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05-06-2018 | Radiotherapy | Article

Safety of combining radiotherapy with immune-checkpoint inhibition

Journal: Nature Reviews Clinical Oncology

Authors: William L. Hwang, Luke R. G. Pike, Trevor J. Royce, Brandon A. Mahal, Jay S. Loeffler

Publisher: Nature Publishing Group UK

Abstract

Immune-checkpoint inhibitors targeting cytotoxic T- lymphocyte antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1), or programmed cell death 1 ligand 1 (PD-L1) have transformed the care of patients with a wide range of advanced-stage malignancies. More than half of these patients will also have an indication for treatment with radiotherapy. The effects of both radiotherapy and immune-checkpoint inhibition (ICI) involve a complex interplay with the innate and adaptive immune systems, and accumulating evidence suggests that, under certain circumstances, the effects of radiotherapy synergize with those of ICI to augment the antitumour responses typically observed with either modality alone and thus improve clinical outcomes. However, the mechanisms by which radiotherapy and immune-checkpoint inhibitors synergistically modulate the immune response might also affect both the type and severity of treatment-related toxicities. Moreover, in patients receiving immune-checkpoint inhibitors, the development of immune-related adverse events has been linked with superior treatment responses and patient survival durations, suggesting a relationship between the antitumour and adverse autoimmune effects of these agents. In this Review, we discuss the emerging data on toxicity profiles related to immune-checkpoint inhibitors and radiotherapy, both separately and in combination, their potential mechanisms, and the approaches to managing these toxicities.
Literature
1.
Lederman, M. The early history of radiotherapy: 1895–1939. Int. J. Radiat. Oncol. 7, 639–648 (1981).
2.
Barton, M. B. et al. Estimating the demand for radiotherapy from the evidence: a review of changes from 2003 to 2012. Radiother. Oncol. 112, 140–144 (2014).PubMed
3.
Delaney, G., Jacob, S., Featherstone, C. & Barton, M. The role of radiotherapy in cancer treatment. Cancer 104, 1129–1137 (2005).PubMed
4.
Citrin, D. E. Recent developments in radiotherapy. N. Engl. J. Med. 377, 1065–1075 (2017).PubMed
5.
Amaravadi, R. K. & Thompson, C. B. The roles of therapy-induced autophagy and necrosis in cancer treatment. Clin. Cancer Res. 13, 7271–7279 (2007).PubMed
6.
Rouschop, K. M. A. et al. Autophagy is required during cycling hypoxia to lower production of reactive oxygen species. Radiother. Oncol. 92, 411–416 (2009).PubMed
7.
Twyman-Saint Victor, C. et al. Radiation and dual checkpoint blockade activate non-redundant immune mechanisms in cancer. Nature 520, 373–377 (2015).PubMed
8.
Ludgate, C. M. Optimizing cancer treatments to induce an acute immune response: radiation abscopal effects, PAMPs, and DAMPs. Clin. Cancer Res. 18, 4522–4525 (2012).PubMed
9.
Sridharan, V. et al. Effects of definitive chemoradiation on circulating immunologic angiogenic cytokines in head and neck cancer patients. J. Immunother. Cancer 4, 32 (2016).PubMedPubMedCentral
10.
de Gonzalez, A. B. et al. Proportion of second cancers attributable to radiotherapy treatment in adults: a cohort study in the US SEER cancer registries. Lancet Oncol. 12, 353–360 (2011).PubMedCentral
11.
Schaapveld, M. et al. Second cancer risk up to 40 years after treatment for Hodgkin’s Lymphoma. N. Engl. J. Med. 373, 2499–2511 (2015).PubMed
12.
Journy, N. M. Y., Morton, L. M., Kleinerman, R. A., Bekelman, J. E. & Berrington de Gonzalez, A. Second primary cancers after intensity-modulated versus 3-dimensional conformal radiation therapy for prostate cancer. JAMA Oncol. 2, 1368 (2016).PubMed
13.
Bhakta, N. et al. The cumulative burden of surviving childhood cancer: an initial report from the St Jude Lifetime Cohort Study (SJLIFE). Lancet 390, 2569–2582 (2017).PubMedPubMedCentral
14.
Turcotte, L. M. et al. Temporal trends in treatment and subsequent neoplasm risk among 5-year survivors of childhood cancer, 1970–2015. JAMA 317, 814 (2017).PubMedPubMedCentral
15.
Larkin, J. et al. Combined nivolumab and ipilimumab or monotherapy in untreated melanoma. N. Engl. J. Med. 373, 23–34 (2015).PubMedPubMedCentral
16.
Borghaei, H. et al. Nivolumab versus docetaxel in advanced nonsquamous non–small-cell lung cancer. N. Engl. J. Med. 373, 1627–1639 (2015).PubMedPubMedCentral
17.
Robert, C. et al. Nivolumab in previously untreated melanoma without BRAF mutation. N. Engl. J. Med. 372, 320–330 (2015).PubMed
18.
Robert, C. et al. Pembrolizumab versus ipilimumab in advanced melanoma. N. Engl. J. Med. 372, 2521–2532 (2015).PubMed
19.
Topalian, S. L. et al. Safety, activity, and immune correlates of anti–PD-1 antibody in cancer. N. Engl. J. Med. 366, 2443–2454 (2012).PubMedPubMedCentral
20.
Ansell, S. M. et al. PD-1 blockade with nivolumab in relapsed or refractory Hodgkin’s lymphoma. N. Engl. J. Med. 372, 311–319 (2015).PubMed
21.
Peggs, K. S., Quezada, S. A., Chambers, C. A., Korman, A. J. & Allison, J. P. Blockade of CTLA-4 on both effector and regulatory T cell compartments contributes to the antitumor activity of anti–CTLA-4 antibodies. J. Exp. Med. 206, 1717–1725 (2009).PubMedPubMedCentral
22.
Azuma, M. et al. B70 antigen is a second ligand for CTLA-4 and CD28. Nature 366, 76–79 (1993).PubMed
23.
Freeman, G. J. et al. Cloning of B7-2: a CTLA-4 counter-receptor that costimulates human T cell proliferation. Science 262, 909–911 (1993).PubMed
24.
Waterhouse, P. et al. Lymphoproliferative disorders with early lethality in mice deficient in Ctla-4. Science 270, 985–988 (1995).PubMed
25.
Khattri, R., Auger, J. A., Griffin, M. D., Sharpe, A. H. & Bluestone, J. A. Lymphoproliferative disorder in CTLA-4 knockout mice is characterized by CD28-regulated activation of Th2 responses. J. Immunol. 162, 5784–5791 (1999).PubMed
26.
Smigiel, K. S., Srivastava, S., Stolley, J. M. & Campbell, D. J. Regulatory T cell homeostasis: steady-state maintenance and modulation during inflammation. Immunol. Rev. 259, 40–59 (2014).PubMedPubMedCentral
27.
Ueda, H. et al. Association of the T cell regulatory gene CTLA4 with susceptibility to autoimmune disease. Nature 423, 506–511 (2003).PubMed
28.
Vaidya, B. et al. An association between the CTLA4 exon 1 polymorphism and early rheumatoid arthritis with autoimmune endocrinopathies. Rheumatology 41, 180–183 (2002).PubMed
29.
Zhernakova, A. et al. CTLA4 is differentially associated with autoimmune diseases in the Dutch population. Hum. Genet. 118, 58–66 (2005).PubMed
30.
Fernández-Mestre, M. et al. Influence of CTLA-4 gene polymorphism in autoimmune and infectious diseases. Hum. Immunol. 70, 532–535 (2009).PubMed
31.
Hudson, L., Rocca, K., Song, Y. & Pandey, J. CTLA-4 gene polymorphisms in systemic lupus erythematosus: a highly significant association with a determinant in the promoter region. Hum. Genet. 111, 452–455 (2002).PubMed
32.
Blomhoff, A. et al. Polymorphisms in the cytotoxic T lymphocyte antigen-4 gene region confer susceptibility to Addison’s disease. J. Clin. Endocrinol. Metab. 89, 3474–3476 (2004).PubMed
33.
Francisco, L. M., Sage, P. T. & Sharpe, A. H. The PD-1 pathway in tolerance and autoimmunity. Immunol. Rev. 236, 219–242 (2010).PubMedPubMedCentral
34.
Okazaki, T., Chikuma, S., Iwai, Y., Fagarasan, S. & Honjo, T. A rheostat for immune responses: the unique properties of PD-1 and their advantages for clinical application. Nat. Immunol. 14, 1212–1218 (2013).PubMed
35.
Shi, F. et al. PD-1 and PD-L1 upregulation promotes CD8+ T cell apoptosis and postoperative recurrence in hepatocellular carcinoma patients. Int. J. Cancer 128, 887–896 (2011).PubMed
36.
Kataoka, K. et al. Aberrant PD-L1 expression through 3′-UTR disruption in multiple cancers. Nature 534, 402–406 (2016).PubMed
37.
Nishimura, H. et al. Autoimmune dilated cardiomyopathy in PD-1 receptor-deficient mice. Science 291, 319–322 (2001).PubMed
38.
Nishimura, H., Nose, M., Hiai, H., Minato, N. & Honjo, T. Development of lupus-like autoimmune diseases by disruption of the PD-1 gene encoding an ITIM motif-carrying immunoreceptor. Immunity 11, 141–151 (1999).PubMed
39.
Boutros, C. et al. Safety profiles of anti-CTLA-4 and anti-PD-1 antibodies alone and in combination. Nat. Rev. Clin. Oncol. 13, 473–486 (2016).PubMed
40.
Postow, M. A. et al. Immunologic correlates of the abscopal effect in a patient with melanoma. N. Engl. J. Med. 366, 925–931 (2012).PubMedPubMedCentral
41.
Mole, R. H. Whole body irradiation; radiobiology or medicine? Br. J. Radiol 26, 234–241 (1953).PubMed
42.
Demaria, S. et al. Ionizing radiation inhibition of distant untreated tumors (abscopal effect) is immune mediated. Int. J. Radiat. Oncol. 58, 862–870 (2004).
43.
Weichselbaum, R. R., Liang, H., Deng, L. & Fu, Y. X. Radiotherapy and immunotherapy: a beneficial liaison? Nat. Rev. Clin. Oncol. 14, 365–379 (2017).PubMed
44.
Cappelli, L. C., Shah, A. A. & Bingham, C. O. Immune-related adverse effects of cancer immunotherapy — implications for rheumatology. Rheum. Dis. Clin. North Am. 43, 65–78 (2017).PubMed
45.
Stone, H., Peters, L. & Milas, L. Effect of host immune capability on radiocurability and subsequent transplantability of a murine fibrosarcoma. J. Natl Cancer Inst. 63, 1229–1235 (1979).PubMed
46.
Ngwa, W. et al. Using immunotherapy to boost the abscopal effect. Nat. Rev. Cancer 18, 313–322 (2018).PubMedPubMedCentral
47.
Deng, L. et al. Irradiation and anti–PD-L1 treatment synergistically promote antitumor immunity in mice. J. Clin. Invest. 124, 687–695 (2014).PubMedPubMedCentral
48.
Schaue, D., Kachikwu, E. L. & McBride, W. H. Cytokines in radiobiological responses: a review. Radiat. Res. 178, 505–523 (2012).PubMedPubMedCentral
49.
Demaria, S. & Formenti, S. C. Radiation as an immunological adjuvant: current evidence on dose and fractionation. Front. Oncol. 2, 153 (2012).PubMedPubMedCentral
50.
Demaria, S. & Formenti, S. C. Role of T lymphocytes in tumor response to radiotherapy. Front. Oncol. 2, 95 (2012).PubMedPubMedCentral
51.
Lugade, A. A. et al. Local radiation therapy of B16 melanoma tumors increases the generation of tumor antigen-specific effector cells that traffic to the tumor. J. Immunol. 174, 7516–7523 (2005).PubMed
52.
Sharabi, A. B. et al. Stereotactic radiation therapy augments antigen-specific PD-1-mediated antitumor immune responses via cross-presentation of tumor antigen. Cancer Immunol. Res. 3, 345–355 (2015).PubMed
53.
Gupta, A. et al. Radiotherapy promotes tumor-specific effector CD8+ T cells via dendritic cell activation. J. Immunol. 189, 558–566 (2012).PubMed
54.
Abuodeh, Y., Venkat, P. & Kim, S. Systematic review of case reports on the abscopal effect. Curr. Probl. Cancer 40, 25–37 (2016).PubMed
55.
Formenti, S. C. & Demaria, S. Combining radiotherapy and cancer immunotherapy: a paradigm shift. J. Natl Cancer Inst. 105, 256–265 (2013).PubMedPubMedCentral
56.
Kalbasi, A., June, C. H., Haas, N. & Vapiwala, N. Radiation and immunotherapy: a synergistic combination. J. Clin. Invest. 123, 2756–2763 (2013).PubMedPubMedCentral
57.
Sharabi, A. B., Lim, M., DeWeese, T. L. & Drake, C. G. Radiation and checkpoint blockade immunotherapy: radiosensitisation and potential mechanisms of synergy. Lancet Oncol. 16, e498–e509 (2015).PubMed
58.
Kachikwu, E. L. et al. Radiation enhances regulatory T cell representation. Int. J. Radiat. Oncol. Biol. Phys. 81, 1128–1135 (2011).PubMed
59.
Persa, E., Balogh, A., Sáfrány, G. & Lumniczky, K. The effect of ionizing radiation on regulatory T cells in health and disease. Cancer Lett. 368, 252–261 (2015).PubMed
60.
Facciabene, A., Motz, G. T. & Coukos, G. T-regulatory cells: key players in tumor immune escape and angiogenesis. Cancer Res. 72, 2162–2171 (2012).PubMedPubMedCentral
61.
Balogh, A. et al. The effect of ionizing radiation on the homeostasis and functional integrity of murine splenic regulatory T cells. Inflamm Res. 62, 201–212 (2013).PubMed
62.
Dewan, M. Z. et al. Fractionated but not single-dose radiotherapy induces an immune-mediated abscopal effect when combined with anti-CTLA-4 antibody. Clin. Cancer Res. 15, 5379–5388 (2009).PubMedPubMedCentral
63.
Bernstein, M. B., Krishnan, S., Hodge, J. W. & Chang, J. Y. Immunotherapy and stereotactic ablative radiotherapy (ISABR): a curative approach? Nat. Rev. Clin. Oncol. 13, 516–524 (2016).PubMedPubMedCentral
64.
Vanpouille-Box, C. et al. DNA exonuclease Trex1 regulates radiotherapy-induced tumour immunogenicity. Nat. Commun. 8, 15618 (2017).PubMedPubMedCentral
65.
DuPage, M. & Jacks, T. Genetically engineered mouse models of cancer reveal new insights about the antitumor immune response. Curr. Opin. Immunol. 25, 192–199 (2013).PubMedPubMedCentral
66.
Dranoff, G. Experimental mouse tumour models: what can be learnt about human cancer immunology? Nat. Rev. Immunol. 12, 61–66 (2011).PubMed
67.
Ryder, M., Callahan, M., Postow, M. A., Wolchok, J. & Fagin, J. A. Endocrine-related adverse events following ipilimumab in patients with advanced melanoma: a comprehensive retrospective review from a single institution. Endocr. Relat. Cancer 21, 371–381 (2014).PubMedPubMedCentral
68.
Michot, J. M. et al. Immune-related adverse events with immune checkpoint blockade: a comprehensive review. Eur. J. Cancer 54, 139–148 (2016).PubMed
69.
Weber, J. S. et al. Phase I/II study of ipilimumab for patients with metastatic melanoma. J. Clin. Oncol. 26, 5950–5956 (2008).PubMed
70.
Di Giacomo, A. M. et al. Ipilimumab and fotemustine in patients with advanced melanoma (NIBIT-M1): an open-label, single-arm phase 2 trial. Lancet Oncol. 13, 879–8868 (2012).PubMed
71.
Margolin, K. et al. Ipilimumab in patients with melanoma and brain metastases: an open-label, phase 2 trial. Lancet Oncol. 13, 459–465 (2012).PubMed
72.
Wolchok, J. D. et al. Ipilimumab monotherapy in patients with pretreated advanced melanoma: a randomised, double-blind, multicentre, phase 2, dose-ranging study. Lancet Oncol. 11, 155–164 (2010).PubMed
73.
Robert, C. et al. Ipilimumab plus dacarbazine for previously untreated metastatic melanoma. N. Engl. J. Med. 364, 2517–2526 (2011).PubMed
74.
Brahmer, J. R. et al. Phase I study of single-agent anti–programmed death-1 (MDX-1106) in refractory solid tumors: safety, clinical activity, pharmacodynamics, and immunologic correlates. J. Clin. Oncol. 28, 3167–3175 (2010).PubMedPubMedCentral
75.
Topalian, S. L. et al. Survival, durable tumor remission, and long-term safety in patients with advanced melanoma receiving nivolumab. J. Clin. Oncol. 32, 1020–1030 (2014).PubMedPubMedCentral
76.
Robert, C. et al. Anti-programmed-death-receptor-1 treatment with pembrolizumab in ipilimumab-refractory advanced melanoma: a randomised dose-comparison cohort of a phase 1 trial. Lancet 384, 1109–1117 (2014).PubMed
77.
Ribas, A. et al. Pembrolizumab versus investigator-choice chemotherapy for ipilimumab-refractory melanoma (KEYNOTE-002): a randomised, controlled, phase 2 trial. Lancet Oncol. 16, 908–918 (2015).PubMedPubMedCentral
78.
Barroso-Sousa, R. et al. Incidence of endocrine dysfunction following the use of different immune checkpoint inhibitor regimens: a systematic review and meta-analysis. JAMA Oncol. 4, 173–182 (2018).PubMed
79.
Hassel, J. C. et al. Combined immune checkpoint blockade (anti-PD-1/anti-CTLA-4): evaluation and management of adverse drug reactions. Cancer Treat. Rev. 57, 36–49 (2017).PubMed
80.
Brahmer, J. R. et al. Management of immune-related adverse events in patients treated with immune checkpoint inhibitor therapy: American Society of Clinical Oncology Clinical Practice Guideline. J. Clin. Oncol. 36, 1–55 (2018).
81.
Dick, J. et al. Use of LDH and autoimmune side effects to predict response to ipilimumab treatment. Immunotherapy 8, 1033–1044 (2016).PubMed
82.
Feng, S. et al. Pembrolizumab-induced encephalopathy: a review of neurological toxicities with immune checkpoint inhibitors. J. Thorac Oncol. 12, 1626–1635 (2017).PubMed
83.
Hwang, W. L. et al. Clinical outcomes in patients with metastatic lung cancer treated with PD-1/PD-L1 inhibitors and thoracic radiotherapy. JAMA Oncol. 4, 253–255 (2018).PubMed
84.
Haratani, K. et al. Association of immune-related adverse events with nivolumab efficacy in non–small-cell lung cancer. JAMA Oncol. 4, 374–378 (2018).PubMed
85.
Weber, J. S. et al. Safety profile of nivolumab monotherapy: a pooled analysis of patients with advanced melanoma. J. Clin. Oncol. 35, 785–792 (2017).PubMed
86.
Snyder, A. et al. Genetic basis for clinical response to CTLA-4 blockade in melanoma. N. Engl. J. Med. 371, 2189–2199 (2014).PubMedPubMedCentral
87.
Vétizou, M. et al. Anticancer immunotherapy by CTLA-4 blockade relies on the gut microbiota. Science 350, 1079–1084 (2015).PubMedPubMedCentral
88.
Ferrara, J. L., Levine, J. E., Reddy, P. & Holler, E. Graft-versus-host disease. Lancet 373, 1550–1561 (2009).PubMedPubMedCentral
89.
Nordlander, A. et al. Graft-versus-host disease is associated with a lower relapse incidence after hematopoietic stem cell transplantation in patients with acute lymphoblastic leukemia. Biol. Blood Marrow Transplant. 10, 195–203 (2004).PubMed
90.
Weiden, P. L., Sullivan, K. M., Flournoy, N., Storb, R. & Thomas, E. D. Antileukemic effect of chronic graft-versus-host disease: contribution to improved survival after allogeneic marrow transplantation. N. Engl. J. Med. 304, 1529–1533 (1981).PubMed
91.
Hall, E. J. & Giaccia, A. J. Radiobiology for the Radiologist (Lippincott Williams & Wilkins, 2011).
92.
Sridharan, V. et al. Definitive chemoradiation alters the immunologic landscape and immune checkpoints in head and neck cancer. Br. J. Cancer 115, 252–260 (2016).PubMedPubMedCentral
93.
Reits, E. A. et al. Radiation modulates the peptide repertoire, enhances MHC class I expression, and induces successful antitumor immunotherapy. J. Exp. Med. 203, 1259–1271 (2006).PubMedPubMedCentral
94.
Citrin, D. E. & Mitchell, J. B. Mechanisms of normal tissue injury from irradiation. Semin. Radiat. Oncol. 27, 316–324 (2017).PubMedPubMedCentral
95.
Soussain, C. et al. CNS complications of radiotherapy and chemotherapy. Lancet 374, 1639–1651 (2009).PubMed
96.
Rube, C. et al. Dose-dependent induction of transforming growth factor beta (TGF-beta) in the lung tissue of fibrosis-prone mice after thoracic irradiation. Int. J. Radiat. Oncol. Biol. Phys. 47, 1033–1042 (2000).PubMed
97.
Simone, C. B. Thoracic radiation normal tissue injury. Semin. Radiat. Oncol. 27, 370–377 (2017).PubMed
98.
Sprung, C., Forrester, H., Siva, S. & Martin, O. Immunological markers that predict radiation toxicity. Cancer Lett. 368, 191–197 (2015).PubMed
99.
Wirsdörfer, F. & Jendrossek, V. The role of lymphocytes in radiotherapy-induced adverse late effects in the lung. Front. Immunol. 7, 591 (2016).PubMedPubMedCentral
100.
Le Jeune, I. et al. The incidence of cancer in patients with idiopathic pulmonary fibrosis and sarcoidosis in the UK. Respir. Med. 101, 2534–2540 (2007).PubMed
101.
Chiyo, M. et al. Impact of interstitial lung disease on surgical morbidity and mortality for lung cancer: analyses of short-term and long-term outcomes. J. Thorac. Cardiovasc. Surg. 126, 1141–1146 (2003).PubMed
102.
Yamaguchi, S. et al. Stereotactic body radiotherapy for lung tumors in patients with subclinical interstitial lung disease: the potential risk of extensive radiation pneumonitis. Lung Cancer 82, 260–265 (2013).PubMed
103.
Ueki, N. et al. Impact of pretreatment interstitial lung disease on radiation pneumonitis and survival after stereotactic body radiation therapy for lung cancer. J. Thorac Oncol. 10, 116–125 (2015).PubMed
104.
Bahig, H. et al. Severe radiation pneumonitis after lung stereotactic ablative radiation therapy in patients with interstitial lung disease. Pract. Radiat. Oncol. 6, 367–374 (2016).PubMed
105.
Theis, V. S., Sripadam, R., Ramani, V. & Lal, S. Chronic radiation enteritis. Clin. Oncol. 22, 70–83 (2010).
106.
Ferreira, M., Muls, A., Dearnaley, D. & Andreyev, H. Microbiota and radiation-induced bowel toxicity: lessons from inflammatory bowel disease for the radiation oncologist. Lancet Oncol. 15, e139–e147 (2014).PubMed
107.
Giaj-Levra, N. et al. Radiotherapy in patients with connective tissue diseases. Lancet Oncol. 17, e109–e117 (2016).PubMed
108.
Gold, D. G., Miller, R. C., Petersen, I. A. & Osborn, T. G. Radiotherapy for malignancy in patients with scleroderma: the Mayo Clinic experience. Int. J. Radiat. Oncol. Biol. Phys. 67, 559–567 (2007).PubMed
109.
Pinn, M. E. et al. Systemic lupus erythematosus, radiotherapy, and the risk of acute and chronic toxicity: the Mayo Clinic experience. Int. J. Radiat. Oncol. Biol. Phys. 71, 498–506 (2008).PubMed
110.
Yu, J. B. et al. Stereotactic body radiation therapy versus intensity-modulated radiation therapy for prostate cancer: comparison of toxicity. J. Clin. Oncol. 32, 1195–1201 (2014).PubMedPubMedCentral
111.
Yu, J. B. et al. Proton versus intensity-modulated radiotherapy for prostate cancer: patterns of care and early toxicity. J. Natl Cancer Inst. 105, 25–32 (2013).PubMed
112.
Nutting, C. M. et al. Parotid-sparing intensity modulated versus conventional radiotherapy in head and neck cancer (PARSPORT): a phase 3 multicentre randomised controlled trial. Lancet Oncol. 12, 127–136 (2011).PubMedPubMedCentral
113.
Folkert, M. et al. Comparison of local recurrence with conventional and intensity-modulated radiation therapy for primary soft-tissue sarcomas of the extremity. J. Clin. Oncol. 32, 3236–3241 (2014).PubMedPubMedCentral
114.
Mesia, R. & Taberna, M. HPV-related oropharyngeal carcinoma de-escalation protocols. Lancet Oncol. 18, 704–705 (2017).PubMed
115.
Bang, A. et al. Multicenter evaluation of the tolerability of combined treatment With PD-1 and CTLA-4 immune checkpoint inhibitors and palliative radiation therapy. Int. J. Radiat. Oncol. Biol. Phys. 98, 344–351 (2017).PubMed
116.
Parker, S. M., Zainib, M., Mattes, M. & Amin, N. Multi-institutional report on toxicities from combined radiation and nivolumab [abstract 39]. J. Clin. Oncol. 36 (Suppl. 5), 38–39 (2018).
117.
Luke, J. J. et al. Safety and clinical activity of pembrolizumab and multisite stereotactic body radiotherapy in patients with advanced solid tumors. J. Clin. Oncol. 36, 1611–1618 (2018).PubMedPubMedCentral
118.
McArthur, H. L. et al. A single-arm, phase II study assessing the efficacy of pembrolizumab (pembro) plus radiotherapy (RT) in metastatic triple negative breast cancer (mTNBC) [abstract 14]. J. Clin. Oncol. 36 (Suppl. 5), 14 (2018).
119.
Barker, C. A. et al. Concurrent radiotherapy and ipilimumab immunotherapy for patients with melanoma. Cancer Immunol. Res. 1, 92–98. (2013).PubMedPubMedCentral
120.
Liniker, E. et al. Activity and safety of radiotherapy with anti-PD-1 drug therapy in patients with metastatic melanoma. Oncoimmunology 5, e1214788 (2016).PubMedPubMedCentral
121.
Qin, R. et al. Safety and efficacy of radiation therapy in advanced melanoma patients treated with ipilimumab. Int. J. Radiat. Oncol. Biol. Phys. 96, 72–77 (2016).PubMed
122.
Aboudaram, A. et al. Concurrent radiotherapy for patients with metastatic melanoma and receiving anti-programmed-death 1 therapy. Melanoma Res. 27, 485–491 (2017).PubMed
123.
Nayak, L., Lee, E. Q. & Wen, P. Y. Epidemiology of brain metastases. Curr. Oncol. Rep. 14, 48–54 (2012).PubMed
124.
Bafaloukos, D. & Gogas, H. The treatment of brain metastases in melanoma patients. Cancer Treat. Rev. 30, 515–520 (2004).PubMed
125.
Hodi, F. S. et al. Improved survival with ipilimumab in patients with metastatic melanoma. N. Engl. J. Med. 363, 711–723 (2010).PubMedPubMedCentral
126.
Dagogo-Jack, I. et al. A retrospective analysis of the efficacy of pembrolizumab in melanoma patients with brain metastasis. J. Immunother. 40, 108–113 (2017).PubMed
127.
Pike, L. R. G. et al. Radiation and PD-1 inhibition: favorable outcomes after brain-directed radiation. Radiother. Oncol. 124, 98–103 (2017).PubMed
128.
Nguyen, S. M., Castrellon, A., Vaidis, O. & Johnson, A. E. Stereotactic radiosurgery and ipilimumab versus stereotactic radiosurgery alone in melanoma brain metastases. Cureus 9, e1511 (2017).PubMedPubMedCentral
129.
Kaidar-Person, O. et al. The incidence of radiation necrosis following stereotactic radiotherapy for melanoma brain metastases: the potential impact of immunotherapy. Anticancer Drugs 28, 669–675 (2017).PubMed
130.
Schoenfeld, J. D. et al. Ipilmumab and cranial radiation in metastatic melanoma patients: a case series and review. J. Immunother. Cancer 3, 50 (2015).PubMedPubMedCentral
131.
Diao, K. et al. Combination ipilimumab and radiosurgery for brain metastases: tumor, edema, and adverse radiation effects. J. Neurosurg. 2018, 1–10 (2018).
132.
Furuse, M., Nonoguchi, N., Kawabata, S., Miyatake, S. & Kuroiwa, T. Delayed brain radiation necrosis: pathological review and new molecular targets for treatment. Med. Mol. Morphol. 48, 183–190 (2015).PubMed
133.
Shaw, E. et al. Radiosurgery for the treatment of previously irradiated recurrent primary brain tumors and brain metastases: initial report of radiation therapy oncology group protocol (90–05). Int. J. Radiat. Oncol. Biol. Phys. 34, 647–654 (1996).PubMed
134.
Leibel, S. A. & Sheline, G. E. Radiation therapy for neoplasms of the brain. J. Neurosurg. 66, 1–22 (1987).PubMed
135.
Verma, N., Cowperthwaite, M. C., Burnett, M. G. & Markey, M. K. Differentiating tumor recurrence from treatment necrosis: a review of neuro-oncologic imaging strategies. Neuro Oncol. 15, 515–534 (2013).PubMedPubMedCentral
136.
Fang, P. et al. Radiation necrosis with stereotactic radiosurgery combined with CTLA-4 blockade and PD-1 inhibition for treatment of intracranial disease in metastatic melanoma. J. Neurooncol 133, 595–602 (2017).PubMed
137.
Kohutek, Z. A. et al. Long-term risk of radionecrosis and imaging changes after stereotactic radiosurgery for brain metastases. J. Neurooncol 125, 149–156 (2015).PubMedPubMedCentral
138.
Martin, A. M. et al. Immunotherapy and symptomatic radiation necrosis in patients with brain metastases treated with stereotactic radiation. JAMA Oncol. https://​doi.​org/​10.​1001/​jamaoncol.​2017.​3993 (2018).CrossRefPubMedPubMedCentral
139.
Skrepnik, T., Sundararajan, S., Cui, H. & Stea, B. Improved time to disease progression in the brain in patients with melanoma brain metastases treated with concurrent delivery of radiosurgery and ipilimumab. Oncoimmunology 6, e1283461 (2017).PubMedPubMedCentral
140.
Colaco, R. J., Martin, P., Kluger, H. M., Yu, J. B. & Chiang, V. L. Does immunotherapy increase the rate of radiation necrosis after radiosurgical treatment of brain metastases? J. Neurosurg. 125, 17–23 (2016).PubMed
141.
Patel, K. R. et al. Ipilimumab and stereotactic radiosurgery versus stereotactic radiosurgery alone for newly diagnosed melanoma brain metastases. Am. J. Clin. Oncol. 40, 444–450 (2017).PubMed
142.
Miller, J. A. et al. Association between radiation necrosis and tumor biology after stereotactic radiosurgery for brain metastasis. Int. J. Radiat. Oncol. 96, 1060–1069 (2016).
143.
Williams, N. L. et al. Phase 1 study of ipilimumab combined with whole brain radiation therapy or radiosurgery for melanoma patients with brain metastases. Int. J. Radiat. Oncol. Biol. Phys. 99, 22–30 (2017).PubMed
144.
Brahmer, J. et al. Nivolumab versus docetaxel in advanced squamous-cell non–small-cell lung cancer. N. Engl. J. Med. 373, 123–135 (2015).PubMedPubMedCentral
145.
Herbst, R. S. et al. Pembrolizumab versus docetaxel for previously treated, PD-L1-positive, advanced non-small-cell lung cancer (KEYNOTE-010): a randomised controlled trial. Lancet 387, 1540–1550 (2016).PubMed
146.
Reck, M. et al. Pembrolizumab versus chemotherapy for PD-L1–positive non–small-cell lung cancer. N. Engl. J. Med. 375, 1823–1833 (2016).PubMed
147.
Fehrenbacher, L. et al. Atezolizumab versus docetaxel for patients with previously treated non-small-cell lung cancer (POPLAR): a multicentre, open-label, phase 2 randomised controlled trial. Lancet 387, 1837–1846 (2016).PubMed
148.
Garon, E. B. et al. Pembrolizumab for the treatment of non–small-cell lung cancer. N. Engl. J. Med. 372, 2018–2028 (2015).PubMed
149.
Kim, M., Schrag, D., Li, L. & Chen, A. B. Predictors of radiation therapy (RT) use among medicare patients with metastatic non-small cell lung cancer (NSCLC) [abstract 124]. J Clin Oncol 33 (suppl. 29), 124 (2015).
150.
Koshy, M. et al. Prevalence and predictors of inappropriate delivery of palliative thoracic radiotherapy for metastatic lung cancer. J. Natl Cancer Inst. 107, djv278 (2015).PubMedPubMedCentral
151.
Lu, C. S. & Liu, J. H. Pneumonitis in cancer patients receiving anti-PD-1 and radiotherapies: three case reports. Medicine 96, e5747 (2017).PubMedPubMedCentral
152.
Shaverdian, N. et al. Previous radiotherapy and the clinical activity and toxicity of pembrolizumab in the treatment of non-small-cell lung cancer: a secondary analysis of the KEYNOTE-001 phase 1 trial. Lancet Oncol. 18, 895–903 (2017).PubMedPubMedCentral
153.
Antonia, S. J. et al. Durvalumab after chemoradiotherapy in stage III non–small-cell lung cancer. N. Engl. J. Med. 377, 1919–1929 (2017).PubMed
154.
Samstein, R. et al. Partial tumor irradiation in a murine model is sufficient for tumor control via activation of an antitumor immune response. Int. J. Radiat. Oncol. Biol. Phys. 99, E616–E617 (2017).
155.
Marusyk, A., Almendro, V. & Polyak, K. Intra-tumour heterogeneity: a looking glass for cancer? Nat. Rev. Cancer 12, 323–334 (2012).PubMed
156.
Gerlinger, M. et al. Intratumor heterogeneity and branched evolution revealed by multiregion sequencing. N. Engl. J. Med. 366, 883–892 (2012).PubMedPubMedCentral
157.
Patel, A. P. et al. Single-cell RNA-seq highlights intratumoral heterogeneity in primary glioblastoma. Science 344, 1396–1401 (2014).PubMedPubMedCentral
158.
Choudhury, A. et al. MRE11 expression is predictive of cause-specific survival following radical radiotherapy for muscle-invasive bladder cancer. Cancer Res. 70, 7017–7027 (2010).PubMedPubMedCentral
159.
Mahoney, K. M., Rennert, P. D. & Freeman, G. J. Combination cancer immunotherapy and new immunomodulatory targets. Nat. Rev. Drug Discov. 14, 561–584 (2015).PubMed
160.
Strojan, P. et al. Treatment of late sequelae after radiotherapy for head and neck cancer. Cancer Treat. Rev. 59, 79–92 (2017).PubMedPubMedCentral
161.
Siddiqui, F. & Movsas, B. Management of radiation toxicity in head and neck cancers. Semin. Radiat. Oncol. 27, 340–349 (2017).PubMed
162.
Nicholas, S. et al. Pelvic radiation and normal tissue toxicity. Semin. Radiat. Oncol. 27, 358–369 (2017).PubMed
163.
Munoz-Schuffenegger, P., Ng, S. & Dawson, L. A. Radiation-induced liver toxicity. Semin. Radiat. Oncol. 27, 350–357 (2017).PubMed
164.
Kwon, E. D. et al. Ipilimumab versus placebo after radiotherapy in patients with metastatic castration-resistant prostate cancer that had progressed after docetaxel chemotherapy (CA184-043): a multicentre, randomised, double-blind, phase 3 trial. Lancet Oncol. 15, 700–712 (2014).PubMedPubMedCentral