What is the rate of dementia following whole brain radiotherapy in patients with brain metastases who survive for over a year?  

The most frequent argument against whole brain RT is debilitating toxicity. However, I am having a hard time finding the most evidence based data on how high this rate is. I'm not sure the PCI literature really answers this question since brain metastases in and of themselves cause neurocognitive decline (something that the PCI patients do not have at the time of RT). 



Answer from: Radiation Oncologist at Academic Institution