COMPARISON BETWEEN RADIOSURGERY AND STEREOTAXIC FRACTIONATED RADIATION FOR THE TREATMENT OF BRAIN METASTASES

This study evaluates the treatment of intracerebral brain metastases w ith single dose stereotactic radiosurgery in comparison to stereotacti c fractionated radiotherapy (SFR). Twenty six patients with 41 lesions were evaluated. Thirty four lesions in 19 patients were treated with radiosurgery, and 7 lesions in 7 patients were treated with SFR. The r adiosurgery group was treated with an average number of isocenters of 1.4, and an average of 9 arcs. The average dose was 2140 cGy delivered to the 70% isodose line. The average volume of the lesions was 5.22 c c. The SFR group lesions received a mean dose to the indicated area de livered by 4 to 6 coplanar fields. The dose was 600 cGy per fraction, 2 to 3 fractions were given. The average volume of the treated lesions was 21.2 cc. Follow-up extended from 2-18 months. Twenty five lesions of the radiosurgery group had image follow-up. The overall local cont rol was seen in 92% of the patients. Six lesions of the SFR group had image follow-up, the local control was 83%. The small number in each g roup, the non-randomized nature of the study, and the relatively short follow-up preclude a definitive conclusion. SFR may be the method of choice for large lesions surrounded by significant edema. The delivery of the dose in large fractions may obviate the transient acute reacti ons seen when radiosurgical dose is delivered to large lesions surroun ded by edema. However, both forms of therapy have proven to be effecti ve in the control of brain metastases.