One hundred eighty patients affected by cerebral arteriovenous malformations (AVMs) underwent radiosurgical treatment in our department. One hundred fifty-three patients have been treated with complete irradiation of the entire AVM nidus. In 27 patients (with large and/or three-dimensional irregular target volumes), only part of the nidus was covered with a dose adequate for obliteration. Follow-up ranged from 88 to 1 months (mean, 43.1 mo). Angiographic control was performed at 12, 24, and 36 months until complete obliteration was attained. The complete obliteration rate was 46% at 1 year and 80% at 2 years. We observed 15 hemorrhages after treatment, and five patients died from them. No bleeding took place after complete angiographic obliteration. The aim of this study is to evaluate the effect of irradiation on bleeding risk after radiosurgery and before complete obliteration. Inclusive parameters of patients considered at risk were as follows: 1) all patients in the time lapse between irradiation and demonstrated complete angiographic obliteration; 2) all patients in the time lapse between irradiation and definitive treatment either by surgery or embolization; and 3) all patients in the time lapse between irradiation and death. These groups include all irradiated patients who still had incompletely obliterated AVMs. They were stratified starting from 0 time (the date of radiosurgery), and the hemorrhages were evaluated every 6 months. In totally irradiated cases, the bleeding risk decreased from 4.8% in the first 6 months after radiosurgery to 0% starting from the 12th month of the follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

The introduction of the CyberKnife extended the indication to 63 patients (>30%) who could not have been treated by single-session radiosurgical techniques. The procedure proved to be safe. Clinical improvement seems to be more frequently observed with the CyberKnife than in our previous linear accelerator experience.

This is the first report describing a technique developed for CyberKnife radiosurgery of cerebral AVMs. The use of different imaging modalities for automatic delineation of the target and critical structures combined with the employment of the inverse treatment planning capability is the crucial point of the procedure. The procedure proved to be safe and efficient.

A case-control study on risk factors for cerebral tumors was conducted on an adult Italian population by the four Neurosurgical Departments of the Veneto Region, i.e. Padua, Treviso, Verona and Vicenza. The study recruited 195 cases of histologically-confirmed cerebral glioma. One hospital control was selected for each case. Cases and controls were matched for age, sex, data of hospitalization and residence. Information on both cases and controls was obtained from a relative. Uninvolved interviewers administered a structured questionnaire including items on the subject's education, occupation, lifestyle, medical history, exposure to radiation for diagnosis or therapy, head trauma and blood group and the medical history of family members. The series of cerebral tumors was first considered as an indistinct set: none of the risk factors examined showed a statistically significant association. A positive association was found with blood group A (OR = 6) when low-grade astrocytomas (n = 41) were considered separately. As for the malignant astrocytomas (n = 132), there was a suggestive but not statistically significant association with the presence of CNS tumors among first- and second-degree relatives (OR = 7.0). On the whole, this study yielded no clear and meaningful association for the various risk factors analyzed.

No abstract