Prospective study of stereotactic radiosurgery without whole brain radiotherapy in patients with four or less brain metastases: incidence of intracranial progression and salvage radiotherapy

This prospective study was conducted to evaluate the treatment outcome after stereotactic radiosurgery (SRS) alone with special attention to its influence on intracranial freedom from progression (FFP), local control, time to whole brain radiotherapy (WBRT), and survival. Forty-one patients with brain metastases who met the inclusion criteria were enrolled in this prospective cohort and treated by SRS alone between January 1998 and September 2001. The overall local control rate was 76%. The one year actuarial intracranial FFP was 33%. Ten patients (24%) had relapse at treated site. Twenty-three patients (56%) had intracranial progression with a median time of 4.25 months (1-24.6). Salvage radiotherapy was given in 21 patients (51%). Only 12 (29%) patients required WBRT with the median time to WBRT after SRS of 4.85 months. Nine patients (22%) underwent additional SRS at the median time of 5 months after the first procedure. The median survival was 10 months. At the time of follow up, 16 patients (39%) were still alive with a range of 6-31 months. This prospective study suggests that the omission of WBRT in the initial treatment of patients with SRS for four or less brain metastases may allow up to 70% of patients to avoid WBRT.