What is the optimal schedule for fractionated SRS treatment of CNS tumors?

I don't think there is one ideal dose/fraction schedule. Doses should be individualized for your institution, including factors such as immobilization, set up, and margins. There are published data on ranges of SRT.

For larger tumors, typically defined as 2 cm to up to 3-4 cm I would favor 24-27 Gy i...

For brain metastasis, if </= 2 cm, I use 27 Gy/ 3 fxs; if >2-5 cm, I use 25-32.5 Gy/ 5 fxs.

For benign tumors, if </= 2 cm, 21-24 Gy/ 3 fxs; if >2-5 cm, 25 Gy/ 5 fxs.

I would say optimal schedule for fractionated SRS depends on the size of the tumor, type of tumor, whether systemic therapy will be given, and other factors. Generally for benign tumors over 3 cm but less than say 5 cm my preference would be 5 daily fractions to be given consecutively. For larger tu...