In the United States in 2009, there were approximately 11,000 new cases of cervical cancer and about 4000 cancer-related deaths. This number makes up approximately 1.5 percent of cancer deaths in women.
Virtually all of cervical cancer can be linked to a cancer-causing virus, called the human papillomavirus (HPV), which has multiple forms, called genotypes. The most common and most carcinogenic HPV are genotypes 16 and 18, but there are others. Fortunately, researchers have developed a vaccine that could significantly decrease death from cervical cancer and possibly eradicate it in time.
Gardasil, one of two FDA-approved HPV vaccines, targets HPV genotypes 16 and 18, which cause nearly 70 percent of cervical cancers and about 50 percent of pre-cancers throughout the world. Gardasil, unlike the less potent Cervarix vaccine, also prevents infection by the HPV genotypes that cause 90 percent of genital warts.
In HPV-naïve (i.e., those never infected with HPV) populations, Gardasil prevented 97 percent to 100 percent of pre-cancers. The big point to understand here is that these vaccines, as with others, are preventive—not therapeutic. They do not prevent disease from occurring in individuals already infected with certain HPV types. The clinical trials suggest that immunization with an HPV vaccine is most effective in individuals who have not been infected with HPV and before sexual activity.
There is wide consensus in the medical community with regard to the use and safety of these vaccines in females before sexual intercourse. The Advisory Committee on Immunization Practices (ACIP) and the American College of Obstetricians and Gynecologists (ACOG) both recommend that HPV vaccination should be routinely offered to females between the ages of 11 and 12 years (and as early as 9 years of age).
However, there is still some debate as to the vaccines effectiveness in women potentially exposed to the various HPV types (i.e., after sexual activity). The Gardasil clinical trial showed that the effectiveness of the vaccine plummeted to 44 percent when women who were sexually active, and therefore much more likely to have been exposed to HPV, were studied. Still, some organizations and physicians are recommending so-called ‘catch-up vaccination’ for females aged 13 to 26 years who have not been previously vaccinated.
Bottom line: For greatest impact, the HPV vaccine should be given to females before the start of sexual activity. Females who are sexually active could still be vaccinated where age-appropriate. However, the vaccine is much less beneficial for females who have already been infected with one of more of the HPV vaccine types. Women should still undertake the routine screening for cervical cancer recommended by their doctors. Most studies do not support immunization of males, since it provides only a small benefit and is not cost effective.
Copyright 2010 Chicago Defender
Dave Montgomery, MD, PhD is a Cardiologist at Northwestern University and a sought after Speaker and Health Coach. http://davemontgomerymd.com
