PURPOSE: To evaluate effectiveness and safety of spot-scanning-based proton radiotherapy (PT) in skull-base chordomas and chondrosarcomas. METHODS AND MATERIALS: Between October 1998 and November 2005, 64 patients with skull-base chordomas (n = 42) and chondrosarcomas (n = 22) were treated at Paul Scherrer Institute with PT using spot-scanning technique. Median total dose for chordomas was 73.5 Gy(RBE) and 68.4 Gy(RBE) for chondrosarcomas at 1.8-2.0 Gy(RBE) dose per fraction. Local control (LC), disease specific survival (DSS), and overall survival (OS) rates were calculated. Toxicity was assessed according to CTCAE, v. 3.0. RESULTS: Mean follow-up period was 38 months (range, 14-92 months). Five patients with chordoma and one patient with chondrosarcoma experienced local recurrence. Actuarial 5-year LC rates were 81% for chordomas and 94% for chondrosarcomas. Brainstem compression at the time of PT (p = 0.007) and gross tumor volume >25 mL (p = 0.03) were associated with lower LC rates. Five years rates of DSS and OS were 81% and 62% for chordomas and 100% and 91% for chondrosarcomas, respectively. High-grade late toxicity consisted of one patient with Grade 3 and one patient with Grade 4 unilateral optic neuropathy, and two patients with Grade 3 central nervous system necrosis. No patient experienced brainstem toxicity. Actuarial 5-year freedom from high-grade toxicity was 94%. CONCLUSIONS: Our data indicate safety and efficacy of spot-scanning based PT for skull-base chordomas and chondrosarcomas. With target definition, dose prescription and normal organ tolerance levels similar to passive-scattering based PT series, complication-free, tumor control and survival rates are at present comparable.
PURPOSE: To evaluate effectiveness and safety of spot-scanning-based proton radiotherapy (PT) in skull-base chordomas and chondrosarcomas. METHODS AND MATERIALS: Between October 1998 and November 2005, 64 patients with skull-base chordomas (n = 42) and chondrosarcomas (n = 22) were treated at Paul Scherrer Institute with PT using spot-scanning technique. Median total dose for chordomas was 73.5 Gy(RBE) and 68.4 Gy(RBE) for chondrosarcomas at 1.8-2.0 Gy(RBE) dose per fraction. Local control (LC), disease specific survival (DSS), and overall survival (OS) rates were calculated. Toxicity was assessed according to CTCAE, v. 3.0. RESULTS: Mean follow-up period was 38 months (range, 14-92 months). Five patients with chordoma and one patient with chondrosarcoma experienced local recurrence. Actuarial 5-year LC rates were 81% for chordomas and 94% for chondrosarcomas. Brainstem compression at the time of PT (p = 0.007) and gross tumor volume >25 mL (p = 0.03) were associated with lower LC rates. Five years rates of DSS and OS were 81% and 62% for chordomas and 100% and 91% for chondrosarcomas, respectively. High-grade late toxicity consisted of one patient with Grade 3 and one patient with Grade 4 unilateral optic neuropathy, and two patients with Grade 3 central nervous system necrosis. No patient experienced brainstem toxicity. Actuarial 5-year freedom from high-grade toxicity was 94%. CONCLUSIONS: Our data indicate safety and efficacy of spot-scanning based PT for skull-base chordomas and chondrosarcomas. With target definition, dose prescription and normal organ tolerance levels similar to passive-scattering based PT series, complication-free, tumor control and survival rates are at present comparable.
Authors: S J Treece; M Mukesh; Y L Rimmer; S J Tudor; J C Dean; R J Benson; D L Gregory; G Horan; S J Jefferies; S G Russell; M V Williams; C B Wilson; N G Burnet Journal: Br J Radiol Date: 2013-01 Impact factor: 3.039