This article is more than 5 years old. Information may no longer be current.
Adolescent sexual behavior: a plea for HPV vaccination for prepubescent boys (as well as girls)
Click Here to Manage Email Alerts
Suspicion abounds that the same papillomaviruses — mainly HPV-16 — that cause virtually all cervical carcinomas are somehow also involved in the genesis of oropharyngeal squamous carcinomas.
Previous studies suggesting this association date back to 1995 and have been strongly supported by a great deal of recent virologic and molecular data. Particularly persuasive epidemiologic results published in The New England Journal of Medicine in May 2007 indicated that not only is HPV-16 DNA integrated in oropharyngeal tumor cell nuclei, but also that most assayed tumors produce specific HPV proteins.
In the 2007 study, the researchers at Johns Hopkins also report that tumors in nonsmokers are disproportionately infected with HPVs. Conversely, viral association is less apparent among heavy users of tobacco or alcohol — a group traditionally at high risk for developing these extremely nasty neoplasms. Moreover, the HPV-positive population is significantly composed of patients who have had multiple sex partners and who have engaged frequently in oral–genital relations.
These results possibly provide insight into the remarkable change in head and neck tumor demography noted during the past two decades. That is, an astonishing increase in tumor incidence is apparent in young adults aged 20 to 45 years — a group previously rarely affected. In parallel, adolescent sexual behavior has changed significantly, with a marked increase in oral–genital sex practices documented in sexually active youth.
If oral–genital (and perhaps oral–oral) transmission of this likely oncogenic virus underlies the epidemic of oral carcinomas, then should we not be vaccinating boys, as well as girls, with the new, highly-efficient HPV vaccine (Gardasil, Merck)? Of course we should, and this rather obvious proposition also has been suggested by the researchers in their article. However, to date the FDA has approved the vaccine only for women aged 9 and older. The three-shot vaccination course is expensive (approximately $360), so many states are providing the vaccine free — but only to girls.
At the American Society of Hematology meetings in December 2007, Dr. Gillison, a researcher of the 2007 study, was asked whether physicians have been informed of the rationale for all-gender protection. At present the answer is “no.” It defies all logic to treat only one sex for a sexually transmitted disease. Men are carriers of the virus that might be transmitted to unprotected women, and, in the case of homosexual men, to other men during anal relations. In fact, anal carcinoma, a virtually incurable tumor, is almost certainly caused by the same HPVs that promote cervical neoplasia.
At the same ASH symposium, an audience member reminded Dr. Gillison that tongue carcinomas are exceedingly common in certain dog strains; these tumors are induced by canine papillomaviruses, as are the even more common transient canine tongue warts. Intriguingly, I know of three nonsmokers with posterior tongue carcinomas who owned pet dogs that died of tongue cancers. To be sure, canine papillomaviruses are not identical to human papillomaviruses. However, recent genomic studies demonstrate that a major viral gene (L1) is, in fact, identical in both canine and human viruses. So far, no evidence that the canine virus can infect cultured human cells has been demonstrated, but the same could have been said for avian influenza viruses years ago. I suggest that physicians include questions related to pet exposure when taking histories from patients with oropharyngeal tumors. I would be most interested in correspondence from anyone who may have seen pairing of canine and human tongue carcinomas.
Dr. Jacob and I go back more years than either of us care to admit, all the way to being house officers on the Harvard Medical Service at Boston City Hospital. He also presently serves today as Chief Medical Editor of HemOnc Today, a sister publication of Infectious Disease News, both of SLACK Inc. I think readers will be interested in his views on HPV vaccine.
– Theodore C. Eickhoff, MD
IDN Chief Medical Editor
For more information:
- Harry S. Jacob, MD, practices internal medicine at the University of Minnesota.
- D’Souza G, Kreimer AR, Viscidi R, et al. Case-control study of human papillomavirus and oropharyngeal cancer. N Engl J Med. 2007;356:1944-1956.