[Hypofractionated stereotactic radiotherapy for brain metastases].
OBJECTIVE
A survey of the literature has been performed to find arguments in order to help the choice between radiosurgery and hypofractionated stereotactic radiotherapy in the treatment of brain metastases.


METHODS
A comparison of two groups of brain metastases treated with hypofractionated stereotactic radiotherapy or radiosurgery, with or without WBRT was performed. Hypofractionated stereotactic radiotherapy: there were eight series including 448 patients published from 2000 to 2009; treated with 5-6 MV X-Rays, non invasive head immobilization, a margin 2 to 10mm; 24 to 40Gy in three to five fractions; a 5 to 8 days duration in six series and 15-16 days in two other series. WBRT (30%) ; radiosurgery: there were 12 series (1994 to 2005) including 2157 patients; an invasive head immobilization, no margin; doses from 10 to 25 Gy; six series over 12 had Gamma Knife radiosurgery and six had Linacs X-Rays. WBRT (30 Gy/10 F/12 days) associated to radiosurgery in several series. The following parameters were compared: median GTV, median survival, 1-year survival rate, local control rate, necrosis and WBRT rates.


RESULTS
Hypofractionated stereotactic radiotherapy series: the parameters were respectively: 0,52-4,47 cm(3) (median 2,8 cm(3)); 5-16 months (median 8,7 months); 68,2-93% (median 82,5%); necrosis rate 3,1%; associated WBRT 30%. Radiosurgery series: the parameters were respectively: 1,3 to 5,5 cm(3) (median 2 cm(3)); 5,5 to 22 months (median 11 months); 71 to 95% (median 85%); 0,5 to 6% (median 2,4%); associated WBRT 58%. Results seem similar in the two groups: Hypofractionated stereotactic radiotherapy with non invasive immobilization could theoretically treat all brain metastases sizes except lesions<10 mm (500 mm(3)). In large volumes,>4200 mm(3) GTV, the toxicity of hypofractionated stereotactic radiotherapy was not reported, thus it was difficult to compare its results with the published reports of radiosurgery toxicity. WBRT was a confusing parameter. Obviously, this initial survey has important limitations, specifically its methodology.


CONCLUSIONS
Radiosurgery and hypofractionated stereotactic radiotherapy could be used to treat brain metastases with GTV>500 mm(3) and < or = 4200 mm(3) (Ø 20mm); for GTV<500 mm(3) (Ø 10mm) an invasive procedure with radiosurgery is necessary. For GTV>4200 mm(3) (Ø 20mm), hypofractionated stereotactic radiotherapy could be proposed, provided further studies, using 4 to 6 Gy fractions, a duration less or equal to 10-12 days and a margin of 2mm will be performed.
Schlienger
M
M
Service d'oncologie-radiothérapie, hôpital Tenon, 4 rue de la Chine, Paris, France. michel.schlienger@tnn.aphp.fr
Nataf
F
F
Huguet
F
F
Pene
F
F
Foulquier
J-N
JN
Orthuon
A
A
Roux
F-X
FX
Touboul
E
E
D001918:Brachytherapy / Q000379:methods*; D001932:Brain Neoplasms / Q000473:pathology / Q000556:secondary* / Q000601:surgery*; D006801:Humans; D009336:Necrosis; D009362:Neoplasm Metastasis / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D015996:Survival Rate; D013997:Time Factors