Response Assessment in Neuro-oncology (RANO): An Update

Malignant brain tumors continue to pose a significant clinical challenge with few effective treatment options. In an effort to foster progress, an international working group was formed to address endpoint assessment in neuro-oncology. This group proposed a set of criteria, which are now termed the Response Assessment in Neuro-Oncology (RANO) criteria. The aim of this working committee is to create standardized guidelines to be able to assess clinical or imaging response following treatment in patients with a variety of brain tumors, which can be applied in future clinical trials. Since the publication of first guidelines in 2010, these criteria have been widely accepted in a variety of clinical trials worldwide. The data generated using these standardized guidelines can be pooled and analyzed in a robust manner to accept or refute a particular treatment modality. The aim of this review is to summarize the current RANO guidelines and recommendations in patients with low-grade glioma, high-grade glioma, brain metastasis, and leptomeningeal metastasis. We have also touched upon the key clinical and imaging criterion used for RANO evaluation as well as role of newer imaging and biomarkers. We have also included the role of extended RANO committees, which are working in close collaboration.