— Christine M. Kukka, Project Manager, HBV Advocate
New guidelines from the American Gastroenterological Association
make it crystal-clear that doctors must screen patients for HBV
infections before starting chemotherapy treatment, and they must use
antivirals to prevent HBV reactivation in those currently or previously
infected.
Despite clear evidence that immunosuppressive
drugs, which weaken the immune system, often cause HBV to reactivate
during cancer treatment, many doctors fail to screen patients for
infection prior to starting chemotherapy. As a result, an HBV infection
can reactivate, endangering the cancer patient’s fragile health.
“Preventing HBV reactivation in these patients
involves screening those at risk, identifying patients for risk based
on HBV (blood test results)... and consideration of prophylaxis
(preventive treatment) with (antivirals),” the report's authors
reported in the January issue of Gastroenterology.
Using recent studies, the authors attempted to
clarify which patients should be screened and which should receive
antivirals during chemotherapy to prevent HBV reactivation. They framed
the guidelines in a question-and-answer format.
Should all patients be screened for HBsAg and the hepatitis B core antibody before starting immunosuppressive drugs? Yes, especially if they are at moderate- or high-risk of hepatitis B.
However, doctors have historically been poor
predictors of hepatitis B risk in their patients. Many patients do not
disclose drug use or sexual behaviors that could place them at high
risk of HBV infection, and many doctors fail to test Asian-Americans
and other ethnic groups who are at high risk of infection because of
their countries of origin.
"...A cost-effectiveness study of HBV screening
in the general population showed that screening is cost-effective even
when the prevalence of HBV infection is as low as 0.3%," the experts
pointed out.
Are antivirals needed in HBsAg–positive patients who need chemotherapy? Absolutely, according to the guidelines, because the risk of reactivation is extremely high.
Are antivirals needed for HBsAg-negative patients who have inactive hepatitis B?
Yes. The guidelines recommend preventive antiviral treatment rather
than simply monitoring patients to see if their hepatitis B
reactivates. While the risk of reactivation is moderate in these
patients, the guidelines still promote preventive antivirals.
Are antivirals needed if previously-infected patients test positive for the hepatitis B surface antibody?
Researchers report HBV reactivation occurs in 4.3% of patients with
surface antibody, but because there are so few studies into this
subgroup of patients, the guidelines suggest doctors not use the
presence of surface antibodies when making a decision to use antivirals
during chemotherapy.
They should also not wait to see if viral load (HBV DNA) increases during chemotherapy before using antivirals.
Which antiviral should be used during chemotherapy?
Should doctors prescribe the cheaper, older antivirals such as
lamivudine (Epivir-HBV) that have high rates of drug resistance, or
should they use new, more potent and expensive drugs such as tenofovir
(Viread) or entecavir (Baraclude)? The guidelines suggest using the
newer, more potent antivirals to prevent the risk of drug resistance.
Despite the lack of studies into the role of
surface antibodies or viral load in assessing risk of HBV reactivation
during chemotherapy, "...the recommendations ... represent a rigorous,
evidence-based summary of extensive literature describing the
prevention and treatment of HBV (reactive-ation)," researchers
concluded. Reviewing these guidelines with patients, "...will facilitate
effective shared decision-making with patients at risk for HBV
reactivation," they concluded.
Source: www.gastrojournal.org/article/
S0016-5085
%2814%2901331-6/fulltext
http://www.hbvadvocate.org/news/HBJ12.3.htm
Labels: AGA Guidelines, screen before chemotherapy
