Cost-Utility Analysis of Early Detection with Ultrasonography of Differentiated Thyroid Cancer: A Retrospective Study on a Korean Population

Abstract

Backgruound: There is debate about ultrasonography screening for thyroid cancer and its cost-effectiveness. This study aimed to evaluate the cost-effectiveness of early screening (ES) versus symptomatic detection (SD) for differentiated thyroid cancer (DTC) in Korea.

Methods: A Markov decision analysis model was constructed to compare the cost-effectiveness of ES and SD. The model considered direct medical costs, health outcomes, and different diagnostic and treatment pathways. Input data were derived from literature and Korean population studies. Incremental cost-effectiveness ratio (ICER) was calculated. Willingness-to-pay (WTP) threshold was set at USD 100,000 or 20,000 per quality-adjusted life year (QALY) gained. Sensitivity analyses were conducted to address uncertainties of the model's variables.

Results: In a base case scenario with 50 years of follow-up, ES was found to be cost-effective compared to SD, with an ICER of $2,852 per QALY. With WTP set at $100,000, in the case with follow-up less than 10 years, the SD was cost-effective. Sensitivity analysis showed that variables such as lobectomy probability, age, mortality, and utility scores significantly influenced the ICER. Despite variations in costs and other factors, all ICER values remained below the WTP threshold.

Conclusion: Findings of this study indicate that ES is a cost-effective strategy for DTC screening in the Korean medical system. Early detection and subsequent lobectomy contribute to the cost-effectiveness of ES, while SD at an advanced stage makes ES more cost-effective. Expected follow-up duration should be considered to determine an optimal strategy for DTC screening.

Keywords: Cost-effectiveness analysis; Endocrine surgical procedures; Papillary thyroid microcarcinoma; Quality of life; Watchful waiting.

Fig. 1.

The clinical scenario of ultrasonography examination for thyroid nodules. The health status in orange boxes are applied to Markov model. f/u, follow-up.

Fig. 2.

Incremental cost-effectiveness ratio (ICER) and difference of net monetary benefit (NMB) according to termination stage of the constructed analysis model. Orange color: symptomatic detection (SD) is cost-effective; Blue color: early screening (ES) is cost-effective. (A) With willingness-to-pay (WTP) of $100,000, the difference of NMB changes to a positive number at stage 10, which means that the NMB of ES is higher than that of SD. (B) With WTP of $20,000, the difference of NMB changes to a positive number at stage 18, which means that the NMB of ES is higher than that of SD.

Fig. 3.

(A) Incremental cost-effectiveness ratio (ICER) according to probability of lobectomy with early screening (ES). (B) ICER according to probability of lobectomy with symptomatic detection (SD). (C) ICER according to utility score after lobectomy. (D) ICER according to utility score after total thyroidectomy. QALY, quality-adjusted life year.

Fig. 4.

Changes in incremental cost-effectiveness ratio (ICER) according to age and mortality. (A) ICER according to age. (B) ICER according to mortality after total thyroidectomy (TT). (C) ICER according to mortality with early screening (ES). (D) Net monetary benefit (NMB) according to mortality with symptomatic detection (SD). At base analysis, (mortality with SD, 0.0086), the NMB of ES is larger than those of SD. At point of 0.0049, the NMB of two strategies are cross over. QALY, quality-adjusted life year.

Fig. 5.

Sensitivity analysis results while changing cost of surgery and ultrasonography. (A) Incremental cost-effectiveness ratio (ICER) and net monetary benefit (NMB) changes according to cost of surgery. (B) ICER according to cost of ultrasonography (cost in tertiary hospital or in primary care clinic). (C) ICER according to ultrasonography interval with or without national insurance. Regular follow-up: once every 6 months for the first year, annual follow-up from 2 to 5 years, every 2 years for 5 to 10 years, every 3 years for 10 to 20 years, and every 5 years after 20 years. QALY, quality-adjusted life year; ES, early screening; SD, symptomatic detection.