CTLA4 and melanoma: In patients with melanoma brain metastasis treated with SRS and anti-CTLA-4 and/or anti-PD-1 at MD Anderson Cancer Center, a multivariate analysis showed that use of chemotherapy within 6 months of SRS and number of lesions treated were predictive of increased RN risk (HR 2.20, 95% CI 1.22–3.97, p = 0.009; HR 1.09, 95% CI 1.03–1.15, p = 0.002)31.