Human papillomavirus (HPV) infections as risk factors for cytological and histological abnormalities in baseline PAP smear-negative women followed-up for 2 years in the LAMS study.

ABSTRACT

OBJECTIVE: To assess the role of HPV as determinant of the incident cytological abnormalities (SIL) and cervical lesions (CIN) during a 24-month follow-up of baseline PAP smear-negative subgroup of women included in the Latin American Screening study (LAMS). STUDY DESIGN: A group of 365 women with normal Pap smear and negative or positive high-risk Hybrid Capture II test were prospectively followed-up for 24 months at Campinas and São Paulo (Brazil). The incidence rate (IR) and risk ratio (RR and 95% CI) of developing cytological or histological abnormality during the follow-up was calculated for HPV-negative and HPV-positive women. RESULTS: During the 12-month follow-up, women HPV-positive at baseline had developed a significantly higher rate of incident LSIL (IR=3.5%, RR=1.4; 95% CI 1.1-1.7) and HSIL (IR=0.7%, RR=1.5; 95% CI 1.4-1.7) abnormality. For HSIL, the IR increased to 2.1% and the RR increased to 1.7 (95% CI 1.5-1.9) among those followed for 24 months. Similarly, women with positive HPV tests were at a higher risk of developing CIN 2-3 (IR=2.6%, RR=1.5; 95% CI 1.4-1.6) during the first 12 months of follow-up, and for those followed for 24 months, this RR increased further to 1.7 (95% CI 1.5-1.9) although the IR was 0.7%. CONCLUSIONS: Oncogenic HPV infections comprise a significant risk factor for incident cervical abnormalities, and HPV test is a useful adjunct to cytology in detecting the high-risk patients among baseline PAP smear-negative women.