Routine on-site evaluation of specimen adequacy during initial ultrasound-guided fine needle aspiration of thyroid nodules: a cost-effectiveness analysis

Abstract

Background: On-site evaluation (OSE) of specimen adequacy during fine needle aspiration (FNA) of thyroid nodules reduces unsatisfactory results but adds cost. We hypothesized that the addition of routine OSE to initial ultrasound-guided FNA of thyroid nodules is not cost-effective.

Methods: Formal cost-effectiveness analysis was performed using a decision model to compare strategies of routine initial OSE versus restriction of OSE to cases of prior inadequate FNA. Adequacy rates for FNA without OSE and detriment to quality-adjusted life expectancy (QALE) for undergoing repeat FNA were estimated on the basis of literature review and institutional experience. Costs were estimated using Medicare limiting charges and Bureau of Labor Statistics wage rates. Sensitivity analysis was used to examine the uncertainty of the model variable estimates.

Results: The routine OSE strategy produced a gain of 0.00007 quality-adjusted life-years (QALYs) at an additional cost of $43.75 for an incremental cost-effectiveness ratio of $639,143/QALY when compared to restriction of OSE to cases with prior inadequate results. During sensitivity analysis, routine OSE became cost-effective if FNA adequacy rate without OSE decreased from 90 to 85 %, cost of OSE decreased from $116 to $75, cost of FNA increased from $366 to $735, hourly wage increased from $23 to $123, or QALE detriment for repeat FNA increased from 0.25 to 1.6 days.

Conclusions: OSE for initial ultrasound-guided FNA of thyroid nodules is not cost-effective unless the adequacy rate without OSE is less than 85 %. When operator performance exceeds this rate, OSE should be reserved for cases with previous inadequate results.