CHICAGO — A high degree of concordance of oral human papilloma virus infection between HPV-positive patients with oropharynx cancer and their sexual partners suggests that partners are at high risk for HPV-related disease, according to a study from the University of Texas M.D. Anderson Cancer Center in Houston.
Investigators reported that HPV was transmitted between HPV+ patients with oropharynx cancer and their sexual partners at a rate approaching 70%. Almost 60% of these cases involved HPV 16, a causative agent in head and neck squamous cell carcinoma, specifically tonsil cancer, as well as in most cervical malignant and premalignant conditions.
"There was a high rate of human papilloma virus transmission between oropharynx cancer (OPC) patients with HPV+ mouth swabs and their spouses or partners," commented first author Dr. Vassiliki Papadimitrakopoulou, a professor in the department of thoracic/head and neck medical oncology at M.D. Anderson. The study was presented as a poster at the annual meeting of the American Society of Clinical Oncology.
Human papilloma virus transmission between sexual partners is well documented in cervical cancer, but not in head and neck squamous cell carcinoma. Investigators thought that information on transmission could help define a population that would benefit from heightened cancer screening and vaccination.
"HPV-related OPC occurs in a younger group of patients than does the tobacco-related squamous cell cancer of the head and neck," noted Dr. Anne Tsao, the study's principal investigator from the same department at M.D. Anderson.
The authors used mouth swabs to gather DNA from 454 individuals, comprising 227 pairs of oropharynx cancer patients and their partners. Samples from 200 patient-partner pairs yielded adequate DNA for analysis, and this was the minimum required to meet the study’s planned accrual.
In situ hybridization and/or p16 immunohistochemistry detected HPV in 84 (86%) of 98 patients, for whom complete information on HPV status in tumor tissue was available at the time of the presentation. Not all of these cases resulted in positive mouth swabs, however.
Of the 200 patient-partner pairs, only 39 pairs (20%) had one or both members with a mouth swab testing positive for HPV. In 28 of these 39 pairs (72%), the mouth swab was positive in patients, and in 19 of these 28 (68%) the partners also had positive mouth swabs. The investigators reported 100% concordance for at least one human papilloma virus genotype in these 19 pairs, confirming that the virus had been exchanged between the partners; 58% of transmission cases involved HPV-16.
In 11 of the 39 pairs, the patient with oropharynx cancer tested negative for HPV, whereas the partner tested positive.
Regardless of HPV status as determined by mouth swabs, 30% of female partners but none of the men in the study reported a history of HPV-related disease. The investigators observed that this generates a hypothesis "that HPV affects the cervix at an earlier age than it does the oropharynx, and that gender may have a role in oncogenic susceptibility and/or chronic transmission of the virus." The data "encourage" screening of female partners and HPV+ female patients for cervical abnormalities, they advised.
"We recommend increased screening of partners of human papilloma virus positive patients in general," said Dr. Papadimitrakopoulou. She cautioned, however: "We don't know that the mouth swab is an adequate screening method."
In a discussion of the study, Anil Chaturvedi, D.V.M., Ph.D, an investigator at the National Cancer Institute, observed, "We know that oral HPV infection is a strong cause of a subset of head and neck cancers [but] very little is currently known about the molecular epidemiology of human papilloma virus infections ... [this study] showed that oral human papilloma virus infection was highly concordant among human papilloma virus-positive patients and their partners. The study underscores the partner population as an ideal high-risk population to perhaps investigate the presence of a premalignant lesion."
Dr. Chaturvedi also expressed concern about the low sensitivity of mouth swabs as a test for HPV, however. "I'd like to note a potential limitation of this particular study, which relates to the low sensitivity of mouth swabs in detecting oral HPV infection, as evidenced by the low percent positive agreement between tumor HPV status and the presence of HPV in oral swabs," he said.