Dose escalation in patients receiving whole-brain radiotherapy for brain metastases from colorectal cancer.
OBJECTIVE
Whole-brain radiotherapy (WBRT) alone is the most common treatment for brain metastases from colorectal cancer, as most patients are not candidates for more aggressive therapies such as resection or radiosurgery. The standard WBRT regimen, 30 Gy in ten fractions (10 x 3 Gy), has generally resulted in poor outcomes. This study investigated whether an escalation of the WBRT dose improves these results.


METHODS
Data from 53 patients receiving WBRT alone for brain metastases from colorectal cancer were retrospectively analyzed. 10 x 3 Gy (n = 35) was compared to higher doses (40 Gy/20 fractions or 45 Gy/15 fractions; n = 18) for overall survival (OS) and local control (LC). Additional factors evaluated for prognostic importance included age, gender, performance status, number of metastases, and extracerebral metastases.


RESULTS
The OS rates at 6 months were 17% after 10 x 3 Gy and 50% after 20 x 2 Gy/15 x 3 Gy (p = 0.014). On multivariate analysis, improved OS was significantly associated with higher WBRT dose (p = 0.047), Karnofsky Performance Score (KPS) > or = 70 (p = 0.034), less than four brain metastases (p = 0.036), and lack of extracerebral metastases (p = 0.010). The LC rates at 6 months were 17% after 10 x 3 Gy and 50% after higher doses (p = 0.018). On multivariate analysis of LC, higher WBRT dose was significant (p = 0.028). A trend was observed for KPS > or = 70 (p = 0.08) and less than four brain metastases (p = 0.06).


CONCLUSIONS
These data suggest that patients with brain metastases from colorectal cancer treated with WBRT alone appeared to benefit from escalation of the radiation dose beyond 10 x 3 Gy in terms of improved OS and LC.
Heisterkamp
Christine
C
Department of Radiation Oncology, University Hospital Schleswig-Holstein, Lübeck, Germany.
Haatanen
Tiina
T
Department of Radiation Oncology, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
Schild
Steven E
SE
Department of Radiation Oncology, Mayo Clinic, Scottsdale, AZ, USA.
Rades
Dirk
D
Department of Radiation Oncology, University Hospital Schleswig-Holstein, Lübeck, Germany. Rades.Dirk@gmx.net.|Department of Radiation Oncology, University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany. Rades.Dirk@gmx.net.
D000368:Aged; D001932:Brain Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000556:secondary*; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D016371:Cranial Irradiation / Q000379:methods*; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D017567:Karnofsky Performance Status; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D015996:Survival Rate