Patients who have a brain metastasis surgically resected have very high local rates of disease relapse, and so the standard of care is to give either whole brain irradiation or stereotactic radiosurgery to the resection cavity in order to prevent disease recurrence. Stereotactic radiosurgery generally offers a more favorable side effect profile than whole brain irradiation, but targeting a surgical resection bed can be a challenge, as post surgical changes make it more difficult to distinguish residual tumor from scar, and much of the dose ends up being focused on the center of the resection cavity, where there are no substantial tumor cells.
