Hoffmann C, et al. – A research was carried out to quantify brain volume reduction after whole-brain radiotherapy (WBRT) and to assess its prognostic significance. The findings of this study suggested that a smaller decrease in brain volume after WBRT was an independent predictor of longer overall survival.

Methods

• The clinicians estimated brain volumes of 91 patients with cerebral metastases during a 150-day period after commencing WBRT, and were compared to their pretreatment volumes.
• They measured the average daily relative change in brain volume of each patient, referred to as the ‘brain volume reduction rate’.
• The prognostic significance of the brain volume reduction rate, as well as of three treatment-related and nine pretreatment factors were appraised by using univariate and multivariate Cox regression analyses.
• They used a one-way analysis of variance to compare the brain volume reduction rate across recursive partitioning analysis (RPA) classes.

Results

• The brain volume reduction rate was highlighted as a significant predictor of overall survival after WBRT (P<.001), as well as the number of brain metastases (P=.002) and age (P=.008).
• In comparison to patients with a poor prognosis (RPA class 3) (P=.001), patients with a relatively favorable prognosis (RPA classes 1 and 2) experienced significantly less brain volume decrease after WBRT.
• No significant correlation was observed between delivered radiation dose and brain volume reduction rate (P=.147).