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Adverse Radiation Effect After Hypofractionated Stereotactic Radiosurgery in 5 Daily Fractions for Surgical Cavities and Intact Brain Metastases.
- Source :
-
International Journal of Radiation Oncology, Biology, Physics . Mar2020, Vol. 106 Issue 4, p772-779. 8p. - Publication Year :
- 2020
-
Abstract
- <bold>Purpose: </bold>Limited data exist quantifying the risk of adverse radiation effect (ARE) specific to hypofractionated stereotactic radiosurgery (HSRS). We present our analyses of the risk of ARE after 5 daily fractions of HSRS to surgical cavities and intact metastases.<bold>Methods and Materials: </bold>One hundred and eighty-seven consecutively treated patients with 118 surgical cavities and 132 intact metastases were retrospectively reviewed. All patients were treated with 5 daily fractions with a 2 mm planning target volume applied. Clinical and dosimetric variables were assessed to identify predictors of ARE.<bold>Results: </bold>The median total prescribed dose was 30 Gy (range, 20-35 Gy) and median follow-up was 12 months. One hundred forty-four patients (77%) received treatment to a single target. Median planning target volumes for resection cavity and intact metastases were 24.9 cm3 and 7.7 cm3, respectively. ARE and symptomatic ARE were observed 21.2% and 10.8% of targets, respectively, and the median time to ARE was 8 months. Time to ARE was <6 months for 38%, 6 to 12 months for 43%, and >12 months for 19% of targets. Multivariable analysis identified intact metastases versus cavities (odds ratio [OR], 3.65; 95% confidence interval [CI], 1.33-10) as a significant predictor of symptomatic ARE. Specific to cavity HSRS, prior whole brain radiation therapy (OR 7.73; 95% CI, 1.67-35.69) and prior stereotactic radiosurgery (OR 8.66; 95% CI, 1.14-65.7) were significant predictors of symptomatic ARE. For intact metastases, the total brain minus gross tumor volume (GTV) receiving 30 Gy (BMC30) was a significant predictor of symptomatic ARE (OR, 1.21; 95% CI, 1.02-1.43), and a volume-based BMC30 threshold of 10.5 cm3 was significant with an OR of 7.21 (95% CI, 1.31-39.45).<bold>Conclusions: </bold>The risk of ARE was greater for intact metastases compared with cavities after HSRS. For intact lesions, the BMC30 was predictive for symptomatic necrosis, and a threshold of 10.5 cm3 may guide treatment planning. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 03603016
- Volume :
- 106
- Issue :
- 4
- Database :
- Academic Search Index
- Journal :
- International Journal of Radiation Oncology, Biology, Physics
- Publication Type :
- Academic Journal
- Accession number :
- 141863309
- Full Text :
- https://doi.org/10.1016/j.ijrobp.2019.12.002