Stereotactic radiosurgery (SRS) with concurrent immunotherapy appears to be effective for the treatment of melanoma brain metastases, according to a study published in Cancer.1
Researchers enrolled 75 patients with 566 lesions, 55% (313) of which were treated with concurrent immunotherapy, defined as within 4 weeks of radiotherapy; 45% (253) were not treated with concurrent therapy. Treatment effect was determined with the Wilcoxon rank-sum test at 1.5, 3, and 6 months post-SRS treatment.
Median percent reduction in lesion volume was significantly improved for patients treated with RSS and immunotherapy concurrently. At 1.5 months, lesions of patients in the “concurrent” cohort were reduced a median of 63.1%, versus 43.2% in the “nonconcurrent” cohort (P < .0001.) At 3 and 6 months, concurrent versus nonconcurrent reductions were 83.0% versus 52.8% (P < .0001) and 94.9% versus 66.2% (P < .0001), respectively.
Results were similarly significant for patients who received anti–programmed cell death protein 1 (anti-PD-1) therapy rather than anti–cytotoxic T-lymphocyte-associated protein 4 (anti–CTLA-4); at 1.5, 3, and 6 months, the anti-PD-1 versus anti-CTLA-4-related reductions were 71.1% versus 48.2%, (P < .0001), 89.3% versus 66.2% (P < .0001), and 95.1% versus 75.9% (P = .0004), respectively.
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The authors concluded both that immunotherapy within 4 weeks of SRS promotes better lesion reduction for patients with melanoma brain metastases, and that anti-PD-1 therapy is superior to anti-CTLA-4 after SRS.
1. Qian JM, Yu JB, Kluger HM, Chiang VLS. Timing and type of immune checkpoint therapy affect the early radiographic response of melanoma brain metastases to stereotactic radiosurgery [published online ahead of print June 10, 2016]. Cancer. doi: 10.1002/cncr.30138.