RANO criteria for brain metastases: what to know

RANO, short for Response Assessment in Neuro-Oncology, helps a clinical team describe whether a brain lesion appears smaller, stable, or larger on follow-up imaging. The review can consider measurable enhancing areas, new lesions, swelling around a lesion, steroid use, and changes in neurological function. A scan can look different because of treatment-related inflammation or tissue injury, so an apparent change is not automatically proof that a tumour is growing.

Brain metastases are secondary tumours that have spread to the brain from another cancer. Breast Cancer, Lung Cancer, and Melanoma are among cancers that can be associated with this pattern. The treating team interprets the scan in context rather than relying on one measurement alone.

Keep imaging appointments and tell the team about headaches, seizures, weakness, balance problems, speech changes, vision changes, memory difficulties, and steroid doses. Bring information about recent radiotherapy, surgery, or medicines because treatment timing can affect scan interpretation. Depending on the number, location, and behaviour of lesions, options may include stereotactic radiosurgery, whole brain radiotherapy, or brain tumour surgery.

Ask how the next scan will be compared with earlier images and whether the team expects treatment effects that could temporarily alter the appearance.

Seek emergency help for a first seizure, a seizure lasting longer than expected, sudden weakness or numbness, new trouble speaking, severe confusion, collapse, or a sudden severe headache with vomiting. Contact the oncology team promptly for worsening headaches, repeated vomiting, increasing sleepiness, or a new change in walking or vision.

Ask which RANO category best describes the scan, what features support that interpretation, and whether treatment effects could be contributing. Ask when repeat imaging is planned, what symptoms should trigger a call, and how the result changes the available treatment choices.