A multicenter analysis of immune checkpoint inhibitors as adjuvant therapy following treatment of isolated brain metastasis.

Background To characterize outcomes of patients with isolated brain metastases managed with local therapy followed by immune checkpoint inhibitor (ICI) therapy. Materials and methods Patients from 4 medical centers were included if they presented with isolated brain metastases treated with local therapy, and received adjuvant treatment with ICI. Results Eleven patients with median size of largest brain metastasis of 3.9 cm, treated with surgical resection (n=8) and/or stereotactic radiosurgery (SRS; n=6) were included. Ipilimumab/nivolumab was the adjuvant ICI used in 4 patients, of which 1 recurred (25%) and none died, compared with 3 of 7 (43%) who recurred and 2 of 7 (29%) who died following adjuvant treatment with ICI monotherapy. All recurrences were intracranial. Conclusion Patients with isolated brain metastases treated with surgery or SRS appeared to benefit from adjuvant ICI, particularly with combination therapy. Recurrences in this setting appear to largely occur intracranially.