EASL 2016: Hepatitis B Treatment Linked to Colorectal and Cervical Cancer

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People with hepatitis B who were treated with nucleoside/nucleotide antivirals did not have an overall higher rate of malignancies, but did show an increased incidence of colorectal and cervical cancer, underlining the need for regular screening, according to a study presented at the recent EASL International Liver Congress in Barcelona.

Antiviral therapy using nucleoside/nucleotide analogs such as entecavir (Baraclude) or tenofovir (Viread) is the mainstay of treatment for chronic hepatitis B. While these drugs can effectively suppress HBV replication during therapy, they usually do not lead to a cure, and thus are often taken for a prolonged period.

Grace Wong from the Chinese University of Hong Kong and colleagues analyzed the incidence of various malignancies among antiviral-treated hepatitis B patients compared to untreated patients.

Prior studies have produced conflicting evidence about whether long-term nucleoside/nucleotide analog therapy increases risk of various cancers, they noted as background. Entecavir, in particular, has been linked to cancer in animal studies.

The researchers conducted a retrospective cohort study using the database of the Hospital Authority, which manages Hong Kong's public hospitals. Using diagnostic codes, they identified 68,492 chronic hepatitis B patients diagnosed between 2000 and 2012. People with pre-existing malignancies at baseline, and those coinfected with hepatitis C, hepatitis delta, hepatitis E, or HIV were excluded.

The outcome of interest was incident or new malignancies other that hepatocellular carcinoma (HCC), a type of liver cancer known to be caused by hepatitis B virus (HBV). Participants were analyzed after a cancer-free "landmark period" of 2, 3, or 4 years after baseline, and followed until death, 7 years, or the end of the study in 2012.

Within this group, 44,949 participants were included in the 3-year landmark analysis. Of these, 4782 (about 11%) had been treated with nucleoside/nucleotide antivirals while 39,712 remained untreated. Demographics and laboratory biomarkers differed between the treated and untreated groups, so the groups were weighted to make them more similar. About 75% of the treated patients were men and the mean age was 46 years.

Results

"This large-scaled population-based study does not suggest an increased risk of all malignancies in [nucleoside/nucleotide analog]-treated chronic hepatitis B patients," the researchers concluded.

However, they recommended, "colorectal and cervical cancer screening should be offered to those with risk factors," and said that "the risks of colorectal and cervical cancers in [nucleoside/nucleotide analog]-treated female patients require independent confirmation."

"In light of these findings we strongly urge regular screening of these cancers to help prevent them from developing in patients taking [nucleoside/nucleotide] analog treatment," Grace stated in an EASL press release.

"This large-scale study determines an important link between [nucleoside/nucleotide] analog treatment and cervical and colorectal cancer," added EASL vice secretary Tom Hemming Karlsen. "The results are important and could change cancer surveillance and management of patients treated for hepatitis B."

6/3/16

Reference

GLH Wong, YK Tse, V Wong, et al. Incidences of All Malignancies in Patients with Chronic Hepatitis B Receiving Long-Term Oral Nucleos(t)Ide Analogue Treatment -- A Study of 45,299 Subjects. EASL International Liver Congress 2016. Barcelona, April 13-17, 2016. Abstract PS052.

Other Source

EASL. ILC 2016: Treatment for chronic Hepatitis B linked to increased rates of colorectal and cervical cancer. Press release. April 15, 2016.