Chordoma of the mobile spine: A retrospective analysis on 146 patients from two reference centers

Abstract

10517 Background: The natural history of chordoma is still poorly known. Methods: We reviewed a large series of patients (pts) from two major reference centers for chordoma. All pts presenting at Istituto Ortopedico Rizzoli, Bologna, and Istituto Nazionale Tumori, Milan, Italy, over 25 years, were reviewed. Clinical and pathologic characteristics were recorded. Local recurrence, distant metastasis, and overall survival (OS) were analyzed both from time of diagnosis and from time of local recurrence/distant metastasis. A multivariable analysis to identify independent prognostic factors was carried out. PDGFR and brachyury expression analysis is ongoing. Results: One hundred forty-six consecutive pts were identified (sacrum 79%, lumbar spine 15%, cervical-dorsal spine 6%; extension at diagnosis: localized 90%, locally-advanced 5%, metastatic 5%; median size 10 cm, IQ range: 6–14). Median follow-up was 140 months (IQ range: 80–205). The 5/10-year OS, local relapse-free survival (LRFS) and distant relapse-free survival (DRFS) were respectively: 76/52%, 51/32%, 86/72%. For pts with primary disease, size independently predicted OS (p-value: 0.004), LRFS (p-value: 0.006) and DRFS (p-value: 0.02), while surgical margins independently predicted only LRFS (p-value: 0.0001) with a trend for OS (p-value 0.1007). Radiotherapy performed in 44 pts did not influence LRFS nor OS, but only 9 pts received >60 Gy. The 5/10-year OS, LRFS, DRFS after the first local relapse were 54/24%, 50/45%, 64/61%. Size of the recurrence and quality of surgical margins did not influence post-relapse OS. The 5/10-year OS after the second local relapse were 20/0%. The overall incidence of metastases was 32% (commonest site: lung). The 5/10-year post-metastases OS was 35/0% (median 3 years). Results on PDGFR and brachyury expression will be provided. Conclusions: Tumor size and surgical margins affected outcome only on initial presentation. Incidence of distant metastases was higher than expected, although with a more indolent course than generally supposed. In spite of its indolent behavior, long-term prognosis was poor, with 26% of pts being continuously disease-free at 10 years. This series may provide an external control for studies on novel targeted agents, which are proving effective in such a rare tumor. No significant financial relationships to disclose.