Infection with
hepatitis C virus (HCV) is associated with an increased risk of head and neck
cancer (HNCs), investigators from the United States report in the Journal of the National Cancer Institute.
The risk of certain cancers was especially high for patients who were also
infected with human papillomavirus (HPV).
Overall, HCV was
associated with an almost three-fold increase in the risk of head and neck
cancers.
“Our results add
to the growing body of epidemiological evidence that HCV infection has extrahepatic manifestations and may well be associated with non-liver related
cancers,” comment the authors. “Clinicians should be aware that nonliver
cancers…can develop in patients chronically infected with HCV.”
Glossary
- extrahepatic
Something that has an
effect outside the liver, for example when viral hepatitis affects the kidneys
or causes depression.
- lymphoma
A
type of tumour affecting the lymph nodes.
Approximately 2.7
to 3.9 million individuals in the United States are chronically infected with
HCV. It is well known that HCV infection increases the risk of liver cancer and
it has also been associated with an increased risk of non-Hodgkin lymphoma.
In 2009,
clinicians from the National Cancer Institute established a centre specialising
in the treatment of cancers in patients with HCV. An unexpectedly large number
of cases of head and neck cancers were observed. Investigators therefore
designed a case-controlled study to determine if HCV infection increased the
risk of these cancers.
Records of
patients who received care at the clinic and who were tested for HCV between
2004 and 2014 were analysed.
Cases were
patients with head and neck cancers, including oropharyngeal and
non-oropharyngeal (oral cavity, nasopharynx, hyopharynx and larynx) cancers.
Controls were patients with smoking-related cancers (lung, oesophagus and
urinary bladder). Biopsy reports were obtained to see if cancers were positive
for HPV. Patients with lymphoma were excluded.
The study
population comprised 1103 patients: 409 cases and 694 controls.
Most patients were
male, white and were born between 1945 and 1965. Approximately half were current
smokers and 52% reported alcohol consumption at the time of cancer diagnosis.
Overall, 11% of patients had antibodies to HCV infection.
HCV prevalence was
higher among patients with oropharyngeal cancers (14%), particularly
HPV-related oropharyngeal cancers (17%) compared to controls (6.5%).
After adjustment
for age, sex, age, smoking and alcohol consumption, HCV was associated with a
more than two-fold increase in the risk of oropharyngeal cancers (OR = 2.04;
95% CI, 1.04-4.01). Separate analyses were then performed for HPV-related and
non-HPV-related oropharyngeal cancers. HCV was associated with an increased
risk of HPV-related cancers (OR = 2.97; 95% CI, 1.31-6.76) but not
non-HPV-related tumours (OR = 1.44; 95% CI, 0.39-5.30).
HCV prevalence was
also higher among patients with non-oropharyngeal cancers (20%) than controls
(6.5%).
After adjustment
for confounding factors, the investigators found that HCV increased the risk of
non-oropharyngeal cancers almost three-fold (OR = 2.85; 95% CI, 1.38-5.88).
Final analysis
showed that HCV was associated with a significant increase in the risk of non-oropharyngeal
cancers (OR = 3.17; 95% CI, 1.49-6.73) but not nasopharyngeal cancers (OR =
1.3; 95% CI, 0.22-7.64).
“HCV is
statistically significantly associated with not only non-oropharyngeal cancer
(except nasopharyngeal) HNCs but also with HPV-related oropharyngeal cancers,”
comment the investigators. “Oncologists treating patients with HNCs should
consider testing patients for HCV to enable early identification and linkage to
care for this disease to prevent progression of underlying liver disease.”
The authors
conclude that HCV appears to increase the risk of head and neck cancers. They
call for further research to validate their findings.