Clinical Efficacy of Tumor Treating Fields for Rec

Authors: Eric T Wong

Publish Date: 2016

Volume: , Issue: , Pages: 67-77

PDF Link

Abstract

Recurrent glioblastoma is defined by growth of the enhancing areas on MRI according to the Macdonald’s or Response Assessment in NeuroOncology RANO criteria but the extent of the tumor is much larger than that can be seen on neuroimaging Patient prognosis is poor and survival is short The Optune device is an FDAapproved treatment for recurrent glioblastoma and it uses Tumor Treating Fields TTFields to disrupt tumor cells as they undergo mitosis In the pivotal EF11 phase III trial that compared TTFields with Best Physician’s Choice chemotherapy the two treatments had comparable efficacy with a respective median overall survival of 66 and 60 months and a hazard ratio of 086 p = 027 The median progression free survival of TTFields and chemotherapy was 22 months and 21 months respectively with a hazard ratio of 081 p = 016 The most common adverse events associated with the device were grade 1 or 2 scalp dermatitis and shifting of the arrays slightly during array change and applying topical corticosteroid can minimize this irritation There were far less hematological and gastrointestinal toxicities when compared to chemotherapy In post hoc analyses of EF11 secondary glioblastomas and low dexamethasone usage were notable prognostic factors for survival In the TTField monotherapy cohort the median overall survival was 110 months among subjects who used ≤41 mg/day dexamethasone and 48 months among those who took 41 mg/day χ2 = 346 p 00001 This dexamethasone effect was also found in the chemotherapy cohort but in a less robust fashion with subjects who used ≤41 mg/day of dexamethasone having a median overall survival of 89 months as compared to those who used 41 mg/day having a median overall survival of 60 months χ2 = 100 p = 00015 Other prognostic factors include a compliance rate of ≥80 no prior treatment with bevacizumab and Karnofsky performance status ≥80 Therefore multiple intrinsic and extrinsic factors can modulate the outcome of the recurrent glioblastoma under the influence of TTFields

Keywords: