Uptake of liquid-based cytology as an adjunct to conventional cytology for cervical screening in NSW, Australia: a cross-sectional and population-based cohort analysis

BACKGROUND Cervical screening is currently recommended every two years in sexually active women aged 18-20 to 69 years in Australia. Direct replacement of conventional cytology with liquid-based cytology (LBC) for cervical screening was rejected for public funding on grounds of cost-effectiveness, first in 2002 and again in 2009, but LBC is performed as an adjunct to conventional cytology in women who elect to pay. The objective of this study was to describe prevalence and predictors of use of LBC in Australia's most populous state, New South Wales (NSW). METHODS We performed cross-sectional and population-based cohort analyses using data from the state Pap Test Register in NSW. We calculated the age-adjusted proportion of women aged 20-69 years electing to have adjunctive LBC over the period from 2006-2010. We also calculated the fully-adjusted odds ratios for the association between subsequent LBC use and age, socioeconomic status, place of residence, previous cytological history and provider type in a cohort of 360,247 women who had an index cervical cytology test in 2006-8. RESULTS Uptake of LBC varied between 29.7% (95% Confidence Interval (CI): 29.5-30.0%) in 2006/7 and 26.6% (95% CI: 26.4-26.9%) in 2009/10. LBC was more likely to be used in women aged 30-44 years, if it had been used previously (OR13.58, 95% CI: 13.33-13.84), if the previous test result was abnormal (OR2.62, 95% CI:2.53-2.72) or unsatisfactory (OR2.37, 95% CI:2.27-3.47), or if a gynaecologist requested the test (OR1.50, 95% CI:1.46-1.54). Uptake was least for women in remote/very remote areas (OR0.68; 95% CI:0.57-0.80 referenced to those in major cities) and in lower socioeconomic groups (OR 0.41, 95% CI:0.40-0.42 for lowest versus highest SES quintile). CONCLUSION In the current environment in NSW, Australia, in which public funding for LBC has not been available, adjunctive uptake of LBC depends strongly on a woman's age, her screening history and socioeconomic factors. These findings provide important context for a current review of technologies used in the National Cervical Screening Program in Australia.