Do you recommend a washout period for a patient receiving intrathecal chemotherapies prior to/after receiving intracranial SRS?

There are not a whole lot of clinical data. A couple of general points: 1) some chemotherapy agents, especially methotrexate, are known to increase CNS toxicity of radiation (especially whole brain RT) when used concurrently; 2) intrathecally administrated chemotherapy nonetheless has generally limi...