[First-line radiosurgery of brain metastases. Interest and results of reduced dose].
BACKGROUND
The minimal radiosurgical dose required to control cerebral metastases remains unknown. The aim of this study was to test whether a lower peripheral dose than usually delivered could effectively control these lesions or not.


METHODS
One hundred and eighty patients presenting 356 lesions were give first-line radiosurgery between 1995 and 2001 in Pitié-Salpêtrière hospital using a 10 MV LINAC. Mean age was 59 years, sex-ratio was 1.65, mean KI was 70. The lung was the most frequent primary site (n=85), followed by melanoma (n=29), kidney (n=21), digestive tract (n=14), breast (n=11), and others (n=20). Seventy-six percent of the patients presented 1 or 2 lesions. Mean tumor Volume was 5.5 cm3. Mean peripheral dose was 14.8Gy, mean isocenter dose was 21.6Gy.


RESULTS
Median survival was 7.6 months, local control rate was 90% at 6 months, 76% at 1 Year and 70% at 2 years. Median "neurological disease free" survival was 15 months. Multivariate analysis demonstrated the influence of two parameters on survival: number of lesions (p=0.001) and KI (p=0.04). The only parameter significantly correlated with disease-free survival was the number of isocenters (p=0.005). Morbidity (grade 2 RTOG) was 7.2% with no perimortality.


CONCLUSIONS
Low peripheral doses delivered by radiosurgery may control brain metastases with the same efficacy and fewer side-effects as the doses usually reported in the literature.
Valéry
Ch-A
ChA
Département de Neurochirurgie, Hôpital de la Pitié-Salpêtrière, Paris. cavalery@club-internet.fr
Noël
G
G
Duyme
M
M
Boisserie
G
G
Mazeron
J-J
JJ
Cornu
Ph
P
Van Effenterre
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D018572:Disease-Free Survival; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery; D012189:Retrospective Studies; D016019:Survival Analysis