RESUMEN
BACKGROUND: Chordomas and chondrosarcomas of the skull base are rare, slowly growing malignant bone neoplasms. Despite their radioresistant properties, proton therapy has been successfully used as an adjunct to resection or as a definitive treatment. Herewith, we present our experience with robustly optimized intensity-modulated proton therapy (IMPT) and related toxicities in skull base chordoma and chondrosarcoma patients treated at HollandPTC, Delft, the Netherlands. METHODS: Clinical data, treatment plans, and acute toxicities of patients treated between July 2019 and August 2021 were reviewed. CT and 3.0T MRI scans for treatment planning were performed in supine position in a thermoplastic mold. In total, 21 dose optimization and 28 dose evaluation scenarios were simulated. Acute toxicity was scored weekly before and during the treatment according to the CTCAE v4.0. Median follow-up was 35 months (range 12-36 months). RESULTS: Overall, 9 chordoma and 3 chondrosarcoma patients with 1-3 resections prior to IMPT were included; 4 patients had titanium implants. Brainstem core and surface and spinal cord core and surface were used for nominal plan robust optimization in 11, 10, 8, and 7 patients, respectively. Middle ear inflammation, dry mouth, radiation dermatitis, taste disorder, and/or alopecia of grades 1-3 were noted at the end of treatment among 6 patients without similar complaints at inclusion; symptoms disappeared 3 months following the treatment. CONCLUSION: Robustly optimized IMPT is clinically feasible as a postoperative treatment for skull base chordoma and chondrosarcoma patients. We observed acceptable early toxicities (grade 1-3) that disappeared within the first 3 months after irradiation.
RESUMEN
PURPOSE: Morphological magnetic resonance (MR) and computed tomography (CT) features are used in combination with histology for diagnosis and treatment selection of primary bone neoplasms. Isolated functional MRI parameters have shown potential in diagnosis. Our goal is to facilitate diagnosis of primary bone neoplasms of the skull base, mobile spine and sacrum, by a comprehensive approach, combining morphological and functional imaging parameters. MATERIALS AND METHODS: Pre-treatment MR of 80 patients with histologically proven diagnosis of a primary bone neoplasm of the skull base, mobile spine and sacrum were retrospectively analyzed for morphological and functional MRI parameters. Functional parameters were measured in 4 circular regions of interest per tumor placed on non-adjacent scan slices. Differences in values of functional parameters between different histologies were analyzed with Dunn's test. RESULTS: Chordomas were the predominant histology (60.0%). Most neoplasms (80.0%) originated in the midline and had geographical (78.2%) bone destruction. Amorphous-type calcification (pre-existing bone) was seen only in chordomas. Homogeneous contrast enhancement pattern was seen only in chondrosarcoma and plasmacytoma. Ktrans and Kep were significantly lower in both chordoma, and chondrosarcoma compared to giant cell tumor of the bone (p = 0.006 - 0.011), and plasmacytoma (p = 0.004 - 0.014). Highest diffusion-weighted MRI apparent diffusion coefficient (ADC) values corresponded to chondrosarcoma and were significantly higher to those of chordoma (p = 0.008). CONCLUSION: We identified the most discriminating morphological parameters and added functional MR parameters based on histopathological features that are useful in making a confident diagnosis of primary bone neoplasms in the skull base, mobile spine and sacrum.
RESUMEN
BACKGROUND: Due to its specific physical characteristics, proton irradiation is especially suited for irradiation of chordomas and chondrosarcoma in the axial skeleton. Robust plan optimization renders the proton beam therapy more predictable upon individual setup errors. Reported experience with the planning and delivery of robustly optimized plans in chordoma and chondrosarcoma of the mobile spine and sacrum, is limited. In this study, we report on the clinical use of robustly optimized, intensity modulated proton beam therapy in these patients. METHODS: We retrospectively reviewed patient, treatment and acute toxicity data of all patients with chordoma and chondrosarcoma of the mobile spine and sacrum, treated between 1 April 2019 and 1 April 2020 at our institute. Anatomy changes during treatment were evaluated by weekly cone-beam CTs (CBCT), supplemented by scheduled control-CTs or ad-hoc control-CTs. Acute toxicity was scored weekly during treatment and at 3 months after therapy according to CTCAE 4.0. RESULTS: 17 chordoma and 3 chondrosarcoma patients were included. Coverage of the high dose clinical target volume was 99.8% (range 56.1-100%) in the nominal and 80.9% (range 14.3-99.6%) in the voxel-wise minimum dose distribution. Treatment plan adaptation was needed in 5 out of 22 (22.7%) plans. Reasons for plan adaptation were either reduced tumor coverage or increased dose to the OAR. CONCLUSIONS: Robustly optimized intensity modulated proton beam therapy for chordoma and chondrosarcoma of the mobile spine is feasible. Plan adaptations due to anatomical changes were required in approximately 23 percent of treatment courses.