Purpose: To assess the progression patterns in patients with multifocal glioblastoma multiforme who had undergone whole brain radiotherapy (WBRT), the historical standard, versus three-dimensional conformal radiotherapy, and to identify predictive treatment and pretreatment factors.
Methods and materials: The records of 50 patients with multifocal glioblastoma multiforme treated with RT were reviewed. Univariate analyses were performed using survival methods and the Cox proportional hazards regression method. Multivariate analyses were performed using the Cox proportional hazards regression method.
Results: The mean age was 61 years, and 71% had a Karnofsky performance status (KPS) score of > or =70. Of the 50 patients, 32% underwent WBRT and 68%, three-dimensional conformal RT. Progression was local in all evaluable patients, as determined by imaging in 38 patients and early neurologic progression in 12. The median time to progression (TTP) was 3.1 months, and the median survival time (MST) was 8.1 months. The significant independent predictors of TTP on multivariate analysis were a KPS score <70 (p = 0.001), the extent of surgery (p = 0.040), a radiation dose <60 Gy (p = 0.027), and the lack of chemotherapy (p = 0.001). The significant independent predictors of a reduced MST were a KPS score <70 (p = 0.022) and the absence of salvage surgery (p = 0.011) and salvage chemotherapy (p = 0.003).
Conclusion: Local progression was observed in all patients. On multivariate analysis, no significant difference was found in the TTP or MST between three-dimensional conformal radiotherapy and WBRT. The KPS was a consistent independent predictor of both TTP and MST. On the basis of the progression pattern, we do not recommend WBRT as a mandatory component of the treatment of multifocal glioblastoma multiforme.