Hypofractionated stereotactic radiotherapy for brain metastases larger than three centimeters

BACKGROUND: To evaluate the efficacy and outcomes of hypofractionated stereotactic radiotherapy (HSRT) for brain metastases > 3 cm. METHODS: From March 2003 to October 2009, 40 patients with brain metastases larger than 3 cm were treated by HSRT. HSRT was applied in 29 patients for primary treatment and in 11 patients for rescue. Single brain metastasis was detected in 21 patients. Whole brain radiotherapy was incorporated into HSRT in 10 patients for primary treatment. HSRT boosts were applied in 23 patients. The diameters of the brain metastases ranged from 3.1 to 5.5 cm (median, 4.1 cm). The median prescribed dose (not including HSRT boosts) was 40 Gy (range, 20-53 Gy) with a median of 10 fractions (range, 4-15 fractions) to the 90% isodose line. The median dose of the boost was 20 Gy (range, 10-35 Gy) in 4 fractions (range, 2-10 fractions). RESULT: The median overall survival time was 15 months. The overall survival and local control rate at 12 months was 55.3% and 94.2%, respectively. Four patients experienced local progression of large brain metastases. Nine patients died of intracranial disease progression. One patient died of radiation necrosis with brain edema. CONCLUSION: HSRT was a safe and effective treatment for patients with brain metastases ranged from 3.1 to 5.5 cm. Dose escalation of HSRT boost may improve local control with an acceptable toxicity.