Can HPV Vaccination Eradicate Cervical Cancer?

Widespread adoption of vaccination programs has nearly eliminated life-threatening diseases like smallpox and polio from many parts of the world. Professor Jack Cuzick thinks the same could be done with cervical cancer. Prof Cuzick is the John Snow Professor of Epidemiology and department head at the Cancer Research UK Centre for Epidemiology, Mathematics, and Statistics, Wolfson Institute of Preventive Medicine, and a well-known figure in oncology.

Prof Cuzick told an attentive audience at the ECCO 15 - ESMO 34 Joint Congress that he believes new human papillomavirus (HPV) vaccines on the horizon, which are effective against 9 strains of HPV, coupled with a shift to molecular HPV screening, could allow countries to eradicate cervical cancer within their borders. According to Prof Cuzick, HPV is responsible for more than 99% of cervical cancer cases. Currently approved vaccines Gardasil and Cervarix only immunize against HPV types 16 and 18, the strains responsible for approximately three-quarters of cases.

During the press conference, Prof Cuzick pointed out some obvious concerns with vaccination, the foremost being that it only works in younger women who have never been exposed to the virus through sexual activity. In sexually active unvaccinated women he said it is “important to determine whether or not the virus is actually there” through screening. Another concern is the durability of the vaccine. Prof Cuzick said the speculation is that HPV vaccination provides lifelong protection, but it will take years of follow-up to establish this definitively. He suggested that to achieve herd immunity will likely require vaccinating boys, as well as girls, and boys are only now becoming part of the HPV vaccination picture.

While vaccination is a feasible approach for the next generation, Prof Cuzick said, “We mustn’t forget the current generation of women.” Many have already been exposed to HPV, which is why he advocates the use of more effective cervical cancer screening methods, like molecular HPV testing. Major European studies involving more than 30,000 women show HPV testing picks up 90% of precursor lesions, whereas cytology, “a technology that is over 50 years old,” he said, “only picks up half of them.”

Adopting HPV screening, an objective computerized test, is an important component of any campaign to eradicate cervical cancer. Prof Cuzick said only persistent HPV infection causes cancer and most cases of HPV will not progress to cancer if treated promptly. Although HPV testing is more expensive than cytology, he believes its higher accuracy rate and the need for less frequent screening will offset the increased costs of the test. “When you’re negative for the HPV test, the duration of protection is much longer than when you’re negative for a smear,” he explained. Prof Cuzick said women aged 25 to 30 years would likely only have to undergo HPV testing every 5 years; HPV-negative women older than 50 years could get tested every 8 years. He also said studies show “self-sampling works quite well for HPV testing,” which would obviate the need to visit a physician for screening.

Prof Cuzick encouraged European governments to take responsibility for educating the public on HPV vaccination because “people are, not surprisingly, a little skeptical of pharmaceutical-based education programs.” Clearly, he was speaking largely to the European audience, because he did not address obstacles the United States has faced in implementing HPV vaccination programs. Groups continue to protest any state or federal attempts to mandate HPV vaccination. Some people feel vaccinating girls against a sexually transmitted disease will encourage them to have premarital sex; others say they have concerns about the safety of the vaccines. These obstacles to adopting universally mandated vaccination for younger girls could seriously hinder attempts to eradicate cervical cancer in the United States.