In search of the most cost-effective monitoring strategy for vestibular schwannoma: A decision analytical modelling study.

Objectives: To assess the cost-effectiveness of frequently used monitoring strategies for vestibular schwannoma (VS).

Design: A state transition model was developed to compare six monitoring strategies for patients with VS: lifelong annual monitoring; annual monitoring for the first 10 years after diagnosis; scanning at 1-5, 7, 9, 12, 15 years after diagnosis and subsequently every 5 years; a personalised monitoring strategy for small and large tumours; scanning at 1, 2 and 5 years after diagnosis and no monitoring. Input data were derived from literature and expert opinion. Quality-adjusted life years (QALYs) and healthcare costs of each strategy were modelled over lifetime. Net monetary benefits (NMBs) were calculated to determine which strategy provided most value for money. Sensitivity analyses were performed to address uncertainty.

Results: Omitting monitoring is least effective with 18.23 (95% CI 16.84-19.37) QALYs per patient, and lifelong annual monitoring is most effective with 18.66 (95% CI 17.42-19.65) QALYs. Corresponding costs were €6526 (95% CI 5923-7058) and €9429 (95% CI 9197-9643) per patient, respectively. Lifelong annual monitoring provided the best value with a NMB of €363 765 (339 040-383 697), but the overall probability of being most cost-effective compared to the other strategies was still only 23%. Sensitivity analysis shows that there is large uncertainty in the effectiveness of all strategies, with largely overlapping 95% confidence intervals for all strategies.

Conclusions: Due to the largely overlapping 95% confidence intervals of all monitoring strategies for VS, it is unclear which monitoring strategy provides most value for money at this moment.