis B screening strategies (such as screen all patients, or screen only high-risk patients) but little evidence to support one strategy over another," Dr. Jessica P. Hwang, from the University of Texas MD Anderson Cancer Center in Houston, told Reuters Health by email.

"Until strong evidence is available to support one particular strategy, ASCO recommends at least screening patients who are at risk for hepatitis B infection or who are about to receive high-risk cancer therapies, such as anti-CD20 monoclonal antibody therapy or stem cell transplantation," she said.

Dr. Hwang and a panel of other experts reviewed recent developments in therapy and reevaluated the earlier recommendation.

The updated opinion supports testing patients for HBV infection before starting chemotherapies such as anti-CD20 monoclonal antibodies and hematopoietic cell transplantation because these therapies can increase the risk of HBV reactivation in patients harboring the infection.

Patients should also undergo screening if they have such HBV risk factors as birthplace in a country with at least 2% HBV prevalence, household or sexual contact with persons with HBV infection, high-risk behaviors like intravenous drug use, or HIV infection.

The expert panel also recommends initiation of antiviral therapy to prevent HBV reactivation for patients about to receive immunosuppressive cancer therapy without delaying cancer therapy and continuation of antiviral therapy for 6 to 12 months after completing cancer therapy.

Cancer patients who neither have HBV risk factors nor anticipate cancer therapy associated with a high risk of HBV reactivation do not require HBV screening before initiation of cancer therapy, although two members of the panel supported universal testing for hepatitis B surface antigen (HBsAg) and selective testing for hepatitis B core antibody (anti-HBc).

"Additional research is needed to investigate and identify the HBV reactivation risk with regard to individual cancer therapeutic agents or regimens and among patients with solid tumors," according to the May 11 Journal of Clinical Oncology online report. "Stronger data, along with validated risk tools, are needed to determine optimal screening strategies before initiation of systemic cancer therapies."

"Meaningful and measurable health outcomes of patients with cancer and HBV infection need to be identified and systematically studied so that potential harms of over- as well as underscreening and treatment may be minimized," the panel concludes. "Future research is needed to identify optimal criteria to help clinicians in their decisions to start and stop antiviral prophylaxis."

"Patients with hepatitis B infection should be identified and carefully managed in order to provide optimal cancer care and prevent poor liver health," Dr. Hwang said. "I think that we need strong evidence from large, multicenter studies to determine the best hepatitis B screening and management strategies. This is going to take strong collaboration among oncology and hepatitis B experts, but I am confident that this will happen."

"The biggest challenge of implementation is that hepatitis B is simply not on the radar screen of most oncologists," Dr. Jordan Feld, from Toronto Western Hospital Liver Center, Toronto, Ontario, Canada told Reuters Health by email. "Because hepatitis B prevalence is low in the general population and reactivation does not happen universally even in those infected, many oncologists will never have seen a severe case in their practice. Unfortunately in many instances, screening only becomes a priority following a severe or even fatal case of hepatitis B reactivation."

"Hepatitis B reactivation is an entirely preventable and potentially very serious or even fatal complication of chemotherapy," he explained. "Prevention requires screening because most patients are asymptomatic and many are unaware of their infection."

"Universal screening, as suggested in the dissenting opinion in the PCO, would likely be a much more effective strategy and much easier to implement," Dr. Feld said. "Universal screening has also been shown to be the most cost-effective approach to this problem, due to the very low cost of the screening test and the gravity of a missed severe reactivation."

Dr. Sarah P. Hammond from Brigham and Women's Hospital's division of infectious diseases, Boston, told Reuters Health by email, "In the past concerns about the added costs and complexity of screening for HBV and the perception that HBV reactivation is a very rare event have been barriers to instituting screening in the oncology community. However, the present recommendations provide clear guidance on the appropriate screening tests and the patient population to be screened."

"More studies are needed to understand if universal screening of cancer patients for HBV infection is superior to the risk-based screening currently recommended," Dr. Hammond said. "In addition, with the advent of more targeted chemotherapy for solid tumors, further studies are urgently needed to better understand if antiviral prophylaxis versus prospective monitoring is best for surface antigen positive patients undergoing chemotherapy for certain solid tumor malignancies."

"Not only the high HBV screening rate but also the high antiviral prophylactic rate are important for the prevention of severe HBV reactivation as well as related events in HBsAg-positive patients undergoing chemotherapy," Dr. Hsien-Chung Yu, from Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, told Reuters Health by email.

In a study he and his colleagues conducted, he said, "by way of a computerized order entry-based therapeutic control system, near 100% HBV screening and 100% antiviral prophylaxis for HBsAg-positive patients achieved zero percent of severe HBV reactivation and related mortality irrespective of the types of chemotherapy."

"Setting a hospital-based strategy for both issues is truly important especially in a HBV endemic area," Dr. Yu said.

One coauthor reported owning stock in Bristol-Myers Squibb; one coauthor reported receiving institutional research support from Gilead Sciences, and one coauthor reported receiving institutional research support from Miltenyi and Neovii.

SOURCE: http://bit.ly/1HlAmNS

J Clin Oncol 2015.

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