America's rising throat cancer cases: why more non-smokers are being diagnosed, the unexpected risk factors, and the warning signs dentists can miss

Throat cancer can grow quietly for years, and in some cases for decades, before any warning signs are noticed.

When symptoms do appear, they are often easy to dismiss: a lingering sore throat, trouble swallowing, a change in the voice, or a painless lump in the neck.

For a long time, the disease was mainly linked to older adults with a history of heavy smoking or drinking.

Now, as tobacco and alcohol use have fallen, doctors are seeing a different pattern.

More patients have no history of smoking, drink only modestly or not at all, and lack the classic risk factors once associated with the disease.

The sharpest increase has been seen in cancers of the tonsils and the base of the tongue, known as oropharyngeal cancer.

The main driver behind this shift is human papillomavirus, or HPV, a common sexually transmitted virus that most people are exposed to at some point in life.

HPV is now believed to cause about 60 to 70 percent of oropharyngeal cancers in the US.

Many people are diagnosed in middle age or later, even though the infection that eventually contributed to their cancer may have been acquired decades earlier.

Researchers are also examining whether aspects of modern life, including vaping, ultra-processed foods, air pollution and microplastics, may add to the risk of head and neck cancers, a broader category that includes cancers of the throat, mouth, nose and voice box.

So what explains America's changing throat cancer burden, who faces the greatest risk, and how can people lower their chances?

What is throat cancer, and how serious is it?

Throat cancer is not a single illness. It is part of the wider group of head and neck cancers, which can affect the mouth, throat, nose, sinuses and voice box.

Because these cancers arise in different places, their causes, treatment and survival rates can vary widely.

In the near future, an estimated 72,770 Americans are expected to be diagnosed with cancers of the mouth, throat or voice box, and about 17,110 are expected to die from them.

The prognosis depends heavily on how early the cancer is found. About 86 percent of patients whose oropharyngeal cancer is detected before it spreads beyond its original site survive at least five years, compared with just 40 percent of those diagnosed at an advanced stage.

Dr Selda Samakoglu, an oncologist at Aveta Biomics who specializes in head and neck cancer, said high-risk HPV strains can disrupt normal cell growth over time and lead to cancer of the tonsils or base of the tongue.

Research has also linked a greater number of oral sex partners with a higher risk of HPV-related throat cancer, although most people who encounter the virus never develop the disease.

One important protection is vaccination.

The HPV vaccine was introduced for girls in the US in 2006, and routine vaccination for boys began in 2011.

The effect has already been substantial.

Because HPV also causes nearly all cervical cancers, vaccination has been followed by an almost 80 percent drop in potentially cancerous changes in cervical cells among young American women.

There are also promising signs for throat cancer.

A recent US study of 1.4 million people found far fewer head and neck cancers among those who had received the HPV vaccine.

Experts say the full benefit may become clearer as vaccinated generations reach the ages when these cancers usually appear.

Dr Samakoglu said the vaccine's long-term impact should become easier to measure as those groups grow older.

Genes are not the whole explanation

Throat cancer can run in families, but inherited genes are thought to explain only a small share of cases.

Having a parent, sibling or child with head and neck cancer is linked to roughly a 70 percent higher risk of developing the disease yourself.

Scientists think genetic differences may make some people more vulnerable to environmental exposures by affecting how the body handles harmful substances and repairs damaged DNA.

Dr Samakoglu said genes can influence how the body responds to exposure.

Rare inherited disorders, including Fanconi anemia, can also greatly raise the risk of certain head and neck cancers by limiting the body's ability to repair DNA damage.

Smoking is falling, but vaping is a concern

Smoking has long been one of the leading causes of throat cancer.

Tobacco smoke contains many cancer-causing chemicals that damage the DNA in throat lining cells, allowing tumors to form over time.

But cigarette use has dropped sharply in the US, especially among younger adults.

At the same time, vaping has grown more popular, leading to concern that e-cigarettes could create a similar threat.

Unlike smoking, the long-term effects of vaping are still unclear. E-cigarettes have been widely used for only about two decades, so researchers do not yet know whether they increase throat cancer risk.

Still, early studies have raised alarms.

A recent review from researchers at the University of New South Wales found evidence that vaping can cause DNA damage, inflammation and other changes in cells lining the mouth and airways, all of which may contribute to cancer.

Some animal studies have also reported tumors after exposure to e-cigarette aerosols, though that does not prove vaping causes cancer in people.

Dr Samakoglu said researchers have found DNA damage in the mouth cells of people who vape, including those who never smoked.

She said it remains unknown how that might affect their long-term throat cancer risk.

Vapes heat liquid rather than burning tobacco, but that heating can create harmful chemicals such as formaldehyde, and metals from the device can enter the vapor people inhale.

Even though vaping usually exposes users to fewer harmful chemicals than cigarettes, experts caution that it is not risk-free.

Concern over ultra-processed foods

Researchers are also examining whether ultra-processed foods, which make up a large share of the American diet, might raise the risk of head and neck cancers.

A 2023 study of more than 450,000 people across Europe found that every 10 percent increase in the share of ultra-processed foods in a person's diet was associated with a 23 percent higher risk of head and neck cancer.

The same study found a 24 percent higher risk of esophageal adenocarcinoma, a cancer of the food pipe.

Interestingly, excess body fat accounted for only a small part of the association, suggesting other factors may be involved.

One theory is that additives and chemicals in processed foods, including emulsifiers and substances created during meat processing, could contribute to inflammation or cell damage.

But researchers have not shown that these foods directly cause head and neck cancers.

Dr Samakoglu said the link still needs to be understood more fully.

She added that the study points to an area worth closer investigation, but does not prove the foods caused the cancers, and other factors such as smoking and alcohol may explain some of the findings.

She also cautioned against assuming that all ultra-processed foods carry the same level of risk.

Microplastics and possible cancer risk

Another emerging concern is microplastics, tiny plastic fragments found in food, drinking water and the air.

Scientists have detected them in tissues throughout the body, raising questions about whether long-term exposure could help drive cancer.

One recent University of Hawaii study found that areas with higher microplastic pollution in coastal waters also had higher rates of certain cancers, including cancers of the mouth and throat.

Another study in Scientific Reports looked at estimated dietary exposure to microplastics in 106 countries and found higher rates of mouth cancer in populations with greater exposure.

Researchers suspect the particles may cause inflammation and DNA damage, while plastic-related chemicals such as bisphenols and phthalates may also play a role.

However, the evidence is still early. Neither study proved that microplastics cause cancer, and population comparisons cannot show whether those who became ill were exposed to more plastic particles.

Dr Samakoglu said laboratory findings are concerning because some particles can trigger inflammation, oxidative stress and DNA damage.

What remains unknown is whether the levels people encounter in daily life can cause similar harm in the mouth or throat.

How pollution may contribute

Air pollution is already known to cause lung cancer, but researchers are becoming more concerned that it may also play a role in cancers of the mouth and throat.

A major focus is fine particulate matter, known as PM2.5, which is about 30 times smaller than a human hair.

These particles come from vehicle exhaust, factories, wildfires and wood-burning stoves, and they can be inhaled deep into the lungs or even enter the bloodstream.

Studies suggest they may also harm cells in the upper airways.

A US study from 2024 found that people exposed to higher levels of PM2.5 were more likely to develop head and neck cancers, especially cancers affecting the mouth and throat.

Scientists think long-term exposure may trigger inflammation and DNA damage, creating conditions that allow cancerous cells to develop.

Dr Samakoglu said the concern is that some air pollutants cause inflammation and DNA damage, which may help cancer form.

Still, although pollution is a proven cause of lung cancer, its role in throat cancer is less certain, and researchers have not yet shown how much it contributes or whether it directly causes the disease.

Can throat cancer be prevented?

There is no guaranteed way to prevent throat cancer, but experts say several steps can significantly lower the risk.

Vaccination against HPV is one of the most important, because it protects against the strains responsible for most virus-related throat cancers.

A recent US study involving more than 1.4 million people found that people vaccinated against HPV were much less likely to develop head and neck cancers, including cancers of the tonsils and base of the tongue.

Even so, researchers say more long-term evidence is needed to show exactly how much protection the vaccine provides against throat cancer.

Avoiding tobacco and limiting alcohol are also among the strongest ways to reduce risk, especially because using both together is far more dangerous than either one alone.

Eating plenty of fruit, vegetables and whole grains may also help, although evidence that any one diet prevents throat cancer remains limited.

Experts also stress the need to notice warning signs.

Dentists screen for head and neck cancer each time they see a patient, Dr Jessica Pharar said, and regular checks can help find the disease at earlier stages.

But HPV-related cancers can grow deep in the tonsils or at the base of the tongue, where they may not be visible during a routine dental visit.

Anyone with a persistent sore throat, trouble swallowing, unexplained hoarseness or a lump in the neck should seek medical advice, especially if symptoms last more than two to three weeks.

Most of these symptoms have harmless causes, but finding cancer early can greatly improve the chances of successful treatment.