Dr. Lucy Gilbert, a gynecological oncologist at the McGill University Health Centre (MUHC), is part of an international clinical team that is testing a new vaccine that will protect women against Human Papilloma Virus, or HPV. This virus, which causes condyloma (genital warts) and precancerous changes in the cervix and lower genital tract, can lead to the development of cervical cancer, the second leading cause of cancer deaths in women.
“This anti-HPV vaccine has the potential to completely eradicate cervical cancer,” says Gilbert. “The vaccine works by fooling the body into generating an immune response that stops the virus in its tracks.” The results of an earlier phase of the clinical trial were published in the prestigious New England Journal of Medicine. In this phase, the vaccine was found to be 100 percent effective against HPV-related disease.
The development of a vaccine against HPV is important. Currently, approximately one-third of sexually active young men and women are infected and since HPV resides on the external genitalia of infected individuals, it is easily passed on, and condoms don’t always prevent transmission. Gilbert says, however, that since the body’s immune system is efficient at eliminating the virus, only 10 percent of infected women will develop a clinically significant disease, such as genital warts or an abnormal Pap test.
“This is a preventable cancer,” says Gilbert. “And prevention is the best strategy because no matter how successful current surgical treatments are, cervical cancer, once formed, exerts a huge psychological and economic toll, even when detected early while still treatable.”
How long immunity lasts after vaccination in unknown and is currently being tested. The new vaccine will also protect women against several forms of HPV, since some forms are responsible for genital warts but not cervical cancer. Once approved for use by the general public, Gilbert hopes that the HPV vaccine will prevent thousands of deaths caused by cervical cancer.
“This is a form of cancer that should be eliminated within 10 years,” says Gilbert. “Once the trials are complete and the vaccine is available to all women, we don’t want to see any more deaths due to cervical cancer.”
Overt clinical symptoms of cervical cancer are preceded by pre-cancerous changes that are easily detectable through screening. Since the latency period for cervical cancer is very long, regular PAP tests are important.