Sacral Chordoma: Surgery Versus Definitive Radiation Therapy in Primary Localized Disease

Inclusion Criteria: * Histologically confirmed diagnosis (brachyury expression) of primary sacral chordoma,of any diameter and arising at any site from S1 to coccyx. * Age≥18years * ECOG-performance status (PS) 0-2 * No previous antineoplastic therapy * Macroscopic tumor detectable at MRI/CT scan * Patient amenable for surgery * Patient amenable for RT * Written informed consent given before the enrolment, according to International Conference on Harmonisation/good clinical practice (ICH/GCP). Exclusion Criteria: * Distant metastasis * Inability to maintain treatment position * Prior radiotherapy to the pelvic region * Prior therapy for sacral chordoma (including surgery, cryoablation, hyperthermia, etc) * Local conditions that increase the risk of RT toxicity (tumor ulcerated skin infiltration, non-healing soft tissue infection, fistula in treatment field) * Rectal wall infiltration * General conditions that increase the risk of RT toxicity (active sclerodermia, xeroderma pigmentosum, cutaneous porphyria) * Presence of a second active cancer (with the exception of non-melanoma skin cancer in-situ cervix neoplasia and other in-situ neoplasia) * Severe comorbidities resulting in a prognosis of less than 6 months * Inability to give informed consent * Other malignancy within the last 5 years * Performance status ≥ 2 (ECOG). * Significant cardiovascular disease (for example, dyspnea \> 2 NYHA) * Significant systemic diseases grade \>3 on the NCI-CTCAE v4.03 scale, that limit …