Abscopal effect in a Hodgkin lymphoma patient treated by an anti-programmed death 1 antibody

Radiation-targeted immunotherapy: A new perspective in cancer radiotherapy

In contemporary oncology, radiation therapy and immunotherapy stand as critical treatments, each with distinct mechanisms and outcomes. Radiation therapy, a key player in cancer management, targets cancer cells by damaging their DNA with ionizing radiation. Its effectiveness is heightened when used alongside other treatments like surgery and chemotherapy. Employing varied radiation types like X-rays, gamma rays, and proton beams, this approach aims to minimize damage to healthy tissue. However, it is not without risks, including potential damage to surrounding normal cells and side effects ranging from skin inflammation to serious long-term complications. Conversely, immunotherapy marks a revolutionary step in cancer treatment, leveraging the body's immune system to target and destroy cancer cells. It manipulates the immune system's specificity and memory, offering a versatile approach either alone or in combination with other treatments. Immunotherapy is known for its targeted action, long-lasting responses, and fewer side effects compared to traditional therapies. The interaction between radiation therapy and immunotherapy is intricate, with potential for both synergistic and antagonistic effects. Their combined use can be more effective than either treatment alone, but careful consideration of timing and sequence is essential. This review explores the impact of various radiation therapy regimens on immunotherapy, focusing on changes in the immune microenvironment, immune protein expression, and epigenetic factors, emphasizing the need for personalized treatment strategies and ongoing research to enhance the efficacy of these combined therapies in cancer care.

Integrating [18F]-Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography with Radiation Therapy and Immunomodulation in Precision Therapy for Solid Tumors

[18F]-FDG positron emission tomography with computed tomography (PET/CT) imaging is widely used to enhance the quality of care in patients diagnosed with cancer. Furthermore, it holds the potential to offer insight into the synergic effect of combining radiation therapy (RT) with immuno-oncological (IO) agents. This is achieved by evaluating treatment responses both at the RT and distant tumor sites, thereby encompassing the phenomenon known as the abscopal effect. In this context, PET/CT can play an important role in establishing timelines for RT/IO administration and monitoring responses, including novel patterns such as hyperprogression, oligoprogression, and pseudoprogression, as well as immune-related adverse events. In this commentary, we explore the incremental value of PET/CT to enhance the combination of RT with IO in precision therapy for solid tumors, by offering supplementary insights to recently released joint guidelines.

Fluorodeoxyglucose-Positron Emission Tomography in Relapsed/Refractory Hodgkin Lymphoma: A Practical Approach

BACKGROUND

Positron emission tomography (PET) with the use of 18F-fluorodeoxyglucose (FDG), implemented with low-dosage computer tomography, is to be considered as the most important evolution of imaging in the management and assessment of classical Hodgkin lymphoma patients.

SUMMARY

According to Lugano response criteria, FDG-PET is mandatory to define metabolic response to frontline therapy and moreover it is important in the definition of nonresponders or refractory disease patients. Refractory disease is reported in about 15% of patients, with some variations based on the choice of first-line chemotherapy, and particularly in advanced stages, up to 40% eventually relapse within 3 years.

KEY MESSAGES

The aim of this review was to highlight a practical way to use FDG-PET in the subset of HL, with some notes of its use in first-line patients, and particularly centered on relapsed or refractory setting with a final focus of the evaluation of response by FDG-PET in the new treatment era of immunocheckpoint inhibitors.

Emerging and Evolving Concepts in Cancer Immunotherapy Imaging

Criteria based on measurements of lesion diameter at CT have guided treatment with historical therapies due to the strong association between tumor size and survival. Clinical experience with immune checkpoint modulators shows that editing immune system function can be effective in various solid tumors. Equally, novel immune-related phenomena accompany this novel therapeutic paradigm. These effects of immunotherapy challenge the association of tumor size with response or progression and include risks and adverse events that present new demands for imaging to guide treatment decisions. Emerging and evolving approaches to immunotherapy highlight further key issues for imaging evaluation, such as dissociated response following local administration of immune checkpoint modulators, pseudoprogression due to immune infiltration in the tumor environment, and premature death due to hyperprogression. Research that may offer tools for radiologists to meet these challenges is reviewed. Different modalities are discussed, including immuno-PET, as well as new applications of CT, MRI, and fluorodeoxyglucose PET, such as radiomics and imaging of hematopoietic tissues or anthropometric characteristics. Multilevel integration of imaging and other biomarkers may improve clinical guidance for immunotherapies and provide theranostic opportunities.

Evaluation of the potential of ultrasound-mediated drug delivery for the treatment of ovarian cancer through preclinical studies

Ovarian cancer (OC) has the greatest mortality rate among gynecological cancers, with a five-year survival rate of <50%. Contemporary adjuvant chemotherapy mostly fails in the case of OCs that are refractory, metastatic, recurrent, and drug-resistant. Emerging ultrasound (US)-mediated technologies show remarkable promise in overcoming these challenges. Absorption of US waves by the tissue results in the generation of heat due to its thermal effect causing increased diffusion of drugs from the carriers and triggering sonoporation by increasing the permeability of the cancer cells. Certain frequencies of US waves could also produce a cavitation effect on drug-filled microbubbles (MBs, phospholipid bilayers) thereby generating shear force and acoustic streaming that could assist drug release from the MBs, and promote the permeability of the cell membrane. A new class of nanoparticles that carry therapeutic agents and are guided by US contrast agents for precision delivery to the site of the ovarian tumor has been developed. Phase-shifting of nanoparticles by US sonication has also been engineered to enhance the drug delivery to the ovarian tumor site. These technologies have been used for targeting the ovarian cancer stem cells and protein moieties that are particularly elevated in OCs including luteinizing hormone-releasing hormone, folic acid receptor, and vascular endothelial growth factor. When compared to healthy ovarian tissue, the homeostatic parameters at the tissue microenvironment including pH, oxygen levels, and glucose metabolism differ significantly in ovarian tumors. US-based technologies have been developed to take advantage of these tumor-specific alterations for precision drug delivery. Preclinical efficacy of US-based targeting of currently used clinical chemotherapies presented in this review has the potential for rapid human translation, especially for formulations that use all substances that are deemed to be generally safe by the U.S. Food and Drug Administration.

Abscopal effect of radiation therapy and nivolumab in a patient with combined small-cell lung cancer: a case report

The paradigm for combined small-cell lung carcinoma (C-SCLC) is according to standard SCLC treatment with poor outcomes. The efficacy of immune checkpoint inhibitor (ICI) monotherapy for pretreated SCLC is still limited. Clinical researches exploring radiotherapy combined with immunotherapy showed promising synergistic effects in several tumors. We report one C-SCLC case after resistant to comprehensive treatment receiving nivolumab combined with radiotherapy achieving clinical complete remission (CCR). The combination module of ICI and radiation could be an option for relapsed C-SCLC, and the prognostic indicators need further research.

Interpretation of 2-[18F]FDG PET/CT in Hodgkin lymphoma patients treated with immune checkpoint inhibitors

The development of immunotherapy has revolutionized cancer treatment, improving the outcome and survival of many patients. Immune checkpoint inhibitors (ICIs), the most common form of immunotherapy, use antibodies to restore T-cells' anti-tumor activity. Immune checkpoint inhibitors are gaining ground in the therapeutic strategy across various cancers. Although widely used in solid tumors, ICIs have shown remarkable efficacy in patients with Hodgkin lymphoma. 2-[¹⁸F]Fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)/CT is the gold standard to stage and monitor responses in Hodgkin lymphoma. This article reviewed the use of 2-[¹⁸F]FDG-PET/CT in patients with Hodgkin lymphoma treated with ICI, focusing on image interpretation for response monitoring and detecting adverse events. Key Points • Immune checkpoint inhibitors have dramatically improved the outcome of patients with cancer. Their mechanisms of action induce inflammatory processes that might translate into a high 2-[¹⁸F]FDG uptake visible on 2-[¹⁸F]FDG-PET/CT, requiring an adaptation of the evaluation criteria. • PET readers should be aware of new patterns of response observed with immunotherapy in assessing treatment response in HL patients. • -[¹⁸F]FDG-PET/CT has an unparalleled ability of assessing tumor response, visualizing signs of immune activation as well as immune-related adverse events in a one-stop-shop examination.

Abscopal effect in the radio and immunotherapy

This review is devoted to a rare in clinical practice, but promising phenomenon of regression distant non-irradiated metastases in combination therapy of cancer patients. R. H. Mole in 1953 suggested introducing the term "abscopal effect" to denote the effect of ionizing radiation "at a distance from the irradiated volume but within the same organism." Currently, it is a hypothesis in the treatment of metastatic cancer, when there is a regression of untreated areas simultaneously with a decrease in the tumor. After the discovery of immune checkpoint cases were increase with patients treated with check-point blockade (especially lymphocyte associated protein 4, programmed cell death 1/programmed cell death 1 ligand 1) and which have an abscopal effect. This review systematizes works covering the time period from 1969 to 2019, which give cases of the abscopal effect at different localizations. However, abscopal effect is a poorly understood phenomenon. In this review, the authors tried to collect all information about the possible mechanisms of the abscopal effect, possible role in antitumor response and frequency abscopal effect at radio/immunotherapy or combined both.

Double-refractory Hodgkin lymphoma: tackling relapse after brentuximab vedotin and checkpoint inhibitors

The approval of brentuximab vedotin (BV) and checkpoint inhibitors (CPI) has revolutionized the management of relapsed/refractory classical Hodgkin lymphoma (cHL) patients. In recent years these agents have rapidly moved to earlier lines of therapy, including post-autologous hematopoietic cell transplant (auto-HCT) consolidation, pre-HCT salvage, and the frontline treatment setting. This shift in practice means that double-refractory (refractory to both BV and CPI) cHL is becoming an increasingly common clinical problem. In patients who are not eligible for clinical trials, conventional cytotoxic and targeted therapies (off label) may be a potential option. In patients who are transplant eligible, early referral to allogeneic HCT should be considered given the significant improvement in transplant outcomes in the contemporary era. Cellular therapy options including CD30.chimeric antigen receptor T cells, Epstein-Barr virus-directed cytotoxic T cells, and CD16A/30 bispecific natural killer cell engagers appear promising and are currently in clinical trials.

Abscopal Effects in Metastatic Cancer: Is a Predictive Approach Possible to Improve Individual Outcomes?

Patients with metastatic cancers often require radiotherapy (RT) as a palliative therapy for cancer pain. RT can, however, also induce systemic antitumor effects outside of the irradiated field (abscopal effects) in various cancer entities. The occurrence of the abscopal effect is associated with a specific immunological activation in response to RT-induced cell death, which is mainly seen under concomitant immune checkpoint blockade. Even if the number of reported apscopal effects has increased since the introduction of immune checkpoint inhibition, its occurrence is still considered rare and unpredictable. The cases reported so far may nevertheless allow for identifying first biomarkers and clinical patterns. We here review biomarkers that may be helpful to predict the occurrence of abscopal effects and hence to optimize therapy for patients with metastatic cancers.

Immune checkpoint inhibition for the treatment of cancers: An update and critical review of ongoing clinical trials

Advances in Cancer immunotherapy in the past few years include the development of medications that modulate immune checkpoint proteins. Cytotoxic T-lymphocyte antigen 4 (CTLA4), programmed cell death protein 1 (PD1), and programmed cell death ligand 1 (PD-L1) are three co-inhibitory receptors that are expressed in the tumor microenvironment. Immune checkpoint inhibitors (ICI) that target these biomarkers unleash the properties of effector T cells that are licensed to kill cancer cells. Immune checkpoint blockade has dramatically changed the treatment landscape of many cancers. In this Review, we describe the current data regarding clinical trials of ICIs in six important cancers, including hepatocellular carcinoma (HCC), renal cell cancer (RCC), hodgkin lymphoma (HL), non-hodgkin lymphoma (NHL), non-small cell lung cancer (NSCLC), and head and neck cancer carcinoma (HNSCC).

'Le Roi est mort, vive le Roi': New Roles of Radiotherapy in the Treatment of Lymphomas in Combination With Immunotherapy

BACKGROUND

immunotherapy (IT), including checkpoint inhibitors (CIs) and Chimeric Antigen Receptor T cell therapy (CAR-T) revolutionized the treatment of relapsing or refractory (r/r) lymphoma. Several preliminary experiences evaluated concomitant administration of radiotherapy and IT.

METHODS

we performed a systematic review of current literature as of March 30, 2020. A total of 1090 records was retrieved, 42 articles were selected on the basis of title and abstract and, after the removal of analyses with no original data or insufficient clinical information, 28 papers were included in the review.

RESULTS

previous studies were mostly represented by case reports/series or small cohorts. Nonetheless, combination of radiotherapy and CIs or CAR-T led to promising outcomes, resulting in extremely high rates of complete response and improving progression free and overall survival compared with data from recent clinical trials. Combination of RT and CIs had a fair toxicity profile with no reports of severe side effects. Within the limits of the small cohorts retrieved, RT seems a superior option compared with systemic treatment as a 'bridge' to CAR-T and could as well reduce severe complications rates. Radiotherapy could elicit immune response against lymphoma, as demonstrated by multiple cases of abscopal effect and its inclusion in anti-neoplastic vaccines protocols.

CONCLUSION

The results of this review warrant the evaluation of combination of RT and immunotherapy in larger and preferably prospective and randomized cohorts to confirm these preliminary impressive outcomes. The optimal dose, fractionation and timing of RT still have to be clarified.

Immune checkpoint inhibition in classical hodgkin lymphoma

Introduction: Hodgkin lymphoma (HL) accounts for 10% of lymphoma cases every year. HL is often curable by conventional chemotherapy and radiotherapy. However, in case of relapsed or refractory HL (r/r HL) after autologous hematopoietic stem cell transplantation (ASCT), few treatment options are currently available. Blockade of the immune checkpoint receptors, programmed death receptor-1 (PD-1), or cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) expressed on T-cells, and their ligands expressed on tumor-associated antigen-presenting cells (APCs), and Hodgkin and Reed/Sternberg (HRS) cells can remove inhibitory signals from anti-tumor T cells. Checkpoint blockade using monoclonal antibodies could be a potential treatment. Nivolumab and pembrolizumab are approved antibodies for the treatment of r/r HL.Areas covered: This paper provides a comprehensive discussion of checkpoint inhibitors in HL treatment, including the most important clinical trials with mono- or combination therapies as a first or second-line treatment of HL.Expert opinion: Relatively high response rates and an acceptable safety profile of checkpoint inhibitors make them an effective therapy for HL. The combination of checkpoint inhibition with other conventional cancer treatments and identifying the mechanisms responsible for resistance to checkpoint inhibition may improve the efficacy and safety of this immunotherapy, and enhance patient quality of life.

Phase II Single-arm Study of Durvalumab and Tremelimumab with Concurrent Radiotherapy in Patients with Mismatch Repair-proficient Metastatic Colorectal Cancer

PURPOSE

Immune checkpoint inhibition (ICI) alone is not active in mismatch repair-proficient (MMR-P) metastatic colorectal cancer (mCRC), nor does radiotherapy alone result in objective systemic benefit. However, combined radiotherapy plus ICI can induce systemic antitumor immunity in preclinical and clinical models.

PATIENTS AND METHODS

In this single-center, phase II study, patients with chemotherapy-refractory MMR-P mCRC received durvalumab 1,500 mg plus tremelimumab 75 mg every 4 weeks plus radiotherapy. The primary endpoint was objective response rate (ORR) in nonirradiated lesions. Treatment and efficacy were correlated with peripheral immune cell profiles.

RESULTS

We enrolled 24 patients, and report outcomes after a median follow-up of 21.8 (range: 15.9-26.3) months. The ORR was 8.3% (2 patients) [95% confidence interval (CI), 1.0-27.0]. The median progression-free survival was 1.8 (95% CI, 1.7-1.9) months, median overall survival was 11.4 (95% CI, 10.1-17.4) months. Twenty five percent of patients (n = 6) had treatment-related grade 3-4 adverse events. We observed increased circulating CD8⁺ T lymphocyte activation, differentiation, and proliferation in patients with objective response.

CONCLUSIONS

This combination of radiotherapy plus ICI study did not meet the prespecified endpoint criteria to be considered worthwhile for further study. However, rare instances of systemic immune augmentation and regression in nonirradiated lesions were observed (an abscopal response). Combination durvalumab and tremelimumab plus radiotherapy is feasible in MMR-P mCRC with a manageable safety profile. Further studies of novel immunotherapy combinations, and identification of biomarkers predictive of abscopal response are warranted.

Effect of radiotherapy on T cell and PD-1 / PD-L1 blocking therapy in tumor microenvironment

Cancer is a worldwide problem that threatens human health. Radiotherapy plays an important role in a variety of cancer treatment methods. The administration of radiotherapy can alter the differentiation pathways and functions of T cells, which in turn improves the immune response of T cells. Radiotherapy can also induce up-regulation of PD-L1 expression, which means that it has great potential for enhancing the therapeutic effect of anti-PD-1/PD-L1 inhibitors and reducing the risk of drug resistance toward them. At present, the combination of radiotherapy and anti-PD-1/PD-L1 inhibitors has shown significant therapeutic effects in clinical tumor research. This review focuses on the mechanism of radiotherapy on T cells reported in recent years, as well as related research progress in the application of PD-1/PD-L1 blockers. It will provide a theoretical basis for the rational clinical application of radiotherapy combined with PD-1/PD-L1 inhibitors.

Addition of Radiotherapy to Immunotherapy: Effects on Outcome of Different Subgroups Using a Propensity Score Matching

Immune checkpoint inhibition (ICI) has been established as successful modality in cancer treatment. Combination concepts are used to optimize treatment outcome, but may also induce higher toxicity rates than monotherapy. Several rationales support the combination of radiotherapy (RT) with ICI as radioimmunotherapy (RIT), but it is still unknown in which clinical situation RIT would be most beneficial. Therefore, we have conducted a retrospective matched-pair analysis of 201 patients with advanced-stage cancers and formed two groups treated with programmed cell death protein 1 (PD-1) inhibitors only (PD1i) or in combination with local RT (RIT) at our center between 2013 and 2017. We collected baseline characteristics, programmed death ligand 1 (PD-L1) status, mutational status, PD-1 inhibitor and RT treatment details, and side effects according to the Common Terminology Criteria for Adverse Events (CTCAE) v.5.0. Patients received pembrolizumab (n = 93) or nivolumab (n = 108), 153 with additional RT. For overall survival (OS) and progression-free survival (PFS), there was no significant difference between both groups. After propensity score matching (PSM), we analyzed 96 patients, 67 with additional and 29 without RT. We matched for different covariates that could have a possible influence on the treatment outcome. The RIT group displayed a trend towards a longer OS until the PD1i group reached a survival plateau. PD-L1-positive patients, smokers, patients with a BMI ≤ 25, and patients without malignant melanoma showed a longer OS when treated with RIT. Our data show that some subgroups may benefit more from RIT than others. Suitable biomarkers as well as the optimal timing and dosage must be established in order to achieve the best effect on cancer treatment outcome.

Abscopal effect induced by modulated radiation therapy and pembrolizumab in a patient with pancreatic metastatic lung squamous cell carcinoma

The main recurrence pattern for lung cancer patients after radical surgery is distant metastasis. The probability of pancreatic metastasis in patients diagnosed with lung squamous cell carcinoma is 0.02%, with a poor prognosis. Chemotherapy is the preferred treatment for recurrence. Single lesions or oligometastasis can be surgically resected, and local lesions with compression symptoms can be treated with radiotherapy. The FDA and NMPA have approved first‐line indications for immunotherapy for lung squamous cell carcinoma. Here, we report the case of a 57‐year‐old male patient with lung squamous cell carcinoma who developed pancreatic metastasis after radical resection. The disease progressed after first‐line chemotherapy, and the patient was treated with immunotherapy combined with radiotherapy. We subsequently observed the abscopal effect of intensity modulated radiation therapy (IMRT) and pembrolizumab with disappearance of lung metastasis after radiotherapy for pancreatic metastasis. The patient’s tumor symptoms were relieved with prolonged survival.

Abscopal Regressions of Lymphoma After Involved-Site Radiation Therapy Confirmed by Positron Emission Tomography

PURPOSE

Patients with abscopal regressions of lymphoma after palliative involved-site radiation therapy (ISRT), detected on sequential ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET), were identified by audit. A retrospective analysis was subsequently conducted to estimate the frequency of abscopal regression in follicular lymphoma (FL).

METHODS AND MATERIALS

Potential cases were identified at multidisciplinary lymphoma meetings and fulfilled these criteria: (1) palliative ISRT given for histologically confirmed lymphoma, (2) >2 lesions visualized on FDG-PET, (3) >1 unirradiated lesion(s) outside ISRT volume, (4) no systemic therapy delivered <2 months before radiation therapy or between radiation therapy and response assessment, (5) complete metabolic response (CMR) in ≥1 unirradiated lesions detected on serial FDG-PET/CT. All ISRT patients with FL treated in 2016 to 2018 were systematically reviewed.

RESULTS

Seven cases of abscopal regression were identified, including 4 patients with FL. In all cases, a CMR was apparent both within the ISRT volume and in ≥1 unirradiated lesions. One patient each was identified with mantle cell lymphoma (4 Gy in 2 fractions), Hodgkin lymphoma (20 Gy in 3 fractions, then 30 Gy in 15 fractions to the same volume), and Richter transformation of chronic lymphatic leukemia (30 Gy in 10 fractions). The 4 patients with FL received either 4 Gy in 2 fractions (n = 3) or 4 Gy followed 8 months later by 30 Gy in 15 fractions (n = 1). From 2016 to 2018, 29 courses of ISRT were prescribed for multifocal FL, after which 4 of 29 (13.8%) abscopal responses were detected, including in 4 of 9 (44.4%) patients with serial PET scans. Two patients, with relapsed disease after initial abscopal responses, experienced durable CMRs with immunotherapies.

CONCLUSIONS

In 4 of 7 cases, PET-detected abscopal regression of lymphoma occurred after 4 Gy, in 2 of 7 cases after repeated ISRT to the same volume, and in 2 of 7 was associated with subsequent complete response to immunotherapy, consistent with an immune basis for the abscopal effect. Abscopal regressions in FL appear to be more common than previously suspected.

Automated Identification of Optimal Portal Venous Phase Timing with Convolutional Neural Networks

OBJECTIVES

To develop a deep learning-based algorithm to automatically identify optimal portal venous phase timing (PVP-timing) so that image analysis techniques can be accurately performed on post contrast studies.

METHODS

681 CT-scans (training: 479 CT-scans; validation: 202 CT-scans) from a multicenter clinical trial in patients with liver metastases from colorectal cancer were retrospectively analyzed for algorithm development and validation. An additional external validation was performed on a cohort of 228 CT-scans from gastroenteropancreatic neuroendocrine cancer patients. Image acquisition was performed according to each centers' standard CT protocol for single portal venous phase, portal venous acquisition. The reference gold standard for the classification of PVP-timing as either optimal or nonoptimal was based on experienced radiologists' consensus opinion. The algorithm performed automated localization (on axial slices) of the portal vein and aorta upon which a novel dual input Convolutional Neural Network calculated a probability of the optimal PVP-timing.

RESULTS

The algorithm automatically computed a PVP-timing score in 3 seconds and reached area under the curve of 0.837 (95% CI: 0.765, 0.890) in validation set and 0.844 (95% CI: 0.786, 0.889) in external validation set.

CONCLUSION

A fully automated, deep-learning derived PVP-timing algorithm was developed to classify scans' contrast-enhancement timing and identify scans with optimal PVP-timing. The rapid identification of such scans will aid in the analysis of quantitative (radiomics) features used to characterize tumors and changes in enhancement with treatment in a multitude of settings including quantitative response criteria such as Choi and MASS which rely on reproducible measurement of enhancement.

Imaging-guided precision medicine in glioblastoma patients treated with immune checkpoint modulators: research trend and future directions in the field of imaging biomarkers and artificial intelligence

Immunotherapies that employ immune checkpoint modulators (ICMs) have emerged as an effective treatment for a variety of solid cancers, as well as a paradigm shift in the treatment of cancers. Despite this breakthrough, the median survival time of glioblastoma patients has remained at about 2 years. Therefore, the safety and anti-cancer efficacy of combination therapies that include ICMs are being actively investigated. Because of the distinct mechanisms of ICMs, which restore the immune system’s anti-tumor capacity, unconventional immune-related phenomena are increasingly being reported in terms of tumor response and progression, as well as adverse events. Indeed, immunotherapy response assessments for neuro-oncology (iRANO) play a central role in guiding cancer patient management and define a “wait and see strategy” for patients treated with ICMs in monotherapy with progressive disease on MRI. This article deciphers emerging research trends to ameliorate four challenges unaddressed by the iRANO criteria: (1) patient selection, (2) identification of immune-related phenomena other than pseudoprogression (i.e., hyperprogression, the abscopal effect, immune-related adverse events), (3) response assessment in combination therapies including ICM, and (4) alternatives to MRI. To this end, our article provides a structured approach for standardized selection and reporting of imaging modalities to enable the use of precision medicine by deciphering the characteristics of the tumor and its immune environment. Emerging preclinical or clinical innovations are also discussed as future directions such as immune-specific targeting and implementation of artificial intelligence algorithms.

Machine learning defined diagnostic criteria for differentiating pituitary metastasis from autoimmune hypophysitis in patients undergoing immune checkpoint blockade therapy

PURPOSE

New-onset pituitary gland lesions are observed in up to 18% of cancer patients undergoing treatment with immune checkpoint blockers (ICB). We aimed to develop and validate an imaging-based decision-making algorithm for use by the clinician that helps differentiate pituitary metastasis (PM) from ICB-induced autoimmune hypophysitis (HP).

MATERIALS AND METHODS

A systematic search was performed in the MEDLINE and EMBASE databases up to October 2018 to identify studies concerning PM and HP in patients treated with cytotoxic T-lymphocyte-associated protein 4 and programmed cell death (ligand) 1. The reference standard for diagnosis was confirmation by histology or response on follow-up imaging. Patients from included studies were randomly assigned to the training set or the validation set. Using machine learning (random forest tree algorithm) with the most-described six imaging and three clinical features, a multivariable prediction model (the signature) was developed and validated for diagnosing PM. Signature performance was evaluated using area under a receiver operating characteristic curves (AUCs).

RESULTS

Out of 3174 screened articles, 65 were included totalising 122 patients (HP: 60 pts, PM: 62 pts). Complete radiological data were available in 82 pts (Training: 62 pts, Validation: 20 pts). The signature reached an AUC = 0.91 (0.82, 1.00), P < 10^-8 in the training set and AUC = 0.94 (0.80, 1.00), P = 0.001 in the validation set. The signature predicted PM in lesions either ≥ 2 cm in size or < 2 cm if associated with heterogeneous contrast enhancement and cavernous extension.

CONCLUSION

An image-based signature was developed with machine learning and validated for differentiating PM from HP. This tool could be used by clinicians for enhanced decision-making in cancer patients undergoing ICB treatment with new-onset, concerning lesions of the pituitary gland.

Impact of Variability in Portal Venous Phase Acquisition Timing in Tumor Density Measurement and Treatment Response Assessment: Metastatic Colorectal Cancer as a Paradigm

PURPOSE

New response patterns to anticancer drugs have led tumor size-based response criteria to shift to also include density measurements. Choi criteria, for instance, categorize antiangiogenic therapy response as a decrease in tumor density > 15% at the portal venous phase (PVP). We studied the effect that PVP timing has on measurement of the density of liver metastases (LM) from colorectal cancer (CRC).

METHODS

Pretreatment PVP computed tomography images from 291 patients with LM-CRC from the CRYSTAL trial (Cetuximab Combined With Irinotecan in First-Line Therapy for Metastatic Colorectal Cancer; ClinicalTrials.gov identifier: NCT00154102) were included. Four radiologists independently scored the scans' timing according to a three-point scoring system: early, optimal, late PVP. Using this, we developed, by machine learning, a proprietary computer-aided quality-control algorithm to grade PVP timing. The reference standard was a computer-refined consensus. For each patient, we contoured target liver lesions and calculated their mean density.

RESULTS

Contrast-product administration data were not recorded in the digital imaging and communications in medicine headers for injection volume (94%), type (93%), and route (76%). The PVP timing was early, optimal, and late in 52, 194, and 45 patients, respectively. The mean (95% CI) accuracy of the radiologists for detection of optimal PVP timing was 81.7% (78.3 to 85.2) and was outperformed by the 88.6% (84.8 to 92.4) computer accuracy. The mean ± standard deviation of LM-CRC density was 68 ± 15 Hounsfield units (HU) overall and 59.5 ± 14.9 HU, 71.4 ± 14.1 HU, 62.4 ± 12.5 HU at early, optimal, and late PVP timing, respectively. LM-CRC density was thus decreased at nonoptimal PVP timing by 14.8%: 16.7% at early PVP ( P < .001) and 12.6% at late PVP ( P < .001).

CONCLUSION

Nonoptimal PVP timing should be identified because it significantly decreased tumor density by 14.8%. Our computer-aided quality-control system outperformed the accuracy, reproducibility, and speed of radiologists' visual scoring. PVP-timing scoring could improve the extraction of tumor quantitative imaging biomarkers and the monitoring of anticancer therapy efficacy at the patient and clinical trial levels.

The Abscopal Effect of Stereotactic Radiotherapy and Immunotherapy: Fool's Gold or El Dorado?

An 'abscopal' effect if often used to refer to distant tumour regression after localised irradiation. Since the first report of the abscopal effect in the 1950s, well-documented cases with radiotherapy alone are very rare. It is widely accepted that the immune response plays an important role in the abscopal effect, although the mechanism is still unclear. With the recent success of cancer immunotherapy, there is growing interest in combining immunotherapy with radiotherapy to boost abscopal response rates. Compared with conventional radiotherapy, stereotactic ablative radiotherapy (SABR) not only delivers ablative dose to the tumour, but may also induce robust immune responses. In this review we examine studies that combine SABR and immunotherapy. We review the preclinical rationale for SABR and immunotherapy combinations, the case for and against abscopal effects, and the current landscape of clinical trials.

Abscopal Effect of Radiotherapy in the Immunotherapy Era: Systematic Review of Reported Cases

Mounting evidence suggests that radiation stimulates the immune system and this contributes to the abscopal effect, which is defined as "response at a distance from the irradiated volume." Though identified more than 50 years ago, the abscopal effect is revisited today. One rationale is that the abscopal effect is often observed with efficient immunotherapy. Here, we give an overview of the clinical data on the abscopal effect, generated by a combination of immunotherapy and radiotherapy (RT). Only papers that included RT in combination with immunotherapy were evaluated according to four main categories including RT parameters, sequencing of therapies, the definition of the abscopal effect, and patient selection. Twenty-four cases in 15 reports were reviewed. The results varied. Patient ages ranged from 24 to 74. RT dose (median total dose 18-58 Gy) varied. Biologically effective dose (BED) 10 was calculated to be a median 49.65 Gy (28-151 Gy). The time to a documented abscopal response ranged from less than a month to 12 months. The large variation concerning fractionation and sequencing of therapies indicates that these conflicting points need to be resolved, to generate for the abscopal effect to be clinically significant.

Time for radioimmunotherapy: an overview to bring improvements in clinical practice

Harnessing the patient's own immune system against an established cancer has proven to be a successful strategy. Within the last years, several antibodies blocking critical "checkpoints" that control the activation of T cells, the immune cells able to kill cancer cells, have been approved for the use in patients with different tumours. Unfortunately, these cases remain a minority. Over the last years, radiotherapy has been reported as a means to turn a patient's own tumour into an in situ vaccine and generate anti-tumour T cells in patients who lack sufficient anti-tumour immunity. Indeed, review data show that the strategy of blocking multiple selected immune inhibitory targets in combination with radiotherapy has the potential to unleash powerful anti-tumour responses and improve the outcome of metastatic solid tumours. Here, we review the principal tumours where research in this field has led to new knowledge and where radioimmunotherapy becomes a reality.

Rationale for combination of radiation therapy and immune checkpoint blockers to improve cancer treatment

Radiation therapy for cancer is considered to be immunosuppressive. However, the cellular response after radiation therapy may stimulate or suppress an immune response. The effect may vary with the tumor type and occasionally tumor regressions have been observed outside the irradiated volume, both in animal studies and in the clinic. A renewed interest in the role of immunity for the observed effect of radiation came with the current recognized role of immune checkpoint blockers (ICBs) for control of selected cancer types. We therefore here review preclinical studies and clinical reports on the interaction of ICBs and radiation as a basis for further clinical trials. Some tumor types where the combination of these modalities seems especially promising are also proposed.

Abscopal effect of radiotherapy combined with immune checkpoint inhibitors

Radiotherapy (RT) is used routinely as a standard treatment for more than 50% of patients with malignant tumors. The abscopal effect induced by local RT, which is considered as a systemic anti-tumor immune response, reflects the regression of non-irradiated metastatic lesions at a distance from the primary site of irradiation. Since the application of immunotherapy, especially with immune checkpoint inhibitors, can enhance the systemic anti-tumor response of RT, the combination of RT and immunotherapy has drawn extensive attention by oncologists and cancer researchers. Nevertheless, the exact underlying mechanism of the abscopal effect remains unclear. In general, we speculate that the immune mechanism of RT is responsible for, or at least associated with, this effect. In this review, we discuss the anti-tumor effect of RT and immune checkpoint blockade and discuss some published studies on the abscopal effect for this type of combination therapy. In addition, we also evaluate the most appropriate time window for the combination of RT and immune checkpoint blockade, as well as the optimal dose and fractionation of RT in the context of the combined treatment. Finally, the most significant purpose of this review is to identify the potential predictors of the abscopal effect to help identify the most appropriate patients who would most likely benefit from the combination treatment modality.

Intratumoral immunotherapy: using the tumor as the remedy

Immune checkpoint-targeted monoclonal antibodies directed at Programmed Death Receptor 1 (PD-1), Programmed Death Ligand 1 (PD-L1) and Cytotoxic T-Lymphocyte Associated Protein 4 (CTLA-4) are currently revolutionizing the prognosis of many cancers. By blocking co-inhibitory receptors expressed by antitumor T cells, these antibodies can break the immune tolerance against tumor cells and allow the generation of durable cancer immunity. Benefits in overall survival over conventional therapies have been demonstrated for patients treated with these immunotherapies, leading to multiple approvals of such therapies by regulatory authorities. However, only a minority of patients develop an objective tumor response with long-term survival benefits. Moreover, the systemic delivery of immunotherapies can be responsible for severe auto-immune toxicities. This risk increases dramatically with anti-PD(L)1 and anti-CTLA-4 combinations and currently hampers the development of triple combination immunotherapies. In addition, the price of these novel treatments is probably too high to be reimbursed by health insurances for all the potential indications where immunotherapy has shown activity (i.e. in more than 30 different cancer types). Intratumoral immunotherapy is a therapeutic strategy which aims to use the tumor as its own vaccine. Upon direct injections into the tumor, a high concentration of immunostimulatory products can be achieved in situ, while using small amounts of drugs. Local delivery of immunotherapies allows multiple combination therapies, while preventing significant systemic exposure and off-target toxicities. Despite being uncertain of the dominant epitopes of a given cancer, one can therefore trigger an immune response against the relevant neo-antigens or tumor-associated antigens without the need for their characterization. Such immune stimulation can induce a strong priming of the cancer immunity locally while generating systemic (abscopal) tumor responses, thanks to the circulation of properly activated antitumor immune cells. While addressing many of the current limitations of cancer immunotherapy development, intratumoral immunotherapy also offers a unique opportunity to better understand the dynamics of cancer immunity by allowing sequential and multifocal biopsies at every tumor injection.

Complete Local and Abscopal Responses from a Combination of Radiation and Nivolumab in Refractory Hodgkin's Lymphoma

Until recently, patients with relapsed Hodgkin's lymphoma after brentuximab vedotin (Bv) treatments had poor treatment outcomes. Checkpoint inhibitors such as nivolumab and pembrolizumab that bind to and inhibit programmed cell death protein-1 (PD-1), have demonstrated an overall response rate of 70% in Hodgkin's lymphoma patients; however, complete response is still low at 20% with median progression-free survival of 14 months. There are ongoing clinical studies to seek out synergistic combinations, with the goal of improving the complete response rates for the cure of Hodgkin's lymphoma. Although radiotherapy has a limited survival benefit in such refractory patients, several preclinical models and anecdotal clinical evidence have suggested that combining local tumor irradiation with checkpoint inhibitors can produce systemic regression of distant tumors, an abscopal effect. Most of these reported studies on the response with local conformal radiotherapy and checkpoint inhibitors in combination with the anti-cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) antibody-ipilimumab are in melanoma. Here we report in our case series that the checkpoint inhibitors that block CTLA4 and B7-homolog 1 (B7-H1) or PD-1 in preclinical radiotherapy models have shown an increased the rate of tumor regression. Our case series demonstrates that combining local irradiation with anti-PD-1 checkpoint blockade treatment is feasible and synergistic in refractory Hodgkin's lymphoma. Correlative studies also suggest that the expression of programmed death-ligand 1 (PD-L1), DNA damage response and mutational tumor burden can be used as potential biomarkers for treatment response.

Radiation therapy and PD-1/PD-L1 blockade: the clinical development of an evolving anticancer combination

Several inhibitors of programmed cell death-1 (PD-1) and programmed death ligand-1 (PD-L1) have been approved as a form of immunotherapy for multiple cancers. Ionizing radiation therapy (RT) has been shown to enhance the priming and effector phases of the antitumor T-cell response rendering it an attractive therapy to combine with PD-1/PD-L1 inhibitors. Preclinical data support the rational combination of the 2 modalities and has paved way for the clinical development of the combination across a spectrum of cancers. In this review, we highlight the preclinical and clinical development of combined RT and PD-1/PD-L1 blockade to date. In addition to a comprehensive evaluation of available safety and efficacy data, we discuss important points of consideration in clinical trial design for this promising combination.

Abscopal, immunological effects of radiotherapy: Narrowing the gap between clinical and preclinical experiences

Radiotherapy-despite being a local therapy that meanwhile is characterized by an impressively high degree of spatial accuracy-can stimulate systemic phenomena which occasionally lead to regression and rejection of non-irradiated, distant tumor lesions. These abscopal effects of local irradiation have been observed in sporadic clinical case reports since the beginning of the 20th century, and extensive preclinical work has contributed to identify systemic anti-tumor immune responses as the underlying driving forces. Although abscopal tumor regression still remains a rare event in the radiotherapeutic routine, increasing numbers of cases are being reported, particularly since the clinical implementation of immune checkpoint inhibiting agents. Accordingly, interests to systematically exploit the therapeutic potential of radiotherapy-stimulated systemic responses are constantly growing. The present review briefly delineates the history of radiotherapy-induced abscopal effects and the activation of systemic anti-tumor immune responses by local irradiation. We discuss preclinical and clinical reports with specific focus on the corresponding controversies, and we propose issues that should be addressed in the future in order to narrow the gap between preclinical knowledge and clinical experiences.

Detection of immune-related adverse events by medical imaging in patients treated with anti-programmed cell death 1

BACKGROUND

Programmed death receptor-1 blocking antibodies (anti-PD1) are a new standard of care in many cancer types. Patients benefit from improved survival but have the risk of immune-related adverse events (irAE). We evaluated if medical imaging procedures, used for anti-tumour response assessment, can detect irAEs.

MATERIALS AND METHODS

All consecutive patients treated with anti-PD1 and with a medical imaging acquisition performed within 2 weeks with irAEs ≥2 were retrospectively included. Data were gathered from June 2014 to February 2017, and a central review was performed. The primary and secondary end-points were i) to evaluate the overall detection rate of irAEs by medical imaging and ii) to provide a comprehensive radiological description of irAEs.

RESULTS

Fifty-three patients (31 women, 22 men; average age: 61 years) were included. The primary tumour was melanoma (n = 32), lung cancer (n = 18) and other (n = 3). Patients were treated with nivolumab (n = 27) or pembrolizumab (n = 26). Of 74 medical imaging procedures analysed (ratio = 1.4 medical imaging per patient), 55 irAE were detected. The detection rate was overall: 74% (95 confidence interval: 63-84%), positron emission tomography with 18F-fludeoxyglucose integrated with computed tomography (18F-FDG PET/CT): 83% (n = 10/12), magnetic resonance imaging: 83% (n = 5/6), computed tomography scan: 79% (n = 19/24), ultrasonography: 70% (n = 19/27), standard X-rays: 40% (n = 2/5), lung/mediastinum: 100% (n = 7/7), enterocolitis: 100% (n = 8/8), hypophysitis: 100% (n = 3/3), thyroiditis: 75% (n = 15/20), hepatitis: 67% (n = 2/3), arthralgia or arthritis: 40% (n = 2/5) and pancreas: 28% (n = 2/7).

CONCLUSION

Medical imaging detected 74% of irAE in patients treated with anti-PD1. Beyond response assessment, medical imaging can detect irAE and guide towards specific management. We described the most frequent sites and patterns of imaging findings.

Immune Checkpoint Inhibition in Hodgkin Lymphoma

Intricate systems of checkpoints such as the programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) axis regulate adaptive immune responses to protect against tissue damage. However, diverse cancers can exploit these pathways to evade or suppress antitumor immunity, leading to tumor progression. Correspondingly, immune checkpoint inhibitors that block PD-1/PD-L1 signaling have shown marked therapeutic efficacy in certain cancers, such as Hodgkin lymphoma. Reed-Sternberg cells, the hallmark cells of Hodgkin lymphoma, commonly overexpress PD-1 ligands, and recent clinical trials have demonstrated impressive response rates with the PD-1 inhibitors nivolumab and pembrolizumab in relapsed or refractory Hodgkin lymphoma, leading to their FDA approval in this setting. Current efforts are underway to improve clinical responses by incorporating PD-1 inhibitors into earlier treatment regimens and identifying therapeutic agents that synergize with PD-1 inhibitors. This review summarizes our understanding of the PD-1/PD-L1 axis in Hodgkin lymphoma, recent clinical studies of anti-PD-1 monotherapy and promising combination immunotherapy in the pipeline.

Limits of radiomic-based entropy as a surrogate of tumor heterogeneity: ROI-area, acquisition protocol and tissue site exert substantial influence

Entropy is a promising quantitative imaging biomarker for characterizing cancer imaging phenotype. Entropy has been associated with tumor gene expression, tumor metabolism, tumor stage, patient prognosis, and treatment response. Our hypothesis states that tumor-specific biomarkers such as entropy should be correlated between synchronous metastases. Therefore, a significant proportion of the variance of entropy should be attributed to the malignant process. We analyzed 112 patients with matched/paired synchronous metastases (SM#1 and SM#2) prospectively enrolled in the MOSCATO-01 clinical trial. Imaging features were extracted from Regions Of Interest (ROI) delineated on CT-scan using TexRAD software. We showed that synchronous metastasis entropy was correlated across 5 Spatial Scale Filters: Spearman's Rho ranged between 0.41 and 0.59 (P = 0.0001, Bonferroni correction). Multivariate linear analysis revealed that entropy in SM#1 is significantly associated with (i) primary tumor type; (ii) entropy in SM#2 (same malignant process); (iii) ROI area size; (iv) metastasis site; and (v) entropy in the psoas muscle (reference tissue). Entropy was a logarithmic function of ROI area in normal control tissues (aorta, psoas) and in mathematical models (P < 0.01). We concluded that entropy is a tumor-specific metric only if confounding factors are corrected.

18F-FDG PET and CT Scans Detect New Imaging Patterns of Response and Progression in Patients with Hodgkin Lymphoma Treated by Anti-Programmed Death 1 Immune Checkpoint Inhibitor

The response evaluation criteria in patients with Hodgkin lymphoma (HL) were designed for the assessment of chemotherapy and targeted molecular agents. We investigated the accuracy of 3-mo ¹⁸F-FDG PET/CT for the identification of HL patients responding to immune-checkpoint blockade by anti-programmed death 1 antibodies (anti-PD1). We also reported the frequency of new immune patterns of response and progression. Methods: Retrospectively, we recruited consecutive HL patients treated by anti-PD1 (pembrolizumab or nivolumab) at Gustave Roussy from 2013 to 2015. ¹⁸F-FDG PET/CT and contrast-enhanced CT scans were acquired every 3 mo. We recorded the best overall response according to the International Harmonization Project Cheson 2014 criteria and LYmphoma Response to Immunomodulatory therapy Criteria (LYRIC) (2016 revised criteria). Patients achieving an objective response at any time during the anti-PD1 treatment were classified as responders. Results: Sixteen relapsed or refractory classic HL patients were included. The median age was 39 y (age range, 19-69 y). The median previous lines of therapy was 6 (range, 3-13). The mean follow-up was 22.6 mo. Nine of 16 patients (56%) achieved an objective response. Two deaths occurred due to progressive disease at 7 mo. ¹⁸F-FDG PET/CT detected all responders at 3 mo and reclassified best overall response in 5 patients compared with CT alone. A decrease in tumor metabolism and volume (SUV_mean, metabolic tumor volume) and increase in healthy splenic metabolism at 3 mo were observed in responders (area under the curve > 0.85, P < 0.04). Five of 16 patients (31%) displayed new imaging patterns related to anti-PD1; we observed 2 transient progressions consistent with indeterminate response according to the LYRIC (2016) (IR2b at 14 mo and IR3 at 18 mo) and 3 patients with new lesions associated with immune-related adverse events. Conclusion: Three-month ¹⁸F-FDG PET/CT scans detected HL patients responding to anti-PD1. New patterns were encountered in 31% of patients, emphasizing the need for further evaluation in larger series and close collaboration between imaging and oncology specialists on a per-patient basis.

Short review of potential synergies of immune checkpoint inhibition and radiotherapy with a focus on Hodgkin lymphoma: radio-immunotherapy opens new doors

Radiotherapy is an established local treatment in patients with various malignancies. Systemic responses following local irradiation have been described as abscopal effects. Modern cancer immunotherapy with immune checkpoint inhibitors has shown impressive response rates and prolongation of survival even in heavily pretreated patients with advanced solid malignancies and lymphomas. Radiotherapy has been shown to modulate immune response, and its application in the context of immune checkpoint inhibition has recently evolved into an active field of research. Prospective studies investigating combination treatment are currently ongoing and will answer questions as to the optimal schedule and radiation dosing. This short review focuses on the immunomodulatory role of radiotherapy and the use of immune checkpoint inhibition with a special focus on Hodgkin lymphoma.

Harnessing the Immunotherapy Revolution for the Treatment of Childhood Cancers

Cancer immunotherapies can be classified into agents that amplify natural immune responses (e.g., checkpoint inhibitors) versus synthetic immunotherapies designed to initiate new responses (e.g., monoclonal antibodies [mAbs], chimeric antigen receptors [CARs]). Checkpoint inhibitors mediate unprecedented benefit in some adult cancers, but have not demonstrated significant activity in pediatric cancers, likely due their paucity of neoantigens. In contrast, synthetic immunotherapies such as mAbs and CAR T cells demonstrate impressive effects against childhood cancers. Intense efforts are underway to enhance the effectiveness of pediatric cancer immunotherapies through improved engineering of synthetic immunotherapies and by combining these with agents designed to amplify immune responses.

Concurrent irradiation with the anti-programmed cell death ligand-1 immune checkpoint blocker durvalumab: Single centre subset analysis from a phase 1/2 trial

PURPOSE

To assess preliminary safety and efficacy results of the anti-programmed cell death ligand-1 (anti-PD-L1) durvalumab in combination with radiotherapy (RT) in an expansion cohort of patients included in a phase 1/2 trial at our institution.

PATIENTS AND METHODS

Data from patients who received concurrent palliative RT with durvalumab (10 mg/kg every 2 weeks via intravenous infusion) were analysed in terms of safety (CTCAE v4.0) and efficacy (RECIST v1.1 and tumour growth rate [TGR]).

RESULTS

Between 02/2014 and 04/2016, 10 patients received palliative local irradiation of 15 isolated lesions. Most patients (90%) had received one or more prior lines of systemic therapy for advanced disease. The median duration of exposure to durvalumab was 5.2 months with a median delivery of 11 cycles (range, 4-38 cycles). RT (conformal 3D RT, 79% and intracranial stereotactic RT, 21%) was delivered at a median biologically-effective dose of 28 Gy (range, 6-92), in a median number of five fractions (range, 1-10) and over a median duration of 6 d (range, 1-14). Five patients (50%) reported an irradiation-related adverse event (AE) grade (G) 1 or 2 and one patient had two G2 AEs. The most frequently reported AE (3/6) was G2 mucositis. There was no G3 or more RT-related AEs. All AEs were transient, lasted less than one week, and were manageable by standard guidelines. There was no unexpected AE. On 10/15 in-field (IF) evaluable lesions, the objective response (OR) rate was 60% (complete response, 2/10 and partial response, 4/10) and 4/10 stable disease (SD). All evaluated IF lesions had a TGR decrease resulting in a significant decrease in the TGR between the two periods (before versus after RT; p < 0.01). Outfields disease evaluation retrieved 10/14 SD and 4/14 progressive disease (PD). There was no out-field OR, no abscopal effect and no out-field difference between the two periods according to TGR (p = 0.09).

CONCLUSION

In this small data set of patients, concurrent palliative RT with the anti-PD-L1 durvalumab was well tolerated. ClinicalTrials.gov number: NCT01693562; EudraCT number: 2012-002206-52.