Linac radiosurgery versus whole brain radiotherapy for brain metastases. A survival comparison based on the RTOG recursive partitioning analysis.
OBJECTIVE
For patients with inoperable brain metastases, whole brain radiotherapy (WBRT) has been the standard treatment for decades. Radiosurgery is an effective alternative strategy, but has failed to show a substantial survival benefit so far. The prognostic factors derived from the RTOG recursive partitioning analysis (RPA) provide a framework that allows a nonrandomized comparison of the two modalities.


METHODS
From 1991 to 1998, 117 patients with one to three previously untreated cerebral metastases underwent single-dose linac radiosurgery (median dose 20 Gy) without adjuvant WBRT. After radiosurgery, 26/117 patients (22%) had salvage WBRT, radiosurgery or neurosurgical resection of recurrent (4/117) and/or new (24/117) metastases. Survival of these patients was compared to a historical group of 138 patients with one to three lesions treated by WBRT (30-36 Gy/3-Gy fractions) from 1978 to 1991; only nine of these patients (7%) had salvage WBRT. All patients were classified into the three RPA prognostic classes based on age, performance score, and presence of extracranial tumor manifestations.


RESULTS
In RPA class I (Karnofsky performance score > or = 70, primary tumor controlled, no other metastases, age < 65 years), radiosurgery resulted in a median survival of 25.4 months (n = 23, confidence interval [CI] 5.8-45.0) which was significantly longer than for WBRT (n = 9, 4.7 months, CI 3.8-5.5; p < 0.0001). In RPA class III (Karnofsky performance score < 70), no significant difference in survival between radiosurgery (n = 20, 4.2 months, CI 3.2-5.3) and WBRT (n = 68, 2.5 months, CI 2.2-2.8) was found. In RPA class II (all other patients), radiosurgery produced a small, but significant survival advantage (radiosurgery: n = 74, 5.9 months, CI 3.2-8.5, WBRT: n = 61, 4.1 months, CI 3.4-4.9; p < 0.04).


CONCLUSIONS
Radiosurgery in patients with one to three cerebral metastases results in a substantial survival benefit only in younger patients with a low systemic tumor burden when compared to WBRT alone. It cannot be excluded that this effect is partially caused by the available salvage options after radiosurgery.
Kocher
Martin
M
Department of Radiation Oncology, University of Cologne, Germany. Martin.Kocher@medizin.uni-koeln.de
Maarouf
Mohammad
M
Bendel
Mark
M
Voges
Juergen
J
Müller
Rolf-Peter
RP
Sturm
Volker
V
D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000401:mortality* / Q000532:radiotherapy* / Q000556:secondary; D018572:Disease-Free Survival; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009382:Neoplasms, Unknown Primary / Q000401:mortality* / Q000532:radiotherapy*; D011379:Prognosis; D016634:Radiosurgery / Q000706:statistics & numerical data*; D020266:Radiotherapy, Conformal / Q000706:statistics & numerical data*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016879:Salvage Therapy / Q000706:statistics & numerical data*; D013534:Survival; D016019:Survival Analysis; D016896:Treatment Outcome