Combining radiosurgery with immunotherapy, particularly PD-1 inhibitors, was found to increase survival in patients with melanoma, according to a recently-published study.

Based on the findings, the researchers noted that there is a significant difference in cancer control depending on the type of immunotherapy used, namely anti-PD-1 inhibitors. The study, published in the Journal of Neuro-Oncology, describes the potential advantage of combining these 2 therapies.

Radiation treatments can increase the PD-L1 signal on tumors, essentially giving the anti-PD-1 or anti-PD-L1 inhibitors a target to act on, the researchers wrote.

Thirty-eight patients were treated with immunotherapy and radiosurgery between 2012 and 2017. Of these patients, median overall survival was not reached, meaning that many of these patients were still alive when data were analyzed.

“Several years ago, a patient might have expected to live months after that diagnosis, but for many patients this is no longer the case,” study author Tyler Robin, MD, PhD, senior resident in radiation oncology at the CU School of Medicine, said in a press release.

Additionally, none of these patients developed severe adverse effects, although 6 patients did experience some adverse reaction.

Twenty-five patients received anti-CTLA4 immunotherapy and 13 patients received anti-PD-1

immunotherapy. According to the study, patients treated with anti-CTLA4 immunotherapies saw the development of new brain metastases at a median of 3.1 months, whereas the median was not reached for patients treated with anti-PD-1 immunotherapies.

Overall, treatments including anti-PD-1 immunotherapy were more successful, indicating an advantage to anti-PD-1 or combination therapy compared with anti-CTLA4, the researchers wrote.

“People are actively investigating the combination of immune checkpoint inhibits and radiation, and our data raise the possibility that PD-1 inhibitors are preferential in this setting,” Dr Robin said in the press release.

Reference

Breeze RE, Smith DE, Rusthoven CG, et al. Immune checkpoint inhibitors and radiosurgery for newly diagnosed melanoma brain metastases. Journal of Neuro-Oncology. Doi: https://doi.org/10.1007/s11060-018-2930-5

In melanoma, radiosurgery may combine well with immunotherapy, especially PD-1 inhibitors [news release]. University of Colorado Cancer Center’s website. http://www.coloradocancerblogs.org/in-melanoma-radiosurgery-may-work-well-with-immunotherapy-especially-pd-1-inhibitors/. Accessed June 27, 2018.