High control rate in patients with chondrosarcoma of the skull base after carbon ion therapy: First report of long‐term results

Abstract

BACKGROUND:The current study was performed to evaluate the safety and effectiveness of irradiation with carbon ions using raster scanning as well as prognostic factors in patients with skull base chondrosarcomas. METHODS: Between 1998 and 2008, 79 patients with chondrosarcoma of the skull base were treated using carbon ions in raster scanning. The applied median total dose was 60 gray equivalent (GyE) at 3 GyE per fraction. Local control and overall survival (OS) were evaluated using the Kaplan-Meier method. Longterm toxicity was quantitatively assessed using questionnaires. RESULTS: The median follow-up after irradiation was 91 months (range, 3 months-175 months). Within the follow-up, 10 patients developed local disease recurrence. The 3-year, 5-year, and 10-year local control rates were 95.9%, 88%, and 88%, respectively; the corresponding OS rates were 96.1%, 96.1%, and 78.9%, respectively. With a median follow-up of 110 months after first diagnosis, the corresponding 3-year, 5-year, and 10-year OS rates were 97.5%, 97.5%, and 91.5%, respectively. Age 45 years and boost volume 55 mL were associated with significantly better local control rates. We observed a clinically relevant improvement in cranial nerve deficits 7 to 10 years after treatment (range, 45.5%-53.3%) compared with the baseline (73.4%). During follow-up, none of the patients in the current study developed a secondary malignancy. CONCLUSIONS: Carbon ion therapy is a safe and effective treatment in patients with chondrosarcoma of the skull base. For further evaluation, a prospective randomized phase 3 trial comparing protons versus carbon ions has been recruiting patients with low-grade and intermediate-grade chondrosarcoma of the skull base since 2009. Cancer 2014;120:1579-85.

Endoscopic endonasal surgical management of chondrosarcomas with cerebellopontine angle extension

“…3,4,15 They often arise from the lateral aspects of the skull base that house cartilage, including the temporooccipital synchondrosis, the sphenoocciput, and the sphenoethmoid complex. 7 The structure most often involved in cases of skull base chondrosarcomas is the clivus (32%), followed by other synchondroses.…”

“…Samii et al reported a neurological complication rate of 33.3% and an incidence of cerebrospinal fluid leakage of 10.3%. 3,14,15 Furthermore, gross-total resection is achievable in only 50% of cases, and there is no evidence that greater extent of resection improves outcome. 3 Chondrosarcomas are considered resistant to radiation and chemotherapy.…”

“…3 Chondrosarcomas are considered resistant to radiation and chemotherapy. 15 The use of adjuvant radiation following resection of cranial chondrosarcomas has been shown to improve tumor control and overall survival, but with modest results compared with cases in which patients were treated with surgery alone.…”

“…15 Multiple modalities can be used, including fractionated photon radiotherapy, particle radiotherapy, or stereotactic radiosurgery. There are no Class I data suggesting that the use of one radiation modality is preferable to use of any other.…”

Efficacy and Safety of Adjuvant Proton Therapy Combined With Surgery for Chondrosarcoma of the Skull Base: A Retrospective, Population-Based Study

“…Currently, surgery, followed by charged-particle irradiation (RT), is considered the reference standard for the treatment of patients with grade I-II CSA of the skull base (2)(3)(4)(5)(6). In the modern era of skull base surgery, the goal is to perform total gross resection, even when total microscopic resection is not possible owing to the proximity of organs at risk (OARs; ie, major blood vessels, cranial nerves, and brainstem).…”