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.
