Fractionated stereotactic radiotherapy of small intracranial malignancies

To retrospectively evaluate the effectiveness of fractionated stereotactic radiotherapy (FSRT) in patients with small intracranial malignancies.

From July 1991 to March 1997, 80 patients with a total of 121 brain or skull-base tumors were treated with FSRT alone, and were followed for periods ranging from 3 to 62 months (median 9.8). The majority of patients received 42 Gy in 7 fractions over 2.3 weeks, but in July 1993, protocols using smaller fraction doses were introduced for patients whose radiation-field diameters were larger than 3 cm or whose tumors were close to critical normal tissues.

For 64 patients with metastatic brain tumors the overall median survival was 8.3 months and 1-year actuarial survival rate was 33%. Significant prognostic factors were: the presence of extracranial tumors, pre-treatment performance status, and the lung as a primary site. Patients without extracranial tumors prior to FSRT had a median survival of 21.2 months. For seven patients with high-grade glioma, 1-year actuarial local control rate was 75%, with a median survival of 10.3 months. For patients with skull-base tumors the local control was achieved in 6 of 6 patients (100%), with a median survival of 30.7 months. No one suffered from acute complications, but three patients, two of whom had undergone FSRT as the third course of radiotherapy, developed late radiation injuries.

Overall high local control and low morbidity rates suggest that FSRT is an effective and safe modality, even for those with a history of prior irradiation. However, patients with risk factors should be treated with smaller fraction doses.