Whole-Brain Radiotherapy with 20 Gy in 5 Fractions for Brain Metastases in Patients with Cancer of Unknown Primary (CUP)

Abstract

Whole brain radiotherapy (WBRT) is the most common treatment for brain metastases. Survival of patients with cancer of unknown primary (CUP) presenting with brain metastases is extremely poor. A radiation program with a short overall treatment time (short-course RT) would be preferable to longer programs if it provides similar outcomes. This study compares short-course RT with 20 Gy in 5 fractions (5 x 4 Gy) given over 5 days to longer programs in CUP patients. Data regarding 101 CUP patients who received either short course WBRT (n=34) with 5 x 4 Gy or long-course WBRT (n=67) with 10 x 3 Gy given over 2 weeks or 20 x 2 Gy given over 4 weeks for brain metastases were analyzed retrospectively. Six additional potential prognostic factors were investigated: age, gender, Karnofsky performance score (KPS), number of brain metastases, extracranial metastases, RPA-(Recursive Partitioning Analysis-)class. On univariate analysis, the radiation program was not associated with survival (p=0.88) nor intracerebral control (p=0.36). Improved survival was associated with KPS >or= 70 (p<0.001), absence of extracranial metastases (p<0.001), and RPA-class 1 (p<0.001). On multivariate analyses, KPS (risk ratio [RR]: 4.55; p<0.001), extracranial metastases (RR: 1.70; p=0.018), and RPA-class (RR: 2.86; p<0.001) maintained significance. On univariate analysis, KPS (p<0.001) and RPA-class (p<0.001) were significantly associated with intracerebral control. On multivariate analyses, KPS (RR: 2.72; p<0.001) and RPA-class (RR: 2.09; p<0.001) remained significant. Short-course WBRT with 5 x 4 Gy provided similar intracerebral control and survival as longer programs for the treatment of brain metastases in CUP patients. 5 x 4 Gy appears preferable because it is more convenient for patients.