Adverse Radiation Effect After Hypofractionated Stereotactic Radiosurgery in 5 Daily Fractions for Surgical Cavities and Intact Brain Metastases

Salman Faruqi; Mark Ruschin; Hany Soliman; Sten Myrehaug; K Liang Zeng; Zain Husain; Eshetu Atenafu; Chia-Lin Tseng; Sunit Das; James Perry; Pejman Maralani; Chris Heyn; Todd Mainprize; Arjun Sahgal

doi:10.1016/j.ijrobp.2019.12.002

Adverse Radiation Effect After Hypofractionated Stereotactic Radiosurgery in 5 Daily Fractions for Surgical Cavities and Intact Brain Metastases

Int J Radiat Oncol Biol Phys. 2020 Mar 15;106(4):772-779. doi: 10.1016/j.ijrobp.2019.12.002. Epub 2020 Jan 9.

Authors

Affiliations

¹ Department of Radiation Oncology, University of Toronto, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada. Electronic address: muhammad.faruqi@albertahealthservices.ca.
² Department of Radiation Oncology, University of Toronto, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada.
³ Department of Biostatistics, University Health Network, Toronto, Ontario, Canada.
⁴ Department of Neurosurgery, St. Michael's Hospital, Toronto, Ontario, Canada.
⁵ Division of Neurology, University of Toronto, Sunnybrook Health Science Centre, Toronto, Ontario, Canada.
⁶ Department of Medical Imaging, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
⁷ Department of Neurosurgery, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.

PMID: 31928848
DOI: 10.1016/j.ijrobp.2019.12.002

Abstract

Purpose: 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.

Methods and materials: 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.

Results: 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).

Conclusions: 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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Brain Neoplasms / radiotherapy*
Brain Neoplasms / secondary*
Brain Neoplasms / surgery
Female
Humans
Male
Radiation Dose Hypofractionation*
Radiosurgery / adverse effects*
Retrospective Studies