Rise in HPV-associated cancers among men reflects low vaccination rates

Issue: September 25, 2016

A federal report released in July showed HPV–associated head and neck cancers are on the rise among men in the United States.

An average of 15,738 cases of HPV–associated oropharyngeal squamous cell carcinoma were diagnosed in the country each year between 2008 and 2012. Of these, approximately 80% were diagnosed in men, according to CDC’s Morbidity and Mortality Weekly Report.

Lois Ramondetta

“We know that there are about 15 high-risk subtypes of HPV, and that HPV-16 and HPV-18 are responsible for the majority of these [head and neck] cancers,” Lois Ramondetta, MD, professor of gynecologic oncology in the department of gynecologic oncology and reproductive medicine at The University of Texas MD Anderson Cancer Center, told HemOnc Today. “By vaccinating our children, we anticipate that more than 28,000 cases of HPV–associated cancers could be prevented annually. Think of all the people in whom we could prevent suffering with this very identifiable change of practice. With our lifestyle changes — including exercise, eating well, avoiding tobacco, using sunscreen and vaccinating against HPV — we could prevent 30% to 50% of all cancers.”

Ramondetta spoke with HemOnc Today about the increase in oropharyngeal cancer rates among men, and the importance of HPV vaccination as a cancer prevention strategy.

Question: What do the most recent statistics suggest for HPV – related cancers among males?

Answer: Statistics from the CDC show the number of HPV–associated cancers is on the rise. HPV–associated cancers are typically located in the head and neck region, as well as the genitals and some reproductive organs, of both men and women. From 2008 to 2012, HPV–associated cancers climbed to nearly 39,000, an increase over the previous 5-year study period. These numbers include more than 11,700 cases of cervical cancer and 12,600 oropharyngeal cancers in males, 70% of which are caused by HPV.

Q: What is the cause for the increase d incidence ?

A: The cause is unclear, but it is believed to be related to sexual activity — more oral sex and partners with increased prevalence of HPV. According to the data, approximately 5% to 10% of adults have HPV detectable in their saliva at any one time. In addition, close to 80% of people are exposed to HPV at some point in their lives, and between 20% and 30% of young people have HPV at any one time.

Q: What does the future look like for HPV – associated cancers?

A: The trend in HPV cancers will continue to rise for the next 30 years or so, until we see an effect from the HPV vaccine. Current vaccination rates in the United States are poor. Only about 40% of all girls and 22% of all boys get the full vaccine series, and many of them receive the vaccine after HPV exposure, which is too late. The average age for cervical cancer diagnosis is between 40 and 50 years, the average age for oropharyngeal cancer diagnosis is in the mid-50s, and anal cancer is usually diagnosed in people in their 60s. Even if we vaccinate all kids by age 15, they will not be the average age for tonsillar/back-of-tongue cancer for 30 more years, so we will have to be patient and trust our scientifically based hypothesis that these cancers will be prevented. We know that vaccinating young people reduces the prevalence of HPV DNA in the oral cavity. However, we hope to see a reduction in cervical cancer incidence sooner, as the average age of diagnosis is earlier. We have already seen a reduction in the diagnosis of genital warts, HPV prevalence on the genitals and precancers of the cervix. Unfortunately, I wish we were already seeing a reduction in cancers. Almost weekly, I see patients with newly diagnosed cervical cancer in my clinic.

Q: What can be done to reverse this trend?

A: Cervical cancer screening can find precancers before they develop into cancer. At this point, there are no screening tools available for detecting oropharyngeal cancers. Although dentists can do visual examination of the soft tissues of the mouth, oropharyngeal cancers often start far back in the crypts of the tonsils and cannot be seen on oral exam, and there often are no symptoms. The most common presentation for HPV oropharyngeal cancer is asymptomatic lymphadenopathy. We are trying to develop a screening tool through the efforts of The University of Texas MD Anderson Cancer Center HPV Cancer Moonshot initiative, which started in 2014. In addition, what we can do now is raise our vaccination rates — especially in male. We need to protect future generations from HPV infection with this safe vaccine, and we need to complete the HPV vaccine series before age 13. CDC researchers emphasize that 28,500 cases of HPV–associated cancer could be prevented by the HPV-9 vaccine.

Q: Have other trends been observed in HPV-related cancers?

A: There is an overall epidemic in male HPV oropharyngeal cancers, or cancers of the tonsil or back of tongue. Anal cancers in both men and women also are on the rise, but this may become more obvious during the next few years. Ninety-percent of anal cancers are associated with HPV and, of those, 90% are caused by HPV-16. Approximately half of all penile cancers also are caused by HPV.

Q: Why are HPV –related oropharyngeal cancers more prevalent in men than women ?

A: Some studies suggest that men are less likely than women to clear an oral HPV infection and, even if they do, it may take longer to clear. This possibly could be because women exposed to HPV vaginally may mount an immune response that prevents them from developing an oral HPV infection. At this time, we cannot explain differences in oral HPV cancers or infections by sexual behavior alone.

Q: How important is it for both boys and girls to get the full HPV-vaccine series?

A: Both boys and girls need to be vaccinated to protect themselves and to stop the spread of HPV to others, just like with any infectious disease. There are more deaths nationally from HPV cancers than from pertussis or meningitis, which are also vaccine-preventable diseases. Among the younger generation, there is a tendency to engage in sexual behaviors at a younger age and to have more partners. If given early before exposure — ideally completing the full series before age 13 — the HPV-9 vaccine should be 100% effective against infections from the nine HPV high-risk subtypes, two of which cause the majority of all cancers.

Q: Is there anything else that you feel is important to mention ?

A: By not informing our patients about the risks to their kids, I do not think we are doing our job to prevent cancer. This is a huge opportunity for all oncologists to prevent cancer. Think about it: We talk about eating healthy, wearing sunscreen, exercising and not smoking, but a big effect could occur by vaccinating against HPV and getting all recommended cancer screenings. – by Jennifer Southall

For more information:

Lois Ramondetta, MD, can be reached at The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030; email:lramonde@mdanderson.org.

Reference:

Viens LJ, et al. MMWR Morb Mortal Wkly Rep. 2016;doi:10.15585/mmwr.mm6526a1.

Disclosure: Ramondetta reports no relevant financial disclosures.