By
Liz Highleyman
The
immune system is able to naturally suppress HBV in many people
with normal immune and others are apparently cured with successful
antiviral treatment. But a low level of virus can remain in
the body and become active -- or reactivate -- if the immune
system is weakened, for example due to HIV infection or use
of immunosuppressive drugs to treat cancer.
The U.S. Centers for Disease Control and Prevention (CDC)
in 2008 recommended routine hepatitis
B screening-- that is, testing for hepatitis B surface
antigen (HBsAg), hepatitis B core antibodies (anti-HBc), and
hepatitis B surface antibodies (anti-HBs) -- for "persons
receiving cytotoxic or immunosuppressive therapy" such
as chemotherapy for malignancies.
The ASCO opinion takes a less aggressive approach due to lack
of data showing benefits of routine testing.
"The evidence is insufficient to determine the net benefits
and harms of routine screening for chronic HBV infection in
individuals with cancer who are about to receive cytotoxic
or immunosuppressive therapy or who are already receiving
therapy," the opinion states.
"Individuals with cancer who undergo certain cytotoxic
or immunosuppressive therapies and have HBV infection or prior
exposure to HBV may be at elevated risk of liver failure from
HBV reactivation," the statement continues. "As
such, HBV screening requires clinical judgment. Physicians
may consider screening patients belonging to groups at heightened
risk for chronic HBV infection or if highly immunosuppressive
therapy is planned."
Highly immunosuppressive treatments include bone marrow stem
cell transplants and chemotherapy regimens that include rituximab
(Rituxan).
If screening is deemed appropriate for an individual patient,
the opinion recommends testing for HBsAg as a serologic marker
for HBV infection. "In some populations, testing for
anti-HBc should also be considered," according to the
statement. However, "[t]here is no evidence to support
serologic testing for anti-HBs in this context."
When evidence of chronic HBV infection is detected, "antiviral
therapy before and throughout the course of chemotherapy may
be considered to reduce the risk of HBV reactivation, although
evidence from controlled trials of this approach is limited,"
the opinion adds. But "[s]creening and/or treating HBV
infection should not delay the initiation of chemotherapy."
The ASCO opinion is subject to controversy. In addition to
the CDC, the American Association for the Study of Liver Diseases
(AASLD) and Memorial Sloan-Kettering Cancer Center also recommend
routine HBV screening before immunosuppressive chemotherapy.
A
retrospective review from Memorial Sloan Kettering Cancer
Center, presented by Emmy Ludwig at the 2010 ASCO annual meeting
last month, found 23 documented cases of HBV reactivation
in cancer patients on immunosuppressive therapy in the prior
3 years at that center, resulting in 19 hospitalizations,
4 deaths, 4 clinically significant delays in cancer treatment,
and 1 liver transplant. But in the nearly 1 year since HBV
screening was implemented, with entecavir
(Baraclude) treatment for those who test positive, there
have been no cases of reactivation.
7/13/10
References
AS
Artz, MR Somerfield, J Feld, and others. American Society
of Clinical Oncology provisional clinical opinion: chronic
hepatitis B virus infection screening in patients receiving
cytotoxic chemotherapy for treatment of malignant diseases.
Journal of Clinical Oncology 28(19): 3199-3202 (Abstract).
July 1, 2010.
RB
Mendelsohn, S Nagula, Y Taur, E Ludwig, and others. Reactivation
of chronic hepatitis B virus in cancer patients receiving
immunosuppression: The case for screening. American Society
of Clinical Oncology Annual Meeting. Chicago, June 4-8, 2010.
Abstract 9088.
Other Source
Zosia
Chustecka. Screening Cancer Patients for Hepatitis B: Should
it Be Routine? Medscape (www.medscape.com).
June 24, 2010.
