Abstract 2586: Evaluation of risk-based colposcopy in the ALTS trial

Abstract

Abstract Objective: Women referred to colposcopy have a wide spectrum of underlying risk of precancer that could influence colposcopic practice and management. We sought to evaluate important risk-strata based on HPV status, cytology, and colposcopic impression in women undergoing colposcopy. Methods: Among participants in the ASCUS-LSIL Triage Study, we stratified women from the immediate colposcopy and HPV triage study arms based on enrollment HPV typing, study cytology, and colposcopic impression. In each group, absolute risk of CIN3+ at enrollment colposcopy and cumulative risk over 2-year follow-up were estimated. Immediate CIN3+ risk of LSIL and HSIL cytology were used as thresholds for colposcopy referral and immediate treatment, respectively. Results: We observed substantial differences in risk of precancer across strata. Women with HSIL cytology, who were HPV16-positive, and high-grade colpscopic impression had a 71% baseline and 78% 2-year risk of CIN3+, respectively. HPV16-positive women with HSIL cytology and low-grade impression, and women with high-grade impression and either HSIL cytology or HPV16 infection, also showed significant CIN3+ risk exceeding the risk of HSIL. In contrast, women with normal colposcopy, <HSIL cytology, and absence of HPV16 infection had the lowest baseline CIN3+ risk (3.2%), below the colposcopy referral threshold in ALTS. Conclusion: Risk assessment at colposcopy can inform colposcopy-biopsy practice and guide management. In the low-risk group, biopsy yields little additional disease and a normal colposcopy may confer higher reassurance that CIN3+ is not present; while in the highest risk groups, immediate treatment without biopsy confirmation could be considered according to current guidelines. Analyses evaluating the benefit of multiple biopsies in these risk strata are underway and will be presented at the meeting. Citation Format: Angela H. Liu, Mark Schiffman, Julia C. Gage, Philip E. Castle, Nicolas Wentzensen. Evaluation of risk-based colposcopy in the ALTS trial. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2586.