Hollywood actor, producer, director, and disease epidemiologist Michael Douglas made news Sunday by settling a puzzle that has dogged cancer specialists for more than a decade. He pronounced that his oral cancer, diagnosed three years ago, was caused by cunnilingus.
With the dispatch, he has pushed the field forward, backward, and every which way in a manner that may be difficult to recover from. Only recently, a solid association had been established between certain types of head and neck cancer and the human papilloma virus (HPV), already well accepted as the cause of cervical cancer, the disease prevented so successfully by the Pap smear. And similar to Douglas’s view of the problem, scientists presenting their findings typically have been met with headlines about oral sex, not the changing epidemiology of a concerning disease.
The basics are fascinating and more than a little alarming. For decades, head and neck cancers were found mostly among older men—and not just any men, but those who were serious drinkers and smokers. In the years of the observations, of course, drinking and smoking were, for the most part, a man’s redoubt. Women hadn’t come a long way, baby, to become addicted to tobacco until relatively recently. And it seemed that alcohol and tobacco worked together in toxic synergy to produce the malignancy.
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But a decade or two ago, the groups at risk for the disease and, as important, the anatomic site of the cancer changed drastically. No longer were drinkers and smokers the ones with the disease but rather abstemious folks—and younger ones, at that—who never had spent time detoxing or trying to kick the habit. Furthermore, the tumor arose from tonsils and the base of the tongue, once rare sites of cancer development, not the oropharynx, as was seen in the old-school version. Next came important work associating HPV with most of these new tongue and tonsil tumors. Articles going back to the 1990s found the first hint, then important subsequent work brought the connection front and center into wide acceptance.
Given the known association between cervical cancer and HPV, and the knowledge that HPV moved from man to woman via vaginal intercourse, as well as the increasing number of cases HPV-triggered rectal and anal cancers among gay men, the notion that HPV-related oral cancer is transmitted by oral sex has a certain surface logic.
Yet there are several problems with the assumption. First is the sex distribution of the cancers. Though the risks for the new oral cancer and its anatomic location have changed fundamentally, one epidemiologic fact has not. It’s still a guy’s disease, by about 3 to 1, same as ever. That raises the next point. Though The Daily Beast is a wholesome family website, one is compelled to make the following indelicate comment: it might be suggested that the introduction of HPV from a turgid penis to a tonsil or to the back of the tongue (cf., Deep Throat) is decidedly more efficient than movement of the same HPV off the female cervix, which no tongue engaged in cunnilingus ever could reach, or just the plain old vagina, then uphill along the 3 or 4 inches from tip of tongue to its base or to the nearby tonsils. This is a mighty far distance for a virus to travel.
Plus, to remain in an indelicate vein, might one assume that the approximate rate of cunnilingus approaches that of fellatio? A three-to-one distribution just doesn’t seem true. Yes, homosexual sex may tip the balance one way or the other, but shouldn’t this be more or less an even tradeoff in a free and democratic America?
That brings us to the usual problem: cancer epidemiology is extremely complex. Something other than exposure is favoring development of the disease in men—perhaps other exposures, perhaps something to do with the hard-luck XY chromosome pair. And what about the fact that HPV is found so commonly in the mouth of people, yet oral cancers remain so rare; clearly more is at work than one virus transmitted by oral sex a generation ago.
Seldom is there a clear-cut smoking gun when one is looking for the cause of a disease—and oral cancer is just such a case in point. Yes, indeed, sexual behavior is at the center of oral HPV, and oral HPV drives a large proportion of the new wave of oral cancers, though let’s not forget the still ongoing old-fashioned cancers related to cigarettes and alcohol. However, which sexual activity is the risky one remains uncertain. In the largest study to date, which brought together all available smaller studies, the authors found that the lifetime number of sex partners conferred as much risk for oral cancer as does oral sex. They also noted that between 8 percent and 40 percent of patients with HPV-associated cancers reported no previous oral sex at all. Other studies have found that early age with loss of virginity is a risk.
So, yes, sexual activity of some sort is a risk, but that’s the most that can be said. It is manly, I suppose, at least in a Hollywood way—or at least interesting PR—to cop to the cunnilingus charge. But the story, like so much that touches the silver screen, is just close enough to a truth to grab a headline and just far enough away to drive experts insane.
Douglas’s announcement, though, will cause a great deal more good than harm by bringing attention both to the signs and symptoms of oral cancer, as well as to prevention of the viral infection, HPV, that causes the cancer. As I previously have written, some strains of HPV, including strain 16, which causes the majority of HPV-associated oral cancers, can be prevented by the newly available vaccine. The trick is to give it to your kid before he or she enters the sexual world—once acquired, HPV is for life and is not weakened by subsequent vaccination. Pre-teens and early teenagers should receive the three-shot series, and at an age much younger than any parent is comfortable accepting. Disease prevention with vaccines—now that’s something that epidemiologists from the CDC to Hollywood all can agree upon.
