VOL. 1 JANUARY 2007
Pap testing and the HPV vaccine - the beginning of the end for cervical cancer? |
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The professional dialogue concerning Pap testing has intensified in recent years because of the widespread adoption of liquid-based cytology, the introduction of Human Papillomavirus (HPV) testing, and importantly, the recent FDA approval of the HPV vaccine.
The American College of Obstetricians and Gynecologists (ACOG) recently released clinical recommendations for the HPV vaccine, in which they encourage use of the vaccine in females aged 9 to 26 years.1 It was noted that data on the vaccine in women older than 26 years and in males is insufficient to make recommendations in these populations.1 The Advisory Committee on Immunization Practices recommends that girls routinely receive the vaccine between ages 11 and 12 years, although obstetrician–gynecologists may not see many girls in this age range. ACOG recommends that the first reproductive health care visit should occur at ages 13 to 15 years and suggests that this represents an ideal time to discuss the potential benefits of the HPV vaccine and offer it to patients.1 The GardasilTM (quadrivalent human papillomavirus types 6, 11, 16, 18, recombinant vaccine) HPV vaccine protects against four strains of HPV (genotypes 6, 11, 16, and 18). Types 16 and 18 are responsible for 70% of cervical cancers while types 6 and 11 are responsible for 90% of genital warts.2 Because of the other 30% of cancer-causing strains not covered by the vaccine, ACOG emphasizes that current cervical cytology screening recommendations remain unchanged and these should be followed regardless of vaccination status. ACOG states that "the vaccine is a preventative tool and is not a substitute for cancer screening."1 Only a cytology-based Pap test can indicate the presence or absence of disease through detection of abnormal changes in cervical cells. ACOG recommends that Pap screening should begin within 3 years of sexual intercourse (or by age 21 years) and then occur annually until age 30 years. Most women can then continue annual testing or choose to be tested every 2 to 3 years after three consecutive negative Pap tests.1 ACOG recommends vaccination for sexually active women aged up to 26 years, although they should be counseled that it may be less effective if the patient has already been exposed to HPV. Women with previous cervical intra-epithelial neoplasia (CIN) can also be vaccinated, although they should be counseled that benefits may be limited. ACOG emphasizes the need for annual cervical cytology screening in both these patient types.1 HPV testing as a criterion prior to vaccination is not currently recommended. ACOG guidelines state that testing provides information on current infections only and that assays can be unreliable and are not widely available.1 Increased costs associated with including a screening requirement would also reduce the cost-effectiveness of vaccination.1 Cervical cancer is the world's second leading cause of cancer death in women, with an estimated 493,000 new cases and 274,000 deaths every year. The recently approved HPV vaccine represents an important advance in cervical cancer prevention particularly in countries without organized screening programs. It should be emphasized that routine cervical cytology screening still remains vital because of the other 30% of cancer-causing strains not covered by the vaccine. Thus, with widespread use of the HPV vaccine and continued routine Pap testing, there is great potential to further decrease the incidence of cervical cancer in future generations.1, 3, 4 References:
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