Efficacy and toxicity of CyberKnife re-irradiation and “dose dense” temozolomide for recurrent gliomas

Abstract

The results suggest that Cyberknife re-treatments are relatively safe using selected dose/fraction schemes. The combination with TMZ improved patients' outcomes with OS and 6-month PFS that favorably compares with alternative treatments, but the incidence of major adverse effects was >40%. Further studies are warranted.

Outcome of salvage treatment for recurrent glioblastoma

“…It has superior local tumor control rates to reoperation for small GBM tumors at the time of recurrence [9]. TMZ has potential radio-sensitizing activity in recurrent gliomas, and the advantage of a salvage treatment combining SRS and TMZ chemotherapy has been suggested [10][11][12].…”

Salvage Stereotactic Radiotherapy for Recurrent Glioblastoma Multiforme: Clinical Outcomes from a Multi-Institutional Registry

“…However, following this regimen, the incidence of major adverse effects was >40%. 29 Other studies examining the concurrent use of salvage SRT with other treatment modalities are warranted given that concurrent chemotherapy (i.e. temozolomide and bevacizumab) 31 One major limitation of our study is the inability to comment on either progression free survival or local control given insufficient data on these parameters.…”

Salvage Radiosurgery for High Grade Glioma in the Era of Modern Systemic Therapy

“…These include studies of radiosurgery using gamma knife, linac and cyberknife technology. [3][4][5][6][7] This paper reports a retrospective single institution experience of 33 patients treated with Gamma Knife radiosurgery for focally recurrent, high grade gliomas. 8 Studies evaluating the role of radiosurgery for focally recurrent glioblastoma have demonstrated longer survival than studies evaluating other salvage treatments but this is likely due to patient selection bias.…”

“…Evaluating the common factors that can contribute to radionecrosis including the dose, fractionation and volume of re-irradiation, this study utilized a higher mean dose prescribed to the 50% isodose line of 17.5 Gy (range: 12 -24 Gy) in a single fraction compared with prior studies that range from 13 Gy in a single fraction up to 37.5 Gy in 15 fractions. 5,[16][17][18] However, this study generally treated smaller volume tumours with a mean tumour volume of 4.8 cm 3 (range: 1.3 -18.2 cm 3 ) compared to other studies that included tumour volumes up to 30 cm 3 . 5,10 In this retrospective series, the rate of adverse radiation effects (ARE) was high, occurring in 26 of 29 patients (89.7%).…”

“…In this study, 48.3% of patients were dependent on dexamethasone due to symptoms in comparison to 83% of patients treated with a mean dose of 20 Gy in two fractions with temozolomide requiring ongoing dexamethasone following treatment. 3 As demonstrated by these variable results, there is a great need for consistent criteria for reporting ARE events to facilitate meaningful comparison of toxicities associated with different radiation regimens and techniques across studies.…”