title: What predicts early volumetric edema increase following stereotactic radiosurgery for brain metastases?
abstract: A volumetric analysis of pre- and post-radiosurgery (PreSRS and PostSRS) edema in patients with cerebral metastases was performed to determine factors of a predictive model assessing the risk of developing increased edema relatively early after SRS. One-hundred-fourteen metastases in 55 patients were analyzed. Selection for this analysis required an MRI ≤ 30 days before SRS and an MRI ≤ 100 days after SRS. Tumor volumes were calculated on PreSRS, SRS, and PostSRS T1-weighted postgadolinium images while edema volumes were calculating using PreSRS and PostSRS fluid-attenuated inversion recovery MR images. An increase in edema was defined as an increase in measurable edema of at least 5%. We developed and evaluated a model predicting the relative risk (RR) of increased edema after SRS. Peritumoral edema increased in 18% (21/114) of the analyzed lesions. Melanoma/renal histology, recursive partitioning analysis class III, and prior WBRT carried RRs of developing postSRS edema increase of 2.45, 2.48, and 3.16, respectively (all P values <0.05). The PreSRS edema/tumor ratio predicted for a RR of 1.007/ratio unit, and steroid dose at time of SRS predicted for a RR of 0.89/mg (all P values <0.05). A predictive model for assessing the RR of increased edema after SRS was developed based from these data and may be useful in identifying patients who might benefit from prophylactic anti-edema therapies before, during, or after SRS. This model could be used as the basis of inclusion criteria for prospective trials investigating novel anti-edema therapies.
authors.affiliation: University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD, 21201, USA. andrew.hanna@som.umaryland.edu.
authors.forename: Andrew
authors.identifier: http://orcid.org/0000-0001-8986-0864
authors.initials: A
authors.lastname: Hanna
authors.affiliation: Department of Radiation Oncology, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: D Hunter
authors.initials: DH
authors.lastname: Boggs
authors.affiliation: Department of Radiation Oncology, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Young
authors.initials: Y
authors.lastname: Kwok
authors.affiliation: Department of Neurosurgery, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Simard
authors.affiliation: Department of Radiation Oncology, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: William F
authors.initials: WF
authors.lastname: Regine
authors.affiliation: Department of Radiation Oncology, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Minesh
authors.initials: M
authors.lastname: Mehta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000556:secondary / Q000601:surgery*; D004487:Edema / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009367:Neoplasm Staging; D009369:Neoplasms / Q000473:pathology / Q000601:surgery*; D011379:Prognosis; D016634:Radiosurgery / Q000009:adverse effects*; D012189:Retrospective Studies; D015996:Survival Rate
keywords: Brain; Edema; Metastasis; Radiographic; Radiosurgery; Volume