The abscopal effect is a phenomenon in which local radiotherapy is associated with the regression of metastatic cancer at a distance from the irradiated site. The abscopal effect may be mediated by activation of the immune system. Ipilimumab is a monoclonal antibody that inhibits an immunologic checkpoint on T cells, cytotoxic T-lymphocyte–associated antigen 4 (CTLA-4). We report a case of the abscopal effect in a patient with melanoma treated with ipilimumab and radiotherapy. Temporal associations were noted: tumor shrinkage with antibody responses to the cancer–testis antigen NY-ESO-1, changes in peripheral-blood immune cells, and increases in antibody responses to other antigens after radiotherapy. (Funded by the National Institutes of Health and others.)

Background Cytokine release syndrome (CRS) has been reported after immunologic manipulations, most often through therapeutic monoclonal antibodies. To our knowledge, CRS after radiation therapy (RT) for cancer has not been reported before. The development of unusual clinical signs and symptoms after RT led us to investigate the possibility of CRS after RT and review the medical literature on this topic. Case presentation A 65 year-old man with untreated chronic lymphocytic leukemia and recurrent, metastatic Merkel cell carcinoma undergoing anti-programmed death 1 (PD1) immunotherapy was referred for palliative RT to sites of progressing metastases. Within hours of each weekly dose of RT, he experienced fever, tachycardia, hypotension, rash, dyspnea, and rigors. Based on clinical suspicion for CRS, blood cytokine measurements were performed 1 h after the second and third dose of RT and demonstrated tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) levels approximately ten-fold higher than normal. These were near normal immediately prior to the third dose of RT, and resolved to normal levels 3 weeks after RT. He experienced rapid regression of irradiated tumors, with development of new sites of metastases soon thereafter. A literature review revealed no clinical cases of CRS after RT for cancer. Conclusions RT during anti-PD1 immunotherapy in a patient with underlying immune dysfunction appeared to be the putative mediator of an immune process which yielded significant increases in pro-inflammatory cytokines, and produced the clinical symptoms meeting the definition of grade 3 CRS. This case demonstrates the capability of RT to elicit immune-related adverse events.

Purpose: To perform the first meta-analysis of the efficacy of skin-directed therapies for cutaneous metastases. Methods: MEDLINE, EMBASE, The Cochrane Library, and ClinicalTrials.gov databases were searched for reports of prospective clinical studies published between 1960 and 2013 that assessed the response of skin-directed therapy for cutaneous metastases (47 of 2,955 unique studies were selected). Primary end points of the study were complete and objective response rates. Secondary analyses were preplanned and included subgroup analyses by skin-directed therapy, histology, and recurrence rates. Meta-analyses were performed with random-effect modeling, and extent of heterogeneity between studies was determined with the Cochran Q and I² tests. Results: After applying exclusion criteria, 47 prospective studies of 4,313 cutaneous metastases were assessed. Five skin-directed therapies were identified: electrochemotherapy, photodynamic therapy, radiotherapy, intralesional therapy, and topical therapy. Among all cutaneous metastases, complete response rate was 35.5% (95% CI, 27.6% to 44.3%) and objective response rate was 60.2% (95% CI, 50.6% to 69.0%). Overall recurrence rate was estimated to be 9.2% (95% CI, 3.7% to 21.2%). Melanoma and breast carcinoma comprised 96.8% of all cutaneous metastases studied and had similar objective response rates (54.5% [95% CI, 48.3% to 60.7%] and 54.0% [95% CI, 48.3% to 59.7%], respectively). Grade ≥ 3 toxicity was reported in less than 6% of patients. Conclusion: Response to skin-directed therapy for cutaneous metastases is high but heterogeneous across treatment modalities, with low rates of recurrence post-treatment. Treatment was generally well tolerated and conferred improvements in quality of life. Standardization of response criteria for cutaneous metastases and treatment algorithms to optimally use the available skin-directed therapies are needed.