Solitary brain metastases treated with the Leksell gamma knife: prognostic factors for patients

Abstract

Purpose: To analyze treatment results, complications, prognostic factors and their statistical significance in surviving patients treated with the Leksell gamma knife (LGK) for solitary brain metastases.

Materials and methods: Between 1992-1998, 237 patients were treated with solitary brain metastasis (SBM). The histological subtypes were as follows: 101 patients (42.6%) non small-cell lung cancer, 42 (17.7%) renal cell carcinoma, 36 (15.2%) breast carcinoma, 30 (12.7%) colorectal carcinomas and 28 (11.8%) melanoma.

Results: A complete or partial regression was observed in 193 (81.4%) patients, cessation of growth activity in 32 (13.5%) and local progression in 12 (5.1%). Local recurrence was observed in nine (4.7%) of 193 patients with complete or partial regression. Acute toxicity appeared in 24 (10%) patients (score 3.4), late complications (score 3.4) were observed in 13 patients (5.5%). Out of 237 patients, 182 patients died with a median survival of 6 months and 55 patients are still alive with a median survival 12 months and with a minimal follow up period of 10 months. The significant prognostic factors for longer survival in these series of patients were: Karnofsky performance status (70% or more), the extent of extra-cerebral disease (no extra-cerebral disease), pretreatment neurological symptoms neurological functional class (NFC 1), histology (renal cell and breast carcinomas) and the dose to the planning target volume (20 Gy and higher).

Conclusions: Radiosurgery provides an effective local control for 90% of treated patients with low morbidity. Several significant prognostic factors were detected for patients' survival. These factors can help to predict better patients' survival after the LGK treatment.