DNA PLOIDY ANALYSIS IS A COST-EFFECTIVE ALTERNATIVE FOR CERVICAL SCREENING

Purpose:

   DNA ploidy analysis, a semi-automated process, has been proposed as a potential alternative for cervical screening; however, this strategy has not been evaluated economically. Our study examined the cost-effectiveness of ploidy analysis in comparison to liquid-based Papanicolaou (Pap) smear in the screening setting.

Methods:

   The use of ploidy was examined with five thresholds corresponding to the number (from 1 to 5) of aneuploid cells in a specimen. For example, the ploidy 3 cell strategy rendered a specimen abnormal if at least 3 aneuploid cells were found. We compared these five ploidy strategies and the liquid-based Pap smear with a no screening strategy as the reference. We developed a state-transition Markov model to simulate the natural history of HPV infection and possible progression into cervical neoplasia in a hypothetical cohort of 12-year-old females (started triennial screening from 21 years). The analysis was conducted using cost in 2012 US$ and effectiveness in quality-adjusted life-years (QALYs) from a health-system perspective throughout a lifetime horizon in the US setting. The willingness-to-pay threshold was $50,000/QALY. We calculated the incremental cost-effectiveness ratios (ICERs) for the various strategies to determine the best ploidy strategy and the overall recommended strategy. The robustness of optimal choices was examined in deterministic and probabilistic sensitivity analyses.

Results:

   In the base-case analysis, the ploidy 4 cell strategy was cost-effective. It increased the quality-adjusted life expectancy by 0.083 QALY and yielded an ICER of $8,774/QALY compared to the no screening strategy. In the deterministic sensitivity analysis, the cost-effectiveness was most sensitive to the cost of the Pap smear procedure, the cost of treating high-grade squamous intraepithelial lesions, the cost of the ploidy analysis, and the ploidy strategies' operating characteristics. For most scenarios, the ploidy 4 cell strategy was cost-effective and was considered the best ploidy strategy. The cost-effectiveness acceptability curves showed that the ploidy 4 cell strategy was more likely to be cost-effective than the Pap smear strategy. 

Conclusion:

   Compared to liquid-based Pap smear screening, ploidy analysis appeared less costly and comparably effective using the standard willingness-to-pay threshold. Screening for cervical neoplasia using DNA ploidy analysis may be a satisfactory alternative, particularly in low-infrastructure settings.

Figure 1. Cost-effectiveness acceptability curves comparing no screening, Papanicolaou smear screening, and the ploidy 4 cell strategy.