The cost-effectiveness of cervical screening in Australia: what is the impact of screening at different intervals or over a different age range?

Objective: To estimate the cost-effectiveness of altering the currently recommended interval and age range for cervical screening of Australian women. Methods: The cost and effectiveness estimates of alternative screening strategies were generated using an established decision model. This model incorporated a Markov model (of the natural history of cervical cancer and pre-cancerous lesions) and decision trees which: 'mapped' the various pathways to cervical cancer screening; the follow-up of abnormal Pap test results; and the management of confirmed lesions. The model simulated a hypothetical large cohort of Australian women from age 15 to age 85 and calculated the accumulated costs and life-years under each screening strategy. Results: Our model estimated that moving from the current two-yearly screening strategy to annual screening (over the same age range) would cost $379,300 per additional life-year saved. Moving from the current strategy to three-yearly screening would yield $117,100 of savings per life-year lost (costs and effects both discounted at 5% per year), with a relatively modest (< 5%) reduction in the total number of life-years saved by the program. Conclusions: Although moving to annual screening would save some additional lives, it is not a cost-effective strategy. Consideration should be given to increasing the recommended interval for cervical screening. However, the net value of any such shift to less effective (e.g. less frequent) and less costly screening strategies will require better evidence about the cost-effectiveness of strategies that encourage non-screeners or irregular screeners to have a Pap test more regularly.