CDA Essentials 2016 • Volume 3 • Issue 8

34 | Volume 3 Issue 7 S upporting Y our P ractice one associated with tobacco and alcohol consumption to the second etiological component: HPV infection. The reality is that we’re seeing two sets of oral cancers: those caused by HPV and those that can be attributed to other risk factors. Today, this knowledge is no longer questioned: HPV is acquired by sexual transmission, it’s one of the most commonly sexually transmitted infections (STI) and it’s the most common viral STI. Dental professionals, by being key opinion leaders among their peers, their patients and their communities, are able to spread word of the advantages of HPV vaccination in terms of long-term prevention of oral cancers. HPV-associated cancers include cancers of the cervix, penis, anus, vulva, vagina and oropharynx. The cancers are all managed differently by different health professionals and are discovered differently as well. The important thing to note is that of the 12.7 million new cancers in 2008, about 5% were caused by HPV (see Table 1 ). Cervical cancer is of tremendous importance, with nearly half a million cases worldwide. And 100% of new cases of cervical cancer are attributable to HPV because, for this particular cancer, HPV is the necessary cause. HPV is also the major cause of anal cancer, a significant cause of other genital cancers, and is gradually—by the minute—becoming a major cause of oropharyngeal cancer. In 2008, the proportion of oropharyngeal cancer cases worldwide related to HPV varied from 13–56%, because in some regions smoking and alcohol are the more important risk factors and in other regions HPV is more important. According to one estimate, HPV causes 72% of oropharyngeal cancers in the U.S. This estimate is from the Centers for Disease Control and Prevention in 2013. It’s a much higher estimate than previous ones, but we now have better science coming down the pipeline about oropharyngeal cancer, and it’s become part of regular practice for dental professionals and head and neck surgeons to test for HPV-16 in oral cancer. Another estimate in the U.S. calculates that 89% of HPV-associated oral and oropharyngeal cancer are preventable by vaccination. Of course, we haven’t yet gotten to that point because girls and boys are getting vaccinated and they haven’t reached the age of being at risk for oral cavity and oropharyngeal cancer. HPV-16 is by far the most common HPV type. Among the 25 alpha HPV types—the ones that infect the mucosal sites—HPV-16 is by far the most carcinogenic and the most important for oropharyngeal cancer. Luckily the vaccines that are available now target HPV-16 quite efficiently. Hopefully the means to control or prevent all HPV-associated cancers will be a single one: HPV vaccination. a Table 1 Global burden of HPV-associated cancers Cancer New cases Attributable to HPV % Attributable to HPV Uterine cervix 530 000 530 000 100% Penis 22 000 11 000 50% Anus 27 000 24 000 88% Vulva 27 000 12 000 43% Vagina 13 000 9 000 70% Oropharynx 85 000 22 000 25.6% (range: 13-56%, region dependent) Total HPV-associated cancers 700 000 610 000* 86.30% *4.8% of 12.7 million new cancers in 2008 Source: FormanD,deMartelC,LaceyCJ,Soerjomataram I,Lortet-TieulentJ,BruniLetal.Globalburdenofhumanpapillomavirusandrelateddiseases. Vaccine 2012;30Suppl5:F12-23. The epidemiolog y of oral cancer is gradually switching, from one associated with tobacco and alcohol consumption to the second etiological component: HPV infection.