Risk assessment to guide cervical screening strategies in a large Chinese population

Three different cervical screening methods [cytology, human papillomavirus(HPV) testing and visual inspection with acetic acid(VIA)] are being considered in China for the national cervical screening program. Comparing risks of CIN3 and cervical cancer (CIN3+) for different results can inform test choice and management guidelines. We evaluated the immediate risk of CIN3+ for different screening results generated from individual and combined tests. We compared tests using a novel statistic designed for this purpose called Mean Risk Stratification (MRS), in a pooled analysis of 17 cross sectional population-based studies of 30,371 Chinese women screened with all 3 methods and diagnosed by colposcopically-directed biopsies. The 3 tests combined powerfully distinguished CIN3+ risk; triple-negative screening conferred a risk of 0.01%, while HPV-positive HSIL+ that was VIA-positive yielded a risk of 57.8%. Among the three screening tests, HPV status most strongly stratified CIN3+ risk. Among HPV-positive women, cytology was the more useful second test. In HPV-negative women, the immediate risks of CIN3+ ranged from 0.01% (negative cytology), 0.00% (ASC-US), 1.1% (LSIL), to 6.6 (HSIL+). In HPV-positive women, the CIN3+ risks were 0.9% (negative cytology), 3.6% (ASC-US), 6.3% (LSIL) and 38.5% (HSIL+). VIA results did not meaningful stratify CIN3+ risk among HPV-negative women with negative or ASC-US cytology; however, positive VIA substantially elevated CIN3+ risk for all other, more positive combinations of HPV and cytology compared with a negative VIA. Because all 3 screening tests had independent value in defining risk of CIN3+, different combinations can be optimized as pragmatic strategies in different resource settings.