Fractionated Stereotactic Radiosurgery Treatment Results for Skull Base Chordomas

Abstract

Chordomas are uncommon neoplasms and there is still controversy regarding establishment of diagnosis and management. The aim of this study was to evaluate efficacy and toxicity of fractionated stereotactic radiosurgery (FSRS) in skull base chordomas. There were 4 female (36%) and 7 male (64%) patients. FSRS was delivered with CyberKnife (Accuray Inc., Sunnyvale, CA). The median tumor volume was 14.7 cc (range, 3.9-40.5 cc). The median marginal tumor dose was 30 Gy (range, 20-36 Gy) in a median 5 fractions (range, 3-5 fractions). The median follow-up time was 42 months (range, 17-63 months). At the time of analysis, 10 (91%) patients were alive and 1 (9%) had died due to tumor progression. Of 10 patients, 8 (73%) had stable disease and the remaining 2 (18%) had progressive disease. The actuarial overall survival (OS) after FSRS was 91% at two-years. Two patients developed radiationinduced brain necrosis as a complication in the 8 th and 28 th months of follow-up, respectively.Our results with robotic FSRS in skull base chordomas are promising for selected patients.However, due to the slow growth pattern of skull base chordomas, a longer follow-up is required to determine exact treatment results and late morbidity.

Management of Chordoma and Chondrosarcoma with Fractionated Stereotactic Radiotherapy

“…A limited number of published series evaluate FSRT for chordomas and chondrosarcomas (10, 23, 31–33), and our study provides additional evidence regarding the efficacy and toxicity associated with its use. Previous work from the North American Gamma Knife Consortium retrospectively examining single fraction treatment demonstrated a 5-year OS of 80% with an improved 5-year OS of 93% in patients with no prior RT (28), consistent with outcomes observed in our data.…”

“…Multiple studies have assessed single fraction stereotactic radiosurgery for chordoma and chondrosarcoma management, but FSRT has theoretical advantages compared to single fraction treatment including a lower risk of radiation toxicity in nearby critical structures and the possibility of safely treating larger tumor volumes with multiple fractions (20, 22, 23, 25–30). A limited number of published series evaluate FSRT for chordomas and chondrosarcomas (10, 23, 31–33), and our study provides additional evidence regarding the efficacy and toxicity associated with its use.…”

“…Advantages of a stereotactic approach for these tumors include augmented biologic effective dose, highly conformal treatment fields, and steep dose reduction outside target volumes (21–23). Further, the limited availability of proton facilities and shorter treatment times with hypofractionated courses makes FSRT logistically attractive.…”

Stereotactic Radiosurgery and Stereotactic Radiotherapy for Malignant Skull Base Tumors

“…In addition, SRT using Novalis (BrainLAB, Tokyo) was done for recurrence in one case, as the recurrent tumors were relatively large and fractionated SRT was deemed better to avoid adverse radiation effects. A number of papers have been published on chordoma SRS/SRT both with particle-beam and photon-beam [3,[19][20][21][22][23][24][25][26][27][28]. However, in early-reported series the treatment results of both chordoma and chondrosarcoma were mixed [29].…”

Proton therapy for brain tumours in the area of evidence-based medicine

“…Numerous modern SRS and SFRT series have shown suboptimal outcomes for sbC patients treated with these radiation modalities. [57][58][59] These suboptimal results may be best explained by the stereotactic margins defined during the planning process and radiation dose delivered to these patients. Regarding the former, Snider et al have shown undisputedly the importance of margins for extracranial chordomas.…”