A multi-institutional study of factors influencing the use of stereotactic radiosurgery for brain metastases.
OBJECTIVE
Stereotactic radiosurgery (SRS) for brain metastases is a relatively well-studied technology with established guidelines regarding patient selection, although its implementation is technically complex. We evaluated the extent to which local availability of SRS affected the treatment of patients with brain metastases.


METHODS
We identified 3030 patients who received whole-brain radiation therapy (WBRT) for brain metastases in 1 of 7 cancer centers in Ontario. Clinical data were abstracted for a random sample of 973 patients. Logistic regression analyses were performed to identify factors associated with the use of SRS as a boost within 4 months following WBRT or at any time following WBRT.


RESULTS
Of 898 patients eligible for analysis, SRS was provided to 70 (7.8%) patients at some time during the course of their disease and to 34 (3.8%) patients as a boost following WBRT. In multivariable analyses, factors significantly associated with the use of SRS boost following WBRT were fewer brain metastases (odds ratio [OR] = 6.50), controlled extracranial disease (OR = 3.49), age (OR = 0.97 per year of advancing age), and the presence of an on-site SRS program at the hospital where WBRT was given (OR = 12.34; all P values were <.05). Similarly, availability of on-site SRS was the factor most predictive of the use of SRS at any time following WBRT (OR = 5.98). Among patients with 1-3 brain metastases, good/fair performance status, and no evidence of active extracranial disease, SRS was provided to 40.3% of patients who received WBRT in a hospital that had an on-site SRS program vs 3.0% of patients who received WBRT at a hospital without SRS (P<.01).


CONCLUSIONS
The availability of on-site SRS is the factor most strongly associated with the provision of this treatment to patients with brain metastases and appears to be more influential than accepted clinical eligibility factors.
Radiation Medicine Program, Princess Margaret Hospital, University Health Network, and Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada. David.Hodgson@rmp.uhn.on.ca
David C
DC
Hodgson
Anne-Marie
AM
Charpentier
Candemir
C
Cigsar
Eshetu G
EG
Atenafu
Angela
A
Ng
Guarav
G
Bahl
Gelareh
G
Zadeh
John
J
San Miguel
Cynthia
C
Menard
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001932:Brain Neoplasms / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery*; D001943:Breast Neoplasms; D002289:Carcinoma, Non-Small-Cell Lung / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery; D002292:Carcinoma, Renal Cell / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery; D015179:Colorectal Neoplasms; D016371:Cranial Irradiation / Q000379:methods; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms; D008175:Lung Neoplasms; D008297:Male; D008545:Melanoma / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery; D008875:Middle Aged; D016017:Odds Ratio; D009864:Ontario; D016634:Radiosurgery / Q000379:methods / Q000706:statistics & numerical data*; D012044:Regression Analysis