Spontaneous Volumetric Tumor Regression During Wait-and-Scan Management of 952 Sporadic Vestibular Schwannomas

Abstract

ObjectiveSpontaneous tumor shrinkage during wait-and-scan management of sporadic vestibular schwannoma is generally considered an uncommon phenomenon. However, most data informing this understanding stem from single-slice linear tumor measurements taken in the axial imaging plane. The objective of the current work was to characterize the regression capacity of sporadic vestibular schwannomas using volumetric tumor measurements.Study DesignRetrospective cohort study using slice-by-slice, three-dimensional volumetric tumor measurements.SettingThree tertiary referral centers.PatientsPatients with sporadic vestibular schwannoma.InterventionsWait-and-scan.Main Outcome MeasuresRegression-free survival rates with regression defined as a decrease of at least 20% of the tumor volume.ResultsAmong 952 patients undergoing a total of 3,505 magnetic resonance imaging studies during observation, 123 experienced volumetric tumor regression after diagnosis at a median of 1.2 years (interquartile range, 0.6–2.9 yr). Volumetric regression-free survival rates (95% confidence interval; number still at risk) at 1, 3, and 5 years after diagnosis were 94% (92–95%; 662), 86% (83–89%; 275), and 78% (73–82%; 132), respectively. Among 405 patients who demonstrated an initial period of tumor growth but continued wait-and-scan management, 48 experienced volumetric regression at a median of 1.2 years (interquartile range, 0.8–2.6 yr) after initial growth. Volumetric regression-free survival rates at 1, 3, and 5 years after initial growth were 94% (92–97%; 260), 84% (79–89%; 99), and 75% (67–83%; 43), respectively. Ultimately, only 82 of the 952 patients studied showed exclusively volumetric tumor regression (i.e., without any periods of tumor growth) by the time of last follow-up.ConclusionSpontaneous volumetric tumor shrinkage during wait-and-scan management occurs more frequently than suggested by previous studies using linear tumor measurements and can even occur after previous episodes of documented tumor growth. These data further highlight the dynamic nature of vestibular schwannoma growth. To this end, the application of natural history data to patient management requires a nuanced approach that parallels the complex tumor behavior of vestibular schwannoma.

Spontaneous shrinkage of vestibular schwannoma with the recovery of impaired hearing: A case report and literature review

“…[ 1 , 2 , 5 , 12 , 13 , 16 , 21 ] Recent studies have shown that 123 of 952 cases demonstrated tumor shrinkage during a median observation period of 1.2 years, suggesting that natural shrinkage may occur more frequently than previously thought. [ 10 ] However, the cause of this natural regression remains unclear.…”

Stratifying Risk of Future Growth Among Sporadic Vestibular Schwannomas

“…Institutional review board approval was obtained from each participating center before data collection (institutional review board numbers 15-008224, 112016-040, and S13-00063, respectively). Although the present analysis is unique, the patient data presented in the current publication overlap with previously published work (16,17). A full description of the methodology used in the current work can be found elsewhere (17), but briefly, slice-by-slice volumetric tumor measurements were performed on consecutive MRI scans for each patient undergoing wait-and-scan management at each participating center.…”

COMMENT UPON: MOSHTAGHI ET AL. PAPER THAT APPEARED IN THE JULY 2023 ISSUE OF OTOLOGY & NEUROTOLOGY TITLED “THE EFFECT OF IMMEDIATE MICROSURGICAL RESECTION OF VESTIBULAR SCHWANNOMA ON HEARING PRESERVATION”

“…By contrast, a 2016 systematic review that compiled data from many studies of VS growth behavior found that 50.1% of followed tumors demonstrated growth at 5 years (4). Numerous studies have identified a lower rate of growth for small tumors compared with larger tumors (5). This implies that reviews encompassing all tumor sizes may overestimate the growth for small tumors.…”