A MULTIINSTITUTIONAL OUTCOME AND PROGNOSTIC FACTOR-ANALYSIS OF RADIOSURGERY FOR RESECTABLE SINGLE BRAIN METASTASIS

Purpose: Recent randomized trials of selected patients with single bra in metastasis comparing resection followed by whole-brain radiotherapy (WBRT) to WBRT alone have shown a statistically significant survival advantage for surgery and WBRT. A multiinstitutional retrospective stu dy was performed, which identified comparable patients who were treate d with stereotactic radiosurgery (RS) and WBRT. Methods and Materials: The RS databases of four institutions were reviewed to identify patie nts who met the following criteria: single-brain metastasis; no prior cranial surgery or WBRT; age > 18 years; surgically resectable lesion; Karnofsky Performance Status (KPS) greater than or equal to 70 at tim e of RS; nonradiosensitive histology. One hundred twenty-two patients mere identified who met these criteria. Patients mere categorized by: (a) status of the primary, (b) status of non-CNS metastasis, (c) age, (d) baseline KPS (from 70-100), (c) histology, (f) time from diagnosis of primary to the detection of the brain metastasis, (g) gender, and (h) tumor volume. RS was performed with a linear accelerator based tec hnique (peripheral dose range was 10-27 Gy, median was 17 Gy). WBRT wa s performed in all but five patients who refused WBRT (dose range was 25-40 Gy, median was 37.5 Gy). Results: The median follow-up for all p atients was 123 weeks. The overall local control rate (defined as lack of progression in the RS volume) was 86%. Intracranial recurrence out side of the RS volume was seen in 27 patients (22%). The actuarial med ian survival from date of RS is 56 weeks, and the 1-year and 2-year ac tuarial survival rates are 53 and 30%. The median duration of function al independence (sustained KPS greater than or equal to 70) is 44 week s. Nineteen of 77 deaths were attributed to CNS progression (25% of al l deaths). Multivariate analysis revealed the following factors to be statistically significant predictors of survival: baseline KPS (p < .0 001) and absence of other sites of metastasis (p = 0.008). Conclusion: The RS in conjunction with WBRT for single brain metastasis can produ ce substantial functional survival, especially in patients with good p erformance status and without extracranial metastasis. These results a re comparable to recent randomized trials of resection and WBRT. The a dvantages of RS over surgery in terms of cost, hospitalization, morbid ity, and wider applicability strongly suggest that a randomized trial to compare RS with surgery is warranted.