Is Oral Sex Really a Leading Risk Factor for Throat Cancer?

A recent op-ed points to oral sex as the leading risk factor for throat cancer. 

The claim came from Hisham Mehanna, PhD, a professor at the Institute of Cancer and Genomic Sciences at the University of Birmingham, in England. His op-ed published in The Conversation in April.

In the op-ed, Mehanna noted that “there has been a rapid increase in throat cancer in the west, to the extent that some have called it an epidemic.” Mehanna attributed the spike to a rise in a type of throat cancer called oropharyngeal cancer, which affects the tonsils and other structures in the back of the throat that make up the oropharynx.

“For oropharyngeal cancer, the main risk factor is the number of lifetime sexual partners, especially oral sex,” Mehanna wrote.

While you may have heard about a possible connection between oral sex and throat cancer, you might be wondering what’s behind this new claim—and whether it’s legitimate. Here’s what you need to know about the link between oral sex and throat cancer.

Is Oral Sex Really the Leading Risk Factor for Throat Cancer?

The leading risk factor for all throat cancer in most developed countries is human papillomavirus (HPV), Neil Gross, MD, director of clinical research in the Department of Head and Neck Surgery at MD Anderson Cancer Center in Houston, Texas, told Health.

HPV is a sexually transmitted infection that’s most often spread through vaginal and anal sex but can also spread through oral sex. The infection can cause oropharyngeal cancer, and cancers of the cervix, vulva, vagina, penis, and anus.

Though the overall risk of oropharyngeal cancer is quite low—men have a lifetime risk of 0.7%; women have a lifetime risk of just 0.2%—HPV is though to cause the majority (70%) of oropharyngeal cancer cases in the United States, according to the Centers for Disease Control and Prevention

“If you have oral sex partners with increasing numbers, you’re at an increased risk of having HPV infection of the throat,” Matin Imanguli, MD, DDS, a head and neck surgeon at the Rutgers Cancer Institute of New Jersey, told Health.

In his op-ed, Mehanna cited results from a 2007 study that found that people with six or more oral-sex partners are 8.5 times more likely to develop oropharyngeal cancer than those who do not practice oral sex.

For a 2021 study published in the journal Cancer, researchers compared people with and without oropharyngeal cancer. They found that having a history of five or more lifetime oral sex partners increased the odds of developing oropharyngeal cancer by 2.5-fold. A history of 10 or more lifetime oral sex partners increased the odds 4.3-fold.

Therefore, “oral sex is a recognized risk factor for human papilloma virus-mediated oropharynx cancers,” George Yang, MD, assistant member in the Section of Head and Neck and Endocrine Oncology at Moffitt Cancer Center, told Health. “Recent data has suggested that the number of sexual partners, number of oral sex partners, age at first episode of oral sex play a complex but important role in determining the amount of risk.”

 How Does HPV Cause Throat Cancer?

About 10% of men and 3% of women in the U.S. have oral HPV. Most people who contract the infection clear it within a few years, said Dr. Imanguli. However, it can spark a process that leads to the development of cancer in some people.

“Oral sex can cause exposure of the back of the throat—oropharynx—to high-risk/cancer-associated subtypes of HPV,” said Dr. Gross. “The most common type associated with this is HPV-16, and the lymph tissue in the back of the throat can develop cancer over time as a result of this infection.”

The development of cancer isn’t something that happens overnight, though. “HPV, when transmitted, can live dormant in cells for many years while the host immune system can keep it in check,” Electra Paskett, PhD, a professor and cancer prevention and control expert at The Ohio State University Wexner Medical Center, told Health. “Years later, the virus can wake and integrate into the cell’s DNA, causing the cells to mutate and develop into cancer.” 

This explains in part why oropharyngeal cancer is rising among older people. “They contracted the virus early in life and then it awakes and develops into cancer,” she said.

How Can You Reduce Your Risk of Throat Cancer?

Not performing oral sex is one way to prevent cancer-causing HPV. Because HPV is often asymptomatic, it can spread easily because many people don’t know they have it. 

Another effective way to reduce your chance of developing cancer is to get the HPV vaccine. Most people are eligible when they turn 9.

Although the vaccine has mostly been advertised as a way to lower the risk of cervical cancer, it can also protect against throat cancer. “If the HPV vaccine is administered before exposure to HPV, it can protect against infection with the high-risk strains associated with throat cancers,” said Dr. Yang. This includes HPV16, the subtype that accounts for a vast majority of cases.

You can also prevent throat cancer by making healthy choices, said Dr. Gross. In addition to HPV—and engaging in oral sex by association—other risk factors for oropharyngeal cancer include alcohol use, a history of smoking, excess body weight, and poor nutrition. “Avoiding risky behaviors, including tobacco and alcohol—except in moderation—are the best ways to avoid head and neck cancer, including throat cancer,” said Dr. Gross.