207 Poster Session 2 - Connective Tissue Oncology Society

Scientific Posters – Poster Session 2Physics, Fondazione IRCCS Istituto Nazionale Dei Tumori,Milano, Italy; 5 Department of Pathology and MolecularBiology, Fondazione IRCCS Istituto Nazionale Dei Tumori,Milano, ItalyObjective: Radical surgery is the gold standard of chordomas,but often it is unfeasible due to the tumor anatomicallocation. Definitive high-dose radiation therapy (RT) isan alternative, as reported for proton-beam RT. IntensityModulated RT (IMRT) allows to deliver high-dose RT withphotons (X-RT). We report on a series of locally advancedchordoma patients treated at our institution with exclusivehigh-dose X-RT alone or in combination with imatinib.Methods: We retrospectively reviewed all consecutivechordoma patients affected by a primary, localized disease,who were referred to the RT Department of our Institutionfrom 2004 to 2012, focusing on those treated with high-doseexclusive X-RT (e.g. ≥70Gy). Among 41 screened patients,19 (M/F = 15/4; median age/range = 66.3/32-86 yrs; site= 89% sacrum, 11% lumbar spine; previous debulkingsurgery: 6) received exclusive high-dose X-RT and areconsidered in the present analysis. 3 more patients are ontreatment, 3 underwent high-dose proton-beam RT, 3 receivedpalliative RT, 13 received complete surgery followedby adjuvant RT, and are not considered in this analysis. In 9cases, RT was administered with concomitant imatinib, 400mg/day. Toxicity, radiological response (tumor shrinkageand signal changes on MRI) and symptomatic improvementwere reviewed. Local progression-free survival (PFS)was calculated from the end of the treatment. Patients deadfor any reason were considered as failed to treatment. Median(range) follow-up was 23 (2-55) months.Results: The averaged delivered dose to the gross tumorvolume (GTV) was 73 Gy (range: 70-78). Overall, therapywas well tolerated (no G3-4 toxicities), without neurologicalside effects, even in the subgroup receiving concomitantimatinib. 5/19 patients had a local recurrence (26%) with amedian local PFS of 41 months (range 14-55). The medianlocal PFS was 24 months (range 2-50). All relapsed patientshad a sacral chordoma, and received 70-72Gy administeredby using a 3DCRT technique.Conclusion: Our series provides preliminary evidence thathigh-dose X-RT in extra-cranial chordoma is feasible, evenin combination with imatinib. Pts who received >73Gywith IMRT/Arc therapy had a better prognosis than thosetreated with 3DCRT at a dose