Reconsidering the Mandate for Six-Month Post-Radiosurgery MRI in the Treatment of Vestibular Schwannoma: Clinical Review and Cost Analysis

Background Stereotactic radiosurgery (SRS) is a common treatment modality for vestibular schwannoma (VS), with a key role in both primary and recurrent/progressive algorithms. Standard practice after SRS includes initial follow-up imaging at 6 and 12 months. Anecdotally, a change in the treatment plan resulting from the 6-month MRI is rare, due in large part to the host of well-characterized radiographic changes that are observed in the early post-SRS period—in particular, pseudoprogression. Given the high cost and inconvenience associated with MRI, and the mandate to improve cost-efficiency across medical care, our objective was to perform a clinical utilization review and cost analysis, to optimize recommendations for post-SRS imaging protocols.

Methods A prospectively maintained SRS database was retrospectively queried for all VS patients with at least 1 year of posttreatment follow-up, 1990 to 2016. Supplemental retrospective chart review of 6-month post-SRS MRI studies and accompanying clinical letters was completed, and all patients were binarily categorized as either proceeding to routine follow-up, defined as continuation to routine 12-month post-SRS MRI, or clinical action, defined as interval scheduling of a clinical visit, imaging study, or operation on the basis of the 6-month post-SRS MRI.

Results A total of 756 total patients underwent SRS for VS during the study period; 69 were excluded for inadequate follow-up. Of the remaining 687, approximately 5% were seen prior to their scheduled 6-month post-SRS MRI for a host of clinical concerns including facial weakness, hearing loss, worsening tinnitus, imbalance, assessment or treatment of an unrelated intracranial pathology, and headache. Among patients who underwent the standard 6-month post-SRS imaging protocol, there were zero instances of clinical action. Medicare-benchmarked multicenter cost estimation data based on 2012–2016 insurance reimbursement reports approximated the per-study charge for a diagnostic MRI of the brain with and without contrast at $1,796. Within the study population, elimination of 6-month MRI assessments would represent an unadjusted total of $1,176,380. Over the past 5 years, during which time we have completed ∼40 annual treatments, the yearly health care cost reduction based on these estimates would be at least $71,840.

Conclusion Our data demonstrate that 6-month post-SRS MRI does not contribute significantly to patient care, as no instance of clinical action to change the care plan based on a routine follow-up study at that time point has been observed in this large, single-institution cohort. While only a multicenter study would definitively confirm our results, on the basis of the present findings we recommend modification of the standard post-SRS protocol, to eliminate a routine 6-month imaging study—absent concerning clinical changes. If extrapolated nationally to the more than 100 active SRS centers, hundreds of patients would be spared an inconvenient, potentially unindicated study, and the systems-level savings in health care dollars would be on the order of millions annually.