Tract changes.

When delivering post-op SRS for resected brain metastases, covering the surgical tract may seem like a trivial matter for superficial tumors, but what about deep tumors? This retrospective study from Stanford takes a look at patterns of failure for 66 deep (>1cm from surface) resected brain mets treated with post-op SRS with or without coverage of the surgical tract. Notably there were several biases in the group that did not have tract coverage (45%) including more breast cancer histology, more prior irradiation, infratentorial location, and greater absolute tumor depth. The main take-home was that both cavity and surgical tract failures were too infrequent to show a significant difference: the risk of tract recurrence was 9% without coverage and 1.5% with coverage at 12 months. However, there did appear to be a significantly higher rate of leptomeningeal failure without tract coverage. TBL: The overall risk of surgical tract failure for deep brain metastases is low when omitted from the SRS target volume so balancing the risk of toxicity should be a careful consideration. | Shi, Pract Radiat Oncol 2020