HPV testing in primary screening of older women

Certain types of the human papilloma virus (HPV) are well established as th e primary cause of cervical cancer. Several studies have shown that HPV tes ting can improve the detection rate of high-grade cervical intraepithelial neoplasia (ClN) but these have been carried out primarily in younger women. In this study we evaluated the role of HPV testing as an adjunct to cytolo gy in women aged 35 or over. An additional aim was to evaluate commercially available kits for HPV testing. A total of 2988 eligible women aged 34 or more attending for routine smear in 40 general practitioner practices recei ved HPV testing in addition to routine cytology, after having given written informed consent. Samples were assayed by polymerase chain reaction (PCR) and two versions of the Hybrid Capture test for HPV, and women were invited for colposcopy if there was any cytological abnormality (including borderl ine smears) or the PCR test was positive. Any apparent abnormality was biop sied and loop-excision was performed as necessary. CIN was judged by histol ogy; 42 women had high-grade GIN, of which six were cytology negative (86% sensitivity for borderline-or worse) and three had a borderline smear (79% sensitivity for mild dyskaryosis or worse). The positive predictive value o f a borderline smear was only 3.1%. Eleven high-grade lesions were negative by the PGR HPV test (sensitivity 74%), The first generation Hybrid Capture II test had a similar sensitivity but an unacceptably high false positive rate (18.3%), while the newer Hybrid Capture II microtitre kit had a 95% se nsitivity and a 2.3% positivity rate in normal women when used at a 2 pg ml (-1) cut-off (positive predictive value 27%). Cytology performed very well in this older cohort of women. The newer Hybrid Capture II microtitre test may be a useful adjunct, especially if the results reported here are reprod ucible in other studies. A combined screening test offers the possibility o f greater protection and/or longer screening intervals, which could reduce the overall cost of the screening programme. (C) 1999 Cancer Research Campa ign.