Hot topics.

In 2021, most people agree post-op radiosurgery for resected brain mets confers the best local control at the least neurocognitive expense. However, not as many agree on the best planning parameters. Should you constrain the hotspot since it’s not going to be within gross tumor? How big should the volume be, and should it cover the surgical tract? Here is a current review to distill the data we have thus far, and table 4 really says it all. Here are the high points. First of all, dose matters, and to maximize local control, the biological equivalent dose (assuming a tumor α/β ratio of 10 Gy) should exceed 40 Gy—this includes delivering ≥16 Gy in a single fraction, ≥24 Gy over 3 fractions, and ≥30 Gy over 5 fractions. GTV shouldn’t include the surgical tract for deep tumors, and GTV to PTV margin is typical 1-3 mm. Finally, hotspots don’t seem to need constraint when confined to the GTV, and treatment should be delivered within 4 weeks from surgery. | Minniti, Radiat Oncol 2021