Although consensus guidelines for post-resection stereotactic radiosurgery (SRS) for brain metastases recommend the surgical corridor leading to the resection cavity be included in the SRS plan, no study has reported patterns of tumor recurrence based on inclusion or exclusion of the corridor as a target. We reviewed tumor control and toxicity outcomes of post-resection SRS for deep brain metastases based on whether or not the surgical corridor was targeted.We retrospectively reviewed patients who had resected brain metastases treated with SRS between 2007 and 2018 and included only 'deep' tumors (defined as located =1.0 cm from the pial surface prior to resection).In 66 deep brain metastases in 64 patients, the surgical corridor was targeted in 43 (65%). There were no statistical differences in the cumulative incidences of progression at 12-months for targeting vs. not targeting the corridor, respectively, for: overall local failure 2% (95% Confidence Interval [CI],0-11%) vs. 9% (95% CI,1-25%; p=0.25), corridor failure 0% (95% CI,0-0%) vs. 9% (95% CI,1-25%; p=0.06), cavity failure 2% (95% CI,0-11%) vs. 0% (95% CI,0-0%; p=0.91), adverse radiation effect 5% (95% CI,1-15%) vs. 13% (95% CI,3-30%; p=0.22). Leptomeningeal disease (7% (95% CI,2-18%) vs. 26% (95% CI,10-45%; p=0.03)) was higher in those without the corridor targeted.Omitting the surgical corridor in post-operative SRS for resected brain metastases was not associated with statistically significant differences in corridor or cavity recurrence or adverse radiation effect. As seen in recent prospective trials of post-resection SRS, the dominant pattern of progression is within the resection cavity; omission of the corridor would yield a smaller SRS volume that could allow for dose escalation to potentially improve local cavity control.
View details for DOI 10.1016/j.prro.2020.04.009
View details for PubMedID 32428766