HPV HANDBOOK - Zervita

3: HPV AND CERVICAL CANCER: PUBLIC HEALTH PERSPECTIVESKey features of the ALTS study• Large, multicentre, randomized trial that has producedcredible data• HPV testing and a single repeat Pap smear each referred asimilar number of women with ASCUS to colposcopy– This use of HPV testing may be cost-effective• >80% of women with low-grade squamous intraepitheliallesions (LSIL) were HPV-positive– HPV testing would not be valuable for LSIL triage becausetoo many women would be referred to colposcopyBethesda system is used, a ‘European’ ASCUS will not necessarily bethe same as an ‘American’ ASCUS. Therefore, unless clinicians in aparticular country are confident that they have a direct correlate of theASCUS classification used in the ALTS trial, it is not valid to adopt theresults of this study for public health purposes without re-validatingthe protocol within their own system. For example, at the time ofwriting, pilot implementation is being undertaken in the NHS inEngland and will be subject to a thorough evaluation before furtherimplementation is considered.The value of HPV testing may lie in its high negative predictive value,since it has been demonstrated that women who are HPV-negative areat low risk of having underlying cervical cancer, even if their cytologytest shows a borderline abnormality. In the ALTS study, the negativepredictive value of HPV testing was found to be 99.5% and, largely onthe basis of these results, the American Society for Colposcopy andCervical Pathology has issued recommendations that ASCUSpositive,HPV-negative women can be returned to routine recall (after1 year, under the American system). Within such a system, therefore,HPV-based triage offers two important advantages: women can bereturned to routine screening without a lengthy period of heightenedsurveillance (with the resultant anxiety that this entails), and womenwho test HPV-positive may be referred to colposcopy sooner thanmight otherwise have been the case.54