Over the past decade, the treatment of advanced melanoma has been enriched by several new immunotherapies, such as immune checkpoint inhibitors for cytotoxic T–lymphocyte-associated antigen 4 (CTLA-4) or programmed cell death 1 (PD-1). However, a considerable proportion of patients do not respond to these drugs,1 and new strategies are needed. Among them, the use of checkpoint inhibitors with concomitant radiotherapy appears relevant.2 The rationale is that the tumor killing can increase tumor antigen in the bloodstream, favoring antigen presentation leading to an immunogenic response to tumor cells outside of the radiation field, defined as the abscopal effect.3 Results of this strategy have mostly been reported for the treatment of brain metastasis with stereotactic ablative radiotherapy (SABR) and anti–PD-1,4,5 ipilimumab,4 or anti–programmed cell death ligand 1 (PD-L1).6 Data concerning extracerebral irradiation and data analyzing the impact of irradiation of several tumor sites with immunotherapy are scarce. To irradiate several tumor sites could indeed increase the diversity of antigen presentation and thus increase the probability of response.
Jérôme Doyen, Alexandra Picard, Arash O. Naghavi, Antoine Thyss, Thierry Passeron, Jean-Philippe Lacour, Henri Montaudié. Clinical Outcomes of Metastatic Melanoma Treated With Checkpoint Inhibitors and Multisite Radiotherapy. JAMA Dermatol. 2017;153(10):1056–1059. doi:10.1001/jamadermatol.2017.2222