Cervical cancer primary prevention

Overview
Prevention of cervical cancer includes a comprehensive approach involving awareness, screening, and usage of preventative vaccinations.

Awareness
According to the US National Cancer Institute's 2005 Health Information National Trends survey, only 40% of American women surveyed had heard of human papillomavirus (HPV) infection and only 20% had heard of its link to cervical cancer. In 2006 an estimated 10,000 women in the US will be diagnosed with this type of cancer and nearly 4,000 will die from it.

Screening
The widespread introduction of the Papanicolaou test, or pap smear for cervical cancer screening has been credited with dramatically reducing the incidence and mortality of cervical cancer in developed countries. The pap smear suggests the presence of cervical intraepithelial neoplasia (premalignant changes in the cervix) before a cancer has developed, allowing for further workup. Recommendations for how often a Pap smear should be done vary from once a year to once every five years. The American Cancer Society recommends that cervical cancer screening should begin approximately three years after the onset of vaginal intercourse and/or no later than twenty-one years of age. If premalignant disease or cervical cancer is detected early, it can be treated relatively noninvasively, and without impairing fertility.

The HPV test is a newer technique for cervical cancer screening which detects the presence of human papillomavirus infection in the cervix. It is more sensitive than the pap smear (less likely to produce false negative results), but less specific (more likely to produce false positive results) and its role in routine screening is still evolving. Since more than 99% of invasive cervical cancers worldwide contain HPV, some researchers recommend that HPV testing be done together with routine cervical screening (Walboomers et al, 1999). But, given the prevalence of HPV (around 80% infection history among the sexually active population) others suggest that routine HPV testing would cause undue alarm to carriers.

Vaccination
Merck & Co. has developed a vaccine against four strains of HPV (6,11,16,18), called Gardasil™. It is now on the market after receiving approval from the US Food and Drug Administration on June 8, 2006. Gardasil is targeted at girls and women of age 9 to 26 because the vaccine only works if given before infection occurs; therefore, public health workers are targeting girls before they begin having sex. The use of the vaccine in men to prevent genital warts and interrupt transmission to women is initially considered only a secondary market. The high cost of this vaccine has been a cause for concern. Gardasil has also been approved in the EU.

GlaxoSmithKline has developed a vaccine called Cervarix™ which has been shown to be 100% effective in preventing HPV strains 16 and 18 and is 100% effective for more than four years. These strains together cause about 70% of cervical cancer cases. Cervarix should be approved by year's end.

Neither Merck & Co. nor GlaxoSmithKline invented the vaccine. The vaccine's key developmental steps are claimed by the National Cancer Institute in the US, the University of Rochester in New York, Georgetown University in Washington, DC, and the Queensland University in Brisbane, Australia. Both Merck & Co. and GlaxoSmithKline have licensed patents from all of these parties.