Background: To investigate the natural history of HPV infection of the uterine cervix following a 10-year prospective observational study.
Patients and methods: Three hundred and thirty women with cytological and colposcopic features of HPV infection +/- CIN 1 were recruited into the study. These women were followed up for a period of 10 years, during which time they had repeated colposcopic assessments and cytological monitoring Those women with evidence of high-grade disease at any stage of follow-up were treated by Large Loop excision of the transformation zone (LLETZ) and excluded from the study. At the end of the surveillance period, 179 women with evidence of persistent HPV infection alone or in conjunction with low-grade disease underwent a shallow diagnostic LLETZ. In total, 51 women defaulted from follow-up.
Results: Thirty-three per cent of the women with cytological and colposcopic features suggestive of persistent HPV infection alone during the 10-year follow-up period had histological evidence of CIN at the end of the study. Two thirds of this disease was graded as CIN 2 or 3. Nineteen per cent of the women with cytological and colposcopic features suggestive of persistent HPV infection and CIN 1 actually had high-grade CIN at histology (CIN 2 and 3). Only 6.1% of the study population had normal histological findings.
Conclusion: The finding that a relatively large percentage of high-grade lesions might have been masked for anything up to a decade by a low-grade phenotype, coupled with the worrying percentage of defaulters from follow-up, indicate that an early decision for intervention (diagnostic and/or therapeutic) may be appropriate if a low-grade abnormality persists after a short surveillance period.