Screening for malignancy after augmentation cystoplasty in children with spina bifida: a decision analysis

Abstract

Purpose: Augmentation cystoplasty is the mainstay of surgical treatment for medically refractory neurogenic bladder in patients with spina bifida. Concerns regarding an increased risk of malignancy have prompted many centers to consider routine postoperative screening. We examine the potential cost-effectiveness of such screening.

Materials and methods: A Markov model was used to compare 2 screening strategies among patients with spina bifida after cystoplasty, namely annual screening cystoscopy and cytology and usual care. Model parameters were informed via a systematic review of post-augmentation malignancy and cost estimates from published reports or government sources.

Results: In a hypothetical cohort the individual increase in life expectancy for the entire cohort was 2.3 months with an average lifetime cost of $55,200 per capita, for an incremental cost-effectiveness ratio of $273,718 per life-year gained. One-way and two-way sensitivity analyses suggest the screening strategy could be cost effective if the annual rate of cancer development were more than 0.26% (12.8% lifetime risk) or there were a greater than 50% increase in screening effectiveness and cancer risk after augmentation. After adjusting for multiple levels of uncertainty the screening strategy had only an 11% chance of being cost effective at a $100,000 per life-year threshold or a less than 3% chance of being cost effective at $100,000 per quality adjusted life-year.

Conclusions: Annual screening for malignancy among patients with spina bifida with cystoplasty using cystoscopy and cytology is unlikely to be cost effective at commonly accepted willingness to pay thresholds. This conclusion is sensitive to a higher than expected risk of malignancy and to highly optimistic estimates of screening effectiveness.