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.

Keywords: Melanoma; brain metastases; immune checkpoint inhibitor; nivolumab; pembrolizumab.