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 threefold 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.”
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 twofold 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 threefold (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.
Mahale P et al. Association between hepatitis C virus and head and neck cancers. J Natl Cancer Inst 108(8): djw035. DOI:10.1093/jnci/djw035 (2016).