You probably know that human papillomavirus (HPV)—AKA the most common sexually transmitted infection (STI)—is the main cause of cervical cancer. But the most common cancer caused by HPV infection actually isn’t cervical. It’s throat cancer. And it’s on the rise, especially in men.
Researchers have just discovered that antibodies to HPV type 16, which is the type responsible for 70% of throat cancer cases in the United States, can develop in the body starting up to 40 years before a diagnosis of throat cancer, according to a study published in Annals of Oncology. That means you could spend literal decades with the HPV infection in your body, increasing your risk, before it becomes a deadly cancer. So why is this slow-growing disease so rarely caught in time?
While screening tests (like a Pap smear) can help catch HPV infections before they develop into cervical cancer, you may be shocked to learn there’s unfortunately no such test for throat cancer. In fact, by the time most people develop symptoms of throat cancer, it’s already quite advanced and therefore harder to treat. But could a test of these antibodies, like the one used in this study, be the answer to this life-threatening problem? Maybe.
"Investigating the range in time prior to diagnosis in which HPV antibodies develop is important to understand how many years an individual who tested positive would be at increased risk, and also gives important insight into the natural history of the disease,” said study author Mattias Johansson, Ph.D., a cancer epidemiologist at the International Agency for Research on Cancer in Lyon, France. “In this study we found that antibodies can, in some cases, develop several decades prior to diagnosis of cancer. If rates of throat cancer continue to rise in the future, this biomarker could provide one means to identify individuals at very high risk of the disease who may benefit from specific preventive measures."
In this particular study, researchers compared 743 throat cancer patients with a control group of 5,814 people without cancer. In the years before any of the participants were diagnosed with cancer, they had their blood samples tested for HPV-16 antibodies. HPV antibodies were present in only 0.4% of people in the control group but in 26.2% of people with throat cancer, although it was a greater problem in white patients (27.2% had antibodies before diagnosis, compared with 7.7% of black throat cancer patients). So what does that mean? Having HPV-16 antibodies in the blood was associated with a 98.2-fold increase in the risk of throat cancer diagnosis in white people and a 17.2-fold increase in black people.
So you might be wondering—why can’t we just use the antibody test they used in the study as a blood test to screen for HPV in the throat so we can stop it in its tracks before it turns into cancer?
"Although HPV-16 antibodies could be a way to identify people at very high risk of cancer, we are currently missing the critical next steps in the screening process,” explains Aimée Kreimer, Ph.D., senior investigator at the Division of Cancer Epidemiology and Genetics at the National Cancer Institute. “Also, even though the antibody marker was very good at discriminating between those who would develop cancer and the controls who would not, with such a rare cancer, many people would still be likely to have a false-positive results."
Researchers say they’ll focus future studies on figuring out the best way to follow-up with people who test positive for HPV-16 antibodies, along with looking into how to identify precancer in the throat, said Dr. Johansson.
“In other words, there is a long way to go before this biomarker can be used in clinical practice,” he said.
What You Can Do to Prevent HPV-Related Throat Cancer
Until such a screening test is developed (and then tested… and then made available to the public—which could take many years), there is one extremely effective way to prevent HPV-related cancer: Yep, it’s the HPV vaccine, which protects against nine high-risk, cancer-causing types of HPV, including HPV-16. Children should be vaccinated, ideally before they ever engage in sexual activity, for the most effectiveness, according to the CDC. However, if you’re older and never got the vaccine, you may still be able to get it and derive some protection from it. Talk to your doctor to see if that’s an option for you.
You can also reduce your risk of HPV infection by practicing safe sex, using a condom with each sexual act—and that includes oral sex, which is suspected to be the main cause of throat infections with HPV that lead to cancer. Dental dams are great, too.
And if you’re past the point where you can get the HPV vaccine and you’re worried about throat cancer, it’s wise to brush up on the symptoms. A painless lump in the neck that doesn’t go away, for example, is a sign you should head to the doctor for an evaluation. Thankfully, HPV-related throat cancer is easier to treat than throat cancers with other causes, like tobacco or alcohol use.