Pembrolizumab with or without radiation therapy for metastatic non-small cell lung cancer: a randomized phase I/II trial

Combination of radiotherapy and PD-L1 blockade induces abscopal responses in EGFR-mutated lung cancer through activating CD8+ T cells

Patients with EGFR-mutated non-small cell lung cancer (NSCLC) respond poorly to immune checkpoint inhibitors (ICIs). It has been reported that the number of CD8+T cells is reduced in EGFR-mutated NSCLC. However, the extent of heterogeneity and effector function of distinct populations of CD8+T cells has not been investigated intensively. In addition, studies investigating whether a combination of radiotherapy and ICIs can improve the efficacy of ICIs in EGFR-mutated lung cancer are lacking. Single-cell RNA sequencing (scRNA-seq) was used to investigate the heterogeneity of CD8+T cell populations in EGFR-mutated NSCLC. The STING pathway was explored after hypofractionated radiation of EGFR-mutated and wild-type cells. Mice bearing LLC-19del and LLC-EGFR tumors were treated with radiotherapy plus anti-PD-L1. The scRNA-seq data showed the percentage of progenitor exhausted CD8+T cells was lower in EGFR-mutated NSCLC. In addition, CD8+T cells in EGFR-mutated NSCLC were enriched in oxidative phosphorylation. In EGFR-mutated and wild-type cells, 8 Gy × 3 increased the expression of chemokines that recruit T cells and activate the cGAS-STING pathway. In the LLC-19del and LLC-EGFR mouse model, the combination of radiation and anti-PD-L1 significantly inhibited the growth of abscopal tumors. The enhanced abscopal effect was associated with systemic CD8+T cell infiltration. This study provided an intensive understanding of the heterogeneity and effector functions of CD8+T cells in EGFR-mutated NSCLC. We showed that the combination of hypofractionated radiation and anti-PD-L1 significantly enhanced the abscopal responses in both EGFR-mutated and wild-type lung cancer by activating CD8+T cells in mice.

Epigenetic modification in radiotherapy and immunotherapy for cancers

Radiotherapy (RT) is one of the primary treatment modalities in managing cancer patients. Recently, combined RT and immunotherapy (IT) (i.e., radio-IT [RIT]) have been aggressively investigated in managing cancer patients. However, several issues in conducting RIT are challenging, such as incorporating advanced irradiation techniques, predictive/prognostic biomarkers, and other treatment modalities. Several clinical efforts and novel biomarkers have been introduced and developed to solve these challenges. For example, stereotactic radiosurgery/stereotactic radiotherapy, stereotactic body radiotherapy/stereotactic ablative body radiotherapy, and FLASH-RT have been applied for delivering precise irradiation to lung and liver tumors in conjunction with IT. Besides, several novel IT agents and incorporations of other therapies, such as targeted and thermal therapies, have been further investigated. The present study reviewed the emerging challenges of RIT in modern oncology. We also evaluated clinical practice, bench research, and multimodality treatments. In addition to several clinically applicable biomarkers, we emphasize the roles of advanced irradiation techniques and epigenetic modification as predictive/prognostic biomarkers and potential therapeutic targets. For example, 6(m) A-based epigenetic agents demonstrate the potential to enhance the treatment effects of RIT. However, further prospective randomized trials should be conducted to confirm their roles.

A phase 2 single-arm trial of high-dose precision targeted radiotherapy added to immunotherapy for patients with metastatic non-small cell lung cancer

HYPOTHESIS

For metastatic non-small cell lung cancer (NSCLC), the addition of radiotherapy (RT) to immune checkpoint inhibitor (ICI) therapy could have synergistic anti-cancer effects and address the most threatening tumors. We posited that the addition of high-dose RT to ICI could prolong progression-free survival (PFS).

METHODS

In this single arm phase 2 trial, 45 patients with metastatic NSCLC who had received an anti-PD-1/anti-PD-L-1 ICI for 4+ weeks were enrolled from July 2017-May 2021. Patients received high-dose RT to 1-4 extracranial tumors and continued ICI until progression or unacceptable toxicity. The primary endpoint was PFS at 24 weeks, comparing to a historical control rate of 35%.

RESULTS

Of 44 evaluable patients, median age was 71, 75% had adenocarcinoma, 64% had polymetastatic disease, and 85% of cancers with known PD-L1 percentage were PD-L1 positive. Median number of treated tumors was two and most common dose was 40 Gy in 10 fractions (41/81 tumors). Median follow-up was 23.3 months. The trial met the primary outcome: 24-week PFS was 60% (95% CI 44-75%), higher than the historical control rate (p<0.001). Median PFS was 6.9 months (95% CI 4.0-13.5 mo) and median OS was 27.4 months (95% CI 20.4-not reached). Several patients with pre-study disease progression on ICI treatment achieved durable responses to study treatment, up to 53 months. Local recurrence rate was low: cumulative incidence of 5% at one, two, and three years. Two dose-limiting toxicities were observed (5%), including one grade 5 pneumonitis.

CONCLUSIONS

The strategy improved 24-week PFS compared to historical controls receiving ICI alone. The excellent local control supports the efficacy of high-dose RT in addressing macroscopic disease.

Factors associated with the use of immune checkpoint inhibitors in older adults with metastatic non-small cell lung cancer and pre-existing autoimmune disease: A SEER-Medicare study

INTRODUCTION

The presence of pre-existing autoimmune disease (PAD) with metastatic non-small cell lung cancer (mNSCLC) poses challenges in the use of immune checkpoint inhibitors (ICI). This study investigated factors influencing ICI utilization in older adults with mNSCLC and PAD.

MATERIALS AND METHODS

A retrospective cohort study with a 12-month baseline prior to treatment initiation was conducted using the SEER-Medicare data. Patients aged 66 years and above diagnosed with mNSCLC between January 2015 and December 2017, who initiated immunotherapy only/chemoimmunotherapy (IT/CIT) or chemotherapy only (CIT) and had at least one PAD diagnosed any time before treatment initiation, were included. Multiple factors, guided by the Model of Health Services Utilization, were analyzed using multivariable logistic regression. Adjusted odds ratios (aORs) and 95.0% CIs were reported.

RESULTS

Among 1,319 patients initiating first-line (1L) systemic therapy, 22.3% received IT/CIT and 77.7% received CT. Patients initiating IT/CIT were more likely to be 76-80 years old (aOR = 1.70, 95.0% CI = 1.02-2.81) and > 80 years old (aOR = 2.49, 95.0% CI = 1.46-4.25), reside in South (aOR = 2.32, 95.0% CI = 1.36-3.96) and West (aOR = 2.27, 95.0% CI = 1.44-3.60) SEER regions, diagnosed in 2016 (aOR = 6.36, 95.0% CI = 3.06-13.22) and 2017 (aOR = 40.45, 95.0% CI = 19.70-83.07), having a longer time to treatment initiation (aOR = 1.14, 95.0% CI = 1.08-1.19), having non-squamous tumor histology (aOR = 1.511, 95.0% CI = 1.048-2.179), and having a prior hospitalization (aOR = 1.63, 95.0% CI = 1.14-2.33). These patients were less likely to have recently used an immunosuppressant (IS) (aOR = 0.06, 95.0% CI = 0.04-0.10).

DISCUSSION

Several factors, such as age, region, cancer diagnosis year, time to treatment initiation, and recent IS use, intricately shape treatment decisions. Further in-depth research on each of these factors is imperative to optimize strategies for this distinctive patient population.

A review of the efficacy and safety of iodine-125 seed implantation for lung cancer treatment

Lung cancer is the second most common, and the deadliest, disease globally. Because it is often diagnosed late, surgical resection is not a viable treatment option for ∼75 % of patients, often resulting in a poor prognosis. Of the available treatments, radioactive iodine-125 (125-I) seed implantation therapy, or brachytherapy, has emerged as a promising option. In this procedure, small radioactive seeds are implanted inside tumor cells to produce sustained effects. Because of the short radial distance of this radiation, 125-I brachytherapy selectively and efficiently kills cancer cells while minimizing injury to adjacent cells. The present review describes the mechanism of 125-I seed implantation in the treatment of lung cancer, its efficacy and safety, and its combination with other therapies. We conclude that radioactive 125-I seed implantation and its use in combination with other therapies are good options for the management of local tumor growth, pain palliation, and improving the life span of patients suffering from lung cancers. This technique can enhance the clinical efficacy of treatment and improve the overall survival of patients with lung cancers. However, standardized dosage regimens and other procedures are still required to achieve treatment homogeneity and provide guidance for the clinical implementation of this technique.

Synthetic vectors for activating the driving axis of ferroptosis

Ferroptosis is a promising strategy for cancer therapy, with numerous inhibitors of its braking axes under investigation as potential drugs. However, few studies have explored the potential of activating the driving axes to induce ferroptosis. Herein, phosphatidylcholine peroxide decorating liposomes (LIPPCPO) are synthesized to induce ferroptosis by targeting divalent metal transporter 1 (DMT1). LIPPCPO is found to boost lysosomal Fe2+ efflux by inducing cysteinylation of lysosomal DMT1, resulting in glutathione peroxidase 4 (GPX4) suppression, glutathione depletion and ferroptosis in breast cancer cells and xenografts. Importantly, LIPPCPO induced ferroptotic cell death is independent of acquired resistance to radiation, chemotherapy, or targeted agents in 11 cancer cell lines. Furthermore, a strong synergistic ferroptosis effect is observed between LIPPCPO and an FDA-approved drug, artesunate, as well as X rays. The formula of LIPPCPO encapsulating artesunate significantly inhibits tumor growth and metastasis and improves the survival rate of breast cancer-bearing female mice. These findings provide a distinct strategy for inducing ferroptosis and highlight the potential of LIPPCPO as a vector to synergize the therapeutic effects of conventional ferroptosis inducers.

Immunotherapy and Radiotherapy for Older Patients with Locally Advanced Non-Metastatic Non-Small-Cell Lung Cancer Who Are Not Candidates for or Decline Surgery and Chemotherapy: A Practical Proposal by the International Geriatric Radiotherapy Group

The standard of care for locally advanced non-small-cell lung cancer (NSCLC) is either surgery combined with chemotherapy pre- or postoperatively or concurrent chemotherapy and radiotherapy. However, older and frail patients may not be candidates for surgery and chemotherapy due to the high mortality risk and are frequently referred to radiotherapy alone, which is better tolerated but carries a high risk of disease recurrence. Recently, immunotherapy with immune checkpoint inhibitors (ICIs) may induce a high response rate among cancer patients with positive programmed death ligand 1 (PD-L1) expression. Immunotherapy is also well tolerated among older patients. Laboratory and clinical studies have reported synergy between radiotherapy and ICI. The combination of ICI and radiotherapy may improve local control and survival for NSCLC patients who are not candidates for surgery and chemotherapy or decline these two modalities. The International Geriatric Radiotherapy Group proposes a protocol combining radiotherapy and immunotherapy based on the presence or absence of PD-L1 to optimize the survival of those patients.

Intranuclear Irradiation Inhibits Solid Tumor Growth by Upregulating Caspase8 and Activating Apoptosis

Radioimmunotherapy (RIT) is a novel and promising cancer treatment method, with ongoing research focusing on RIT antibody selection, radionuclides, treatment options, and benefited patient groups. As we dive into the mechanisms of tumor biology, a deeper exploration of how RIT affects tumor tissue is needed to provide new ways to improve clinical treatment outcome and patient prognosis. We labeled the anti-PD-L1 monoclonal antibody atezolizumab with iodine-131 (131I), separated and purified the labeled mAb with Sephadex G-25 medium gel filtration resin, and tested product stability. We detected the in vivo activity of 131I-PD-L1 mAb by analyzing its in vivo biodistribution and performing SPECT imaging and then set different treatment groups to study the effect of 131I-atezolizumab on the survival of tumor-bearing mice. Western blot, real-time quantitative PCR, and immunohistochemistry were used to detect the expression level of Caspase8 and Nlrp3 in tumor. TUNEL fluorescence staining was used to detect the apoptosis in the tumor. The radiopharmaceutical molecular probe 131I-atezolizumab showed high stability and in vivo biological activity. The treatment regimen adopted had a positive effect on the survival of tumor-bearing mice. 131I internal irradiation upregulated Caspase8 in tumor and ultimately inhibited solid tumor growth by activating apoptosis pathways. We also found a significant increase in the expression of NLRP3, which plays an important role in the pyroptosis pathway, in tumor. In summary, our data demonstrated that radiopharmaceuticals combined with immunotherapy affected tumor tissue by modulating relevant biological pathways, thereby achieving better antitumor effects compared with single therapy and providing new insights for promoting better patient prognosis and combination treatment strategies.

Safety of combined ablative radiotherapy and immune checkpoint inhibitors in three phase I trials

BACKGROUND

Stereotactic body radiotherapy (SBRT) is safe and effective for treatment of extracranial metastatic disease, but its safety when combined with immune checkpoint inhibitors (ICI) has not yet been comprehensively reported. Here we report adverse events (AEs) associated with combined SBRT and ICI using prospectively-collected data on patients in three trials investigating multi-site SBRT combined with ICI.

METHODS

Patients were included from three prospective trials of ICI (pembrolizumab; nivolumab/urelumab or nivolumab/cabiralizumab; nivolumab/ipilimumab) with SBRT to 1-4 sites. AEs were recorded prospectively using the CTCAE v4.0. Survival was analyzed using Kaplan-Meier method with a 90-day landmark. Association of patient characteristics with cumulative incidence of AEs was assessed using Fine-Gray regression.

RESULTS

213 patients were included, with a median follow-up of 10 months. Over the follow-up period, 50 % and 27 % of patients experienced at least one grade ≥ 2 or grade ≥ 3 AE, respectively. Cumulative incidences of grade ≥ 2 and grade ≥ 3 AEs at 6 months were 47 % and 23 %, respectively. Three grade 5 AEs rated "possibly" related to treatment occurred outside the 90-day dose-limiting toxicity window. Landmarked survival analysis of patients with or without grade ≥ 3 AEs showed no significant difference in progression-free or overall survival. Dual-agent ICI was significantly associated with grade ≥ 3 AE.

CONCLUSION

This analysis features the largest prospectively evaluated cohort of patients treated with combination ablative SBRT and ICI to date and provides context for future trial design. We conclude that multi-site SBRT and ICI can be safely co-administered when SBRT is delivered with prioritization of normal tissue constraints.

Palliative Thoracic Radiotherapy in the Era of Modern Cancer Care for NSCLC

Palliative thoracic radiotherapy provides rapid and effective symptom relief in approximately two-thirds of NSCLC patients treated. In patients with poor performance status, the degree of palliation appears unrelated to the radiation dose or fractionation schedule. Conversely, in patients with good performance status, higher radiation doses administered over longer periods have shown modest survival benefits. These findings stem from studies conducted before the advent of immunotherapy and targeted therapy in clinical practice. Currently, there are no large prospective studies specifically dedicated to palliative radiotherapy conducted in this new treatment era. Modern radiotherapy technologies are now widely available and are increasingly used for palliative purposes in selected patients, reflecting the expanded array of therapeutic options for disseminated NSCLC and improved prognosis. Some traditional tenets of palliative thoracic radiotherapy, such as the improvement of overall survival with a protracted radiation schedule and the use of simple, cost-effective radiation techniques for palliative purposes, may no longer hold true for patients receiving immunotherapy or targeted therapy. The application of IMRT or SBRT in the context of palliative radiotherapy for NSCLC is not yet sufficiently explored, and this is addressed in this review. Moreover, new risks associated with combining palliative radiotherapy with these systemic treatments are being explored and are discussed within the context of palliative care. The optimal timing, doses, fractionation schedules, and treatment volumes for radiotherapy combined with immunotherapy or targeted therapy are currently subjects of investigation. In emergencies, radiotherapy should be used as a life-saving measure without delay. However, for other indications of palliative thoracic radiotherapy, decisions regarding doses, timing relative to systemic treatments, and treatment volumes should be made in a multidisciplinary context, considering the patient's prognosis, anticipated outcomes, and access to potentially effective treatments. We still lack robust data from prospective studies on this matter. This review examines and discusses available evidence on the use of palliative thoracic radiotherapy within the framework of modern treatment strategies for NSCLC.

Overcoming Resistance to Checkpoint Inhibitors with Combination Strategies in the Treatment of Non-Small Cell Lung Cancer

Lung cancer continues to contribute to the highest percentage of cancer-related deaths worldwide. Advancements in the treatment of non-small cell lung cancer like immune checkpoint inhibitors have dramatically improved survival and long-term disease response, even in curative and perioperative settings. Unfortunately, resistance develops either as an initial response to treatment or more commonly as a progression after the initial response. Several modalities have been utilized to combat this. This review will focus on the various combination treatments with immune checkpoint inhibitors including the addition of chemotherapy, various immunotherapies, radiation, antibody-drug conjugates, bispecific antibodies, neoantigen vaccines, and tumor-infiltrating lymphocytes. We discuss the status of these agents when used in combination with immune checkpoint inhibitors with an emphasis on lung cancer. The early toxicity signals, tolerability, and feasibility of implementation are also reviewed. We conclude with a discussion of the next steps in treatment.

Radiotherapy, immunity, and immune checkpoint inhibitors

Radiotherapy exerts immunostimulatory and immunosuppressive effects, both locally, within the irradiated tumour microenvironment, and systemically, outside the radiation field. Inspired by preclinical data that showed synergy between radiotherapy and immune checkpoint inhibitors, multiple clinical trials were initiated with the hypothesis that combined treatment with radiotherapy and immune checkpoint inhibitors could stimulate a robust systemic immune response and improve clinical outcomes. However, despite early optimism, radioimmunotherapy trials in the curative and metastatic settings have met with little success. In this Review, we summarise the immunostimulatory effects of radiotherapy that provided the theoretical basis for trials of combination radiotherapy and immune checkpoint inhibitors. We also discuss findings from clinical trials incorporating radiotherapy and immune checkpoint inhibitors and examine the success of these trials in the context of the immunosuppressive effects of radiotherapy. We conclude by highlighting targets for relieving radiotherapy-induced immunosuppression with the goal of enhancing the combined effects of radiotherapy and immune checkpoint inhibitors.

Integrative Approaches in Non-Small Cell Lung Cancer Management: The Role of Radiotherapy

Treatment guidelines for non-small cell lung cancer (NSCLC) vary by several factors including pathological stage, patient candidacy, and goal of treatment. With many therapeutics and even more combinations available in the NSCLC clinician's toolkit, a multitude of questions remain unanswered vis-a-vis treatment optimization. While some studies have begun exploring the interplay among the many pillars of NSCLC treatment-surgical resection, radiotherapy, chemotherapy, and immunotherapy-the vast number of combinations and permutations of different therapy modalities in addition to the modulation of each constituent therapy leaves much to be desired in a field that is otherwise rapidly evolving. Given NSCLC's high incidence and lethality, the experimentation of synergistic benefits that combinatorial treatment may confer presents a ripe target for advancement and increased understanding without the cost and burden of novel drug development. This review introduces, synthesizes, and compares prominent NSCLC therapies, placing emphasis on the interplay among types of therapies and the synergistic benefits some combinatorial therapies have demonstrated over the past several years.

Scleroderma-like Lesions in a Patient Undergoing Combined Pembrolizumab and Routine Chemotherapy: A Case Report and Literature Review

Triple-negative breast cancer (TNBC) represents a challenging malignancy with limited treatment options and a poor prognosis. Adjuvant therapies, including chemotherapy and immune checkpoint inhibitors (ICI), are commonly employed following breast conservation surgery. However, these treatments can lead to various adverse effects, including cutaneous complications and connective tissue disorders. Here, we present the case of a 54-year-old woman with TNBC who developed morphea, a form of localized scleroderma, following adjuvant chemotherapy and pembrolizumab administration. This case highlights the rarity of drug-induced morphea and emphasizes the importance of recognizing and managing such adverse events in breast cancer patients. We discuss the clinical characteristics, diagnostic challenges, and treatment considerations associated with drug-induced scleroderma-like lesions, as well as the potential mechanisms underlying their development. Furthermore, we review the literature on the incidence, clinical features, and outcomes of scleroderma-like lesions induced by chemotherapy and ICIs. This case underscores the need for increased awareness of immune-related adverse events in patients receiving immunotherapy, as well as the importance of individualized treatment approaches to optimize patient care and outcomes.

A real-world analysis of stereotactic body radiotherapy combined with immunotherapy in advanced or recurrent non-small cell lung cancer (NSCLC): A single-center experience

Background

We aimed to assess the value of stereotactic body radiotherapy (SBRT) delivered under the situation of controlled or progressed disease during ICI therapy in advanced or recurrent NSCLC.

Methods

We retrospectively collected patients with advanced or recurrent NSCLC who received SBRT concurrently with ICI in our institution between January 2017 and December 2021. Patients were divided into two groups, including those for whom SBRT was delivered initially or to the residual tumors during the first- or later-line ICI treatment (Group 1), and those for whom SBRT was given to the progressed tumors irrespective of first- or later-line ICI treatment (Group 2).

Results

A total of 144 patients were included. With median follow-up duration of 25.6 (range: 3.6 to 56.2) months, median progression-free survival (PFS) was 13.7 (95 % CI: 10.4 to 17.1) months and median overall survival (OS) was 52.8 [95 % CI: 30.6 to not available (NA)] months. In Group 1 (n = 78), median PFS was 17.9 (95 % CI: 14.5 to 29.8) months while median OS was not reached and 5-year OS rate was 61.2 %. In Group 2 (n = 66), median PFS was 8.0 (95 % CI: 6.0 to 13.1) months and median OS was 30.6 (95 % CI: 21.5 to NA) months.

Conclusions

SBRT combined with ICI demonstrated favorable survival for advanced or recurrent NSCLC, delivered in a controlled-disease situation as well as to progressed diseases with salvage-intent. Future prospective studies are warranted to investigate the optimal SBRT dose regimen and appropriate combination strategy to synergize ICI.

Radiotherapy and immunology

The majority of cancer patients receive radiotherapy during the course of treatment, delivered with curative intent for local tumor control or as part of a multimodality regimen aimed at eliminating distant metastasis. A major focus of research has been DNA damage; however, in the past two decades, emphasis has shifted to the important role the immune system plays in radiotherapy-induced anti-tumor effects. Radiotherapy reprograms the tumor microenvironment, triggering DNA and RNA sensing cascades that activate innate immunity and ultimately enhance adaptive immunity. In opposition, radiotherapy also induces suppression of anti-tumor immunity, including recruitment of regulatory T cells, myeloid-derived suppressor cells, and suppressive macrophages. The balance of pro- and anti-tumor immunity is regulated in part by radiotherapy-induced chemokines and cytokines. Microbiota can also influence radiotherapy outcomes and is under clinical investigation. Blockade of the PD-1/PD-L1 axis and CTLA-4 has been extensively investigated in combination with radiotherapy; we include a review of clinical trials involving inhibition of these immune checkpoints and radiotherapy.

Fraction Dose Escalation of Hypofractionated Radiotherapy with Concurrent Chemotherapy and Subsequent Consolidation Immunotherapy in Locally Advanced Non-Small Cell Lung Cancer: A Phase I Study

PURPOSE

This phase I trial aimed to determine the maximum tolerated fraction dose (MTFD) of hypofractionated radiotherapy (hypo-RT) combined with concurrent chemotherapy and subsequent consolidation immune checkpoint inhibitors (cICI) for patients with locally advanced non-small cell lung cancer.

PATIENTS AND METHODS

Split-course hypo-RT and hypoboost combined with concurrent chemotherapy was administered at three dose levels (DL), using a stepwise dose-escalation protocol. The sophisticated esophagus-sparing technique was implemented to restrict the dose to the esophagus. Patients who did not experience disease progression or unresolved ≥grade 2 (G2+) toxicities after RT received cICI. Each DL aimed to treat six patients. The MTFD was defined as the highest DL at which ≤2 patients of the six who were treated experienced treatment-related G3+ toxicity and ≤1 patient experienced G4+ toxicity within 12 months post-RT.

RESULTS

Eighteen patients were enrolled, with six patients in each DL. All patients completed hypo-RT and concurrent chemotherapy, and 16 (88.9%) received at least one infusion of cICI, with a median of 10 infusions. Within the 12-month assessment period, one patient in DL1 experienced G3 pneumonitis, and one patient in DL3 developed G3 tracheobronchitis. The MTFD was not reached. The objective response rate was 100%. With a median follow-up of 20.9 months, the 1-year overall survival and progression-free survival rates were 94.4% and 83.3%, respectively.

CONCLUSIONS

Utilizing the split-course hypo-RT and hypoboost approach, a fraction dose of 5 Gy to a total dose of 60 Gy, combined with concurrent chemotherapy and subsequent cICI, was well tolerated and yielded a promising objective response rate and survival outcomes.

Is Single-Site Radiation Therapy Enough to Augment the Immune System and Enhance Immunotherapy for Metastatic Disease?

Despite the promise of combining immunotherapy and radiotherapy (RT) for metastatic cancers, existing randomized data have not been consistent on whether RT to a single irradiated site improves clinical outcomes. Mechanistically, this could result from a low quantity/diversity of tumor antigens released for immune detection, immunosuppressive molecules released by tumor masses, and the lack of immune infiltration into tumor bulk. Herein, multi-site RT is discussed as a potential solution, given that it can directly improve upon each of the mechanistic issues. Just as it is illogical to use systemic therapy alone in place of a dedicated local therapeutic option (e.g., RT) for most stage II-III malignancies, so too is illogical to irradiate one site only in case of metastatic neoplasms instead of implementing systemic therapy and/or multi-site RT. Although it may theoretically be possible to address all systemic disease with systemic therapy, that notion assumes that all areas of systemic disease will be responsive to systemic therapy in the first place. However, in reality, certain sites may develop innate or acquired resistance to systemic therapy, hence opening the door to multi-site localized treatment strategies. Further investigation is required to address whether multi-site RT would be effective in the setting of suboptimal immune function and/or resistance/refractoriness to multiple prior systemic therapies. Methods to improve the effectiveness of multi-site RT are also discussed, such as ablatively-/definitively-dosed RT, along with staggered timing of RT administration (pulsed RT).

Beyond success: unveiling the hidden potential of radiotherapy and immunotherapy in solid tumors

Immunotherapy, particularly with immune checkpoint inhibitors, has significantly transformed cancer treatment. Despite its success, many patients struggle to respond adequately or sustain long-lasting clinical improvement. A growing consensus has emerged that radiotherapy (RT) enhances the response rate and overall efficacy of immunotherapy. Although combining RT and immunotherapy has been extensively investigated in preclinical models and has shown promising results, establishing itself as a dynamic and thriving area of research, clinical evidence for this combination strategy over the past five years has shown both positive and disappointing results, suggesting the need for a more nuanced understanding. This review provides a balanced and updated analysis of the combination of immunotherapy and RT. We summarized the preclinical mechanisms through which RT boosts antitumor immune responses and mainly focused on the outcomes of recently updated clinical trials, including those that may not have met expectations. We investigated the optimization of the therapeutic potential of this combined strategy, including key challenges, such as fractionation and scheduling, lymph node irradiation, and toxicity. Finally, we offered insights into the prospects and challenges associated with the clinical translation of this combination therapy, providing a realistic perspective on the current state of research and potential future directions.

Efficacy and safety of concurrent immune checkpoint inhibitors combined with radiotherapy or chemoradiotherapy for advanced non-small cell lung cancer: A systematic review and single-arm meta-analysis

BACKGROUND

The recent usage of immunotherapy combined with chemoradiotherapy has improved survival in advanced non-small cell lung cancer (NSCLC) patients. However, determining the most effective therapy combination remains a topic of debate. Research suggests immune checkpoint inhibitors (ICIs) post-chemoradiotherapy enhance survival, but the impact of concurrent ICIs during chemoradiotherapy on rapid disease progression is unclear. This meta-analysis aims to assess the effectiveness and safety of concurrent ICIs with radiotherapy or chemoradiotherapy in advanced non-small cell lung cancer.

METHODS

We searched PubMed, Embase, the Cochrane Library, and Web of Science for relevant studies, extracting data on overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and adverse events (AEs).

RESULTS

The analysis included ten studies with 490 participants. Stage III NSCLC ORR was 81.8%, while Stage IV ORR was 39.9%. One-year PFS and OS for Stage III were 68.2% and 82.6%, compared to 27.9% and 72.2% for Stage IV. Common adverse events included anemia (46.6%), nausea (47.6%), rash (36.4%), and radiation pneumonitis (36.3%).

CONCLUSIONS

Our meta-analysis shows concurrent ICIs with chemoradiotherapy are effective and safe in advanced NSCLC, particularly in stage III patients at risk of progression before starting ICIs after chemoradiotherapy. The findings support further phase III trials. The review protocol was registered on PROSPERO (CRD42023493685) and is detailed on the NIHR HTA programme website.

Randomized Phase II Study Evaluating the Addition of Pembrolizumab to Radium-223 in Metastatic Castration-resistant Prostate Cancer

The checkpoint immunotherapeutic pembrolizumab induces responses in a small minority of patients with metastatic castration-resistant prostate cancer (mCRPC). Radium-223 (R223) may increase immunogenicity of bone metastases and increase pembrolizumab (P) activity. In a randomized phase II study, we assessed the effect of R223+P compared with R223 on tumor immune infiltration, safety, and clinical outcomes in patients with mCRPC. The primary endpoint was differences in CD4+ and CD8+ T-cell infiltrate in 8-week versus baseline bone metastasis biopsies; secondary endpoints were safety, radiographic progression-free survival (rPFS), and overall survival (OS). Of the 42 treated patients (29 R223+P, 13 R223), 18 R223+P and 8 R223 patients had evaluable paired tumor biopsies. Median fold-change of CD4+ T cells was -0.7 (range: -9.3 to 4.7) with R223+P and 0.1 (-11.1 to 3.7) with R223 (P = 0.66); for CD8+ T cells, median fold-change was -0.6 (-7.4 to 5.3) with R223+P and -1.3 (-3.1 to 4.8) with R223 (P = 0.66). Median rPFS and OS was 6.1 (95% confidence interval: 2.7-11.0) and 16.9 months [12.7-not reached (NR)], respectively, with R223+P and 5.7 (2.6-NR) and 16.0 (9.0-NR), respectively, with R223. Although R223+P was well tolerated with no unexpected toxicity, the combination did not improve efficacy. High-dimensional flow cytometry demonstrated minimal immune modulation with R223, whereas R223+P induced CTLA-4 expression on circulating CD4+ T cells. Clinical responders possessed lower circulating frequencies of Ki67+ T and myeloid cells at baseline and higher circulating frequencies of TIM-3+ T and myeloid cells by week 9. Although R223+P did not induce T-cell infiltration into the tumor microenvironment, exhaustion of induced peripheral T-cell immune responses may dampen the combination's clinical activity.

The incidence of and risk factors for radiation pneumonitis in patients treated with simultaneous bevacizumab and thoracic radiotherapy

BACKGROUND

First-line chemotherapy combined with bevacizumab is one of the standard treatment modes for patients with advanced non-small cell lung cancer (NSCLC). Thoracic radiotherapy (TRT) can provide significant local control and survival benefits to patients during the treatment of advanced NSCLC. However, the safety of adding TRT has always been controversial, especially because of the occurrence of radiation pneumonia (RP) during bevacizumab treatment. Therefore, in this study, we used an expanded sample size to evaluate the incidence of RP when using bevacizumab in combination with TRT.

PATIENTS AND METHODS

Using an institutional query system, all medical records of patients with NSCLC who received TRT during first-line chemotherapy combined with bevacizumab from 2017 to 2020 at Shandong Cancer Hospital and Institute were reviewed. RP was diagnosed via computed tomography and was classified according to the RTOG toxicity scoring system. The risk factors for RP were identified using univariate and multivariate analyses. The Kaplan-Meier method was used to calculate progression-free survival (PFS) and overall survival (OS).

RESULTS

Ultimately, 119 patients were included. Thirty-eight (31.9%) patients developed Grade ≥ 2 RP, of whom 27 (68.1%) had Grade 2 RP and 11 (9.2%) had Grade 3 RP. No patients developed Grade 4 or 5 RP. The median time for RP occurrence was 2.7 months (range 1.2-5.4 months). In univariate analysis, male, age, KPS score, V20 > 16.9%, V5 > 33.6%, PTV (planning target volume)-dose > 57.2 Gy, and PTV-volume > 183.85 cm3 were correlated with the occurrence of RP. In multivariate analysis, male, V20 > 16.9%, and PTV-volume > 183.85 cm3 were identified as independent predictors of RP occurrence. The mPFS of all patients was 14.27 (95% CI, 13.1-16.1) months. The one-year and two-year PFS rates were 64.9% and 20.1%, respectively. The mOS of all patients was 37.09 (95% CI, 33.8-42.0) months. The one-year survival rate of all patients was 95%, and the two-year survival rate was 71.4%.

CONCLUSIONS

The incidence of Grade ≥ 2 RP in NSCLC patients who received both bevacizumab and TRT was 31.9%. Restricting factors such as V20 and PTV will help reduce the risk of RP in these patients. For patients who receive both bevacizumab and TRT, caution should be exercised when increasing TRT, and treatment strategies should be optimized to reduce the incidence of RP.

The Role of Thoracic Vertebral Body Dosimetry in Minimizing Acute Hematologic Toxicities of Patients With Non-Small Cell Lung Cancer Receiving Lung Radiation Therapy and Immunotherapy

PURPOSE

Hematologic toxicities (HTs) are among the most common toxicities of combined immunotherapy and radiation therapy (RT). It remains essential to prevent RT-induced HTs because they can cause treatment discontinuation (influencing antitumoral effects) and because lymphopenia might dampen the effects of immunotherapy. To date, there are no studies examining the effect of thoracic vertebral body (TVB) RT dose on HTs in patients with non-small cell lung cancer receiving combined lung RT and programmed cell death (ligand) 1 immunotherapy.

METHODS AND MATERIALS

For standardization, all doses were reported as 2-Gy equivalents (EQD2). Mirroring publications before the immunotherapy era, TVB volumes referred to T1-T10, and specific dosimetric parameters (DmeanEQD2, V5EQD2-V60EQD2) were analyzed. Logistic regression estimated associations between grade ≥3 HTs (HT3+) and dosimetric/clinical parameters. Normal tissue complication probability (NTCP) models were constructed by logistic regression analysis modeling for HT3+. Receiver operating characteristic (ROC) analysis delineated TVB dosimetric thresholds, the stratification of which was able to evaluate post-RT absolute lymphocyte count and immunotherapy responses. Areas under the curve (AUCs) for NTCP models were corroborated by bootstrapping (optimism-corrected) methodology.

RESULTS

In 132 patients, there were 26 (19.7%) instances of HT3+. On multivariate analysis, DmeanEQD2 and V5EQD2 to V20EQD2 were associated with HT3+ (P < .05 for all). The NTCP models illustrated a 50% probability of HT3+ at a DmeanEQD2 = 39.8 Gy, V5EQD2 = 87.4%, V10EQD2 = 77.0%, and V20EQD2 = 68.4%. ROC analysis delineated optimal thresholds of HT3+ with DmeanEQD2 ± 30.2 Gy, V5EQD2 ± 69.1%, V10EQD2 ± 64.6%, and V20EQD2 ± 53.5%. Patients treated with values above those cutoffs had over double the risk of HT3+, with significant differences in post-RT absolute lymphocyte count and immunotherapy responses (P < .05 for all). AUCs for each individual parameter ranged from 0.743 to 0.798, and combining all 4 aforementioned cutoffs into a ROC curve resulted in a qualitatively higher AUC (0.836).

CONCLUSIONS

This hypothesis-generating work suggests that TVB dosimetry may equate with HT3+ in patients with non-small cell lung cancer undergoing combined lung RT/immunotherapy. Applying TVB dose constraints in this population could reduce HT3+ and avoid dampening of immunotherapy responses, but prospective validation is required.

A Phase 2 Study of In Situ Oncolytic Virus Therapy and Stereotactic Body Radiation Therapy Followed by Pembrolizumab in Metastatic Non-Small Cell Lung Cancer

PURPOSE

A phase 2 study of stereotactic body radiation therapy (SBRT) and in situ oncolytic virus therapy in metastatic non-small cell lung cancer (mNSCLC) followed by pembrolizumab (STOMP) was designed to explore the dual approach in enhancing single pembrolizumab with ADV/HSV-tk plus valacyclovir gene therapy and SBRT in mNSCLC.

METHODS AND MATERIALS

STOMP is a single-arm, open-label phase 2 study. Patients with mNSCLC received intratumoral injections of ADV/HSV-tk (5 × 1011 vp) and SBRT (30 Gy in 5 fractions) followed by pembrolizumab 200 mg IV every 3 weeks until disease progression or intolerable toxicity. The primary endpoint was overall response rate (ORR) (complete response [CR] and partial response [PR]). Secondary endpoints included clinical benefit rate (CBR) (CR, PR and stable disease [SD]), progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

28 patients were enrolled, of whom 27 were evaluated for response. The ORR was 33.3%, including 2 CR (7.4%) and 7 PR (25.9%). CBR was 70.4%. Six of eight (75.0%) patients who were immune checkpoint inhibitor (ICI) refractory derived clinical benefits. Responders had durable responses with median PFS, and OS not reached. The entire cohort had a median PFS of 7.4 months (95% CI, 5.1-9.6 months), and median OS of 18.1 months (95% CI, 15.4-20.9 months). The combination was well tolerated, with grade 3 or higher toxicity in 6 (21.4%) patients.

CONCLUSIONS

The dual approach of in situ ADV/HSV-tk plus valacyclovir gene therapy and SBRT as a chemotherapy-sparing strategy to enhance the antitumor effect of pembrolizumab is a well-tolerated encouraging treatment in patients with mNSCLC.

M, Gross CP, Slotman BJ, Chiang AC, Park HS. Differential Effect of Consolidative Thoracic Radiation Therapy in Extensive-Stage Small Cell Lung Cancer Based on Sex

Purpose

The landmark randomized trial on chest irradiation in extensive disease small cell lung cancer (CREST) demonstrated that consolidative thoracic radiation therapy (cTRT) improved overall (OS) and progression-free survival (PFS) after initial chemotherapy (chemo) in extensive-stage small cell lung cancer, with potentially increased benefit in women compared with men. It is unknown whether similar findings would apply after chemoimmunotherapy became the standard first-line treatment. In this analysis, we report national practice patterns and survival outcomes of cTRT according to patient sex.

Methods and Materials

We included patients from de-identified electronic health record-derived database diagnosed with stage IV small cell lung cancer (2014-2021) who completed 4 to 6 cycles of first-line systemic therapy (platinum-doublet chemotherapy or chemoimmunotherapy). We evaluated OS and PFS using multivariable Cox proportional hazards regression with receipt of cTRT as an independent variable and stratified by sex. As a sensitivity analysis, we weighted the models by the inverse probability of receiving cTRT.

Results

A total of 1227 patients were included (850 chemotherapy, 377 chemoimmunotherapy). There were no statistically significant differences in baseline characteristics between patients who did and did not receive cTRT. Among women, cTRT was associated with superior OS (adjusted hazard ratio [HR], 0.67; 95% CI, 0.52-0.87) and PFS (HR, 0.63; 95% CI, 0.49-0.82) compared with those not receiving cTRT. Conversely, no OS or PFS benefit with cTRT was observed in men (OS HR, 1.03; 95% CI, 0.80-1.31; PFS HR, 1.12; 95% CI, 0.85-1.47). Findings were similar in weighted analyses.

Conclusions

The survival efficacy of cTRT may be moderated by sex, with female patients appearing more likely to benefit than male patients. These findings reflect sex-based survival trends with similar effect sizes to those observed in the CREST trial. Although the underpinnings of this association need to be elucidated, stratification by sex should be considered for randomized-controlled trials studying cTRT in extensive-stage small cell lung cancer.

Combining Dual Checkpoint Immunotherapy with Ablative Radiation to All Sites of Oligometastatic Non-Small Cell Lung Cancer: Toxicity and Efficacy Results of a Phase 1b Trial

PURPOSE

Ablative local treatment of all radiographically detected metastatic sites in patients with oligometastatic non-small cell lung cancer (NSCLC) increases progression-free survival (PFS) and overall survival (OS). Prior studies demonstrated the safety of combining stereotactic body radiation therapy (SBRT) with single-agent immunotherapy. We investigated the safety of combining SBRT to all metastatic tumor sites with dual checkpoint, anticytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4), and anti-programmed cell death ligand 1 (anti-PD-L1) immunotherapy for patients with oligometastatic NSCLC.

METHODS AND MATERIALS

We conducted a phase 1b clinical trial in patients with oligometastatic NSCLC with up to 6 sites of extracranial metastatic disease. All sites of disease were treated with SBRT to a dose of 30 to 50 Gy in 5 fractions. Dual checkpoint immunotherapy was started 7 days after completion of radiation using anti-CTLA-4 (tremelimumab) and anti-PD-L1 (durvalumab) immunotherapy for a total of 4 cycles followed by durvalumab alone until progression or toxicity.

RESULTS

Of the 17 patients enrolled in this study, 15 patients received at least 1 dose of combination immunotherapy per protocol. The study was closed early (17 of planned 21 patients) due to slow accrual during the COVID-19 pandemic. Grade 3+ treatment-related adverse events were observed in 6 patients (40%), of which only one was possibly related to the addition of SBRT to immunotherapy. Median PFS was 42 months and median OS has not yet been reached.

CONCLUSIONS

Delivering ablative SBRT to all sites of metastatic disease in combination with dual checkpoint immunotherapy did not result in excessive rates of toxicity compared with historical studies of dual checkpoint immunotherapy alone. Although the study was not powered for treatment efficacy results, durable PFS and OS results suggest potential therapeutic benefit compared with immunotherapy or radiation alone in this patient population.

CDKL1 potentiates the antitumor efficacy of radioimmunotherapy by binding to transcription factor YBX1 and blocking PD-L1 expression in lung cancer

BACKGROUND

The evasion of the immune response by tumor cells through programmed death-ligand 1 (PD-L1) has been identified as a factor contributing to resistance to radioimmunotherapy in lung cancer patients. However, the precise molecular mechanisms underlying the regulation of PD-L1 remain incompletely understood. This study aimed to investigate the role of cyclin-dependent kinase-like 1 (CDKL1) in the modulation of PD-L1 expression and the response to radioimmunotherapy in lung cancer.

METHODS

The tumorigenic roles of CDKL1 were assessed via cell growth, colony formation, and EdU assays and an in vivo nude mouse xenograft model. The in vitro radiosensitization effect of CDKL1 was evaluated using a neutral comet assay, γH2AX foci formation analysis, and a clonogenic cell survival assay. The protein‒protein interactions were confirmed via coimmunoprecipitation and GST pulldown assays. The regulation of PD-L1 by CDKL1 was evaluated via chromatin immunoprecipitation (ChIP), real-time quantitative PCR, and flow cytometry analysis. An in vitro conditioned culture model and an in vivo C57BL/6J mouse xenograft model were developed to detect the activation markers of CD8+ T cells and evaluate the efficacy of CDKL1 overexpression combined with radiotherapy (RT) and an anti-PD-L1 antibody in treating lung cancer.

RESULTS

CDKL1 was downregulated and suppressed the growth and proliferation of lung cancer cells and increased radiosensitivity in vitro and in vivo. Mechanistically, CDKL1 interacted with the transcription factor YBX1 and decreased the binding affinity of YBX1 for the PD-L1 gene promoter, which consequently inhibits the expression of PD-L1, ultimately leading to the activation of CD8+ T cells and the inhibition of immune evasion in lung cancer. Moreover, the combination of CDKL1 overexpression, RT, and anti-PD-L1 antibody therapy exhibited the most potent antitumor efficacy against lung cancer.

CONCLUSIONS

Our findings demonstrate that CDKL1 plays a crucial role in regulating PD-L1 expression, thereby enhancing the antitumor effects of radioimmunotherapy. These results suggest that CDKL1 may be a promising therapeutic target for the treatment of lung cancer.

Efficacy and safety of thoracic radiotherapy in extensive-stage small-cell lung cancer patients receiving first-line immunotherapy plus chemotherapy: a propensity score matched multicentre retrospective analysis

BACKGROUND

Platinum-etoposide chemotherapy combined with immune checkpoint inhibitors (ICIs) has been recommended as the first-line standard treatment for extensive-stage small-cell lung cancer (ES-SCLC). However, the effect of thoracic radiotherapy (TRT) on these patients is still unknown. This study aimed to evaluate the efficacy and safety of TRT for ES-SCLC patients who responded to first-line ICIs and chemotherapy (CHT).

METHODS

Patients who received 4 to 6 cycles of ICIs and CHT as first-line therapy at three hospitals between 2018 and 2022 were included in the analysis. All patients were divided into two groups based on whether they received TRT as first-line treatment, and propensity score matching (PSM) was performed to ensure that the characteristics of two groups were well-balanced. The primary endpoints were overall survival (OS) and progression-free survival (PFS), and the secondary endpoint was toxic effects.

RESULTS

A total of 276 patients were included, and the median follow-up time was 22.3 (range, 4.0-53.73) months. After PSM, 197 patients were further analysed, and 99 of whom received TRT. The baseline characteristics were well-balanced between patients in the TRT and non-TRT groups. There were significant differences in PFS between the TRT and non-TRT groups, with the median PFS of 10.76 and 7.63 months, respectively (P = 0.014). Significantly improved OS was observed in the TRT group (21.67 vs. 16.6 months, P = 0.009). In addition, the use of TRT was an independent prognostic factor for PFS and OS of ES-SCLC patients receiving ICIs plus CHT. In terms of safety, no significant increase of any grades adverse event (AE) (P = 0.874) and G3-4 AE (P = 0.909) was observed for patients receiving TRT. Radiation esophagitis, gastrointestinal and hematologic toxicities were the most common AEs in TRT group, which were tolerable. And high-dose radiotherapy was associated with higher incidence of pneumonitis.

CONCLUSION

Addition of TRT showed significant survival benefits and well tolerability in ES-SCLC patients receiving platinum-etoposide CHT and ICIs, which could be a feasible first-line treatment strategy for ES-SCLC patients.

Radiotherapy in the management of lung oligometastases

In recent years, the development of both medical imaging and new systemic agents (targeted therapy and immunotherapy) have revolutionized the field of oncology, leading to a new entity: oligometastatic disease. Adding local treatment of oligometastases to systemic treatment could lead to prolonged survival with no significant impact on quality of life. Given the high prevalence of lung oligometastases and the new systemic agents coming with increased pulmonary toxicity, this article provides a comprehensive review of the current state-of-art for radiotherapy of lung oligometastases. After reviewing pretreatment workup, the authors define several radiotherapy regimen based on the localization and size of the oligometastases. A comment on the synergistic combination of medical treatment and radiotherapy is also made, projecting on future steps in this specific clinical setting.

Abscopal effect in maxillary sinus cancer: Insights from two case reports and a literature review

BACKGROUND

The abscopal effect is a rare phenomenon in which localized radiation therapy triggers tumor reduction in nontargeted areas. Although this phenomenon has been observed in various cancer types, it remains infrequent and not fully understood.

CASE

Two patients with maxillary sinus cancer with distant metastases were treated with radiotherapy after immune checkpoint inhibitor (ICI) therapy. The patients demonstrated abscopal effects following ICI therapy and radiotherapy, showing shrinkage in metastatic areas not directly targeted by radiation.

CONCLUSION

This report was reviewed to examine the synergistic effects of ICI and radiotherapy and to identify optimal strategies to enhance the abscopal effect in clinical practice. It has also touched on various ongoing debates and clinical trials aimed at understanding and exploiting this effect to improve cancer treatment. The exact mechanisms and optimal treatment protocols remain areas for future research.

Radiotherapy in the management of synchronous metastatic lung cancer

Metastatic lung cancer classically portends a poor prognosis. The management of metastatic lung cancer has dramatically changed with the emergence of immune checkpoint inhibitors, targeted therapy and due to a better understanding of the oligometastatic process. In metastatic lung cancers, radiation therapy which was only used with palliative intent for decades, represents today a promising way to treat primary and oligometastatic sites with a curative intent. Herein we present through a literature review the role of radiotherapy in the management of synchronous metastatic lung cancers.

Regulatory role of RGMb in lung injury promoted by the combination of carbon ion irradiation and anti-PD-1 antibody through Erk1/2 and p38 MAPK pathways

The combination of carbon ion radiotherapy and anti-PD-1 antibody represents a new approach to treating thoracic tumors. However, the lung damage caused by this combination therapy may limit its use, and the potential mechanisms for this are worthy of investigation. The objective of this research was to examine the potential involvement of repulsive guidance molecule b (RGMb) in lung damage promoted by the utilization of carbon ion irradiation combined with an anti-PD-1 antibody. The C57BL/6 mice have been randomly separated into four distinct groups: control, anti-PD-1, whole thorax carbon ion irradiation, and irradiation in combination with anti-PD-1 treatment groups (combination group). Detection of pathological changes in lung tissue using HE staining. Detection of pulmonary fibrosis by Masson staining and the hydroxyproline assay. ELISA to detect TNF-α, TGF-β, IL-6, and IL-1β expression levels within lung homogenates. The expression of RGMb, p38 MAPK, and Erk1/2 pathways was detected using a fully automated digital Western blotting system WES (ProteinSimple, USA). Flow cytometry was employed to analyze tissue-resident memory T cells (TRM) within the lung. Subsequently, the siRNA gene was employed to induce the downregulation of RGMb in mice in order to validate the involvement of RGMb in radiation-immune lung injury. The present study observed a significant increase in both inflammatory and fibrotic indicators within the mice group's lung tissue that received the combination treatment. The combination group exhibited elevated levels of TGF-β, TNF-α, IL-6, and IL-1β in lung homogenates. Anti-PD-1 antibody and carbon ion irradiation, upregulated RGMb, phospho-p38 MAPK and phospho-Erk1/2. The results obtained from the flow cytometry analysis indicated that the combination group was significantly higher in the number of clonal expansion TRMs, which were predominantly characterized by the expression of CD8+CD103+CD69-TRMs. The downregulate of RGMb via siRNA in mice resulted in a decrease in phospho-p38 MAPK and phospho-Erk1/2. The combination group exhibited a reduction in TNF-α, TGF-β, IL-6, and IL-1β in their lung tissues, and the number of CD8+CD103+CD69-TRM was significantly reduced. The combination group exhibited a significant improvement in inflammatory and fibrotic indicators within the lung tissues. Anti-PD-1 antibody and carbon ion irradiation synergistically regulate RGMb, leading to strong clonal expansion of lung TRM through the p38 MAPK and Erk1/2 pathways. The present study offers valuable insights into the treatment of lung injury due to the combined administration of carbon ion radiotherapy and anti-PD-1 antibody therapy.

A Pilot Study of Pembrolizumab Combined With Stereotactic Ablative Radiotherapy for Patients With Advanced or Metastatic Sarcoma

OBJECTIVES

Immunotherapy with immune checkpoint inhibitors has shown only limited success in the management of metastatic soft tissue sarcoma. Overall response rates (ORR) with single agent pembrolizumab were 18% and median PFS was 18 weeks on the clinical trial SARC028. One strategy to improve the responses to immunotherapy is with stereotactic body radiation therapy (SBRT), which can enhance the antitumor CD8 T cell response through the release of tumor-specific antigens, potentially priming a more diverse class of T cell receptors.

METHODS

This is a phase 0, pilot prospective study taking place at a single center with 2 arms. In Arm A, patients are treated with pembrolizumab 400 mg IV infusion on day 1 of a 42-day cycle. Stereotactic body radiation therapy (SBRT) is delivered in 1-5 fractions starting on C1D15-28 and given every other day. In Arm B, patients who have started an immune checkpoint inhibitor within 60 days are treated with SBRT in addition to the current therapy.

RESULTS

In this study we outline testing the feasibility of adding SBRT to pembrolizumab.

CONCLUSION

The ultimate goal of combination therapy is improved overall response, including tumors not treated with SBRT. This trial can be found registered online: NCT05488366.

Combining spatially fractionated radiation therapy (SFRT) and immunotherapy opens new rays of hope for enhancing therapeutic ratio

Spatially Fractionated Radiation Therapy (SFRT) is a form of radiotherapy that delivers a single large dose of radiation within the target volume in a heterogeneous pattern with regions of peak dosage and regions of under dosage. SFRT types can be defined by how the heterogeneous pattern of radiation is obtained. Immune checkpoint inhibitors (ICIs) have been approved for various malignant tumors and are widely used to treat patients with metastatic cancer. The efficacy of ICI monotherapy is limited due to the "cold" tumor microenvironment. Fractionated radiotherapy can achieve higher doses per fraction to the target tumor, and induce immune activation (immodulate tumor immunogenicity and microenvironment). Therefore, coupling ICI therapy and fractionated radiation therapy could significantly improve the outcome of metastatic cancer. This review focuses on both preclinical and clinical studies that use a combination of radiotherapy and ICI therapy in cancer.

[Interest of focal radiotherapy in case of oligoprogression under immunotherapy in the treatment of metastatic non-small cell lung cancer]

INTRODUCTION

The prognosis of metastatic non-small cell lung cancer (NSCLC) has been improved by the use of immune checkpoint inhibitors (ICI). Unfortunately, in some cases, cancer cells will develop resistance mechanisms. In case of progression in a limited number of lesions (oligoprogression), focal treatment with radiotherapy is proposed while continuing the ICI therapy.

METHODS

A cohort of 37 patients with metastatic NSCLC treated with nivolumab (anti-PD-1) in second or subsequent line and who received focal radiotherapy for oligoprogression with continuation of nivolumab was compared with a control cohort of 87 patients no oligoprogressor treated par immunotherapy.

RESULTS

After a median follow-up of 37 months [18; 62], the median progression free survival (PFS) in the radiotherapy-treated cohort was 15.04 versus 5.04 months in the control cohort, with a statistically significant difference (P=0.048). The median PFS following focal radiotherapy in the oligoprogressor group was 7.5 months. In univariate analysis, the presence of lung metastasis was associated with increased PFS, in contrast to the presence of brain metastases, which were associated with decreased PFS in the radiotherapy group. The median overall survival was not reached in both groups, with no significant difference between the two cohorts.

CONCLUSION

The combination of focal radiotherapy in case of oligoprogression and continued treatment with nivolumab in the treatment of metastatic NSCLC in the second or subsequent line of treatment seems to be with an increase in PFS.

Pembrolizumab monotherapy for non-small cell lung cancer (NSCLC): can patient stratification be improved in the UK Tayside population? A retrospective cohort study

OBJECTIVE

Pembrolizumab is a programmed cell death protein-1 (PD-1) inhibitor used to treat advanced patients with non-small cell lung cancer (NSCLC) with a programmed cell death ligand-1 (PD-L1) tumour proportion score (TPS) ≥50. Further sub-division of TPS-based stratification has not been evaluated in the UK, although smoking-induced tumour mutational burden and the immunogenic effects of prior radiotherapy are suggested to improve response.

AIMS

To investigate if PD-L1 TPS ≥80%, smoking status or radiotherapy before or within 2 months of treatment influenced progression-free survival (PFS) in patients with NSCLC treated with pembrolizumab monotherapy.

METHODS

PD-L1 TPS, smoking status and radiotherapy exposure were compared in patients with NSCLC in National Health Service (NHS) Tayside (n=100) treated with pembrolizumab monotherapy between 1 November 2017 and 18 February 2022. Survival estimates were compared using log-rank analysis, and Cox proportional hazards analysis was used to investigate the influence of potential confounding factors, including tumour stage and performance status.

RESULTS

PFS was not significantly different (log-rank HR=0.330, p=0.566) comparing patients with PD-L1 TPS 50-79% and PD-L1 TPS ≥80%. Smokers had significantly improved PFS (log-rank HR=4.867, p=0.027), while patients receiving radiotherapy had significantly decreased PFS (log-rank HR=6.649, p=0.012). A Cox regression model confirmed that both radiotherapy (p=0.022) and performance status (p=0.009) were independent negative predictors of PFS.

CONCLUSIONS

More rigorous PD-L1 TPS stratification did not influence survival outcomes. Smoking history improved PFS, although it was not an independent response predictor, while radiotherapy and performance status independently influenced clinical response. We suggest that further stratification of PD-L1 TPS is not warranted, while performance status and radiotherapy treatment may be additional clinically useful biomarkers of response to pembrolizumab in patients with NSCLC.

Predicting response to immunotherapy in non-small cell lung cancer- from bench to bedside

Background

Immune checkpoint inhibitor (ICI) therapy is first-line treatment for many advanced non-small cell lung cancer (aNSCLC) patients. Predicting response could help guide selection of intensified or alternative anti-cancer regimens. We hypothesized that radiomics and laboratory variables predictive of ICI response in a murine model would also predict response in aNSCLC patients.

Methods

Fifteen mice with lung carcinoma tumors implanted in bilateral flanks received ICI. Pre-ICI laboratory and computed tomography (CT) data were evaluated for association with systemic ICI response. Baseline clinical and CT data for 117 aNSCLC patients treated with nivolumab were correlated with overall survival (OS). Models for predicting treatment response were created and subjected to internal cross-validation, with the human model further tested on 42 aNSCLC patients who received pembrolizumab.

Results

Models incorporating baseline NLR and identical radiomics (surface-to-mass ratio, average Gray, and 2D kurtosis) predicted ICI response in mice and OS in humans with AUCs of 0.91 and 0.75, respectively. The human model successfully sorted pembrolizumab patients by longer vs. shorter predicted OS (median 35 months vs. 6 months, p=0.026 by log-rank).

Discussion

This study advances precision oncology by non-invasively classifying aNSCLC patients according to ICI response using pre-treatment data only. Interestingly, identical radiomics features and NLR correlated with outcomes in the preclinical study and with ICI response in 2 independent patient cohorts, suggesting translatability of the findings. Future directions include using a radiogenomic approach to optimize modeling of ICI response.

Oligometastasis: Expansion of Curative Treatments in the Field of Oncology

Oligometastasis is defined as the presence of several limited metastatic lesions and is generally limited to three or fewer than five metastatic lesions. Previously, the treatment of metastatic cancer aimed to alleviate symptoms rather than cure them; however, the use of immunotherapy or targeted therapy has greatly improved patient life expectancy. Additionally, the effectiveness and safety of local treatment have recently been proven for oligometastatic cancers and have significantly improved patient survival and decreased recurrence rates. A few metastatic studies on lung cancer have demonstrated the usefulness of combining radiation therapy and immunotherapy. Recently, local and targeted therapy combinations have shown promising results in treating non-small cell lung cancer, predominantly caused by the epidermal growth factor receptor and anaplastic lymphoma kinase gene mutations, suggesting the potential of these new treatment strategies. It is well known that oligometastasis has better clinical results than polymetastasis; however, research on the biological profile of oligometastasis is still lacking. Studies using circulating tumor DNA and circulating tumor cells are at the initial stages of providing a better understanding of oligometastatic cancers, and the biological characteristics of these cancers may be revealed based on more diverse studies. With the development of these treatments, the prognosis for patients with oligometastatic cancers is steadily improving, and if the biological profile is revealed, customized treatment may be provided.

Reflecting on the cardiac toxicity in non-small cell lung cancer in the era of immune checkpoint inhibitors therapy combined with thoracic radiotherapy

In recent years, immune checkpoint inhibitors (ICIs) have become a widely used treatment for non-small cell lung cancer (NSCLC), and the combination with traditional radiotherapy (RT) has shown significant potential in prolonging patient survival. However, both thoracic RT and ICIs can lead to cardiac toxicity, including radiation-induced heart damage (RIHD) and immunotherapy-related heart damage (IRHD). It still remains uncertain whether the combination of thoracic RT and immunotherapy will exacerbate acute or late cardiovascular (CV) toxicity and incidence. In this review, we summarize safety data from relevant clinical studies regarding CV toxicity for the combination therapy in NSCLC patients, explore the underlying synergetic mechanisms and common risk factors, and proposed treatment and management strategies. We hope to increase emphasis on the long-term assessment of CV toxicity risks associated with the combination therapy, and reduce the incidence of CV deaths resulting from such regimens.

Safety and Tolerability of Low-Dose Radiation and Stereotactic Body Radiotherapy + Sintilimab for Treatment-Naïve Stage IV PD-L1+ Non-Small Cell Lung Cancer Patients

PURPOSE

Low-dose radiotherapy (LDRT) may enhance the synergistic antitumor effect of combined immunotherapy and stereotactic body radiotherapy (SBRT). The safety and efficacy of this novel triple-combination therapy were evaluated for the first time as first-line treatment for patients with metastatic non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

This prospective phase I study enrolled 29 patients and included a dose-escalation and dose-expansion phase. Patients received SBRT [30 Gray (Gy)/3f] to small lesions and LDRT (2 Gy/1f, 4 Gy/2f, or 10 Gy/5f) to a large lesion concurrently, followed by sintilimab (a programmed death-1 inhibitor). The primary endpoint was safety and tolerability; secondary endpoints included objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).

RESULTS

No dose-limiting toxicities were observed during the dose-escalation phase; 4 Gy/2f was the recommended LDRT dose. Median follow-up was 15.6 months. Treatment-related adverse events (TRAE) occurred in 96.6% (28/29) of patients [grade ≥ 3; 20.7% (6/29)]; 2 patients (6.9%) discontinued due to TRAEs. Seven patients experienced pneumonitis (grade 2, n = 6; grade 3, n = 1). Immune-related adverse events were noted in 58.6% (17/29) of patients. In patients with tumor assessment (n = 28), ORR and confirmed ORR were 60.7% and 57.1%, respectively. Median PFS was 8.6 months (95% confidence interval, 3.7-16.5), and median OS was not reached. Exploratory analyses suggested both expanded and newly emerging T-cell receptor clonotypes were associated with better PFS.

CONCLUSIONS

The findings indicate that the novel SBRT + LDRT + sintilimab therapy is safe and promising in patients with programmed death ligand-1-positive, driver gene-negative primary metastatic NSCLC.

Stereotactic ablative radiotherapy with or without immunotherapy for early-stage or isolated lung parenchymal recurrent node-negative non-small-cell lung cancer: an open-label, randomised, phase 2 trial

BACKGROUND

Stereotactic ablative radiotherapy (SABR) is the standard treatment for medically inoperable early-stage non-small-cell lung cancer (NSCLC), but regional or distant relapses, or both, are common. Immunotherapy reduces recurrence and improves survival in people with stage III NSCLC after chemoradiotherapy, but its utility in stage I and II cases is unclear. We therefore conducted a randomised phase 2 trial of SABR alone compared with SABR with immunotherapy (I-SABR) for people with early-stage NSCLC.

METHODS

We did an open-label, randomised, phase 2 trial comparing SABR to I-SABR, conducted at three different hospitals in TX, USA. People aged 18 years or older with histologically proven treatment-naive stage IA-IB (tumour size ≤4 cm, N0M0), stage IIA (tumour size ≤5 cm, N0M0), or stage IIB (tumour size >5 cm and ≤7 cm, N0M0) as per the American Joint Committee on Cancer version 8 staging system or isolated parenchymal recurrences (tumour size ≤7 cm) NSCLC (TanyNanyM0 before definitive surgery or chemoradiotherapy) were included in this trial. Participants were randomly assigned (1:1; using the Pocock & Simon method) to receive SABR with or without four cycles of nivolumab (480 mg, once every 4 weeks, with the first dose on the same day as, or within 36 h after, the first SABR fraction). This trial was unmasked. The primary endpoint was 4-year event-free survival (local, regional, or distant recurrence; second primary lung cancer; or death). Analyses were both intention to treat (ITT) and per protocol. This trial is registered with ClinicalTrials.gov (NCT03110978) and is closed to enrolment.

FINDINGS

From June 30, 2017, to March 22, 2022, 156 participants were randomly assigned, and 141 participants received assigned therapy. At a median 33 months' follow-up, I-SABR significantly improved 4-year event-free survival from 53% (95% CI 42-67%) with SABR to 77% (66-91%; per-protocol population, hazard ratio [HR] 0·38; 95% CI 0·19-0·75; p=0·0056; ITT population, HR 0·42; 95% CI 0·22-0·80; p=0·0080). There were no grade 3 or higher adverse events associated with SABR. In the I-SABR group, ten participants (15%) had grade 3 immunologial adverse events related to nivolumab; none had grade 3 pneumonitis or grade 4 or higher toxicity.

INTERPRETATION

Compared with SABR alone, I-SABR significantly improved event-free survival at 4 years in people with early-stage treatment-naive or lung parenchymal recurrent node-negative NSCLC, with tolerable toxicity. I-SABR could be a treatment option in these participants, but further confirmation from a number of currently accruing phase 3 trials is required.

FUNDING

Bristol-Myers Squibb and MD Anderson Cancer Center Alliance, National Cancer Institute at the National Institutes of Health through Cancer Center Core Support Grant and Clinical and Translational Science Award to The University of Texas MD Anderson Cancer Center.

Combining stereotactic body radiotherapy with immunotherapy in stage IV non-small cell lung cancer

Immunotherapy has revolutionized the treatment of metastatic non-small cell lung cancer (NSCLC). Oligometastasis has been associated with better prognosis than widespread metastatic disease and may be curable by stereotactic body radiotherapy (SBRT). SBRT can stimulate immunogenic anti-tumor activity, which can be further augmented when combined with immunotherapy, such as immune checkpoint inhibitors (ICIs). Thus, its combination with immunotherapy was recognized as a promising treatment option, especially in the metastatic setting. However, the most optimal approach to combine SBRT with immunotherapy remains controversial with early clinical evidence emerging. Here, we review the current clinical evidence supporting the combination of SBRT with immunotherapy in the treatment of metastatic NSCLC. Also, we discuss the current controversies and areas for further exploration associated with this treatment strategy.

Contribution of chemotherapy in immunoradiotherapy combinations

Several preclinical data have suggested the ability of radiation therapy to modulate the intrinsic immunogenicity of cancer cells and the tumor microenvironment, with the aim of increasing responses to checkpoint inhibitors. Early results showing a restoration of checkpoint inhibitors response in patients following irradiation have generated a lot of enthusiasm around radiation therapy beyond its usual role in local disease control. Prospective clinical trials evaluating immunoradiotherapy combinations have provided proof-of-concept that radiation therapy may induce tumor-specific T immune responses in patients treated with checkpoint inhibitors. However, these results are not always reproducible, reflecting the existence of factors related to either radiation therapy, immunotherapy and/or the host, which influence the efficacy of these combinations. Anticancer chemotherapy can play a role in amplifying the immune-radiation response by promoting tumor immunogenicity and modulating the tumor microenvironment.

[Radiation-induced lymphopenia: Lymphocytes as a new organ at risk]

Taking the immune system into account in the fight against tumors has upset the cancer treatment paradigm in the 21st century. Combination treatment strategies associating radiotherapy with immunotherapy are being increasingly implemented in clinical practice. In this context, lymphocytes, whether lymphocytes infiltrating the tumour, circulating blood lymphocytes or lymphocytes residing within the lymph nodes, are key players in cellular and humoral anti-tumor immunity. The significant radiosensitivity of lymphocytes was demonstrated in the early 1990s. Along with the cells of the digestive mucosa, lymphocytes are thus among the most radiosensitive cell types in the body. Compared to the old practices of external radiotherapy, current intensity modulated treatments have allowed a considerable improvement in acute and late toxicity, at the cost of a significant increase in the volume irradiated at low doses. This is not without consequence on the incidence of radiation-induced lymphopenia, with prognostic implications for many tumor types. Thus, in order not to hinder the action of antitumor immunity and the efficacy of immunotherapy, it is essential to consider lymphocytes as a new organ at risk in its own right. In this development, based on current data from the literature, we will begin by justifying the necessary prevention of radiation-induced lymphopenia, before providing the tools currently known to apprehend lymphocytes as a new multicompartments. Finally, we will broaden the perspective by outlining ways to develop research in this area.

Challenges in synergizing radiotherapy with immunotherapy to unlock the abscopal effect in metastatic NSCLC: A systematic review

BACKGROUND

With the recent success of immunotherapy, there is a growing interest in combining radiation with immunotherapy to boost abscopal response rates. Several challenges exist in determining how to synergize these two modalities in the treatment of metastatic NSCLC.

METHODS

References for this review were identified through searches of MEDLINE/PubMed and Clinicaltrials.gov databases with the search terms "abscopal", "radiation OR radiotherapy," "NSCLC", and "lung" on the index date of July 2022 from 2000-2022. This systematic review focuses primarily on clinical papers.

DISCUSSION

Early work combining radiotherapy with immunotherapy show promise in unlocking the abscopal effect. Preliminary evidence suggests that radiotherapy regimens with <5 fractions and smaller fields may be superior to regimens with 15 fractions and larger fields. There does not appear to be enough evidence to draw conclusions about the optimal timing of radiotherapy in relation to immunotherapy or the optimal anatomical location of radiation to induce the abscopal effect. Several studies suggest selecting patients with a higher absolute lymphocyte count (ALC) and lower neutrophil-to-lymphocyte ratio (NLR) may help to further boost abscopal response rates. Furthermore, selecting tumors with programmed death ligand-1 (PD-L1) expression, mismatch repair deficiency, and higher tumor mutational burden may similarly achieve this goal. Lastly, additional work is needed to minimize and predict for severe toxicity associated with combination therapy.

Immune Checkpoint Inhibitors after Radiation Therapy Improve Overall Survival Rates in Patients with Stage IV Lung Cancer

This exploratory and retrospective study aimed to evaluate whether there is a difference in the overall survival (OS) rates of patients with stage IV lung cancer who underwent radiation therapy (RT) depending on the presence or absence of immune checkpoint inhibitors (ICIs) and the timing of their use. Eighty patients with histologically confirmed stage IV lung cancer were enrolled, and ICIs were administered to thirty (37.5%). ICIs were administered before RT and after RT in 11 and 20 patients, respectively. The median follow-up period was 6 (range: 1-37) months. Patients treated with ICIs had significantly better OS rates than those not treated with ICIs (p < 0.001). The 6-month OS rates in patients treated with and without ICIs were 76.3% and 34.5%, respectively. The group that received ICI therapy after RT had a significantly better OS rate than the group that received ICI therapy prior to RT (6-month OS: 94.7% vs. 40.0%, p < 0.001). In the multivariate analysis, performance status (0-1 vs. 2-4) and ICI use after RT were significant factors for OS (p = 0.032 and p < 0.001, respectively). Our results suggest that ICI administration after RT may prolong the OS of patients with stage IV lung cancer.

Neoadjuvant SBRT combined with immunotherapy in NSCLC: from mechanisms to therapy

The utilisation of neoadjuvant immunotherapy has demonstrated promising preliminary clinical outcomes for early-stage resectable non-small-cell lung cancer (NSCLC). Nevertheless, it is imperative to develop novel neoadjuvant combination therapy regimens incorporating immunotherapy to further enhance the proportion of patients who derive benefit. Recent studies have revealed that stereotactic body radiotherapy (SBRT) not only induces direct tumour cell death but also stimulates local and systemic antitumour immune responses. Numerous clinical trials have incorporated SBRT into immunotherapy for advanced NSCLC, revealing that this combination therapy effectively inhibits local tumour growth while simultaneously activating systemic antitumour immune responses. Consequently, the integration of SBRT with neoadjuvant immunotherapy has emerged as a promising strategy for treating resectable NSCLC, as it can enhance the systemic immune response to eradicate micrometastases and recurrent foci post-resection. This review aims to elucidate the potential mechanism of combination of SBRT and immunotherapy followed by surgery and identify optimal clinical treatment strategies. Initially, we delineate the interplay between SBRT and the local tumour immune microenvironment, as well as the systemic antitumour immune response. We subsequently introduce the preclinical foundation and preliminary clinical trials of neoadjuvant SBRT combined with immunotherapy for treating resectable NSCLC. Finally, we discussed the optimal dosage, schedule, and biomarkers for neoadjuvant combination therapy in its clinical application. In conclusion, the elucidation of potential mechanism of neoadjuvant SBRT combined immunotherapy not only offers a theoretical basis for ongoing clinical trials but also contributes to determining the most efficacious therapy scheme for future clinical application.

Immune modulation during anti-cancer radio(immuno)therapy

Cancer can affect all human organs and tissues and ranks as a prominent cause of death as well as an obstruction to increasing life expectancy. A notable breakthrough in oncology has been the inclusion of the immune system in fighting cancer, potentially prolonging life and providing long-term benefits. The concept of "immunotherapy" has been discussed from the 19th and early 20th centuries by Wilhelm Busch, William B. Coley and Paul Ehrlich. This involves distinct approaches, including vaccines, non-specific cytokines and adoptive cell therapies. However, despite the advances made in recent years, questions on how to select the best therapeutic options or how to select the best combinations to improve clinical outcomes are still relevant for scientists and clinicians. More than half of cancer patients receive radiotherapy (RT) as part of their treatment. With the advances in RT and immunotherapy approaches, it is reasonable to consider how to enhance immunotherapy with radiation and vice versa, and to investigate whether combinations of these therapies would be beneficial. In this chapter, we will discuss how the immune system responds to cancer cells and different cancer therapies with a focus on combination of RT and immunotherapy (radioimmunotherapy, RIT).

Radiation and immune checkpoint inhibitors in the treatment of oligometastatic non-small-cell lung cancer: a practical review of rationale, recent data, and research questions

The combined use of stereotactic ablative radiotherapy (SABR) and immune checkpoint inhibitors (ICIs) is an emerging treatment paradigm for oligometastatic non-small-cell lung cancer (NSCLC). Recent phase I and II trial data suggest that SABR to multiple metastases in addition to ICI use is safe and effective with promising progression-free survival and overall survival signals. There is great interest in capitalizing on combined immunomodulation from these two modalities for the treatment of oligometastatic NSCLC. Ongoing trials seek to validate the safety, efficacy, and preferred sequencing of SABR and ICI. This narrative review of the role of SABR when combined with ICI in oligometastatic NSCLC discusses the rationale for this bimodality treatment, summarizes recent clinical trial evidence, and proposes key principles of management based on the available evidence.

Advances in Radiotherapy Immune Modulation: From Bench-to-Bedside and Back Again

Pre-clinical and clinical data clearly demonstrate the immune modulatory effects of radiotherapy (RT) but clinical trials testing RT + immunotherapy have been equivocal. An improved understanding of the immune modulatory effects of RT and how practical parameters of RT delivery (site and number of lesions, dose, fractionation, timing) influence these effects are needed to optimally combine RT with immunotherapy. Additionally, increased exploration of immunotherapy combinations with RT, beyond immune checkpoint inhibitors, are needed. A "bench-to-bedside and back again" approach will improve our understanding of RT immune modulation and allow for the implementation of more effective RT + immunotherapy strategies.