Treatment of newly diagnosed glioblastoma in the elderly: a network meta‐analysis

Background A glioblastoma is a fatal type of brain tumour for which the standard of care is maximum surgical resection followed by chemoradiotherapy, when possible. Age is an important consideration in this disease, as older age is associated with shorter survival and a higher risk of treatment‐related toxicity. Objectives To determine the most effective and best‐tolerated approaches for the treatment of elderly people with newly diagnosed glioblastoma. To summarise current evidence for the incremental resource use, utilities, costs and cost‐effectiveness associated with these approaches. Search methods We searched electronic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase to 3 April 2019, and the NHS Economic Evaluation Database (EED) up to database closure. We handsearched clinical trial registries and selected neuro‐oncology society conference proceedings from the past five years. Selection criteria Randomised trials (RCTs) of treatments for glioblastoma in elderly people. We defined ‘elderly' as 70+ years but included studies defining ‘elderly' as over 65+ years if so reported. Data collection and analysis We used standard Cochrane methods for study selection and data extraction. Where sufficient data were available, treatment options were compared in a network meta‐analysis (NMA) using Stata software (version 15.1). For outcomes with insufficient data for NMA, pairwise meta‐analysis were conducted in RevMan. The GRADE approach was used to grade the evidence. Main results We included 12 RCTs involving approximately 1818 participants. Six were conducted exclusively among elderly people (either defined as 65 years or older or 70 years or older) with newly diagnosed glioblastoma, the other six reported data for an elderly subgroup among a broader age range of participants. Most participants were capable of self‐care. Study quality was commonly undermined by lack of outcome assessor blinding and attrition. NMA was only possible for overall survival; other analyses were pair‐wise meta‐analyses or narrative syntheses. Seven trials contributed to the NMA for overall survival, with interventions including supportive care only (one trial arm); hypofractionated radiotherapy (RT40; four trial arms); standard radiotherapy (RT60; five trial arms); temozolomide (TMZ; three trial arms); chemoradiotherapy (CRT; three trial arms); bevacizumab with chemoradiotherapy (BEV_CRT; one trial arm); and bevacizumab with radio