Stereotactic radiotherapy for large solitary brain metastases

To assess effectiveness and toxicity levels of stereotactic radiation therapy without whole brain radiation therapy in patients with solitary brain metastases larger than 3cm. Between June 2007 and March 2009, 12 patients received fractionated stereotactic radiation therapy and 24 patients underwent stereotactic radiosurgery. For the fractionated stereotactic radiation therapy group, 3×7.7Gy were delivered to the planning target volume (PTV); median volume and diameter were 29.4 cm3 and 4.4cm, respectively. For the stereotactic radiosurgery group, 14Gy were delivered to the PTV; median volume and diameter were 15.6 cm3 and 3.7cm, respectively. Median follow-up was 218 days. For the fractionated stereotactic radiation therapy group, local control rates were 100% at 360 days and 64% at 720 days; for the stereotactic radiosurgery group, rates were 58% at 360 days and 48% at 720 days (P=0.06). Median survival time was 504 days for the fractionated stereotactic radiation therapy group and 164 days for the stereotactic radiosurgery group (P=0.049). Two cases of grade 2 toxicity were observed in the fractionated stereotactic radiation therapy group, and 6 cases of grade 1–2 toxicity, in the stereotactic radiosurgery group. This study provides data to support that fractionated stereotactic radiation therapy without whole brain radiation therapy with a margin dose of 3 fractions of 7.7Gy for treatment of solitary large brain metastases is efficient and well-tolerated. Because of the significant improvement in overall survival, this schedule should be assessed in a randomized trial. Évaluer l’efficacité et la tolérance d’une irradiation en conditions stéréotaxiques de métastases uniques cérébrales de plus de 3cm sans irradiation encéphalique totale. Entre juin 2007 et mars 2009, 12 patients ont reçu une radiothérapie stéréotactique hypofractionnée et 24 patients une radiochirurgie. Pour le groupe qui a reçu une radiothérapie stéréotaxique hypofractionnée, trois fractions de 7,7Gy ont été délivrées dans le volume cible prévisionnel ; les médianes des volumes et des diamètres des métastases étaient respectivement de 29,4 cm3 et 4,4cm. Pour le groupe qui a reçu la radiochirurgie, 14Gy ont été délivrés au volume cible prévisionnel ; les médianes des volumes et des diamètres des métastases étaient respectivement de 15,6 cm3et 3,7cm. Le suivi médian était de 218jours. Après radiothérapie stéréotaxique hypofractionnée, les taux de contrôle local étaient de 100 % à 360jours