Objective. To characterize the 6- and 18-month cumulative risk of cervical intraepithelial neoplasia grade 2 or worse (CIN 2+) and grade 3 or worse (CIN 3+) in women aged 30 years and older after a low-grade squamous intraepithelial lesion (LSIL) cytology and high-risk human papillomavirus (HPV)-negative screening result in routine clinical practice.
Materials and Methods. Comprehensive quality assurance databases of screening test and biopsy results from the Regional Laboratory of the Kaiser Permanente Northern California Health Plan were reviewed. All women aged 30 years and older with LSIL cytology were sorted by high-risk HPV status. Associated biopsy results were tabulated, and the corresponding risks of CIN 2+ and CIN 3+ diagnosed within 18 months after LSIL cytology were calculated overall and by decade of age.
Results. During the 6-year period, from 2003 to 2008, 4,113 LSIL cases were interpreted in women aged 30 years and older for which corresponding high-risk HPV and biopsy results were available. The proportion of women with LSIL testing positive for HPV declined with age, from 89% in the group aged 30 to 39 years to 76% in women older than 50 years (p < .001). Of 622 women with HPV-negative LSIL cytology, there was no case of cancer detected at colposcopy occurring within 6 months of the screening test. The 18-month risks of CIN 2+ and CIN 3+ were 3.5% and 1.4%, respectively.
Conclusions. The risk of CIN 3+ is sufficiently low in women aged 30 years and older with high-risk HPV-negative LSIL that 1 year follow-up rather than immediate colposcopy should be considered when it occurs in routine clinical practice.