It’s an exciting time in medicine when we can talk about eradicating cancer. Today, a new study shows that this is a reality for both cervical and oropharyngeal cancers caused by the human papilloma virus. And this impact could be great.
For 2018, the American Cancer Society estimates that in the U.S., about 13,240 new cases of invasive cervical cancer will be diagnosed, leading to about 4,170 deaths. A recent Australian study shows that the rates of cervical cancer have decreased dramatically in Australia thanks to the widespread adoption of the HPV vaccine in that country.
In fact, Australia is expected to reduce its cervical cancer diagnosis rate to fewer than four women per 100,000 annually, which means the disease would no longer qualify as a public-health problem.
But there’s another silver lining to the HPV vaccine that often hides in the shadows: HPV vaccines can potentially eradicate oropharyngeal cancer, too. You might be surprised to learn that oropharyngeal cancer currently surpasses cervical cancer in incidence rates, and is now the most commonly diagnosed HPV-related cancer in the U.S., according to Bruce Haughey, MD, a board certified otolaryngologist and fellowship-trained head, neck and skull base cancer surgeon at Florida Hospital Celebration Health. Oropharyngeal cancer affects significantly more men than women, at a five to one ratio. This means that the HPV vaccine can save a significant number of both women and men’s lives.
Dr. Haughey shares his comments about the impact of this study and the very recent change in the U.S. to recommend more widespread adoption of the HPV vaccine for adults.
“HPV infections, as opposed to the cancers they can cause, are very common. Worldwide, there are 80 to 100 million people who have HPV, especially among younger populations,” says Dr. Haughey. He further explains that while exposure to HPV is normally cleared by the body’s immune system, there are many whose immune systems do not overcome it, leading to longer term HPV infection.
Although most HPV infections show no symptoms, persistent genital HPV infection is known to cause 99 percent of cervical cancers in women. HPV can also cause other types of anogenital cancer, head and neck cancers, and genital warts in both men and women.
“While rates of cervical cancer have dramatically decreased over the years due to pap smear screenings and HPV vaccination among girls and young women, the rapidly increasing incidence of HPV-related oropharyngeal cancer are concerning, especially among men,” states Dr. Haughey.
How the HPV Vaccine Works
Dr. Haughey advises, “The HPV vaccine works like many other vaccines; it introduces antigenic properties of the virus that challenge the body’s immune system to clone up immune cells to fight the virus or infection if you are exposed to it.”
The current HPV vaccines provide immunity to the most common strains of HPV linked to tumors caused by human papilloma viruses — both cervical and oropharyngeal.
He adds that there are about 150 strains of HPV, but just a few high-risk HPV strains that we know of at this time are causative for cancer. HPV-related oropharynx and cervix cancer is predominately caused by subtype 16 and 18 in the cervix and 16 in the oropharynx.
“The currently available HPV vaccine protects against nine HPV subtypes, including 16 and 18,” states Dr. Haughey.
The Impact of the HPV Vaccine
While not as shocking as the decrease in Australian cervical cancer rates, rates in the U.S. have declined. One study found a 29 percent decrease in cervical cancer rates post introduction of the HPV vaccine in 2006 and between the years of 2011 and 2014.
But while cervical cancer incidence is decreasing, rates of HPV-related oropharyngeal cancer are increasing at an alarming rate, mainly among men. Dr. Haughey shares that the latest numbers available suggest that in the U.S., the incidence of oropharyngeal cancer among males is 19,000 cases with a trajectory toward 20,000, whereas cervical cancer affects 12,000 women annually.
Dr. Haughey emphasizes, “It will take longer for rates of oropharyngeal cancer to reduce with the HPV vaccine. Since the vaccine was first indicated for only women, male vaccination has lagged behind. That’s partly why we are now seeing more men being diagnosed compared to women.”
Changing HPV Vaccine Recommendations
“Now that the HPV vaccine is authorized for boys and males, we hope to see a catch up of decreased oropharyngeal cancer rates,” says Dr. Haughey. He explains that there will be a latent interval because it takes 10 years for a marked reduction and 20-30 years or more for complete eradication, with population-wide vaccination.
The U.S. Food and Drug Administration (FDA) recently expanded approval of the Gardasil 9 vaccine for women and men aged 27 to 45 years. The HPV vaccine was previously indicated for females and males ages nine to 26.
“I recommend that adults speak to their primary care physician, or for women, their women’s health physician, about the HPV vaccination,” says Dr. Haughey. He adds, “If you have young children, talk to their pediatrician about recommended HPV vaccination protocols as well.”
“It’s important to clarify that the HPV vaccine is not a treatment modality for oropharyngeal cancer at this time. But even if you have one strain of HPV infection, the vaccine could potentially offer additional protection against other strains known to cause oropharyngeal and cervical cancer. Also, if you had oropharyngeal cancer that was successfully treated in the past, vaccination could potentially prevent new primary growths in other susceptible locations within the throat, by inducing immunity,” explains Dr. Haughey.
Hope for the Future
There might be even more promise for the HPV vaccine in the future. “I just returned from the International Papillomavirus Conference in Australia, and recent research is focused on therapeutic HPV vaccination along with other types of immune stimulation, such as the concept of adoptive immunity,” notes Dr. Haughey.
In addition, Dr. Haughey explains that research is also narrowing in on cytology screening technologies for oropharyngeal cancer that could be compared to that of the pap smear.
“The benefit of the pap smear is that it finds premalignant cells very early by cytology, but if we try to do cytology of tonsils (the most common location for oropharyngeal cancer) it’s not proven to be successful because the abnormal cells occur deep within the tonsil. Furthermore, and other locations of primary oropharyngeal cancer such as the tongue base are difficult to access. Different, non-pap smear technology to screen for precancerous oropharyngeal cells is being studied and might be on the horizon,” Dr. Haughey concludes.
Learn more about Dr. Bruce Haughey and the Florida Hospital Cancer Institute.