Several studies have used the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire core 30 (EORTC QLQ-C30) and the brain cancer module (QLQ-BN20) scales to assess quality of life. The latter consists of 20 items including visual disorder, motor dysfunction, various disease symptoms, treatment toxicity and future uncertainty. A change of 10 points or more on these scales can be considered clinically relevant.