Radiotherapy combined with immunotherapy: the dawn of cancer treatment

Construction of a novel radioresistance-related signature for prediction of prognosis, immune microenvironment and anti-tumour drug sensitivity in non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) is a fatal disease, and radioresistance is an important factor leading to treatment failure and disease progression. The objective of this research was to detect radioresistance-related genes (RRRGs) with prognostic value in NSCLC.

METHODS

The weighted gene coexpression network analysis (WGCNA) and differentially expressed genes (DEGs) analysis were performed to identify RRRGs using expression profiles from TCGA and GEO databases. The least absolute shrinkage and selection operator (LASSO) regression and random survival forest (RSF) were used to screen for prognostically relevant RRRGs. Multivariate Cox regression was used to construct a risk score model. Then, Immune landscape and drug sensitivity were evaluated. The biological functions exerted by the key gene LBH were verified by in vitro experiments.

RESULTS

Ninety-nine RRRGs were screened by intersecting the results of DEGs and WGCNA, then 11 hub RRRGs associated with survival were identified using machine learning algorithms (LASSO and RSF). Subsequently, an eight-gene (APOBEC3B, DOCK4, IER5L, LBH, LY6K, RERG, RMDN2 and TSPAN2) risk score model was established and demonstrated to be an independent prognostic factor in NSCLC on the basis of Cox regression analysis. The immune landscape and sensitivity to anti-tumour drugs showed significant disparities between patients categorized into different risk score subgroups. In vitro experiments indicated that overexpression of LBH enhanced the radiosensitivity of A549 cells, and knockdown LBH reversed the cytotoxicity induced by X-rays.

CONCLUSION

Our study developed an eight-gene risk score model with potential clinical value that can be adopted for choice of drug treatment and prognostic prediction. Its clinical routine use may assist clinicians in selecting more rational practices for individuals, which is important for improving the prognosis of NSCLC patients. These findings also provide references for the development of potential therapeutic targets.

Immunity/metabolism dual-regulation via an acidity-triggered bioorthogonal assembly nanoplatform enhances glioblastoma immunotherapy by targeting CXCL12/CXCR4 and adenosine-A2AR pathways

Blocking the C-X-C motif chemokine ligand-12/C-X-C motif chemokine receptor-4 (CXCL12/CXCR4) signal offers the potential to induce immunogenic cell death (ICD) and enhance immunotherapy of glioblastoma (GBM). However, traditional intracellular targeted delivery strategies and adenosine-mediated tumor immunosuppression limit its therapeutic efficacy. Herein, we present an acidity-triggered self-assembly nanoplatform based on bioorthogonal reaction to potentiate GBM immunotherapy through dual regulation of metabolism and immune pathways. AMD3100 (CXCR4 antagonist) and CPI-444 (adenosine 2A receptor inhibitor) were formulated into micelles, denoted as AMD@iNPDBCO and CPI@iNPN3, respectively. Upon administration, the pH-sensitive poly(2-azepane ethyl methacrylate) group of AMD@iNPDBCO responds to the acidic tumor microenvironment, exposing the DBCO moiety, resulting in highly efficient bioorthogonal reaction with azide group on CPI@iNPN3 to form large-sized aggregates, ensuring extracellular drug release. The combination of AMD3100 and CPI-444 contributes to ICD induction, dendritic cell maturation, and immunosuppressive milieu alleviation by reducing tumor-associated macrophages, myeloid-derived suppressor cells, and regulatory T cells, leading to a robust antitumor response, thereby significantly prolonging survival in orthotopic GBM-bearing mice. Furthermore, the nanoplatform remarkably amplifies immuno-radiotherapy by potently evoking cytotoxic CD8+ T cell priming, and synergized with immune checkpoint blockade by delaying CD8+ T cell exhaustion. Our work highlights the potential of the in situ assembly nanoplatform tailored for delivery of extracellular-targeted therapeutic agents for boosting GBM immunotherapy.

Combination of radiotherapy and ICIs in advanced hepatocellular carcinoma: A systematic review of current evidence and future prospects (Review)

Hepatocellular carcinoma (HCC) is a global health concern because of its rising prevalence and high fatality rates. Conventional treatments for advanced HCC (aHCC) have limited success, emphasizing the need for novel treatment options. Radiotherapy (RT) treatments, such as stereotactic body radiation and proton therapy, improve local tumor management via precision targeting. Moreover, immune checkpoint inhibitors (ICIs) that target the programmed cell death protein 1(PD-1)/PD ligand 1 (PD-L1) and cytotoxic T lymphocyte associated protein 4 (CTLA-4) pathways have promise for systemic antitumor effectiveness. The combination of RT and ICIs takes advantage of their complementary mechanisms: RT kills immunogenic cells and controls the tumor microenvironment to increase antigen presentation, whereas ICIs enhance and maintain antitumor immune responses. This combination enhances tumor regression and immune response in aHCC, improving response rate and progression-free survival with manageable safety. The present review aimed to summarize the rationale for combining RT + ICIs in patients with aHCC and clinical outcomes, as well as ways to enhance this combination technique. The combination of these models is a promising technique for improving outcomes for patients with aHCC and warrants further investigation.

Extracellular vesicles as the common denominator among the 7 Rs of radiobiology: From the cellular level to clinical practice

Extracellular vesicles (EVs) are lipid-bound particles released by tumor cells and widely explored in cancer development, progression, and treatment response, being considered as valuable components to be explored as biomarkers or cellular targets to modulate the effect of therapies. The mechanisms underlying the production and profile of EVs during radiotherapy (RT) require addressing radiobiological aspects to determine cellular responses to specific radiation doses and fractionation. In this review, we explore the role of EVs in the 7 Rs of radiobiology, known as the molecular basis of a biological tissue response to radiation, supporting EVs as a shared player in all the seven processes. We also highlight the relevance of EVs in the context of liquid biopsy and resistance to immunotherapy, aiming to establish the connection and utility of EVs as tools in contemporary and precision radiotherapy.

Circular RNAs in glioma progression: Fundamental mechanisms and therapeutic potential: A review

Gliomas are the most common primary malignant brain tumors, characterized by aggressive invasion, limited therapeutic options, and poor prognosis. Despite advances in surgery, radiotherapy, and chemotherapy, the median survival of glioma patients remains disappointingly low. Therefore, identifying glioma-associated therapeutic targets and biomarkers is of significant clinical importance. Circular RNAs (circRNAs) are a class of naturally occurring long non-coding RNAs (lncRNAs), notable for their stability and evolutionary conservation. Increasing evidence indicates that circRNA expression is dysregulated in gliomas compared to adjacent non-tumor tissues and contributes to the regulation of glioma-related biological processes. Furthermore, numerous circRNAs function as oncogenes or tumor suppressors, mediating glioma initiation, progression, and resistance to temozolomide (TMZ). Mechanistically, circRNAs regulate glioma biology through diverse pathways, including acting as miRNA sponges, binding RNA-binding proteins (RBPs), modulating transcription, and even encoding functional peptides. These features highlight the potential of circRNAs as diagnostic and prognostic biomarkers, as well as therapeutic targets for glioma. This review summarizes the dysregulation and functions of circRNAs in glioma and explores key mechanisms through which they mediate tumor progression, including DNA damage repair, programmed cell death (PCD), angiogenesis, and metabolic reprogramming. Our aim is to provide a comprehensive perspective on the multifaceted roles of circRNAs in glioma and to highlight their potential for translational application in targeted therapy.

In-Depth Analysis of the Necessity and Optimization Strategies for Adjuvant Radiotherapy Following Neoadjuvant Immunotherapy in the New Era of Esophageal Cancer Treatment

As immunotherapy rises to prominence in cancer treatment, the therapeutic approach to esophageal cancer is undergoing significant transformations. This review emphasizes the necessity and optimization pathways for adjuvant postoperative radiotherapy after neoadjuvant therapy in patients with esophageal cancer in the immunotherapy era. Initially, we review the advancements in neoadjuvant treatment strategies. Subsequently, we evaluate the role of postoperative radiotherapy and the latest advancements in radiotherapy target volume definition and dose optimization following neoadjuvant therapy, as well as the implications of tumor immunotherapy on postoperative radiotherapy strategies. In conclusion, in the new era of immunotherapy, postoperative radiotherapy following neoadjuvant therapy for esophageal cancer holds significant value. Optimization strategies should follow individualized treatment principles and comprehensively consider tumor biology, patient status, and treatment resources to achieve optimal therapeutic outcomes and quality of life, thereby driving continuous innovation in esophageal cancer treatment.

Application potential of injectable hydrogels in the post-surgical window period following tumor surgery

Chemotherapy is one of the primary modalities for the treatment of malignant diseases. The outcomes, however, are different between tumors of various origins, which hinder clinical applications. The advantages of chemotherapies in patients with hematological lesions are more obvious than those seen in solid tumors. This might be attributed to the availability of drug concentration and exposure time. Based on this phenomenon, we hypothesis that localized drug administration is expected to be more potential for solid tumors, particularly for the residual tumors in post-operative "window period". The presence of residual tumors after surgical resection are the major factors leading to tumor recurrence after surgery. The methods of dealing with this problem are yet to be found. Conventional chemotherapies are scarcely applied in the post-surgical window period due to their unselected and unexpected side effects. This article studied the advantages and disadvantages of prominent formulations currently utilized in the field of local implantation in cancer treatment, with the notable superiority of injectable hydrogel platforms being most appealing. These platforms not only enhance wound healing of the patients with less side effects, during the "window period" following tumor surgery, but also effectively eradicate residual tumors by facilitating the establishment of a favorable microenvironment. Additionally, the challenges seen in this field and future directions are discussed, which is expected to provide insights for pharmaceutical professionals and clinical applications.

Carbon ion irradiation mobilizes antitumor immunity: from concept to the clinic

Carbon ion radiotherapy (CIRT), a type of particle therapy, is at the forefront of clinical oncology treatments due to its superior physical properties and biological performance. Although CIRT has demonstrated outstanding therapeutic outcomes in clinical settings, the biological mechanisms underpinning its effects, particularly its immunogenic potential and the superiority of its induced antitumor immune response compared to photon radiotherapy, remain areas of active investigation. This review summarizes the latest research progress on the mechanisms of antitumor immune responses triggered by CIRT and discusses preclinical and clinical studies related to combined CIRT and immunotherapy (CCIT). Against the backdrop of extensive research and significant clinical efficacy achieved by combining radiotherapy with immunotherapy, this review provides a theoretical foundation for a better understanding of the superior tumor cell-killing effects of CIRT and the underlying immunological mechanisms. Further insights into the factors affecting the efficacy, toxic effects, and developmental limitations of this combination therapy mode will be instrumental in guiding the conduction of CCIT studies.

Developments in pancreatic cancer emerging therapies, diagnostic methods, and epidemiology

Pancreatic cancer is still one of the deadliest malignancies, characterised by late-stage diagnosis, aggressive biology, and considerable resistance to conventional treatments. Despite improvements in understanding the molecular mechanisms and innovations in treatment, the overall survival remains abysmal: fewer than 9 % of patients survive beyond 5 years. By 2030, PC is predicted to become the second leading cause of cancer-related deaths in the U.S. owing to chemoresistance, rapid metastatic spread, and limited effective immunotherapeutic choices. This review highlights current progress in this field, including epidemiology, risk factors, diagnostic tools, and emerging biomarkers. Recent progress in genetic and molecular profiling has provided important information about pancreatic cancer. It has identified key mutations in genes like KRAS, TP53, CDKN2A, and SMAD4 that play a major role in driving the disease. Such revelations have provided the impetus to explore novel targeted therapies against these mutations. Furthermore, the advances in liquid biopsies incorporating circulating tumour cells, circulating tumour DNA, and exosomes hold substantial promise for early diagnosis, treatment response monitoring, and detection of minimal residual disease-any of which could radically transform PC management. While very limited options for the treatment of advanced-stage PC remain, the only potential curative treatment is surgery, yet only 10-15 % of patients are diagnosed with potentially resectable disease. Researchers are looking into new methods to help more patients qualify for surgery. This involves using chemotherapy and radiotherapy to reduce the size of the tumor before the operation. New chemotherapy treatments like FOLFIRINOX (which includes 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin) have improved results for some patients, but they can still cause significant side effects. Immunotherapy, though revolutionary in other cancers, has had limited success in PC due to the tumour's immunosuppressive microenvironment. Researchers are looking into using immune checkpoint inhibitors together with chemotherapy, radiation, and drugs that target the surrounding tissue to improve the body's immune response. There is also considerable excitement surrounding personalised approaches with adoptive cell therapies such as CAR-T cells and TILs, which are trialled with early evidence of potential efficacy. Attempts are also being made to address the dense desmoplastic stroma of the tumour that characterises PC. Drugs that can fight resistance or new medicines that might affect the tumor environment, stop changes in surrounding tissues, and improve how drugs are delivered have shown some potential in laboratory tests so far. Nanoparticle-based drug delivery systems are also being developed to improve the bioavailability and targeted delivery of chemotherapy.

Musculoskeletal abscopal effect: a review of the important imaging findings and their clinical relevance

The abscopal effect is a rare but important phenomenon in which targeted therapy of the primary tumor, mainly radiation therapy, leads to the regression of malignant cells at distant sites from the primary tumor and outside the field of treatment. Radioembolization is a developing area of interventional oncology, typically involving microscopic radioactive spheres loaded with yttrium-90. The abscopal effect on distant bone metastases has been previously reported in patients following palliative radiotherapy; however, it has also been observed with more targeted radiation treatments, such as yttrium-90, primarily outside the musculoskeletal system. Musculoskeletal radiologists should be familiar with the abscopal effect, as the indications for radiation therapy are on the rise, and recent advancements in immune therapy have resulted in the induction of the abscopal effect. Herein, we present a case of the abscopal effect in musculoskeletal metastatic disease following targeted radioembolization. We also review the literature on the abscopal effect involving metastatic bone lesions resulting from different types of cancer therapy. Finally, we present recent advancements in cancer treatment with the aim of utilizing this effect.

PAI-1-driven SFRP2high cancer-associated fibroblasts hijack the abscopal effect of radioimmunotherapy

The abscopal effect of radioimmunotherapy, wherein tumor shrinkage occurs beyond the irradiated field, is therapeutically promising but clinically rare. The mechanisms underlying this effect remain elusive. Here, in vivo genome-wide CRISPR screening identifies SFRP2 as a potential stromal regulator of the abscopal effect. SFRP2 exhibits cancer-associated fibroblast (CAF)-specific expression and radioimmunotherapy-mediated upregulation in unirradiated tumors. Conditional Sfrp2 knockout in CAFs boosts the abscopal effect by rewiring the vascular-immune microenvironment to promote CD8+ T cell recruitment to unirradiated tumors. In vivo lineage tracing reveals that elevated SFRP2 correlates with radioimmunotherapy-driven pericyte lineage commitment. Serum proteomics reveals that irradiated-tumor-secreted PAI-1 triggers distant tumor pericyte cell-fate transition into SFRP2high CAFs via the LRP1/p65 axis. Pharmacologically blocking SFRP2 or PAI-1 enhances the abscopal effect in humanized patient-derived xenograft models. Our findings collectively illustrate that PAI-1-induced SFRP2high CAFs serve as critical stromal regulator to hijack the abscopal effect, providing promising targets for enhancing radioimmunotherapy effectiveness.

Mechanisms of the FLASH effect: current insights and advances

Radiotherapy is a fundamental tool in cancer treatment, utilized in over 60% of cancer patients during their treatment course. While conventional radiotherapy is effective, it has limitations, including prolonged treatment durations, which extend patient discomfort, and toxicity to surrounding healthy tissues. FLASH radiotherapy (FLASH-RT), an innovative approach using ultra-high-dose-rate irradiation, has shown potential in selectively sparing normal tissues while maintaining unaltered tumor control. However, the precise mechanisms underlying this "FLASH effect" remain unclear. This mini-review explores key hypotheses, including oxygen depletion, radical-radical interactions, mitochondrial preservation, differential DNA damage repair, and immune modulation. Oxygen levels significantly affect tissue response to radiation by promoting radical recombination, preserving mitochondrial function, and differentially activating DNA repair pathways in normal versus tumor tissues. However, the extent to which oxygen depletion contributes to the FLASH effect remains debated. Additionally, FLASH-RT may modulate the immune response, reducing inflammation and preserving immune cell function. To further enhance its therapeutic potential, FLASH-RT is increasingly being combined with complementary strategies such as radioprotectors, immunomodulators, and nanotechnology platforms. These combinations aim to amplify tumor control while further reducing normal tissue toxicity, potentially overcoming current limitations. Despite promising preclinical evidence, the exact mechanisms and clinical applicability of FLASH-RT require further investigation. Addressing these gaps is crucial for optimizing FLASH-RT and translating its potential into improved therapeutic outcomes for cancer patients. Continued research is essential to harness the full benefits of the FLASH effect, offering a paradigm shift in radiation oncology.

Attenuated Salmonella carrying IL-21 overexpression plasmid enhances radiotherapy efficacy in a preclinical model of melanoma

Melanoma, known for its aggressive behavior and tendency to metastasize to the brain and lungs, is a formidable challenge in oncology. Radiotherapy is a potent treatment for localized solid tumors, effective against both intracranial and extracranial metastases. Yet, some melanoma patients exhibit substantial resistance to radiotherapy, with the underlying mechanisms of this resistance remaining elusive. While radiotherapy can stimulate the infiltration of immune cells, thereby triggering a range of immunostimulatory effects, it can also suppress the tumor microenvironment (TME), limiting its effectiveness. In physiological conditions, cytokines inhibit the activity of immunosuppressive cells through paracrine and autocrine signaling, while also activating immune cells to boost antitumor responses. Here, we found that Interleukin (IL)-21 expression was higher in the mice with good radiotherapy response to melanoma than in the mice with poor radiotherapy response. Interestingly, we also observed the higher infiltration of M2 TAMs and lower CD8+ T cells in the group with poor radiotherapy response. To tackle this issue, we explored the therapeutic potential of a plasmid encoding IL-21, delivered via attenuated Salmonella, in mice bearing melanomas. Our findings revealed that IL-21 administration significantly reduced M2 TAMs infiltration and enhanced CD8+ T cells infiltration and granzyme B (GZMB) expression within melanoma tumors. Most importantly, the combination of IL-21 with radiotherapy led to markedly tumor reduction compared to either treatment alone. This research highlights the potential of IL-21 as a valuable adjunct to radiotherapy in the treatment of melanoma, presenting a promising strategy for enhancing antitumor immune responses and optimizing patient outcomes.

Immunomodulatory nanoplatforms with multiple mechanisms of action in cancer treatment

Cancer immunotherapies have transformed oncology by utilizing the immune system to target malignancies; however, limitations in efficacy and potential side effects remain significant challenges. Nanoparticles have shown promise in enhancing drug delivery and improving immune activation, with the potential for numerous modifications to tailor them for specific environments or targets. Integrating nanoplatforms offers a promising avenue to overcome these hurdles, enhancing treatment outcomes and reducing adverse effects. By improving drug delivery, targeting, and immune modulation, nanoplatforms can unlock the full potential of cancer immunotherapy. This review explores the role of nanoplatforms in addressing these limitations and enhancing cancer immunotherapy outcomes, examining various types of nanoplatforms. Understanding the mechanisms of immunomodulation through nanoplatform deliveries is crucial. We discuss how these nanoplatforms interact with the tumor microenvironment, modulate tumor-associated macrophages and regulatory T cells, activate immune cells directly, enhance antigen presentation, and promote immunological memory. Further benefits include combination approaches integrating nanoplatforms with chemotherapy, radiotherapy, and phototherapy. Immunotherapy is a relatively new approach, but numerous clinical studies already utilize nanoplatform-based immunotherapies with promising results. This review aims to provide insights into the potential of nanoplatforms to enhance cancer immunotherapy and pave the way for more effective and personalized treatment strategies.

Water-Dispersible MXene Governs Glycolysis for Cancer Synergistic Therapy

Targeted delivery of glucose oxidase (GOx) using MXene remains a great challenge due to its poor dispersion and susceptibility to oxidation, and the hypoxia and high glutathione (GSH) contents make the situation even more worrying. Herein, a bovine serum albumin-mediated non-chemical modification strategy is developed, endowing titanium carbide MXene with long-time water-dispersion and further integrating it as a glycolysis-controllable therapy system without any chemotherapeutic agents. The system also constructs an effective O2 cycling and GSH degradation pathway, which fundamentally adjusts the tumor microenvironment and greatly elevates both in vivo and in vitro therapy effects. Reactive oxygen species are also generated and disrupt the balance of oxidative stress. Moreover, the reduced efficiency of mitochondrial energy production significantly inhibits the level of glycolysis and hinders energy supply. The study presents an effective cancer treatment combining starvation/photothermal therapy, which has superior anti-cancer effects due to the dual effects of reducing glucose levels and diminishing cellular energy production capacity.

Concurrent immunotherapy improves progression-free survival but increases toxicity in unresectable stage III NSCLC

BACKGROUND

The PACIFIC trial established consolidation immunotherapy (IO) after concurrent chemoradiotherapy as the standard treatment for unresectable stage III non-small cell lung cancer (NSCLC) by improving survival. However, the optimal timing of IO remains debated. This study analyzes the survival benefits and risks of IO concurrent with radiotherapy (RT) versus IO following RT.

METHODS

A systematic search of multiple databases identified studies comparing IO concurrent with RT and IO following RT in unresectable stage III NSCLC. Data on overall survival (OS), progression-free survival (PFS), and adverse events (AEs) were analyzed using the "meta" package in R, along with a single-center cohort study.

RESULTS

The meta-analysis showed improved PFS with IO concurrent with RT, with significant differences at 1 year (69.5 % vs 57.6 %) and 1.5 years (56.3 % vs 45.7 %). OS was slightly better with IO following RT, with fewer severe AEs (≥grade 3: 52.6 % vs 37.2 %). A single-center cohort validated superior PFS for the concurrent group (HR = 2.039, 95 % CI: 1.014-4.322, P = 0.046). Shorter intervals between RT and IO were associated with better PFS in the following group (HR = 1.002, 95 % CI: 1.001-1.003, P = 0.002).

CONCLUSION

Concurrent IO with RT during chemoradiotherapy significantly improved PFS in unresectable stage III NSCLC, though OS did not benefit due to a higher incidence of severe AEs. Earlier IO initiation after RT was associated with better PFS. Our findings suggest the potential benefits of concurrent IO for selected patients.

The role of cGAS-STING in remodeling the tumor immune microenvironment induced by radiotherapy

The activation of the cGAS-STING pathway occurs when tumor cell DNA is damaged by ionizing radiation. Once triggered, this pathway reshapes the tumor immune microenvironment by promoting the maturation, activation, polarization, and immune-killing capacity of immune cells, as well as by inducing the release of interferons and the expression of immune-related genes. In addition, the gut microbiota and various mechanisms of programmed cell death interact with the cGAS-STING pathway, further influencing its function in remodeling the immune microenvironment after radiotherapy. Therefore, investigating the mechanisms of the cGAS-STING pathway in reshaping the tumor immune microenvironment post-radiotherapy can not only optimize the efficacy of combined radiotherapy and immunotherapy but also provide new research directions and potential targets for cancer treatment.

Combination therapy with immune checkpoint inhibitors in colorectal cancer: Challenges, resistance mechanisms, and the role of microbiota

Colorectal cancer (CRC) is still one of the leading causes of cancer deaths worldwide. Even though there has been progress in cancer immunotherapy, the results of applying immune checkpoint inhibitors (ICIs) have been unsatisfactory, especially in microsatellite stable (MSS) CRC. Single-agent ICIs that target programmed cell death-1 (PD-1)/ PD-L1, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), T cell Ig- and mucin-domain-containing molecule-3 (TIM-3), and lymphocyte activation gene (LAG)-3 have emerged as having specific benefits. However, many primary and secondary resistance mechanisms are available in the tumor microenvironment (TME) that prevent it from happening. Combination strategies, such as the use of anti-PD-1 and anti-CTLA-4, can be effective in overcoming these resistance pathways, but toxicities remain a significant concern. Moreover, ICIs have been integrated with various treatment modalities, including chemotherapy, radiotherapy, antibiotics, virotherapy, polyadenosine diphosphate-ribose polymerase (PARP) inhibitors, and heat shock protein 90 (HSP90) inhibitors. The outcomes observed in both preclinical and clinical settings have been encouraging. Interestingly, manipulating gut microbiota via fecal microbiota transplantation (FMT) has been identified as a new strategy to increase the efficacy of immunotherapy in CRC patients. Therefore, integrating ICIs with other treatment approaches holds promise in enhancing the prognosis of CRC patients. This review focuses on the unmet need for new biomarkers to select patients for combination therapies and the ongoing work to overcome resistance and immune checkpoint blockade.

Chemotherapy-Free Treatment with Radiotherapy and Immunotherapy for Locally Advanced Non-Small Cell Lung Cancer

Background: Concurrent chemoradiotherapy (CRT) followed by immunotherapy is a standard treatment for locally advanced non-small cell lung cancer (LA-NSCLC), yet many patients are ineligible due to treatment-related toxicity or poor functional status. Chemotherapy-free approaches using radiotherapy (RT) and immunotherapy may offer a safer and equally effective alternative in select patient populations. Methods: A comprehensive literature review was conducted using PubMed, Google Scholar, and relevant conference proceedings focusing on trials between 2000 and 2024. Studies investigating chemotherapy-free regimens combining RT and immunotherapy in LA-NSCLC were analyzed, with emphasis on clinical outcomes, biomarker use, treatment sequencing, radiation dose/fractionation, and safety. Results: Multiple Phase I/II trials reported promising efficacy with one-year progression-free survival (PFS) ranging from 39% to 76%. Toxicity was generally acceptable, though higher-grade adverse events were more frequent in older, frail populations. Trials integrating PD-L1 expression, tumor mutational burden (TMB), and circulating tumor DNA (ctDNA) showed potential for improved patient stratification. Variation in immunotherapy timing (induction, concurrent, or consolidation) and radiation schedules highlight the need for optimization. Conclusions: Chemotherapy-free regimens represent a promising treatment strategy for patients with LA-NSCLC, especially those that are ineligible for standard CRT. Biomarker-driven patient selection and the rational integration of RT and immunotherapy are critical to improving outcomes. Randomized trials are warranted to establish the efficacy and safety of these emerging approaches.

Nanoassemblies loaded with low-dose paclitaxel can enhance the response of lung cancer immunotherapy by activating dendritic cells

Background

The immune tolerance of the tumor immune microenvironment (TIME) restricts the response to immune checkpoint inhibitors (ICIs). Targeted activation of dendritic cells (DCs) in the TIME seems to be a scheme for improving the therapeutic effect of ICIs treatment. The purpose of this study was to utilize nanotechnology to reprogram the immunosuppressive tumor immune microenvironment in situ, improving the response of ICIs to lung cancer.

Methods

In this study, a folic acid (FA)-modified nanoassembly (NA) loaded with low-dose paclitaxel (PTX) (FA-PTX NA), self-assembled by distearoylphosphatidylethanolamine-methoxy polyethylene glycol 2000-folic acid (DSPE-mPEG2000-FA) and PTX, was designed to reprogram the DC function of the TIME to sensitize cells to cancer immunotherapy. The characteristics of FA-PTX NAs were studied, and the cytotoxicity, cellular uptake, and DC stimulation of FA-PTX NAs were evaluated in vitro using a Lewis lung carcinoma (LLC) cell line and bone marrow-derived cells (BMDCs). Following this, the effect of the reprogrammed TIME and on the sensitization to immunotherapy in vivo were examined in a C57BL/6 mouse LLC subcutaneous xenograft model.

Results

The prepared FA-PTX NAs exhibited a slightly negative surface charge, appropriate size and shape, good drug release profiles, and high drug encapsulation efficiency and blood compatibility. The FA-PTX NAs were effectively uptaken by bone BMDCs, increasing the activation and expression of the costimulatory factor of BMDCs in vitro. In the LLC xenograft model treated with intravenous injection of FA-PTX NAs, the numbers of CD4+ and CD8+ T cells in the TIME increased significantly, the killing activity of tumor-specific cytotoxic T lymphocytes (CTLs) was significantly enhanced, and at the same time, the concentration of transforming growth factor β (TGF-β) decreased significantly. Furthermore, the infiltrated CD8+ T cells in TIME were mainly distributed in the tumor parenchyma. The combination of FA-PTX NAs and ICIs effectively inhibited the growth of LLC xenograft tumor, demonstrating a greater effect than that of ICIs alone. Moreover, it was found that apoptosis induction, increase in CD4+ and CD8+ T-cell infiltration, and improvement in the distribution of CD8+ T cells were involved in the anticancer mechanism of this combination treatment.

Conclusions

The NA loaded with low-dose PTX can reprogram the DC function in the TIME and exert a synergistic anticancer effect with ICIs in lung cancer treatment. Increased sensitization to ICI therapy as stimulated by PTX-enhanced NAs has potential applications in lung cancer immunotherapy.

Unveiling Cellular Responses and Underlying Immune Effects Induced by Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT) is an emerging modality for cancer treatment. Although its concept was proposed in the last century, progress has been relatively slow because limitations in neutron source technology and boron compounds. In recent years, with the increased availability of neutron devices and improvements in boron compounds, the radiobiological effects of BNCT have been investigated more deeply, leading to a surge of research findings in the field. Therefore, a systematic review of the current status of BNCT is particularly warranted. In this review, we integrate the latest studies to provide a comprehensive and detailed description of the direct and indirect mechanisms by which BNCT induces cell killing, as well as the subsequent cellular responses. More importantly, we propose that BNCT exhibits a stronger immunologic foundation and immunogenicity than traditional radiation therapy, indicating significant potential for its combined application with immunotherapy. These results offer a robust theoretical foundation for the future clinical use of BNCT and indicate that continued investigation of BNCT in conjunction with immunotherapy may pave the way for more advanced cancer treatment strategies.

Sonrotoclax (BGB-11417) synergistically amplifies the radiotherapy-elicited anti-tumor immune response

Escape from apoptosis is one of the main hallmarks of cancer. The imbalance of BCL-2 family members is a key factor leading to radiotherapy resistance. Targeting BCL-2 can overcome radiotherapy resistance by promoting apoptosis. Nevertheless, the function of BCL-2 in regulating the tumor immune microenvironment (TIME) is still not well understood. Herein, we discovered that the specific BCL-2 inhibitor sonrotoclax (BGB-11417) boosted the effectiveness of radiotherapy in an immune-mediated manner. Using flow cytometry, we found that sonrotoclax combined with radiotherapy polarized tumor-associated macrophages (TAMs) toward the M1-type and promoted the infiltration of Gzmb+ CD8+ T cells into the tumor. Mechanistically, we demonstrated that the combination of sonrotoclax and radiotherapy induced immunogenic ferroptosis of cancer cells by inhibiting GPX4 expression, released tumor-associated damage-associated molecular patterns (DAMPs) and subsequently activated the NF-κB pathway in TAMs. Moreover, the combination therapy also led to aberrant cytosolic DNA abundance and activated the cGAS-STING pathway in cancer cells, leading to the release of type I interferons and enhanced activation of CD8+ T cells. Meanwhile, the activation of cGAS-STING pathway also led to the upregulation of PD-L1 expression. Further combination of sonrotoclax and radiotherapy plus anti-PD-L1 exerted the most significant anti-tumor effects. Overall, our study indicated that sonrotoclax enhanced the anti-tumor immune response of radiotherapy through non-apoptotic roles of BCL-2, and shed light on the further clinical evaluation of the triple combination therapy of sonrotoclax, radiotherapy and immunotherapy.

Radiotherapy-induced alterations in tumor microenvironment: metabolism and immunity

Tumor metabolism plays a pivotal role in shaping immune responses within the tumor microenvironment influencing tumor progression, immune evasion, and the efficacy of cancer therapies. Radiotherapy has been shown to impact both tumor metabolism and immune modulation, often inducing immune activation through damage-associated molecular patterns and the STING pathway. In this study, we analyse the particular characteristics of the tumour metabolic microenvironment and its effect on the immune microenvironment. We also review the changes in the metabolic and immune microenvironment that are induced by radiotherapy, with a focus on metabolic sensitisation to the effects of radiotherapy. Our aim is to contribute to the development of research ideas in the field of radiotherapy metabolic-immunological studies.

Cytokine-based immunotherapy for gastric cancer: targeting inflammation for tumor control

Emerging cancer immunotherapy methods, notably cytokine-based ones that modify immune systems' inflammatory reactions to tumor cells, may help slow gastric cancer progression. Cytokines, tiny signaling proteins that communicate between immune cells, may help or hinder cancer growth. Pro-inflammatory cytokines encourage tumor development, whereas antitumor ones help the host reject cancer cells. This study considers cytokine-targeted methods for gastric cancer pro-inflammatory and antitumor immune responses. Researchers want to renew immune cells like cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells by delivering cytokines like interleukin-2 (IL-2), interferons (IFNs), and tumor necrosis factor-alpha (TNF-α) to activate inflammatory pathways and combat tumors. Since cytokines have significant pleiotropic effects, their therapeutic use is difficult and may cause excessive systemic inflammation or immunological suppression. This review covers current advancements in synthetic cytokines, cytokine-conjugates, and local administration of these aimed to enhance the therapeutic index: increase the potential to kill cancer cells while minimizing off-target damage. The study examines the relationship between cytokines and tumor microenvironment (TME), revealing the role of immunosuppressive cytokines like IL-10 and transforming growth factor-beta (TGF-β) in promoting an immune-evasive phenotype. These results suggest that inhibitory pathway targeting, and cytokine-based therapy may overcome resistance mechanisms. Cytokine-based immunotherapies combined with immune checkpoint inhibitors are predicted to change gastric cancer therapy and rebuild tumor-immune microenvironment dynamics, restoring antitumor immunity. Comprehensive data from current clinical studies will assist in establishing the position of these treatments in gastric cancer.

Bionic gene delivery system activates tumor autophagy and immunosuppressive niche to sensitize anti-PD-1 treatment against STK11-mutated lung adenocarcinoma

Clinical data have shown that Serine/Threonine Kinase 11 (STK11) mutation may be associated with an immunosuppressive tumor microenvironment (ITEM) and poor prognosis and failure of anti-PD-1 (αPD1) treatment in non-small cell lung cancer (NSCLC). To explore the potential of restoring STK11 protein in immunotherapy, a bionic gene delivery system was prepared by coating the STK11-encoded DNA-cationic polymer complex core with the tumor cell membrane, termed STK11@PPCM. STK11@PPCM could specifically bind with NSCLC cells and achieve precise delivery of STK11-encoded DNA. The released DNA effectively restored the STK11 protein expression, consequently reactivating autophagy and immunogenic cell death (ICD) in cancer cells. The liberated damage-associated molecular patterns (DAMPs) and autophagosome induced dendritic cells (DCs) maturation, which in turn enhanced CD8 + T cell infiltration, M1 macrophage polarization, and proinflammatory factor expression, thereby reversing the ITEM. Moreover, STK11@PPCM was also found to improve the sensitivity of cancer cells to αPD1 by increasing the expression of PD-L1, which was confirmed in STK11-mutated NSCLC cell xenografted mouse models, constructed by CRISPR-Cas9 knockout technology. This work demonstrated for the first time that restoration of functional STK11 can effectively reverse ITME and boost αPD1 efficacy in NSCLC, offering a new therapeutic approach for STK11-mutated lung adenocarcinoma in clinic.

A Metformin-Based Multifunctional Nanoplatform as a DNA Damage Amplifier for Maximized Radio-Immunotherapy to Overcome Radiotherapy Resistance

Radiotherapy (RT) has been highlighted to be an effective strategy for antitumor immunity activation by causing direct DNA damages, but it generally suffers from low response rates due to the compromised cytosolic DNA (cDNA) recognition by cyclic GMP-AMP synthase (cGAS). Simultaneous DNA repair and clearance system regulation for enhanced cDNA accumulation is a useful approach to improve immune response rates, which remains seldom reported to our knowledge. Here, we report the construction of a metformin (MET)-based multifunctional nanocomplex, CS-MET/siTREX1 (CSMT), consisting of biguanide-decorated CS (CS-MET) as the vector and 3'-5' DNA exonuclease TREX1 siRNA (siTREX1) as the therapeutic gene for RT-induced antitumor immunity enhancement by amplifying the initial DNA damage signals. The uniqueness of this study is the development of CSMT as a specific DNA damage amplifier to promote cDNA accumulation for maximizing radio-immunotherapy and circumventing RT resistance. Specifically, the CSMT nanocomplexes show not only enhanced gene transfection efficiency by MET modification but also synergistic therapeutic effects including MET's inhibition on DNA repair and siTREX1's attenuation on cDNA clearance, which leads to the greatest inhibitory effect in a Hepa1-6 proximal/distal tumor model with a high tumor growth inhibition (TGI) value of 99.1% for the primary tumor and significantly compromised distal tumor growth by inducing immunogenic cell death (ICD), promoting tumor-associated neutrophil (TAN) polarization, and stimulating tumor-specific memory T-cell generation. Overall, the CSMT nanocomplexes developed herein hold great translatable promises for overcoming RT resistance in clinics.

Efficacy and safety of concurrent programmed cell death protein 1 inhibitor and definitive radiotherapy with immunonutrition support in esophageal squamous cell cancer: a phase II multicenter clinical trial

BACKGROUND

Esophageal cancer is one of the most common malignant tumors, with China accounting for 50% of the world's total incidence. Concurrent chemoradiotherapy (cCRT) with platin-based dual-drug regimen is the standard treatment for inoperable, locally advanced esophageal cancer in patients with a good performance status. However, certain patients possess risk factors that heighten toxicity and reduce their tolerance to cCRT, thereby challenging the feasibility of standard treatment. This study evaluates an alternative therapeutic approach combining programmed cell death protein 1 inhibitor (PD-1 inhibitor), definitive radiotherapy, and immunonutrition support for patients with unresectable non-metastatic esophageal cancer expressing PD-L1 who are intolerant to cCRT.

METHODS

This is a phase II, single-arm, multicenter clinical trial involving patients with histologically confirmed unresectable esophageal squamous cell carcinoma (ESCC), who exhibit positive PD-L1 and are unsuitable for cCRT. Participants will receive a total radiotherapy dose of 50-60 Gy in 25-30 fractions, sintilimab (200 mg every three weeks), alongside, supplemented by enteral nutritional emulsion (600-1600 ml/day). The primary endpoint is the 1-year progression-free survival rate, with secondary endpoints including objective response rate, overall survival and incidence of adverse events.

CONCLUSION

This research has the potential to redefine treatment for inoperable ESCC patients who cannot tolerate conventional therapies. By evaluating a less toxic regimen that combines immunotherapy, radiotherapy, and nutritional support, we aim to determine if this approach can improve both survival rates and quality of life. The synergistic effects of immunonutrition support and PD-1 inhibitor will also be explored.

TRIAL REGISTRATION

NCT06342167.

Efficacy and safety of radiotherapy combined with immune checkpoint inhibitors for advanced or unresectable hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND

To evaluate the efficacy and safety of radiotherapy with immune checkpoint inhibitors (ICIs), with or without anti-vascular endothelial growth factor (anti-VEGF) agents, in the treatment of advanced or unresectable hepatocellular carcinoma (HCC).

METHODS

Databases including Web of Science, PubMed, Embase, Cochrane Library databases, American Society of Clinical Oncology, and European Society for Medical Oncology were systematically searched. The search included publications up to August 31, 2024. Primary outcome measures included objective response rate (ORR), disease control rate (DCR), incidence of treatment-related adverse events (TRAEs), and TRAEs (grade ≥3).

RESULTS

Twenty-one articles were included in this study (927 participants). Following RECIST 1.1, for external radiotherapy combined with ICIs, the ORR and DCR were 56 % (95 % CI 0.48-0.64, I2=65.91 %) and 88 % (95 % CI 0.77-0.96, I2=87.19 %), respectively; for yttrium-90 combined with ICI, they were 31 % (95 %CI 0.20-0.43, I2=0 %) and 73 % (95 %CI 0.48-0.92, I2=75.23 %), respectively. According to CTCAE criteria, for external radiotherapy combined with ICIs, the incidence of TRAEs (all grades) was 95 % (95 % CI 0.89-0.98, I2=70.79 %), and the incidence of TRAEs (grades ≥3) was 35 % (95 % CI 0.23-0.48, I2=87.54 %); for yttrium-90 combined with ICIs, they were 78 % (95 %CI 0.48-0.98, I2=88.15 %) and 22 % (95 %CI 0.04-0.47, I2=83.69 %), respectively. Subgroup analyses indicated that sequential therapy demonstrated a higher DCR than concurrent therapy, while the combination of intensity-modulated radiotherapy, ICIs, and anti-VEGF agents showed improved efficacy but was associated with increased toxicity.

CONCLUSIONS

Radiotherapy combined with ICI demonstrates substantial efficacy and manageable safety in advanced or unresectable HCC. Sequential therapy may enhance therapeutic effectiveness while reducing TRAEs.

Propensity score analysis of high-dose rate brachytherapy, immune checkpoint inhibitors, and docetaxel in second-line advanced NSCLC treatment

This study evaluated the efficacy and safety of combining high-dose-rate brachytherapy, immune checkpoint inhibitors, and docetaxel as second-line treatment for advanced NSCLC, given the poor prognosis after first-line therapy. We conducted a single-center, retrospective, propensity score-matched study comparing HDR brachytherapy plus ICIs and docetaxel (study group) versus ICIs plus docetaxel (control group) in patients with advanced NSCLC who progressed after prior treatment without known driver gene mutations or uninvestigated mutation status. After propensity score matching, 21 patients were included in each group. The study group had a higher ORR (42.9% vs. 28.6%). Median OS was 18.6 months for the study group and 12.8 months for the control group (HR 0.45, 95% CI 0.20-0.85, P = 0.042). Median PFS was 8.6 vs. 5.6 months (HR   0.29, 95% CI 0.15-0.55, P < 0.001). The DCR was higher in the study group (71.4% vs. 61.9%). Treatment-related AEs were manageable, with no significant increase in grade 3/4 toxicities in the study group. Results suggest that combining high-dose rate brachytherapy, immune checkpoint inhibitors, and docetaxel may improve survival and response rates in advanced NSCLC after first-line therapy. Prospective randomized trials are necessary to confirm these findings and validate the strategy's effectiveness.

Induction of macrophage efferocytosis in pancreatic cancer via PI3Kγ inhibition and radiotherapy promotes tumour control

BACKGROUND

The immune suppression mechanisms in pancreatic ductal adenocarcinoma (PDAC) remain unknown, but preclinical studies have implicated macrophage-mediated immune tolerance. Hence, pathways that regulate macrophage phenotype are of strategic interest, with reprogramming strategies focusing on inhibitors of phosphoinositide 3-kinase-gamma (PI3Kγ) due to restricted immune cell expression. Inhibition of PI3Kγ alone is ineffective in PDAC, despite increased infiltration of CD8+ T cells.

OBJECTIVE

We hypothesised that the immune stimulatory effects of radiation, and its ability to boost tumour antigen availability could synergise with PI3Kγ inhibition to augment antitumour immunity.

DESIGN

We used orthoptic and genetically engineered mouse models of pancreatic cancer (LSL-KrasG12D/+;Trp53R172H/+;Pdx1-Cre). Stereotactic radiotherapy was delivered using contrast CT imaging, and PI3Kγ inhibitors by oral administration. Changes in the tumour microenvironment were quantified by flow cytometry, multiplex immunohistochemistry and RNA sequencing. Tumour-educated macrophages were used to investigate efferocytosis, antigen presentation and CD8+ T cell activation. Single-cell RNA sequencing data and fresh tumour samples with autologous macrophages to validate our findings.

RESULTS

Tumour-associated macrophages that employ efferocytosis to eradicate apoptotic cells can be redirected to present tumour antigens, stimulate CD8+ T cell responses and increase local tumour control. Specifically, we demonstrate how PI3Kγ signalling restricts inflammatory macrophages and that inhibition supports MERTK-dependent efferocytosis. We further find that the combination of PI3Kγ inhibition with targeted radiotherapy stimulates inflammatory macrophages to invoke a pathogen-induced like efferocytosis that switches from immune tolerant to antigen presenting.

CONCLUSIONS

Our data supports a new immunotherapeutic approach and a translational rationale to improve survival in PDAC.

Where lung cancer and tuberculosis intersect: recent advances

Lung cancer (LC) and tuberculosis (TB) represent two major global public health issues. Prior evidence has suggested a link between TB infection and an increased risk of LC. As advancements in LC treatment have led to extended survival rates for LC patients, the co-occurrence of TB and LC has grown more prevalent and poses novel clinical challenges. The intricate molecular mechanisms connecting TB and LC are closely intertwined and many issues remain to be addressed. This review focuses on resemblance between the immunosuppression in tumor and granuloma microenvironments, exploring immunometabolism, cell plasticity, inflammatory signaling pathways, microbiomics, and up-to-date information derived from spatial multi-omics between TB and LC. Furthermore, we outline immunization-related molecular mechanisms underlying these two diseases and propose future research directions. By discussing recent advances and potential targets, this review aims to establish a foundation for developing future therapeutic strategies targeting LC with concurrent TB infection.

Immunological Effects of Proton Radiotherapy: New Opportunities and Challenges in Cancer Therapy

Radiation therapy can be categorised by particle type into photon, proton and heavy ion therapies. Proton radiotherapy is highlighted due to its unique physical properties, such as the Bragg peak and minimal exit dose, which offer superior dose distribution. This makes proton radiotherapy especially advantageous for treating tumours near vital organs with complex structures, such as gliomas near the brain, nasopharyngeal carcinoma near the brainstem and mediastinal tumours near the heart. Proton irradiation can induce distant effects through immunogenicity within the target area. The reduced low-dose zone outside the target provides better lymphatic system protection and immune benefits. Additionally, combining proton radiotherapy with immunotherapy may offer further biological advantages. These features make proton radiotherapy a promising option in cancer treatment. This article may aid in the understanding of proton radiotherapy and its immune effects and lead to new effective options for tumour treatment.

Dual-Functioning Metal-Organic Frameworks: Methotrexate-Loaded Gadolinium MOFs as Drug Carriers and Radiosensitizers

Cancer remains a critical global health challenge, necessitating advanced drug delivery systems through innovations in materials science and nanotechnology. This study evaluates gadolinium metal-organic frameworks (Gd-MOFs) as potential drug delivery systems for anticancer therapy, particularly when combined with radiotherapy. Gd-MOFs were synthesized using terephthalic acid and gadolinium (III) chloride hexahydrate and then loaded with methotrexate (MTX). Characterization via fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), magnetic resonance imaging (MRI), and X-ray diffraction (XRD) confirmed their correct structure and stability. Effective MTX loading and controlled release were demonstrated. Anticancer effects were assessed on human healthy bronchial epithelial cells (BEAS-2B) and human lung cancer cells (A549) using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay under in vitro radiation therapy. MTX/Gd-MOF combined with radiotherapy showed a greater reduction in cancer cell viability (41.89% ± 2.75 for A549) compared to healthy cells (56.80% ± 1.97 for BEAS-2B), indicating selective cytotoxicity. These findings highlight the potential of Gd-MOFs not only as drug delivery vehicles but also as radiosensitizers, enhancing radiotherapy efficacy and offering promising evidence for their use in combinatory cancer therapies to improve treatment outcomes.

The dynamic role of ferroptosis in cancer immunoediting: Implications for immunotherapy

Currently, cancer immunotherapy strategies are primarily formulated based on the patient's present condition, representing a "static" treatment approach. However, cancer progression is inherently "dynamic," as the immune environment is not fixed but undergoes continuous changes. This dynamism is characterized by the ongoing interactions between tumor cells and immune cells, which ultimately lead to alterations in the tumor immune microenvironment. This process can be effectively elucidated by the concept of cancer immunoediting, which divides tumor development into three phases: "elimination," "equilibrium," and "escape." Consequently, adjusting immunotherapy regimens based on these distinct phases may enhance patient survival and improve prognosis. Targeting ferroptosis is an emerging area in cancer immunotherapy, and our findings reveal that the antioxidant systems associated with ferroptosis possess dual roles, functioning differently across the three phases of cancer immunoediting. Therefore, this review delve into the dual role of the ferroptosis antioxidant system in tumor development and progression. It also propose immunotherapy strategies targeting ferroptosis at different stages, ultimately aiming to illuminate the significant implications of targeting ferroptosis at various phases for cancer immunotherapy.

Targeting USP1 Potentiates Radiation-Induced Type I IFN-Dependent Antitumor Immunity by Enhancing Oligo-Ubiquitinated SAR1A-Mediated STING Trafficking and Activation

The magnitude of Type I interferon (IFN) mediated innate immune response within the tumor microenvironment (TME) critically influences the effectiveness of radiotherapy. Unfortunately, due to a myriad of resistance mechanisms, the double-stranded DNA (dsDNA) signals produced by tumor cells postradiotherapy often induce a diminished response from immune cells. Through chemical screening targeting deubiquitinating enzymes, we identified USP1 (Ubiquitin Specific Peptidase 1) inhibitor as an enhancer of post-radiotherapy dsDNA responses. Mechanistically, within the context of immune-stimulatory cells in TME, USP1 serves as a suppressor in the stress-mediated stages of the cGAS (Cyclic GMP-AMP synthase) -STING (Stimulator of interferon genes protein) signaling pathway, specifically affecting the trafficking of STING from endoplasmic reticulum to Golgi apparatus. It is elucidated that SAR1A (Secretion associated Ras related GTPase 1A) requires K27-linked oligo-ubiquitination to assemble the STING-COP-II (Coat protein II) transport complex for STING trafficking. USP1 counteracts this activation by removing SAR1A ubiquitination, thereby blocking STING trafficking and activation. Consequently, pharmacological USP1 inhibition using ML323 sustains SAR1A ubiquitination and COP-II complex formation, significantly enhancing STING trafficking and subsequent Type I IFN production. This intervention substantially amplifies radiotherapy-induced immune activation in the TME, providing a strategic approach to overcome therapeutic resistance and synergize radiotherapy with immunotherapies.

A PD-L1 siRNA-Loaded Boron Nanoparticle for Targeted Cancer Radiotherapy and Immunotherapy

Although the combination of radiotherapy and immunotherapy is regarded as a promising clinical treatment strategy, numerous clinical trials have failed to demonstrate synergistic effects. One of the key reasons is that conventional radiotherapies inevitably damage intratumoral effector immune cells. Boron Neutron Capture Therapy (BNCT) is a precise radiotherapy that selectively kills tumor cells while sparing adjacent normal cells, by utilizing 10B agents and neutron irradiation. Therefore, combinational BNCT-immunotherapy holds promise for achieving more effective synergistic effects. Here it develops a 10B-containing polymer that self-assembled with PD-L1 siRNA to form 10B/siPD-L1 nanoparticles for combinational BNCT-immunotherapy. Unlike antibodies, PD-L1 siRNA can inhibit intracellular PD-L1 upregulated by BNCT, activating T-cell immunity while also suppressing DNA repair. This can enhance BNCT-induced DNA damage, promoting immunogenic cell death (ICD) and further amplifying the antitumor immune effect. The results demonstrated that BNCT using 10B/siPD-L1 nanoparticles precisely killed tumor cells while sparing adjacent T cells and induced a potent antitumor immune response, inhibiting distal and metastatic tumors.

Advances in PSMA-Targeted Radionuclide Therapeutics

OPINION STATEMENT

Prostate-specific membrane antigen targeted radionuclide therapies (PSMA-TRT) such as 177Lu-PSMA-617 hold great promise in improving clinical outcomes at various stages of prostate cancer. The FDA approval of 177Lu-PSMA-617 represents a significant advancement in the treatment of metastatic castration-resistant prostate cancer (mCRPC). The VISION trial demonstrated improved radiographic progression-free survival (rPFS) and overall survival (OS) with 177Lu-PSMA-617 in patients with mCRPC who had already receive androgen receptor pathway inhibitor (ARPI) and taxane chemotherapy. Exploration of 177Lu-PSMA-617 in earlier stages of prostate cancer, such as in the PSMAfore trial for patients who have not received chemotherapy, holds great promise for improving long-term outcomes and delaying exposure to chemotherapy. Combining 177Lu-PSMA-617 with other therapies, including chemotherapy, PARP inhibitors, and immunotherapy, is an area of active investigation. This review will also discuss alternative radionuclides (such as actininum-225 and terbium-161) and delivery vehicles (such as PSMA-I&T), which we find promising. Predictive biomarkers and dosimetry will be crucial for identifying patients most likely to benefit from PSMA-TRT. Continued research and refinement of these therapies will lead to PSMA-targeted treatments becoming an integral part of prostate cancer management.

Dual-pathway tumor radiosensitization strategy based on engineered bacteria capable of targeted delivery of AuNPs and specific hypoxia alleviation

BACKGROUND

Radiotherapy efficacy remains constrained by two key challenges: dose-dependent toxicity to healthy tissues at high radiation doses and hypoxia-mediated tumor radioresistance. While radiosensitizers like gold nanoparticles can enhance tumor-specific radiation deposition, their targeted delivery to tumors presents a significant hurdle. Bacteria have emerged as promising bio-carriers that not only actively target tumors and penetrate complex microenvironments, but can also be genetically engineered as multifunctional platforms for radiosensitizer delivery and hypoxia alleviation.

RESULTS

An integrated nanosystem (PCM@AuNPs), composed of engineered bacteria (PCM) and gold nanoparticles (AuNPs), is used to increase the effectiveness of radiotherapy. PCM can target and colonize tumor sites more effectively, thus improving the delivery efficiency of radiosensitizers. Furthermore, PCM overexpresses catalase (CAT), which decomposes excess H2O2 into O2, helping to mitigate hypoxia in the TME. Under X-ray irradiation, PCM@AuNPs significantly enhance radiosensitization, leading to improved tumor growth inhibition while maintaining good biocompatibility.

CONCLUSIONS

An effective strategy based on an integrated nanosystem (PCM@AuNPs) for radiosensitization through multiple pathways is developed. This novel engineered bacterial strategy holds great promise for enhancing radiosensitization in cancer therapy.

Systemic immunomodulation by irreversible electroporation versus stereotactic ablative body radiotherapy in locally advanced pancreatic cancer: the CROSSFIRE trial

BACKGROUND

Irreversible electroporation (IRE) and stereotactic ablative body radiotherapy (SABR) are cytoreductive therapies for locally advanced pancreatic cancer (LAPC). Both may signify immunogenic cell death. We aimed to compare systemic immune responses between the treatments.

METHODS

As part of the randomized phase II CROSSFIRE trial (NCT02791503), comparing the oncological efficacy of IRE to SABR in patients with LAPC, pre- and post-treatment (2 weeks and 3 months) peripheral blood samples were collected. Frequency and activation status of lymphocytic and myeloid subsets were determined using flow cytometry. T cell responses to pancreatic cancer associated with Wilms tumor-1 (WT-1) and survivin tumor antigens were determined by interferon-γ enzyme-linked immunospot assay.

RESULTS

In total, 20 IRE and 20 SABR-treated participants were analyzed (20 men; median age 65 (IQR 55-70)). IRE induced immediate decreases in systemic regulatory T cell (Treg) and conventional type-1 dendritic cell rates, coinciding with CD4+/CD8+ T cell activation by upregulation of PD-1, which was associated with improved overall survival (OS). SABR similarly induced immediate CD4+/CD8+ T cell activation by upregulation of Ki67 and CD25 but resulted in asynchronously delayed Treg downregulation. SABR also induced a durable increase in CD4+ EM T cells, associated with improved OS. Ablation-induced WT-1 or survivin-specific T cell responses were observed in 9/16 (56%) immune competent participants (IRE n=5, SABR n=4) and were associated with longer OS.

CONCLUSION

Distinct immune stimulatory responses associated with improved OS, suggest that SABR might benefit from combined Treg depletion strategies while IRE could benefit from PD-1 checkpoint inhibition.

TRIAL REGISTRATION NUMBER

The trial was registered on clinical trials.gov (NCT02791503).

Tislelizumab plus anlotinib with or without radiotherapy as first-line therapy in advanced hepatocellular carcinoma: a single center, non-randomized retrospective case-control study

The purpose of this study was to investigate the efficacy and safety of tislelizumab (monoclonal antibody) plus anlotinib (tyrosine kinase inhibitor) with or without radiotherapy in advanced hepatocellular carcinoma (HCC). Ninety patients with advanced HCC were divided into two groups: tislelizumab plus anlotinib with radiotherapy (TAR group) and tislelizumab plus anlotinib (TA group) based on the treatment received. Radiotherapy was performed on two or three days during the first cycle of tislelizumab plus anlotinib. The radiotherapy requirements were dose95% ≥ 14.2-46 Gy for tumor volume. Efficacy was evaluated according to the modified Response Evaluation Criteria for Solid Tumors. Adverse events (AEs) were evaluated using the National Cancer Institute-Common Terminology Criteria for Adverse Events 4.0. The primary endpoint was the objective response rate (ORR). The secondary endpoints were progression-free survival (PFS), overall survival (OS), and the disease control rate (DCR). The ORR and DCR in the TAR group were 24.5% (62.2% and 37.7%, p = 0.03) and 22.3% higher (75.6% and 53.3%, p = 0.04), respectively, compared to the TA group. The median OS and PFS in the TAR group were prolonged 4.5 months [21.0 and 16.5 months, χ2 = 8.99, p = 0.00, 95% confidence interval (CI) 0.295-0.774] and 4.0 months (11.0 and 7.0 months. χ2 = 11.73, p = 0.00. 95% CI 0.989-2.502), respectively, compared to the TA group. The risks of disease progression and mortality in the TAR group were reduced by 53.0% (hazard ratio (HR) = 0.470, 95% CI 0.294-0.753) and 49.3% (HR = 0.507, 95% CI 0.315-0.815) compared to the TA group. The OS and PFS rates at 1 and 2 years increased by 28.9% (97.8% and 68.9%, p = 0.00) and 20.0% (42.2% and 22.2%, p = 0.07) and 28.9% (42.2% and 13.3%, p = 0.00) and 15.6% (20.0% and 4.4%, p = 0.05), respectively, in the TAR group compared to the TA group. Most patients mainly presented with grade 1/2 tolerable acute AEs (p > 0.05). No AEs were related to radiotherapy, and no fatalities occurred. The results indicate that tislelizumab plus anlotinib and radiotherapy is a safe and effective treatment for advanced HCC. Trial registration: ChiCTR2000039022 (10/13/2020). Retrospective.

Distinct immune responses to proton and photon radiotherapy: implications for anti-PD-L1 combination therapy in colorectal cancer

BACKGROUND

Ionizing radiation can influence the antitumor immune response, either activating or suppressing the immune system depending on the tumor type and radiotherapy modality. While photon radiation (RT) combined with immunotherapy (IT) is widely studied in clinical trials, proton radiation (PT) combined with IT has not been thoroughly investigated in clinical or preclinical studies despite its radiobiological advantages. This study aims to explore the immune effects of a hypofractionated PT scheme compared to RT and its efficacy with anti-PD-L1 immunotherapy.

METHODS

Balb/c mice bearing subcutaneous CT26 colon tumors were treated with RT or PT, delivered with 3 × 8 Gy. Seven days post-treatment, transcriptomic analysis and immune response assessments to characterize lymphoid cells, myeloid cells, and PD-L1 expression were performed. Tumor growth was monitored to evaluate the efficacy of combining RT or PT with anti-PD-L1 IT.

RESULTS

The RNA sequencing analysis demonstrated an overexpression of genes involved in the interferon type I pathway after both RT and PT. Tumor microenvironment analysis showed enhanced immune cell infiltration in tumors after both treatments. Immunoactivating cells infiltration was observed, with LT CD8 + cells infiltration after both RT and PT, more significantly after RT. NK and TAM1 cells infiltrated only after RT. Immunosuppressive cell populations were induced by PT, including MDSCs, while Tregs infiltrated both RT and PT treated tumors. PD-L1 expression was significantly induced only by RT. The combination of anti-PD-L1 with RT or PT resulted in tumor growth delay compared to RT or PT alone, with a significant survival benefit observed only after the combination of RT and IT.

CONCLUSIONS

This study demonstrates that hypofractionated RT and PT induced both similar and significantly distinct immune responses. PT triggers a stronger immunosuppressive response than RT. Optimizing the combination of PT with IT, including dose, fractionation, and sequencing is crucial for improving treatment efficacy.

Bistable dynamics of TAN-NK cells in tumor growth and control of radiotherapy-induced neutropenia in lung cancer treatment

Neutrophils play a crucial role in the innate immune response as a first line of defense in many diseases, including cancer. Tumor-associated neutrophils (TANs) can either promote or inhibit tumor growth in various steps of cancer progression via mutual interactions with cancer cells in a complex tumor microenvironment (TME). In this study, we developed and analyzed mathematical models to investigate the role of natural killer cells (NK cells) and the dynamic transition between N1 and N2 TAN phenotypes in killing cancer cells through key signaling networks and how adjuvant therapy with radiation can be used in combination to increase anti-tumor efficacy. We examined the complex immune-tumor dynamics among N1/N2 TANs, NK cells, and tumor cells, communicating through key extracellular mediators (Transforming growth factor (TGF-$ \beta $), Interferon gamma (IFN-$ \gamma $)) and intracellular regulation in the apoptosis signaling network. We developed several tumor prevention strategies to eradicate tumors, including combination (IFN-$ \gamma $, exogenous NK, TGF-$ \beta $ inhibitor) therapy and optimally-controlled ionizing radiation in a complex TME. Using this model, we investigated the fundamental mechanism of radiation-induced changes in the TME and the impact of internal and external immune composition on the tumor cell fate and their response to different treatment schedules.

DNA-Capturing Manganese-Coordinated Chitosan Microparticles Potentiate Radiotherapy via Activating the cGAS-STING Pathway and Maintaining Tumor-Infiltrating CD8+ T-Cell Stemness

The radiotherapy-induced release of DNA fragments can stimulate the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) pathway to prime antitumor immunity, but this pathway is expected to be less potent because of the inefficient cytosolic delivery of negatively charged DNA fragments. In this study, manganese-coordinated chitosan (CS-Mn) microparticles with selective DNA-capturing capacity are concisely prepared via a coordination-directed one-pot synthesis process to potentiate the immunogenicity of radiotherapy. The obtained CS-Mn microparticles that undergo rapid disassembly under physiological conditions can selectively bind with DNA to form positively charged DNA-CS assemblies because of the strong electrostatic interaction between linear chitosan and DNA molecules. They thus enable efficient cytosolic delivery of DNA in the presence of serum to cooperate with Mn2+ to activate the cGAS-STING pathway in dendritic cells. Upon intratumoral injection, the CS-Mn microparticles markedly enhance the efficacy of radiotherapy against both irradiated and distal tumors in different tumor models via collectively promoting tumor-infiltrating CD8+ T-cell stemness and the activation of innate immunity. The radiosensitization effect of CS-Mn microparticles can be further augmented by concurrently applying anti-programmed cell death protein 1 (anti-PD-1) immunotherapy. This work highlights an ingenious strategy to prepare Trojan horse-like DNA-capturing microparticles as cGAS-STING-activating radiosensitizers for effective radioimmunotherapy.

Impact of circulating lymphocyte kinetics following radiotherapy on patient survival: A model-based meta-analysis

INTRODUCTION

Radiation-induced lymphopenia (RIL) has been shown to adversely affect the prognosis of cancer patients undergoing radiotherapy (RT). This model-based meta-analysis investigated the prognostic significance of lymphocyte counts both early and late after RT and examined the dose‒response relationship between post-RT lymphocyte levels and patient survival.

METHODS

A literature search of published articles on the effect of RIL on cancer prognosis was conducted using the PubMed and Cochrane databases. A survival model was developed, incorporating absolute lymphocyte count (ALC) thresholds during (1 month after RT initiation, nadir) and 6 months after RT (recovery) as covariates to estimate progression-free survival (PFS) and overall survival (OS). This survival model, with the lymphocyte count cutoff as a covariate, was then used to simulate the benefit of increased PFS and OS in populations without lymphopenia or severe lymphopenia compared to the total population.

RESULTS

A total of 35 studies met the inclusion criteria for survival analysis. Our survival model revealed an increase in survival in the subgroup without lymphopenia compared to the total population. The subgroup without lymphopenia 1 month after RT initiation showed a 10.28 % and 3.92 % increase in 24-month PFS and OS, respectively. The subgroup without lymphopenia at 6 months showed a 5.82 % and 2.78 % increase in 24-month PFS and OS, respectively.

CONCLUSION

This study highlights the critical role of lymphocyte nadir and recovery following RT in patient prognosis and strengthens the evidence for a causal relationship between RIL and patient outcomes. Expanding the dataset and including randomized controlled trials would provide a more comprehensive understanding of monitoring or knowledge of ALC profiles following RT.

Safety and Efficacy of Radiotherapy Combined With Sintilimab in Advanced NSCLC Patients Who Progressed on First or Second Line Therapy: A Prospective, Multiple Center, and Single-Arm Study

BACKGROUND

This study explored the safety and efficacy of combining radiotherapy with sintilimab in non-small cell lung cancer (NSCLC) patients who have progressed after first or second-line therapy.

METHODS

In this multicenter, single-arm trial, patients with NSCLC who had progressed after first or second-line therapy were enrolled. Participants received hypofractionated stereotactic body radiotherapy (SBRT) (requiring a single-site biological dose of more than 30 Gy or planned to reach 30 Gy) followed by sintilimab every 3 weeks until disease progression or unacceptable toxicity occurred.

RESULTS

From March 1, 2019, to July 27, 2023, 14 patients were enrolled across two centers. The cohort included 64.3% males and 35.7% females, with a median age of 67 years (range 57-73 years). All participants completed radiation therapy and received at least one cycle of sintilimab. The overall response rate (ORR) was 21.4% (3/14) and the disease control rate (DCR) was 71.4% (10/14). The absent radiation response (ARR) was 14.3% (2/14). The median PFS was 4.17 months (95% CI: 1.15-8.69 months), with a 6-month PFS rate of 42.9%. The median OS was 16.17 months (95% CI: 11.69-20.64 months). Overall, 10 patients (71.4%) experienced at least one treatment-emergent adverse event (TEAE). Grade 3 adverse events included one case each of immune-related myocarditis, thrombocytopenia, and checkpoint inhibitor pneumonitis (CIP). Four patients (28.6%) had immune-related adverse events (irAEs) including skin rash and pruritus (2/14, grade 1), immune-related myocarditis (1/14, grade 3), and CIP (1/14, grade 3).

CONCLUSIONS

Radiotherapy combined with sintilimab for NSCLC patients who progressed after first-or second-line therapy showed promising efficacy outcomes.

Metal-Protein Hybrid Materials: Unlocking New Frontiers in Biomedical Applications

Metal-protein hybrid materials represent a novel class of functional materials that exhibit exceptional physicochemical properties and tunable structures, rendering them remarkable applications in diverse fields, including materials engineering, biocatalysis, biosensing, and biomedicine. The design and development of multifunctional and biocompatible metal-protein hybrid materials have been the subject of extensive research and a key aspiration for practical applications in clinical settings. This review provides a comprehensive analysis of the design strategies, intrinsic properties, and biomedical applications of these hybrid materials, with a specific emphasis on their potential in cancer therapy, drug and vaccine delivery, antibacterial treatments, and tissue regeneration. Through rational design, stable metal-protein hybrid materials can be synthesized using straightforward methods, enabling them with therapeutic, delivery, immunomodulatory, and other desired functionalities. Finally, the review outlines the existing limitations and challenges associated with metal-protein hybrid materials and evaluates their potential for clinical translation, providing insights into their practical implementation within biomedical applications.

Manganese dioxide-based in situ vaccine boosts antitumor immunity via simultaneous activation of immunogenic cell death and the STING pathway

In situ vaccine (ISV) can activate the anti-tumor immune system by inducing immunogenic cell death (ICD) at the tumor site. However, the development of tumor ISV still faces challenges due to insufficient tumor antigens released by tumor cells and the existence of tumor immunosuppressive microenvironment (TIME). Targeting the STING pathway has been reported to enhance the adjuvant effects of in situ tumor vaccines by initiating innate immunity. Based on this, we developed a potent in situ cancer vaccine, MBMA-RGD ISV, which simultaneously induces ICD and activates the STING pathway to achieve sustained anti-tumor immunity. Specifically, a water-soluble prodrug Mit-ALA was synthesized from the chemotherapeutic agent mitoxantrone (Mit) and the photosensitizer precursor 5-aminolevulinic acid (5-ALA) by pH-responsive ester bonds, which was then loaded into pre-synthesized BSA-MnO2 nanoparticles and functionalized with the targeting Arg-Gly-Asp (RGD) peptide to obtain MBMA-RGD ISV. This ISV actively targets tumor cells by binding integrin receptors and then gradually releases antitumor components in response to tumor microenvironment (TME). The released 5-ALA is metabolized in mitochondria to produce photosensitizer PpIX. Under laser irradiation, the photodynamic property of PpIX coupled with the photothermal effect of Mit synergistically induced ICD, resulting in the release of tumor antigens and evoking adaptive immunity. Meanwhile, released Mn2+ and Mit synergistically activate the STING pathway by inducing DNA damage, further enhancing antitumor immunity. Moreover, large amounts of oxygen released by MnO2 relieved the hypoxia microenvironment, thus sensitizing photodynamic therapy and improving the immunosuppressive state of TME. Therefore, MBMA-RGD ISV efficiently activates systemic antitumor immunity in vitro and in vivo, providing new strategies and ideas for the development of tumor ISV. STATEMENT OF SIGNIFICANCE: Using a biocompatible BSA-MnO2 nanoplatform, we developed a dual-prodrug tumor in situ vaccine (ISV) with tumor microenvironment-responsive action for synergistic cancer immunotherapy. Once internalized by tumor cells, the MBMA-RGD ISV responded to intracellular H+, H2O2, and GSH, releasing its therapeutic "cargo." Under laser irradiation, the combined effects of photodynamic therapy (PDT) and photothermal therapy (PTT) induced immunogenic cell death (ICD), effectively recruiting and stimulating dendritic cells (DCs). Concurrently, STING pathway activation, triggered by DNA damage, enhanced DC maturation. Moreover, the MnO2 component alleviated hypoxia within the tumor microenvironment by releasing significant amounts of oxygen, which facilitated the repolarization of macrophages from the M2 phenotype to the M1 phenotype. Therefore, MBMA-RGD ISV demonstrated potent suppression of tumor metastasis and recurrence without notable side effects in mouse tumor models.

Vax-Innate: improving therapeutic cancer vaccines by modulating T cells and the tumour microenvironment

T cells have a critical role in mediating antitumour immunity. The success of immune checkpoint inhibitors (ICIs) for cancer treatment highlights how enhancing endogenous T cell responses can mediate tumour regression. However, mortality remains high for many cancers, especially in the metastatic setting. Based on advances in the genetic characterization of tumours and identification of tumour-specific antigens, individualized therapeutic cancer vaccines targeting mutated tumour antigens (neoantigens) are being developed to generate tumour-specific T cells for improved therapeutic responses. Early clinical trials using individualized neoantigen vaccines for patients with advanced disease had limited clinical efficacy despite demonstrated induction of T cell responses. Therefore, enhancing T cell activity by improving the magnitude, quality and breadth of T cell responses following vaccination is one current goal for improving outcome against metastatic tumours. Another major consideration is how T cells can be further optimized to function within the tumour microenvironment (TME). In this Perspective, we focus on neoantigen vaccines and propose a new approach, termed Vax-Innate, in which vaccination through intravenous delivery or in combination with tumour-targeting immune modulators may improve antitumour efficacy by simultaneously increasing the magnitude, quality and breadth of T cells while transforming the TME into a largely immunostimulatory environment for T cells.

Efficacy and safety of integrating consolidative thoracic radiotherapy with immunochemotherapy in extensive-stage small cell lung cancer: a real-world retrospective analysis

Background

Extensive-stage small cell lung cancer (ES-SCLC) remains a challenging malignancy with a poor prognosis. The integration of immunochemotherapy and combined consolidative thoracic radiotherapy (cTRT) presents a potential paradigm shift in treatment. This study aims to evaluate the real-world efficacy and safety of this approach.

Methods

In a single-center retrospective study conducted at Shandong Cancer Hospital, electronic medical records of 828 ES-SCLC patients treated between January 1, 2022, and December 31, 2023, were reviewed. Patients were divided into three cohorts based on treatment strategies: chemoradiotherapy (cohort A), immunochemotherapy without/with cTRT (cohort B/C). Propensity score matching was utilized to adjust for baseline differences. The primary outcomes were real-world progression-free survival (rwPFS) and overall survival (OS). Secondary outcomes included the incidence and severity of specific interested adverse events (AEs).

Results

Of the 374 patients analyzed, cohort C showed significant improvements in rwPFS and OS compared to cohort A. The median rwPFS in cohort C (10.9 months) was longer than that of cohorts A (7.6 months) and B (8.0 months). The 12-month rwPFS rate was highest in cohort C (41%), compared to cohorts A (19%) and B (34%). The incidence of grade 3 or higher AEs was comparable across cohorts, with myelosuppression being the most common. However, the incidence of grade 3 or higher pneumonitis was notably higher in cohorts B and C, aligning with previous reports.

Conclusions

The combination of cTRT with immunochemotherapy for ES-SCLC showed improved rwPFS and OS, indicating potential benefit in this population. The overall safety profile remained manageable. These findings highlight the need for further prospective studies to confirm the optimal integration of cTRT in ES-SCLC treatment strategies.