Toxicity and Local Control Outcomes for Brain Metastases Managed with Resection and Aggressive Reirradiation after Initial Radiosurgery Failure

Abstract

The optimal salvage management of patients with local recurrence after radiosurgery for brain metastases is unknown. We report toxicity and tumor control outcomes in such salvage cases managed with a paradigm of repeat resection to confirm recurrence (rather than necrosis) followed by aggressive retreatment with radiosurgery or brachytherapy. We hypothesize that aggressive re-irradiation is safe in these cases where previously irradiated tissue has been surgically removed. A retrospective chart review at a single institution identified 85 metastases in 69 patients that were treated with radiosurgery and then underwent resection after progressive imaging changes for confirmation of necrosis vs disease progression at that site. From these, there were 25 lesions in 23 patients that then underwent re-irradiation either with radiosurgery (n=18) or intracavitary brachytherapy with Cesium-131 seeds (n=7). Toxicity was measured according to the following metrics: steroids initiated or increased within 3 months, imaging evidence of treatment effect vs disease progression in the treated lesion at any time point, further intervention for local recurrence or necrosis, and any grade 3/4 neurologic events related to progression, edema, or necrosis of the treated lesion. Local control (with failure defined by sustained progression on imaging) was measured from time of retreatment. Median follow-up from time of re-irradiation was 5.6 months (range 1 – 40.8 months). Dose for repeat radiosurgery was 18-25 Gy in 3-5 fractions, and brachytherapy dose was 55-65 Gy at 5 mm depth. Toxicity outcomes are reported in Table 1. Twelve percent (all treated with radiosurgery for salvage) underwent additional surgery for suspected progression, and pathology showed necrosis/treatment effect without disease recurrence in all 3 cases. Local control at 6 and 12 months was 79% and 60%, respectively, with 100% local control in all 6 patients surviving > 1 year. Aggressive re-irradiation after resection for pathologic confirmation appears to be appropriately safe for the majority of patients after local failure of initial radiosurgery. Long term local control is achieved for some patients. Abstract MO_16_2605; Table 1.Proportion of patients experiencing toxicityN (%)Steroids within 3 months9 (36)Imaging evidence of radionecrosis/progression7 (28)Neurologic grade 3 or 4 event6 (24)Radionecrosis requiring surgery3 (12) Open table in a new tab