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- Tuleasca, Constantin, et al.
(författare)
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Impact of the Mean Cochlear Biologically Effective Dose on Hearing Preservation After Stereotactic Radiosurgery for Vestibular Schwannoma: A Retrospective Longitudinal Analysis
- 2024
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Ingår i: Neurosurgery. - 0148-396X .- 1524-4040. ; 94:1, s. 174-182
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVES: Stereotactic radiosurgery (SRS) is a useful alternative for small- to medium-sizedvestibular schwannoma. To evaluate whether biologically effective dose (BEDGy2.47), calculated for mean (BEDGy2.47 mean)and maximal (BEDGy2.47 max) cochlear dose, is relevant for hearing preservation. METHODS: This is a retrospective longitudinal single-center study. Were analyzed 213 patients with useful baselinehearing. Risk of hearing decline was assessed for Gardner–Robertson classes and pure tone average (PTA) loss. The meanfollow-up period was 39 months (median 36, 6-84).RESULTS: Hearing decline (Gardner–Robertson class) 3 years after SRS was associated with higher cochlear BEDGy2.47 mean(odds ratio [OR] 1.39, P = .009). Moreover, BEDGy2.47 mean was more relevant as compared with BEDGy2.47 max (OR 1.13, P = .04).Risk of PTA loss (continuous outcome, follow-up minus baseline) was significantly corelated with BEDGy2.47 mean at 24 (betacoefficient 1.55, P = .002) and 36 (beta coefficient 2.01, P = .004) months after SRS. Risk of PTA loss (>20 dB vs ≤) was associatedwith higher BEDGy2.47 mean at 6 (OR 1.36, P = .002), 12 (OR 1.36, P = .007), and 36 (OR 1.37, P = .02) months. Risk of hearingdecline at 36 months for the BEDGy2.47 mean of 7–8, 10, and 12 Gy2.47 was 28%, 57%, and 85%, respectively. CONCLUSION: Cochlear BEDGy2.47 mean is relevant for hearing decline after SRS and more relevant as compared withBEDGy2.47 max. Three years after SRS, this was sustained for all hearing decline evaluation modalities. Our data suggestthe BEDGy2.47 mean cut-off of ≤8 Gy2.47 for better hearing preservation rates.
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| 2. |
- Tuleasca, Constantin, et al.
(författare)
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The Relevance of Biologically Effective Dose for Hearing Preservation After Stereotactic Radiosurgery for Vestibular Schwannomas : A Retrospective Longitudinal Study
- 2023
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Ingår i: Neurosurgery. - : Ovid Technologies (Wolters Kluwer Health). - 0148-396X .- 1524-4040. ; 92:6, s. 1216-1226
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Stereotactic radiosurgery has become a common treatment approach for small-to-medium size vestibular schwannomas.OBJECTIVE: To evaluate relationship between time (beam-on and treatment) and risk of hearing decline after stereotactic radiosurgery for vestibular schwannomas in patients with Gardner–Robertson (GR) baseline classes I and II.METHODS: This retrospective longitudinal single-center study included 213 patients with GR I and II treated between June 2010 and December 2019. Risk of passing from GR classes I and II (coded 0) to other classes III, IV, and V (coded 1) and the increase in pure tone average (continuous outcome) were evaluated using a mixed-effect regression model. Biologically effective dose (BED) was further assessed for an alpha/beta ratio of 2.47 (Gy2.47).RESULTS: Binary outcome analysis revealed sex, dose rate, integral dose, time [beam-on time odds ratio 1.03, P = .03, 95% CI 1.00-1.06; treatment time (P = .02) and BED (P = .001) as relevant. Fitted multivariable model included the sex, dose rate, and BED. Pure tone average analysis revealed age, integral dose received by tumor, isocenter number, time (beam-on time odds ratio 0.20, P = .001, 95% CI 0.083-0.33) and BED (P = .005) as relevant.CONCLUSION: Our analysis showed that risk of hearing decline was associated with male sex, higher radiation dose rate (cutoff 2.5 Gy/minute), higher integral dose received by the tumor, higher beam-on time ≥20 minutes, and lower BED. A BED between 55 and 61 was considered as optimal for hearing preservation.
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