(CNN) The vaccine given to prevent cervical cancer in women could end up saving men's lives, too.

Evidence is mounting that the HPV vaccine is also effective in preventing other HPV-related cancers , including those of the head and neck. Although most people who get HPV do not develop cancer, rates of HPV-related head and neck cancers are dramatically rising for men aged 40 to 50, according to Dr. Maura L. Gillison, the Jeg Coughlin Chair of Cancer Research at the Ohio State University Comprehensive Cancer Center.

When Gillison recently gave a presentation showing the increasing rate of HPV-related head and neck cancer among men, her audience was shocked. "I've never shown a slide where the audience gasps," she said.

"The risk of getting this cancer is strongly related to when you were born. If you are currently a 40- to 45-year-old man, your risk of getting this cancer is dramatically higher than a 40- to 45-year-old man three or four decades ago," Gillison said.

Today's 40- to 50-year-old men have had more sexual partners and have engaged in more oral sex than previous generations, according to experts , significantly raising their risk of an HPV-related head and neck cancer.

Actor Michael Douglas made headlines in 2013 when he announced he was battling an HPV-related cancer and that he got it from performing oral sex. Douglas was 68 when he was diagnosed, but many of the men being diagnosed with these HPV-related cancers are much younger.

What's a Gen X'er to do?

HPV is usually acquired when young. It can lay dormant, and most oropharyngeal cancer (a type of head and neck cancer) is diagnosed decades later, beginning around age 40 to 50. And the more partners you have, the greater your risk.

HPV vaccines weren't recommended and approved in the United States until 2006. And the vaccine was not even recommended for boys until 2011.

So what's an aging Gen X'er to do?

"You're starting to get colonoscopies; you're starting to get checked for prostate cancer. This is one more thing to add to that list that you really have to watch for," said Brian Hill, founder of the Oral Cancer Foundation

Warning signs of HPV-related head and neck cancer • Persistent lump on neck • Persistent earache on one side • Swelling or lump in the mouth • Chronic sore throat • Difficult or painful swallowing • Change in voice Source: Oral Cancer Foundation, Dr. Carole Fakhry

Symptoms of HPV-related head and neck cancer include a change in voice, a sore throat that doesn't go away, an earache on one side and difficult or painful swallowing.

Hill's story is typical: His doctors initially assumed he had an enlarged lymph node due to an infection. Two doctors gave him antibiotics before he was diagnosed with late-stage oropharyngeal cancer. His experience led him to form the Oral Cancer Foundation.

Finding the disease at an early stage is lifesaving. When it's diagnosed early, these HPV-related cancers are survivable, according to Dr. Carole Fakhry of the Johns Hopkins Head & Neck Cancer Center. "If you have a lump in your neck, make sure to get checked.

"A very common story is: 'I was shaving and I noticed this lump in my neck," she said. "And he goes through two or three rounds of antibiotics and then someone finally thinks about cancer."

'Dental hygienists are becoming the best screeners'

Traditionally, cancers of the head and neck were often linked to alcohol or smoking, and these non-HPV cancers tend to be located at the front of the mouth and the voice box. Incidence of these cancers are dropping.

"The truth of the matter is that smoking-related cancers are declining ," Fakhry said. "On the other hand, cancers related to HPV are increasing."

HPV-related cancers usually originate in the back of the mouth. "Most of these cancers are tonsils and back-of-tongue cancers," she said. "Tonsils are basically these crypts, and tumors grow deep within these crypts, so these tumors can be hard to find."

Since tumors are often hidden, dentists and dental hygienists are becoming the first line of attack. Men may also be more likely to visit a dentist regularly than a doctor, according to Hill.

"Dental hygienists are becoming the best screeners for this. They're becoming the point at the end of the spear when it comes to screening and finding abnormalities," he said.

Dentists and hygienists are encouraged to look for telltale signs of HPV-related cancer: asymmetrical or swollen tonsils, or a lesion in the back of the throat. But these cancers are notoriously tough to spot and tend to be diagnosed after patients develop a lump in the neck.

So what can you do?

"Make sure you get your kids vaccinated (for HPV)," Fakhry said.

Dr. Dan Beachler, lead author of a new study that found further evidence the HPV vaccine protects against multiple types of HPV-related cancers, agrees: "We still don't know that much about oral HPV. Primary prevention through vaccination might have the most potential."

Besides the cervix and the head and neck, some strains of HPV can also lead to cancer of the anus, penis and vulva.

A preventive HPV vaccine is most effective when given to children before they become exposed to HPV. The three dose series is recommended at age 11 or 12.

Initially recommended just for girls, the Centers for Disease Control and Prevention now recommends that boys be vaccinated, too. In addition, vaccination is recommended through the age of 26 in women and through age 21 in men who were not vaccinated previously.

"Young people do not avoid oral sex. That being a given, the best thing we can do is increase the vaccination rate. The second thing we can do is be highly aware of signs and symptoms," Hill said.

And don't panic. Although HPV-related cancers are on the rise, they're still uncommon.

"Even though the rates are dramatically increasing, it's still a relatively rare cancer. We don't want to create a panic. We just want to raise awareness," Gillison said.