More Oral Sex, More Oral Cancer

Studies from Maura L. Gillison and others found that oral sex is linked to HPV, even when many confounding variables (such as tobacco and alcohol, number of sexual partners, etc.) have been controlled. Recall that the human papillomavirus (HPV) is commonly spread via oral sex : HPV increases the probability of getting an oral cancer. This is true whether women practice oral sex on men or men practice oral sex on women.

Case-Control Study of Human Papillomavirus and Oropharyngeal Cancer

RESULTS

Certain kinds of sexual behavior were significantly associated with oropharyngeal cancer after adjustment for confounding variables (Table 2). The association with oropharyngeal cancer increased significantly with the number of vaginal-sex partners or oral-sex partners (P for trend = 0.002 and 0.009, respectively) and was markedly elevated among patients with a high lifetime number of such partners (Table 2). […]

To explore whether the association between sexual behaviors and oropharyngeal cancer could be explained by HPV-16 exposure, we reevaluated the associations using multivariate models after adjusting for HPV-16 L1 serologic status. … associations of sexual behaviors with oropharyngeal cancer became stronger when the analysis was restricted to patients with an HPV-16–positive tumor (Table 2). A high lifetime number of oral-sex or vaginal-sex partners, engagement in casual sex, early age at first intercourse, and infrequent use of condoms each were associated with HPV-16-positive oropharyngeal cancer (Table 2).

The association between HPV-16 exposure and oropharyngeal cancer was investigated among patients with varied use of tobacco and alcohol. The association was greatly increased among patients without a history of smoking or drinking who were seropositive for HPV-16 L1 (odds ratio, 44.8; 95% CI, 5.9 to 338.5) or had an oral HPV-16 infection (odds ratio, 43.7; 95% CI, 4.2 to 452.7).

We evaluated whether combined exposure to HPV and tobacco or alcohol further increased the odds that oropharyngeal cancer would develop. No evidence of synergy was found (Table 4, top): combined exposure to HPV and heavy tobacco and alcohol use was not additive (synergy index <1). Moreover, when the analysis was restricted to patients who were seropositive for the HPV-16 L1 protein, the odds of oropharyngeal cancer were not increased among heavy users of tobacco or alcohol (Table 4, bottom). By contrast, among patients who were seronegative for the HPV-16 L1 protein, the odds of oropharyngeal cancer were increased among heavy users of tobacco or alcohol, and the odds of oropharyngeal cancer were further increased among heavy users of both tobacco and alcohol (synergy index >1) (Table 4, bottom). […]

In the multivariate analysis, oropharyngeal cancer was independently associated with HPV-16 L1 seropositivity (odds ratio, 32.2; 95% CI, 14.6 to 71.3), poor dentition (odds ratio, 4.1; 95% CI, 1.6 to 10.6), infrequent toothbrushing (odds ratio, 6.9; 95% CI, 1.6 to 30.3), history of squamous-cell carcinomas of the head and neck in a first-degree family member (odds ratio, 5.4; 95% CI, 1.0 to 30.8), and heavy tobacco use (odds ratio, 2.5; 95% CI, 1.1 to 6.0) after adjustment for age, sex, and alcohol use. These factors were collectively estimated to be responsible for 90% of cases of oropharyngeal cancers (the attributable risk; 95% CI, 72 to 96), with 55% of cases (95% CI, 45 to 63) attributable to HPV-16 exposure alone. […]

To corroborate the in situ data, we tested for serum antibodies against HPV-16 oncoprotein E6, E7, or both, which have high specificity but moderate sensitivity for the detection of invasive cancer associated with HPV-16. 26 Such antibodies were found in 64% of the case patients and in 4% of the control patients (odds ratio, 58.4; 95% CI, 24.2 to 138.3; P<0.001) (Table 2).

DISCUSSION

Although HPV-16 alone accounts for more than 90% of cases of HPV-positive squamous-cell carcinomas of the head and neck, 8 a more accurate and probably higher proportion might be found by testing for other types of HPV (e.g., types 18, 31, 33, and 35), which are infrequently detected in oropharyngeal cancers. […]

The public health implications of our findings are underscored by the annual increases in the incidence of tonsillar and base-of-tongue cancers in the United States since 1973. 36, 37 The widespread oral sexual practices among adolescents may be a contributing factor in this increase. 38

Other studies tell us that oral cancer is often discovered when it is too late. The incidence of HPV-16 has increased dramatically over the last decades, although people with HPV do not necessarily develop oral cancer, and it affects men more often than it affects women.

Study Cites Increase in Cancers From HPV

Researchers tested tumor samples from 271 patients with certain types of throat cancer diagnosed from 1984 to 2004. The [HPV type 16] virus was found in only 16 percent of the samples from the 1980s — but in 72 percent of those collected after 2000.

Oral Cancer Facts : Rates of occurrence in the United States

Often oral cancer is only discovered when the cancer has metastasized to another location, most likely the lymph nodes of the neck. Prognosis at this stage of discovery is significantly worse than when it is caught in a localized intra oral area. Besides the metastasis, at these later stages, the primary tumor has had time to invade deep into local structures. Oral cancer is particularly dangerous because in its early stages it may not be noticed by the patient, as it can frequently prosper without producing pain or symptoms they might readily recognize, and because it has a high risk of producing second, primary tumors. This means that patients who survive a first encounter with the disease, have up to a 20 times higher risk of developing a second cancer. This heightened risk factor can last for 5 to 10 years after the first occurrence. There are several types of oral cancers, but around 90% are squamous cell carcinomas. It is estimated that approximately $3.2 billion is spent in the United States each year on treatment of head and neck cancers. (2010 numbers)

FACTS about HPV

HPVs, also called human papillomaviruses, are a group of more than 150 related viruses. More than 40 of these viruses can be easily spread through direct skin-to-skin contact during vaginal, anal, and oral sex. Some types of HPV can cause genital warts. Other types can cause cancers of the penis, anus, or oropharynx (back of the throat, including base of the tongue and tonsils.) HPV types 6 and 11 cause 90 percent of all genital warts.

[…] Types 16 and 18 are responsible for about 70 percent of all cases of cervical cancer (1). HPV also causes anal cancer. 85 percent of all anal cases are caused by HPV-16. Close to half of vaginal, vulvar, and penile cancers are caused by HPV types 16 and 18 (2). Its only recently, HPV infections have been found to cause cancer of the oropharynx, which is the middle part of the throat including the soft palate, the base of the tongue, and the tonsils.

In the United States, more than half of the cancers diagnosed in the oropharynx are linked to HPV-16 (3). Oral HPV infection is more common among men than women, explaining why men are more prone than women to develop an HPV related head and neck cancer. […]

About 1 percent of the population had an HPV 16 infection, with it being five times more common in men than women, correlating with the higher incidence of HPV-related cancer in men than women. … Patients infected with oral HPV type 16 have a 14 times greater risk of developing one of these cancers.

Oral HPV More Common in Men Than Women

Over all, 10.1 percent of men were infected orally with HPV of one type or another, compared with 3.6 percent of women. The reason for the higher rate among men was unclear. The men in the study tended to have higher numbers of sexual partners than the women, but statistical analyses showed that this accounted for 16 percent of the difference in virus prevalence. One line of speculation was that hormonal differences in women might play a protective role, or that oral sex on women for some reason causes a greater likelihood of transmission.

One-Third of Women With Only One Sexual Partner Contract HPV Within a Year, Study Finds

Nearly one-third of college-aged women who have had just one sexual partner contracted human papillomavirus within one year of becoming sexually active, according to a study to be published this week in the Journal of Infectious Diseases, the Canadian Press/CBC News reports.

For the study, Rachel Winer of the University of Washington and colleagues followed 125 women ages 18 to 22 who had not had sex previously or who first had sex with one male partner in the three months prior to the beginning of the study. The women were asked to keep diaries of their sexual activities and to estimate how many sexual partners their partners had had. The women also underwent a gynecological exam every four months. Researchers stopped collecting data from women who reported beginning a sexual relationship with a second partner.

One-third of the women had become infected with HPV within one year of starting their first sexual relationship, and 50% of the women were infected with HPV three years later, despite the fact they’d still only had a single sexual partner, the study found. The study also found that the rate of HPV was higher among women who estimated that their partners had had at least two previous sexual partners. […]

Winer said the study, which was funded by the National Institute of Allergy and Infectious Diseases, “shows that even just with one partner there’s a high risk of infection.” She added that HPV is “different” from other sexually transmitted infections “in that it’s just very common among everyone who’s having sex. So even just being exposed to one partner makes you susceptible to infection,” she said.

Another striking finding, from Gillison again, is that open-mouthed kissing is linked to oral HPV, even when oral sex is held constant :

“French” kissing ups risk of oral HPV infection

Similar risk factors applied to the college-aged men. For them, having at least six recent oral sex or open-mouthed kissing partners were independently associated with increased odds of developing oral HPV infection.

For the 28 percent of college-aged men who reported never having performed oral sex, having at least 10 lifetime or at least five recent open-mouthed kissing partners was associated with a significantly higher risk of developing oral HPV infection.

Like any other cancers, oral cancers are rare, especially HPV-related oral cancers, but the fact that the “rates of HPV-related throat cancer had risen 225 percent in the previous 16 years” is of great concern. My guess is that this poison called ‘sexual revolution’ is very likely to account much for this increase of HPV-16 prevalence over the last decades. Anyway, this is probably a sad news for white men, but not for asian men. Asians certainly do not think much, if any, about sex. But the contrary is true for white men who generally speak and think about sex virtually all the time : “the median number of young men’s thought about sex stood at almost 19 times per day”.

I found here a laughable comment : “Oh no, hope my girlfriend doesnt read about this”. I would not be surprised if men are much more skeptical than women about these studies but I hope that most men do not think that way. At this point, women should pass this information on.

More about cancer :
Risk: The Science and Politics of Fear – Chapter 10, The Chemistry of Fear

2 comments on “More Oral Sex, More Oral Cancer

  1. Luke Lea says:

    The good news is that oral cancers from oral sex are not nearly as lethal as the other kind (90 percent survival vs. 50 percent my oncologist at Vanderbilt told my last year).

  2. 猛虎 says:

    Luke Lea,

    “90 percent survival vs. 50 percent my oncologist at Vanderbilt told my last year”

    If “oral cancer is only discovered when the cancer has metastasized” this means that your likelihood of survival is weak. The last stage of any cancer (i.e., stage 4) is usually known to be fatal, because the tumor is spread throughout the body.

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