STEREOTACTIC RADIOSURGERY FOR CAVERNOUS MALFORMATIONS - KJELLBERGS EXPERIENCE WITH PROTON-BEAM THERAPY IN 98 CASES AT THE HARVARD CYCLOTRON

OBJECTIVE: The lack of treatment options for surgically inaccessible c avernous malformations has made radiosurgery a possible alternative to conservative management. The few previous reports of radiosurgical ef ficacy have been limited by small numbers, short follow-up, or lack of attention to the full spectrum of end points, including neurological disability. In an attempt to elucidate the risk-to-benefit ratio of ra diosurgery for cavernous malformations, we undertook a retrospective a nalysis of of 95 patients with 98 lesions treated by the late Raymond N. Kjellberg. METHODS: Patients were followed for an average of 5.4 ye ars (range, 0.3-12.3 yr), and data regarding hemorrhage, seizure, neur ological disability, and incidence of radiation-induced complications were gathered. RESULTS: The analysis revealed a drop in annual hemorrh age rates from 17.3% per lesion per year before treatment to 4.5% per lesion per year after a latency period of 2 years. Improvement in seiz ure control was evident. However, a 16% incidence of permanent neurolo gical deficit and a 3% mortality rate were attributable to radiographi cally confirmed radiation-induced complications. Neurological disabili ty scores, measured by the modified Rankin disability scale, indicated a significant decline in neurological functioning during the follow-u p interval, a result of the combined effects of radiation-related inju ry, hemorrhage, and clinical progression of the lesion. CONCLUSION: We conclude that although radiosurgery does seem to reduce hemorrhage, t here is potential for complications and continued lesion progression a fter radiosurgery. These risks and benefits must be carefully balanced against the natural history of untreated lesions if the use of radios urgery is considered.