Ketogenic diets as an adjuvant therapy in glioblastoma (KEATING): A mixed methods randomised feasibility study

Abstract

Abstract Background There is increasing interest in the use of ketogenic diets (KD) as adjuvant therapy for glioblastoma (GBM). Trial aims: i) investigate protocol feasibility; ii) assess patient/carer acceptability; iii) explore the decision-making of patients’ invited to participate in KEATING; and iv) inform phase III trial design. Methods Prospective, feasibility study, with embedded qualitative design randomised 12 newly-diagnosed GBM patients to three months of medium chain triglyceride ketogenic diet (MCTKD) or the modified ketogenic diet (MKD) during chemoradiotherapy. Primary outcome was retention; secondary outcomes included recruitment rate, dietary acceptability, progression free survival (PFS) and overall survival (OS). Semi-structured interviews were conducted with a representative sample of patients and relatives (n=15). Results Recruitment targets were achieved, but recruitment rate was low (28.6%). Retention was poor; only 4 of 12 completed the three-month diet (MCTKD n=3; MKD n=1). Median duration until discontinuing was 5.2 weeks (0–7 weeks; n=8). Participants made instantaneous decisions without deliberation: relatives supported diet implementation. Decliners made considered decisions factoring diet burden and quality of life. A three-month diet was undesirable to these patients. Median PFS was 11.4 weeks and OS was 67.3 weeks. Conclusion Recruitment to a ketogenic-glioblastoma trial is possible. To assess effectiveness in a phase III clinical trial, a six week intervention period is proposed. Future trials should optimise and adequately support the decision-making of patients. The role of relatives should not be underestimated.