Integration of radiotherapy and immunotherapy for treatment of oligometastases

Strategies for overcoming tumour resistance to immunotherapy: harnessing the power of radiation therapy

Immune checkpoint inhibitors (ICI) have revolutionized cancer treatment; yet their efficacy remains variable across patients. This review delves into the intricate interplay of tumour characteristics contributing to resistance against ICI therapy and suggests that combining with radiotherapy holds promise. Radiation, known for its ability to trigger immunogenic cell death and foster an in situ vaccination effect, may counteract these resistance mechanisms, enhancing ICI response and patient outcomes. However, particularly when delivered at high-dose, it may trigger immunosuppressive mechanism and consequent side-effects. Notably, low-dose radiotherapy (LDRT), with its capacity for tumour reprogramming and reduced side effects, offers the potential for widespread application. Preclinical and clinical studies have shown encouraging results in this regard.

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.

Radiotherapy Enhances Metastasis Through Immune Suppression by Inducing PD-L1 and MDSC in Distal Sites

PURPOSE

Radiotherapy (RT) is a widely employed anticancer treatment. Emerging evidence suggests that RT can elicit both tumor-inhibiting and tumor-promoting immune effects. The purpose of this study is to investigate immune suppressive factors of radiotherapy.

EXPERIMENTAL DESIGN

We used a heterologous two-tumor model in which adaptive concomitant immunity was eliminated.

RESULTS

Through analysis of PD-L1 expression and myeloid-derived suppressor cells (MDSC) frequencies using patient peripheral blood mononuclear cells and murine two-tumor and metastasis models, we report that local irradiation can induce a systemic increase in MDSC, as well as PD-L1 expression on dendritic cells and myeloid cells, and thereby increase the potential for metastatic dissemination in distal, nonirradiated tissue. In a mouse model using two distinct tumors, we found that PD-L1 induction by ionizing radiation was dependent on elevated chemokine CXCL10 signaling. Inhibiting PD-L1 or MDSC can potentially abrogate RT-induced metastasis and improve clinical outcomes for patients receiving RT.

CONCLUSIONS

Blockade of PD-L1/CXCL10 axis or MDSC infiltration during irradiation can enhance abscopal tumor control and reduce metastasis.

Enhanced Photodynamic Therapy Synergizing with Inhibition of Tumor Neutrophil Ferroptosis Boosts Anti-PD-1 Therapy of Gastric Cancer

For tumor treatment, the ultimate goal in tumor therapy is to eliminate the primary tumor, manage potential metastases, and trigger an antitumor immune response, resulting in the complete clearance of all malignant cells. Tumor microenvironment (TME) refers to the local biological environment of solid tumors and has increasingly become an attractive target for cancer therapy. Neutrophils within TME of gastric cancer (GC) spontaneously undergo ferroptosis, and this process releases oxidized lipids that limit T cell activity. Enhanced photodynamic therapy (PDT) mediated by di-iodinated IR780 (Icy7) significantly increases the production of reactive oxygen species (ROS). Meanwhile, neutrophil ferroptosis can be triggered by increased ROS generation in the TME. In this study, a liposome encapsulating both ferroptosis inhibitor Liproxstatin-1 and modified photosensitizer Icy7, denoted LLI, significantly inhibits tumor growth of GC. LLI internalizes into MFC cells to generate ROS causing immunogenic cell death (ICD). Simultaneously, liposome-deliver Liproxstatin-1 effectively inhibits the ferroptosis of tumor neutrophils. LLI-based immunogenic PDT and neutrophil-targeting immunotherapy synergistically boost the anti-PD-1 treatment to elicit potent TME and systemic antitumor immune response with abscopal effects. In conclusion, LLI holds great potential for GC immunotherapy.

Thermal Ablation Combined with Immune Checkpoint Blockers: A 10-Year Monocentric Experience

PURPOSE

We report a 10-year experience in cancer therapy with concomitant treatment of percutaneous thermal ablation (PTA) and immune checkpoint blockers (ICBs).

MATERIAL AND METHODS

This retrospective cohort study included all patients at a single tertiary cancer center who had received ICBs at most 90 days before, or 30 days after, PTA. Feasibility and safety were assessed as the primary outcomes. The procedure-related complications and immune-related adverse events (irAEs) were categorized according to the Common Terminology Criteria for Adverse Events v5.0 (CTCAE). Efficacy was evaluated based on overall survival (OS), progression-free survival (PFS), and local progression-free survival (LPFS) according to the indication, ablation modality, neoplasm histology, and ICB type.

RESULTS

Between 2010 and 2021, 78 patients (57% male; median age: 61 years) were included. The PTA modality was predominantly cryoablation (CA) (61%), followed by radiofrequency ablation (RFA) (31%). PTA indications were the treatment of oligo-persistence (29%), oligo-progression (14%), and palliation of symptomatic lesions or prevention of skeletal-related events (SREs) (56%). Most patients received anti-PD1 ICB monotherapy with pembrolizumab (n = 35) or nivolumab (n = 24). The feasibility was excellent, with all combined treatment performed and completed as planned. Ten patients (13%) experienced procedure-related complications (90% grade 1-2), and 34 patients (44%) experienced an irAE (86% grade 1-2). The only factor statistically associated with better OS and PFS was the ablation indication, favoring oligo-persistence (p = 0.02). Tumor response was suggestive of an abscopal effect in four patients (5%).

CONCLUSIONS

The concomitant treatment of PTA and ICBs within 2-4 weeks is feasible and safe for both palliative and local control indications. Overall, PTA outcomes were found to be similar to standards for patients not on ICB therapy. While a consistently reproducible abscopal effect remains elusive, the safety profile of concomitant therapy provides the framework for continued assessment as ICB therapies evolve.

Ferroptosis in cancer immunity and immunotherapy: Multifaceted interplay and clinical implications

Ferroptosis is a type of cell death characterized by iron-dependent phospholipid peroxidation and reactive oxygen species overproduction. Ferroptosis induces immunogenic cell death and elicits anti-tumor immune responses, playing an important role in cancer immunotherapy. Ferroptosis suppression in cancer cells impairs its immunotherapeutic efficacy. To overcome this issue, ferroptosis inducers (FINs) have been combined with other cancer therapies to create an anti-tumor immune microenvironment. However, the ferroptosis-based crosstalk between immune and tumor cells is complex because oxidative products released by ferroptotic tumor cells impair the functions of anti-tumor immune cells, resulting in immunotherapeutic resistance. In the present article, we have reviewed ferroptosis in tumor and immune cells and summarized the crosstalk between ferroptotic tumor cells and the immune microenvironment. Based on the existing literature, we have further discussed future perspectives on opportunities for combining ferroptosis-targeted therapies with cancer immunotherapies.

Comprehensive single-cell analysis demonstrates radiotherapy-induced infiltration of macrophages expressing immunosuppressive genes into tumor in esophageal squamous cell carcinoma

Radiotherapy (RT) combined with immunotherapy is promising; however, the immune response signature in the clinical setting after RT remains unclear. Here, by integrative spatial and single-cell analyses using multiplex immunostaining (CODEX), spatial transcriptome (VISIUM), and single-cell RNA sequencing, we substantiated the infiltration of immune cells into tumors with dynamic changes in immunostimulatory and immunosuppressive gene expression after RT. In addition, our comprehensive analysis uncovered time- and cell type-dependent alterations in the gene expression profile after RT. Furthermore, myeloid cells showed prominent up-regulation of immune response-associated genes after RT. Notably, a subset of infiltrating tumor-associated myeloid cells showing PD-L1 positivity exhibited significant up-regulation of immunostimulatory (HMGB1 and ISG15), immunosuppressive (SIRPA and IDO1), and protumor genes (CXCL8, CCL3, IL-6, and IL-1AB), which can be targets of immunotherapy in combination with PD-L1. These datasets will provide information on the RT-induced gene signature to seek an appropriate target for personalized immunotherapy combined with RT and guide the timing of combination therapy.

Tumor-Targeted Interleukin 2 Boosts the Anticancer Activity of FAP-Directed Radioligand Therapeutics

We studied the antitumor efficacy of a combination of 177Lu-labeled radioligand therapeutics targeting the fibroblast activation protein (FAP) (OncoFAP and BiOncoFAP) with the antibody-cytokine fusion protein L19-interleukin 2 (L19-IL2) providing targeted delivery of interleukin 2 to tumors. Methods: The biodistribution of 177Lu-OncoFAP and 177Lu-BiOncoFAP at different molar amounts (3 vs. 250 nmol/kg) of injected ligand was studied via SPECT/CT in mice bearing subcutaneous HT-1080.hFAP tumors, and self-absorbed tumor and organ doses were calculated. The in vivo anticancer effect of 5 MBq of the radiolabeled preparations was evaluated as monotherapy or in combination with L19-IL2 in subcutaneously implanted HT-1080.hFAP and SK-RC-52.hFAP tumors. Tumor samples from animals treated with 177Lu-BiOncoFAP, L19-IL2, or both were analyzed by mass spectrometry-based proteomics to identify therapeutic signatures on cellular and stromal markers of cancer and on immunomodulatory targets. Results: 177Lu-BiOncoFAP led to a significantly higher self-absorbed dose in FAP-positive tumors (0.293 ± 0.123 Gy/MBq) than did 177Lu-OncoFAP (0.157 ± 0.047 Gy/MBq, P = 0.01) and demonstrated favorable tumor-to-organ ratios at high molar amounts of injected ligand. Administration of L19-IL2 or 177Lu-BiOncoFAP as single agents led to cancer cures in only a limited number of treated animals. In 177Lu-BiOncoFAP-plus-L19-IL2 combination therapy, complete remissions were observed in all injected mice (7/7 complete remissions for the HT-1080.hFAP model, and 4/4 complete remissions for the SK-RC-52.hFAP model), suggesting therapeutic synergy. Proteomic studies revealed a mechanism of action based on the activation of natural killer cells, with a significant enhancement of the expression of granzymes and perforin 1 in the tumor microenvironment after combination treatment. Conclusion: The combination of OncoFAP-based radioligand therapeutics with concurrent targeting of interleukin 2 shows synergistic anticancer effects in the treatment of FAP-positive tumors. This experimental finding should be corroborated by future clinical studies.

Integration of liquid biopsy and immunotherapy: opening a new era in colorectal cancer treatment

Immunotherapy has revolutionized the conventional treatment approaches for colorectal cancer (CRC), offering new therapeutic prospects for patients. Liquid biopsy has shown significant potential in early screening, diagnosis, and postoperative monitoring by analyzing circulating tumor cells (CTC) and circulating tumor DNA (ctDNA). In the era of immunotherapy, liquid biopsy provides additional possibilities for guiding immune-based treatments. Emerging technologies such as mass spectrometry-based detection of neoantigens and flow cytometry-based T cell sorting offer new tools for liquid biopsy, aiming to optimize immune therapy strategies. The integration of liquid biopsy with immunotherapy holds promise for improving treatment outcomes in colorectal cancer patients, enabling breakthroughs in early diagnosis and treatment, and providing patients with more personalized, precise, and effective treatment strategies.

Radiation dose, schedule, and novel systemic targets for radio-immunotherapy combinations

Immunotherapy combinations are being investigated to expand the benefit of immune checkpoint blockade across many cancer types. Radiation combinations, in particular using stereotactic body radiotherapy, are of keen interest because of underlying mechanistic rationale, safety, and availability as a standard of care in certain cancers. In addition to direct tumor cytotoxicity, radiation therapy has immunomodulatory effects such as induction of immunogenic cell death, enhancement of antigen presentation, and expansion of the T-cell receptor repertoire as well as recruitment and increased activity of tumor-specific effector CD8+ cells. Combinations of radiation with cytokines and/or chemokines and anti-programmed death 1 and anticytotoxic T-lymphocyte antigen 4 therapies have demonstrated safety and feasibility, as well as the potential to improve long-term outcomes and possibly induce out of irradiated field or abscopal responses. Novel immunoradiotherapy combinations represent a promising therapeutic approach to overcome radioresistance and further enhance systemic immunotherapy. Potential benefits include reversing CD8+ T-cell exhaustion, inhibiting myeloid-derived suppressor cells, and reversing M2 macrophage polarization as well as decreasing levels of colony-stimulating factor-1 and transforming growth factor-β. Here, we discuss current data and mechanistic rationale for combining novel immunotherapy agents with radiation therapy.

Therapeutic application of manganese-based nanosystems in cancer radiotherapy

Radiotherapy is an important therapeutic modality in the treatment of cancers. Nevertheless, the characteristics of the tumor microenvironment (TME), such as hypoxia and high glutathione (GSH), limit the efficacy of radiotherapy. Manganese-based (Mn-based) nanomaterials offer a promising prospect for sensitizing radiotherapy due to their good responsiveness to the TME. In this review, we focus on the mechanisms of radiosensitization of Mn-based nanosystems, including alleviating tumor hypoxia, increasing reactive oxygen species production, increasing GSH conversion, and promoting antitumor immunity. We further illustrate the applications of these mechanisms in cancer radiotherapy, including the development and delivery of radiosensitizers, as well as their combination with other therapeutic modalities. Finally, we summarize the application of Mn-based nanosystems as contrast agents in realizing precision therapy. Hopefully, the present review will provide new insights into the biological mechanisms of Mn-based nanosystems, as well as their applications in radiotherapy, in order to address the difficulties and challenges that remain in their clinical application in the future.

Optimal timing for local ablative treatment of bone oligometastases in non-small cell lung cancer

Oligometastases is a term commonly used to describe a disease state characterized by a limited number of distant metastases, and represents a transient phase between localized and widespread systemic diseases. This subgroup of stage IV cancer has increased in clinical importance due to the possibility of curative rather than palliative treatment. Among advanced lung cancer patients, 30-40% show bone metastases, and can show complications such as pathological fractures. Many prospective studies have shown efficacy of localized treatment in oligometastatic non-small cell lung cancer (NSCLC) in improving progression-free survival and overall survival. Compared to metastases in other organs, bone metastases are unique in terms of tumor microenvironment and clinical outcomes. Radiotherapy is the most frequently used treatment modality for local ablative treatment for both primary and metastatic lesions. Stereotactic body radiation therapy demonstrated more rapid and effective pain control compared to conventional 3D conformal radiotherapy. Radiotherapy improved outcomes in terms of time-to-skeletal related events skeletal-related events (SRE), hospitalization for SRE, pain relief, and overall survival in patients with bone metastases. Decision on timing of local ablative treatment depends on patient's overall clinical status, treatment goals, potential side effects of each approach, and expected initial responses to systemic anti-cancer treatment.

Local treatment in oligometastasis from breast cancer: an overview

Oligometastasic breast cancer (OMBC) consists of breast cancer patient with a limited number of systemic metastases (≤ 5), all of them candidates for local ablative treatment with the intention of achieving long-term control of the metastasis and, eventually, an increase in survival The first consensus for the management of patients with oligometastatic breast cancer (OMBC) was published in 2007, establishing that a more aggressive multidisciplinary strategy is recommended in order to increase the survival while maintaining a good quality of life. The current scientific evidence is based on observational studies, mainly retrospective, systematic reviews and meta-analyses, and only a randomized nonexclusive study of oligometastatic (OM) published. All trials with Stereotactic Body Radiation Therapy (SBRT) in OM cancer have shown excellent tolerance and good local control, although first trials on Lung SBRT did not prove so excellent tolerance and had some deaths due to bronchus irradiation and secondary hemoptysis. There are multiple ongoing studies researching the benefit of SBRT in oligometastatic breast cancer. Despite the lack of impact on survival seen in the NRG BR-002 Trial, SBRT probably allows the delay of the systemic treatment until progression, and so, improves the quality of life of patients. We have to wait for the results of the ongoing and future studies for clarification of the role of local treatment in OMBC.

Diagnostic Performance of Contrast Enhanced CT Alone or in Combination with (Non-)Enhanced MRI for Colorectal Liver Metastasis

RATIONALE AND OBJECTIVES

To compare the diagnostic performance of contrast enhanced CT (CE-CT), CE-CT combined with non-enhanced MRI (NE-MRI) or contrast enhanced MRI (CE-MRI) for colorectal liver metastasis (CRLM).

MATERIALS AND METHODS

Sixty-six colorectal cancer patients with 198 focal liver lesions who underwent preoperative abdominal CE-CT and MRI examinations were included respectively. The images were assessed independently by two readers in three protocols (1: CE-CT, 2: CE-CT+NE-MRI, 3: CE-CT+CE-MRI). The diagnostic performance of each protocol was analyzed by receiver operating characteristic (ROC) curve and the areas under ROC (AUCs) were calculated and compared.

RESULTS

The detection rates of protocol 2 were 90.9%-92.9% for liver lesions and 86.4%-89.6% for CRLM, and both significantly higher than protocol 1 of 82.8%-85.4% and 76.8%-80.8% (p<0.001-0.001), whereas similar to protocol 3 of 91.9%-94.4% and 87.2%-91.2% (p 0.250-1.000). The AUCs of protocol 2 were greater than protocol 1 for all lesions (0.914-0.934 vs. 0.779-0.799, p<0.001) and lesions < 10mm (0.726-0.776 vs. 0.528-0.561, p<0.001), and were not inferior to that of protocol 3 (0.929-0.949 in all lesions and 0.754-0.821 in lesion < 10mm, p 0.053-0.162).

CONCLUSION

CE-CT combined with NE-MRI offered superior diagnostic performance for CRLM compared to CE-CT alone and showed comparable performance to CE-CT combined with CE-MRI.

Panaxadiol targeting IL2 inducible T cell kinase promotes T cell immunity in radiotherapy

Ginseng, as a traditional Chinese medicine, has a good protective effect against radiotherapy, but its mechanism in radiotherapy still needs to be further explored. The active ingredients of Ginseng were analyzed according to pharmacodynamics in the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) database, and the target genes of active ingredients were screened by UniProt, PubChem and Swiss target prediction database. The differentially expressed genes of GSE6871 and GSE20162 were analyzed from the GEO database. Further, cluster analysis and enrichment analysis were carried out through protein-protein interaction network to determine hub gene. Next, build the drug-disease target network, conduct molecular docking simulation, and determine the key ingredients and targets of Ginseng on radiotherapy. We screened 16 active ingredients of Ginseng and 747 target genes from the TCMSP database. Eighty-two common differentially expressed genes were obtained by the GEO database. After topological analysis, we finally determined CD28, FYN, IL2 inducible T cell kinase (ITK), MYC and CD247 as hub genes. After integrating the drug-disease target network and molecular docking, we found that Panaxadiol, as an active ingredient of Ginseng, can target ITK to participate in T cell signal receptor pathway and act on radiotherapy. Panaxadiol can act on the key target ITK of radiotherapy, participate in T cell signal receptor pathway, and then affect the proliferation, differentiation and immune response of radiotherapy T cells, so as to reduce the side effects of radiotherapy.

Partial tumor irradiation plus pembrolizumab in treating large advanced solid tumor metastases

BACKGROUNDWe previously demonstrated the safety of stereotactic body radiotherapy followed by pembrolizumab (SBRT+P) in patients with advanced solid tumors. This phase I clinical trial was expanded to study the safety of partial tumor irradiation (partial-Rx). We assessed irradiated local failure (LF) and clinical outcomes with correlations to biomarkers including CD8+ T cell radiomics score (RS) and circulating cytokines.METHODSPatients received SBRT to 2-4 metastases and pembrolizumab for up to 7 days after SBRT. Tumors measuring up to 65 cc received the full radiation dose (complete-Rx), whereas tumors measuring more than 65 cc received partial-Rx. Landmark analysis was used to assess the relationship between tumor response and overall survival (OS). Multivariable analysis was performed for RS and circulating cytokines.RESULTSIn the combined (expansion plus original) cohort, 97 patients (219 metastases) were analyzed and received SBRT+P. Forty-six (47%) patients received at least 1 partial-Rx treatment. There were 7 (7.2%)dose-limiting toxicities (DLTs). 1-year LF was 7.6% overall, and 13.3% and 5.4% for partial-Rx and complete-Rx tumors, respectively (HR 2.32, 95% CI 0.90-5.97, P = 0.08). The overall, unirradiated, and irradiated objective response rates were 22%, 12%, and 34%, respectively. Irradiated tumor response to SBRT+P was associated with prolonged OS; 1-year OS was 71% (responders), 42% (mixed-responders), and 0% (nonresponders) (P < 0.01). High-RS was significantly associated with improved LF, progression-free survival (PFS), and OS. Elevated circulating IL-8 was independently associated with inferior PFS and OS.CONCLUSIONSBRT+P is safe in patients with large, advanced solid tumors. Additional studies are warranted to assess noninferiority of complete versus partial irradiation of tumors in the setting of immunotherapy.TRIAL REGISTRATIONClinicaltrials.gov NCT02608385FUNDINGMerck Investigator Studies Program; Hillman Fellows for Innovative Cancer Research Program; NIH grants UM1CA186690-06, P50CA254865-01A1, P30CA047904-32, and R01DE031729-01A1.

Radiotherapy plus camrelizumaband irinotecan for oligometastatic esophageal squamous cell carcinoma patients after first-line immunotherapy plus chemotherapy failure: An open-label, single-arm, phase II trial

BACKGROUND AND PURPOSE

Immunotherapy has revolutionized the treatment of advanced and metastatic esophageal squamous cell carcinoma (ESCC), but most patients eventually developed disease progression. Immuno-resistance is becoming an unavoidable clinical problem. Oligometastasis is a limited-metastatic state, and patients at this stage should be evaluated for the addition of metastasis-directed local intervention, which may be associated with improved prognosis. As an immunomodulator, radiotherapy may exhibit synergistic effect when added to immunotherapy. This study assessed the efficacy and safety of low-dose radiotherapy plus immunotherapy and second-line chemotherapy in oligometastatic ESCC.

MATERIALS AND METHODS

In this phase II trial (ChiCTR2000040533), oligometastatic ESCC patients after first-line immunotherapy plus chemotherapy failure were treated with low dose radiotherapy plus camrelizumab and second-line irinotecan chemotherapy. The primary endpoint was progression-free survival (PFS). Secondary endpoints were overall survival (OS), objective response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR), and safety. Abscopal response rate (ARR) and abscopal control rate (ACR) were also been explored.

RESULTS

Between November 19, 2018 and March 17, 2021, 49 patients were enrolled. With a median follow-up of 12.8 months, median PFS and OS were 6.9 months (95%CI, 4.6-9.3) and 12.8 months (95%CI, 10.1-15.5), respectively. ORR was 40.8% (95%CI, 27.3-55.7). DCR was 75.5% (95%CI, 60.8-86.2). ARR was 34.7% (95%CI, 22.1-49.7). ACR was 69.4% (95%CI, 54.4-81.3). The most common adverse effects of any grade were myelosuppression, weight loss and fatigue. Grade 3 or 4 treatment-related adverse events occurred in 31 (63.3%) patients, with the most common being leukopenia (30.6%). No treatment-related deaths occurred.

CONCLUSION

Low dose radiotherapy plus camrelizumab and irinotecan exhibited survival benefit with manageable safety for oligometastatic ESCC patients after first-line immunotherapy plus chemotherapy failure. It deserves to be validated in a larger trial.

Safety and feasibility of toripalimab plus lenvatinib with or without radiotherapy in advanced BTC

Background

Toripalimab shows antitumor efficacy in cholangiocarcinoma. Radiotherapy (RT) may enhance systemic responses of PD-1 inhibitors and lenvatinib. This study was designed to assess the safety and feasibility of toripalimab plus lenvatinib with or without RT in advanced BTC.

Methods

This study involved 88 patients with advanced BTC receiving toripalimab plus lenvatinib with or without RT from the clinical trials (NCT03892577). Propensity score matching (PSM) (1:1) analysis was used to balance potential bias. The overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and adverse events (AEs) were evaluated.

Results

After PSM, the final analysis included 40 patients: 20 receiving toripalimab plus lenvatinib without RT (NRT); 20 receiving toripalimab plus lenvatinib with RT. The AEs were more frequent in the RT group than in the NRT group without treatment-associated mortality. The addition of RT did not cause specific AEs. The median PFS was significantly longer with RT (10.8 versus 4.6 months, p<0.001). The median OS was 13.7 months with RT versus 9.2 months in the NRT group (p=0.008). The ORR was 35% (95% CI: 12.1-57.9) in the RT group versus 20% (95% CI: 0.8-39.2) in the NRT group.

Conclusions

The addition of RT may enhance the efficacy of toripalimab plus lenvatinib. Toripalimab plus lenvatinib with RT have a good safety profile without an increase in specific toxicities in advanced BTC patients.

Delineating the molecular landscape of different histopathological growth patterns in colorectal cancer liver metastases

Background

Histopathological growth patterns (HGPs) have shown important prognostic values for patients with colorectal cancer liver metastases, but the potential molecular mechanisms remain largely unknown.

Methods

We performed an exploratory analysis by conducting the RNA sequencing of primary colorectal lesions, colorectal liver metastatic lesions and normal liver tissues.

Findings

We found that desmoplastic HGPs of the metastatic lesions were significantly enriched in EMT, angiogenesis, stroma, and immune signaling pathways, while replacement HGPs were enriched in metabolism, cell cycle, and DNA damage repair pathways. With the exception of immune-related genes, the differentially expressed genes of the two HGPs from colorectal liver metastases were mostly inherited from the primary tumor. Moreover, normal liver tissue in the desmoplastic HGP subgroup was markedly enriched in the fibrinous inflammation pathway.

Conclusions

We surmised that HGPs are observable morphological changes resulting from the regulation of molecular expressions, which is the combined effect of the heterogeneity and remodeling of primary tumors seeds and liver soils.

Combined Radiomics-Clinical Model to Predict Radiotherapy Response in Inoperable Stage III and IV Non-Small-Cell Lung Cancer

Purpose: Radiotherapy is a promising treatment option for lung cancer, but patients' responses vary. The purpose of the study was to investigate the potential of radiomics and clinical signature for predicting the radiotherapy sensitivity and overall survival of inoperable stage III and IV non-small-cell lung cancer (NSCLC) patients. Materials: This retrospective study collected 104 inoperable stage III and IV NSCLC patients at the Yunnan Cancer Hospital from October 2016 to September 2020. They were divided into radiation-sensitive and non-sensitive groups. We used analysis of variance (ANOVA) to select features and support vector machine (SVM) to build the radiomic model. Furthermore, the logistic regression method was used to screen out clinically relevant predictive factors and construct the combined model of radiomics-clinical features. Finally, survival was estimated using the Kaplan-Meier method. Results: There were 40 patients in the radiation-sensitive group and 64 in the non-sensitive group. These patients were divided into training set (73 cases) and testing set (31 cases) according to the ratio of 7:3. Nine radiomics features and one clinical feature were significantly associated with radiotherapy sensitivity. Both the radiomics model and combined model have good predictive performance (the areas under the curve (AUC) values of the testing set were 0.864 (95% confidence interval [CI]: 0.683-0.996) and 0.868 (95% CI: 0.689-1.000), respectively). Only platelet level status was associated with overall survival. Conclusion: The combined model constructed based on radiomics and clinical features can effectively identify the radiation-sensitive population and provide valuable clinical information. Patients with higher platelet levels may have a poor prognosis.

FLASH X-ray spares intestinal crypts from pyroptosis initiated by cGAS-STING activation upon radioimmunotherapy

DNA-damaging treatments such as radiotherapy (RT) have become promising to improve the efficacy of immune checkpoint inhibitors by enhancing tumor immunogenicity. However, accompanying treatment-related detrimental events in normal tissues have posed a major obstacle to radioimmunotherapy and present new challenges to the dose delivery mode of clinical RT. In the present study, ultrahigh dose rate FLASH X-ray irradiation was applied to counteract the intestinal toxicity in the radioimmunotherapy. In the context of programmed cell death ligand-1 (PD-L1) blockade, FLASH X-ray minimized mouse enteritis by alleviating CD8⁺ T cell-mediated deleterious immune response compared with conventional dose rate (CONV) irradiation. Mechanistically, FLASH irradiation was less efficient than CONV X-ray in eliciting cytoplasmic double-stranded DNA (dsDNA) and in activating cyclic GMP-AMP synthase (cGAS) in the intestinal crypts, resulting in the suppression of the cascade feedback consisting of CD8⁺ T cell chemotaxis and gasdermin E-mediated intestinal pyroptosis in the case of PD-L1 blocking. Meanwhile, FLASH X-ray was as competent as CONV RT in boosting the antitumor immune response initiated by cGAS activation and achieved equal tumor control in metastasis burdens when combined with anti-PD-L1 administration. Together, the present study revealed an encouraging protective effect of FLASH X-ray upon the normal tissue without compromising the systemic antitumor response when combined with immunological checkpoint inhibitors, providing the rationale for testing this combination as a clinical application in radioimmunotherapy.

MRI-guided Radiotherapy (MRgRT) for treatment of Oligometastases: Review of clinical applications and challenges

PURPOSE

Early clinical results on the application of magnetic resonance imaging (MRI) coupled with a linear accelerator to deliver MR-guided radiation therapy (MRgRT) have demonstrated feasibility for safe delivery of stereotactic body radiotherapy (SBRT) in treatment of oligometastatic disease. Here we set out to review the clinical evidence and challenges associated with MRgRT in this setting.

METHODS AND MATERIALS

We performed a systematic review of the literature pertaining to clinical experiences and trials on the use of MRgRT primarily for the treatment of oligometastatic cancers. We reviewed the opportunities and challenges associated with the use of MRgRT.

RESULTS

Benefits of MRgRT pertaining to superior soft-tissue contrast, real-time imaging and gating, and online adaptive radiotherapy facilitate safe and effective dose escalation to oligometastatic tumors while simultaneously sparing surrounding healthy tissues. Challenges concerning further need for clinical evidence and technical considerations related to planning, delivery, quality assurance (QA) of hypofractionated doses, and safety in the MRI environment must be considered.

CONCLUSIONS

The promising early indications of safety and effectiveness of MRgRT for SBRT-based treatment of oligometastatic disease in multiple treatment locations should lead to further clinical evidence to demonstrate the benefit of this technology.

Real-world utilization of PD-1/PD-L1 inhibitors with palliative radiotherapy in patients with metastatic non-small cell lung cancer

Background

Programmed cell death protein 1 (PD‐1) blockade plus radiotherapy may be a promising strategy to improve the prognosis of patients with metastatic non‐small cell lung cancer (NSCLC). However, the optimum combined scheme, treatment time of radiotherapy, and irradiated lesion have not been fully determined.

Methods

A total of 321 metastatic NSCLC patients treated with immunotherapy were identified. Among them, 107 patients received PD‐1/PD‐ligand 1 (PD‐L1) inhibitors with radiotherapy, while the remaining cases did not receive radiotherapy. Data on overall survival (OS), progression‐free survival (PFS), treatment response and adverse events were collected. Comparisons based on type of radiation, timing of radiotherapy and number of irradiated lesions were performed.

Results

The median OS in PD‐1/PD‐L1 inhibitors plus radiotherapy was longer than in nonradiotherapy (22.8 vs. 16.6 months, p = 0.022). The median PFS showed a similar trend in this study (9.4 vs. 6.2 months, p = 0.042). Moreover, the combined strategy demonstrated a superior disease control rate and abscopal control rate versus without radiotherapy (both p ≤ 0.001). Further multivariate analysis in the immunotherapy and radiotherapy groups revealed that age below 65 (p = 0.004), Eastern Cooperative Oncology Group performance scores of 0–1 (p = 0.001), oligometastasis (p = 0.006), concurrent combination (p = 0.002), and treated with SRT (p = 0.013) were associated with longer OS. There was a similar incidence of adverse events between the two groups (both p ≥ 0.05).

Conclusions

The combination of PD‐1/PD‐L1 inhibitors plus palliative radiotherapy demonstrated favorable survival and good tolerability in metastatic NSCLC patients.

Predictors of Pneumonitis in Combined Thoracic Stereotactic Body Radiotherapy and Immunotherapy

PURPOSE

Thoracic stereotactic body radiotherapy (SBRT) is associated with high rates of local control but carries a risk of pneumonitis. Immunotherapy is a standard treatment for patients with metastatic disease but can also cause pneumonitis. To evaluate the feasibility and safety of thoracic SBRT with systemic immunotherapy, clinical outcomes of patients treated with immune checkpoint blockade (ICB) and SBRT on prospective trials were reviewed.

METHODS AND MATERIALS

Three consecutive phase 1 trials of combination SBRT and ICB conducted between 2016-2020 for widely metastatic solid tumors were reviewed. The protocols mandated adherence to NRG BR001/BR002 OAR constraints, resulting in <100% coverage of some target volumes. ICB was administered either sequentially (within 7 days after completion of SBRT) or concurrently (before or at the start of SBRT), depending on protocol. Endpoints included pneumonitis, dose-volume constraints, local failure, and overall survival (OS). The cumulative incidence estimator and Kaplan-Meier method were used.

RESULTS

123 patients met eligibility with 311 metastases irradiated. The most common histologies included non-small cell lung cancer (33%) and colorectal cancer (12%). Median follow up was 12 months. The overall rate of grade 3+ pneumonitis was 8.1%. 1-year local failure was 3.6%. Established dosimetric parameters were significantly associated with the development of pneumonitis (p<0.05). In most patients, the lungs were not challenged with high doses of radiation, defined as receiving ≥75% of the maximum for a given lung dose-volume constraint. Patients who were challenged were not found to have a significantly higher risk of pneumonitis.

CONCLUSIONS

In the largest series of thoracic SBRT and immunotherapy, local control was excellent with acceptable toxicity and support the conclusion that established dose-volume constraints for the lung are safe. However, these results highlight the potential value in reporting of OARs being challenged with doses approaching protocol specified limits.

Autophagy, ferroptosis, pyroptosis, and necroptosis in tumor immunotherapy

In recent years, immunotherapy represented by immune checkpoint inhibitors (ICIs) has led to unprecedented breakthroughs in cancer treatment. However, the fact that many tumors respond poorly or even not to ICIs, partly caused by the absence of tumor-infiltrating lymphocytes (TILs), significantly limits the application of ICIs. Converting these immune “cold” tumors into “hot” tumors that may respond to ICIs is an unsolved question in cancer immunotherapy. Since it is a general characteristic of cancers to resist apoptosis, induction of non-apoptotic regulated cell death (RCD) is emerging as a new cancer treatment strategy. Recently, several studies have revealed the interaction between non-apoptotic RCD and antitumor immunity. Specifically, autophagy, ferroptosis, pyroptosis, and necroptosis exhibit synergistic antitumor immune responses while possibly exerting inhibitory effects on antitumor immune responses. Thus, targeted therapies (inducers or inhibitors) against autophagy, ferroptosis, pyroptosis, and necroptosis in combination with immunotherapy may exert potent antitumor activity, even in tumors resistant to ICIs. This review summarizes the multilevel relationship between antitumor immunity and non-apoptotic RCD, including autophagy, ferroptosis, pyroptosis, and necroptosis, and the potential targeting application of non-apoptotic RCD to improve the efficacy of immunotherapy in malignancy.

Successful treatment of induced oligometastasis and repeated oligoprogression of advanced lung adenocarcinoma with immunotherapy and radiotherapy

Highly active and durable systemic therapies such as targeted therapy and immunotherapy can convert widespread metastatic disease into oligometastatic status, for which metastasis‐directed local intervention can control and potentially prolong survival. Radiation therapy is an effective therapeutic option for oligometastatic and oligoprogressive disease. Here, we present a case of induced oligometastasis and repeated oligoprogressive lung cancer in which more than 6 years of survival was achieved with a combination of immunotherapy and radiotherapy.

Tumor-activated carrier-free prodrug nanoparticles for targeted cancer Immunotherapy: Preclinical evidence for safe and effective drug delivery

As immunogenic cell death (ICD) inducers initiating antitumor immune responses, certain chemotherapeutic drugs have shown considerable potential to reverse the immunosuppressive tumor microenvironment (ITM) into immune-responsive tumors. The application of these drugs in nanomedicine provides a more enhanced therapeutic index by improving unfavorable pharmacokinetic (PK) profiles and inefficient tumor targeting. However, the clinical translation of conventional nanoparticles is restricted by fundamental problems, such as risks of immunogenicity and potential toxicity by carrier materials, premature drug leakage in off-target sites during circulation, low drug loading contents, and complex structure and synthetic processes that hinder quality control (QC) and scale-up industrial production. To address these limitations, tumor-activated carrier-free prodrug nanoparticles (PDNPs), constructed only by the self-assembly of prodrugs without any additional carrier materials, have been widely investigated with distinct advantages for safe and more effective drug delivery. In addition, combination immunotherapy based on PDNPs with other diverse modalities has efficiently reversed the ITM to immune-responsive tumors, potentiating the response to immune checkpoint blockade (ICB) therapy. In this review, the trends and advances in PDNPs are outlined, and each self-assembly mechanism is discussed. In addition, various combination immunotherapies based on PDNPs are reviewed. Finally, a physical tumor microenvironment remodeling strategy to maximize the potential of PDNPs, and key considerations for clinical translation are highlighted.

Association of Radiation Therapy With Risk of Adverse Events in Patients Receiving Immunotherapy: A Pooled Analysis of Trials in the US Food and Drug Administration Database

Importance

Immune checkpoint inhibitors (ICIs) and radiation therapy (RT) are widely used to treat various cancers, but little data are available to guide clinicians on ICI use sequentially with RT.

Objective

To assess whether there is an increased risk of serious adverse events (AEs) associated with RT given within 90 days prior to an ICI.

Design, Setting, and Participants

Individual patient data were pooled from 68 prospective trials of ICIs submitted in initial or supplemental licensing applications in the US Food and Drug Administration (FDA) databases through December 2019. Two cohorts were generated: (1) patients who received RT within the 90 days prior to beginning ICI therapy and (2) those who did not receive RT within the 90 days prior to beginning ICI therapy, and AE frequencies were determined. A 1:1 propensity score-matched analysis was performed.

Interventions

All patients received an ICI (atezolizumab, avelumab, cemiplimab, durvalumab, ipilimumab, nivolumab, or pembrolizumab); 1733 received RT within the 90 days prior to starting ICI therapy, and 13 956 did not.

Main Outcomes and Measures

The primary outcome was frequency and severity of AEs. Incidence of AEs was compared descriptively between participants who did vs did not receive RT in the propensity score-matched set. Because all analyses are exploratory (ie, not preplanned and no alpha allocated), assessment for statistical significance of the differences between groups was not considered appropriate.

Results

A total of 25 469 patients were identified; 8634 were excluded because they lacked comparators who had received RT (n = 976), did not receive an ICI (n = 4949), received RT outside of the target window (n = 2338), or had missing data in 1 or more variables used in the propensity analysis (n = 371), leaving 16 835 patients included in the analysis. The majority were younger than 65 years (9447 [56.1%]), male (10 459 [62.1%]), and White (13 422 [79.7%]). Patients receiving RT had generally similar rates of AEs overall to those patients who did not receive RT. The average absolute difference in rates across the AEs was 1.2%, and the difference ranged from 0% for neurologic AEs to 8% for fatigue. No difference in grade 3 to 4 AEs was observed between the 2 groups (absolute difference ranged from 0.01% to 2%). These findings persisted after propensity score matching.

Conclusions and Relevance

In this pooled analysis, administration of an ICI within 90 days following RT did not appear to be associated with an increased risk of serious AEs. Thus, it would appear to be safe to administer an ICI within 90 days of receiving RT. These findings should be confirmed in future prospective trials.

Durable Metastatic Melanoma Remission Following Pembrolizumab and Radiotherapy: A Case Report of Prophylactic Immunosuppression in a Patient with Myasthenia Gravis and Immune-Mediated Colitis

Immune checkpoint inhibitors (ICIs) and radiotherapy (RT) combinations for various metastatic cancers are increasingly utilized, yet the augmentation of anti-cancer immunity including distant tumor responses by RT remains ill-characterized. Immunosuppressive tumor microenvironments and defective anti-tumor immune activation including immune-related adverse events (irAEs) likely limit dramatic immuno-radiotherapy combinations, though it remains unclear which immune characteristics mediate dramatic systemic tumor regression in only a small subset of patients. Moreover, the efficacy of ICI treatment in patients receiving immunosuppressive therapies for autoimmune conditions or irAEs is convoluted, yet clinically valuable. Here, we report a case of a 75-year-old man with myasthenia gravis and metastatic melanoma who experienced complete and durable systemic regression after receiving pembrolizumab and single-lesion RT while on prednisone for myasthenia gravis prophylaxis and vedolizumab for immune-mediated colitis after previously experiencing mixed response on pembrolizumab monotherapy. We discuss the potential paradoxical effects and clinical considerations of immunosuppressive regimens in patients with underlying autoimmune disease or adverse immune reactions while receiving immuno-radiotherapy combinations.

Crossed Pathways for Radiation-Induced and Immunotherapy-Related Lung Injury

Radiation-induced lung injury (RILI) is a form of radiation damage to normal lung tissue caused by radiotherapy (RT) for thoracic cancers, which is most commonly comprised of radiation pneumonitis (RP) and radiation pulmonary fibrosis (RPF). Moreover, with the widespread utilization of immunotherapies such as immune checkpoint inhibitors as first- and second-line treatments for various cancers, the incidence of immunotherapy-related lung injury (IRLI), a severe immune-related adverse event (irAE), has rapidly increased. To date, we know relatively little about the underlying mechanisms and signaling pathways of these complications. A better understanding of the signaling pathways may facilitate the prevention of lung injury and exploration of potential therapeutic targets. Therefore, this review provides an overview of the signaling pathways of RILI and IRLI and focuses on their crosstalk in diverse signaling pathways as well as on possible mechanisms of adverse events resulting from combined radiotherapy and immunotherapy. Furthermore, this review proposes potential therapeutic targets and avenues of further research based on signaling pathways. Many new studies on pyroptosis have renewed appreciation for the value and importance of pyroptosis in lung injury. Therefore, the authors posit that pyroptosis may be the common downstream pathway of RILI and IRLI; discussion is also conducted regarding further perspectives on pyroptosis as a crucial signaling pathway in lung injury treatment.

Tumor metastasis: Mechanistic insights and therapeutic interventions

Cancer metastasis is responsible for the vast majority of cancer-related deaths worldwide. In contrast to numerous discoveries that reveal the detailed mechanisms leading to the formation of the primary tumor, the biological underpinnings of the metastatic disease remain poorly understood. Cancer metastasis is a complex process in which cancer cells escape from the primary tumor, settle, and grow at other parts of the body. Epithelial-mesenchymal transition and anoikis resistance of tumor cells are the main forces to promote metastasis, and multiple components in the tumor microenvironment and their complicated crosstalk with cancer cells are closely involved in distant metastasis. In addition to the three cornerstones of tumor treatment, surgery, chemotherapy, and radiotherapy, novel treatment approaches including targeted therapy and immunotherapy have been established in patients with metastatic cancer. Although the cancer survival rate has been greatly improved over the years, it is still far from satisfactory. In this review, we provided an overview of the metastasis process, summarized the cellular and molecular mechanisms involved in the dissemination and distant metastasis of cancer cells, and reviewed the important advances in interventions for cancer metastasis.

Bioengineered miR-124-3p prodrug selectively alters the proteome of human carcinoma cells to control multiple cellular components and lung metastasis in vivo

With the understanding of microRNA (miRNA or miR) functions in tumor initiation, progression, and metastasis, efforts are underway to develop new miRNA-based therapies. Very recently, we demonstrated effectiveness of a novel humanized bioengineered miR-124-3p prodrug in controlling spontaneous lung metastasis in mouse models. This study was to investigate the molecular and cellular mechanisms by which miR-124-3p controls tumor metastasis. Proteomics study identified a set of proteins selectively and significantly downregulated by bioengineered miR-124-3p in A549 cells, which were assembled into multiple cellular components critical for metastatic potential. Among them, plectin (PLEC) was verified as a new direct target for miR-124-3p that links cytoskeleton components and junctions. In miR-124-3p-treated lung cancer and osteosarcoma cells, protein levels of vimentin, talin 1 (TLN1), integrin beta-1 (ITGB1), IQ motif containing GTPase activating protein 1 (IQGAP1), cadherin 2 or N-cadherin (CDH2), and junctional adhesion molecule A (F11R or JAMA or JAM1) decreased, causing remodeling of cytoskeletons and disruption of cell-cell junctions. Furthermore, miR-124-3p sharply suppressed the formation of focal adhesion plaques, leading to reduced cell adhesion capacity. Additionally, efficacy and safety of biologic miR-124-3p therapy was established in an aggressive experimental metastasis mouse model in vivo. These results connect miR-124-3p-PLEC signaling to other elements in the control of cytoskeleton, cell junctions, and adhesion essential for cancer cell invasion and extravasation towards metastasis, and support the promise of miR-124 therapy.

The International Society of RNA Nanotechnology and Nanomedicine (ISRNN): The Present and Future of the Burgeoning Field

The International Society of RNA Nanotechnology and Nanomedicine (ISRNN) hosts an annual meeting series focused on presenting the latest research achievements involving RNA-based therapeutics and strategies, aiming to expand their current biomedical applications while overcoming the remaining challenges of the burgeoning field of RNA nanotechnology. The most recent online meeting hosted a series of engaging talks and discussions from an international cohort of leading nanotechnologists that focused on RNA modifications and modulation, dynamic RNA structures, overcoming delivery limitations using a variety of innovative platforms and approaches, and addressing the newly explored potential for immunomodulation with programmable nucleic acid nanoparticles. In this Nano Focus, we summarize the main discussion points, conclusions, and future directions identified during this two-day webinar as well as more recent advances to highlight and to accelerate this exciting field.

Radiotherapy and immunotherapy: open questions and future strategies

Immune checkpoint blockade (ICB) improves outcomes for some patients with advanced or metastatic cancers. Despite demonstrable progress, many patients do not respond to ICB. Recently, clinical trials have focused on combinations of ICB with radiation therapy. Although two recent Phase III randomized trials demonstrated improved survival with adjuvant ICB following chemoradiation, other Phase I/II/III trials are either negative or inconclusive, but do yield suggestive results and promising insights into future therapeutic strategies. We provide a selective review of a subset of these trials and attempt to integrate with basic laboratory findings where relevant to define issues pertaining to the combination of radiotherapy and immunotherapy.

Turning tumors from cold to inflamed to improve immunotherapy response

Immune checkpoint inhibitors have revolutionized the treatment landscape for a number of cancers over the last few decades. Nevertheless, a majority of patients still do not benefit from these treatments. Such patient-specific lack of response can be predicted, in part, from the immune phenotypes present in the tumor microenvironment. We provide a perspective on options to reprogram the tumors and their microenvironment to increase the therapeutic efficacy of immunotherapies and expand their efficacy against cold tumors. Additionally, we review data from current preclinical and clinical trials aimed at testing the different therapeutic options in monotherapy or preferably in combination with checkpoint inhibitors.

[Abscopal effect: Myth or reality?]

The abscopal effect has been mentioned since 1953. The increase in knowledge about the immune system and the development of immunotherapies support its potential therapeutic interest. While it is accepted that radiotherapy induces an immune response, demonstrating its systemic impact is not easy. The preclinical basis is solid but its clinical validation pending. Radiotherapy rarely induces tumor reduction at a distance from the beams, probably due to its immunosuppressive effect. This is why a synergy between radiotherapy and systemic treatments targeting these immunosuppressive mechanisms was observed. Several parameters can modulate the induction of the abscopal effect. Among these, the fractionation of the dose seems to be determining with currently a pre-eminence of hypofractionated stereotaxis. On the other hand, even if the choice of more immunogenic targets (liver, lung) should be favoured, the optimal number of lesions to be irradiated remains to be defined as well as the minimum volume allowing sufficient release of tumor antigens. The impact of radiation-induced lymphopenia on radiotherapy/immunotherapy efficacy needs to be assessed more precisely, as does the effect of radiotherapy techniques on them. Finally, the choice of immunotherapy(ies) and the combination regimen with radiotherapy remain under discussion. A sequential scheme appears to provide less toxicities but the concomitant would lead to a better response. The study of these different parameters should allow us to deliver optimized radiotherapy/immunotherapy(ies) combinations to our metastatic patients in order to benefit as many people as possible from this abscopal effect.

Radiochemotherapy upregulates expression of checkpoint receptors on circulating T cells

PURPOSE

This study assesses changes of circulating leukocyte subpopulations and the expression of checkpoint receptors in T cells in patients undergoing radiochemotherapy.

MATERIALS AND METHODS

Fifty-seven patients with either esophageal cancer or cervical cancer who received radiochemotherapy were recruited into this study. Serial blood collection was carried out before and during treatments. Leukocyte subpopulations and the level of PD-1 and CTLA-4 in T cells were determined by flow cytometry. The plasma concentrations of 34 human cytokines, chemokines, and growth factors were quantified.

RESULTS

Significant decreases of lymphocyte count and percentage of T cells and B cells were observed during radiochemotherapy. Percentages of PD-1^hi and CTLA-4^hi populations in T cells increased after treatments. Proportion of activated T cells showed no significant difference. No significant changes in the plasma concentrations of the 34 humoral mediators except mild decreases of six cytokines.

CONCLUSION

Elevated expression of PD-1 and CTLA-4 in T cells in patients receiving radiochemotherapy, which suggests that exhaustion-like T-cell dysfunction develops during cancer cytotoxic treatments.

Predictive Role of Prior Radiotherapy and Immunotherapy-Related Adverse Effects in Advanced NSCLC Patients Receiving Anti-PD-1/L1 Therapy

The present study evaluated the impact of prior radiotherapy (RT) on patients with advanced non-small cell lung cancer (NSCLC) receiving therapy with immune checkpoint inhibitors (ICIs) and further assessed the prognostic factors in patients receiving both RT and ICI. Patients diagnosed with NSCLC at the Catholic Medical Center and Asan Medical Center between January 2016 and October 2020 and who received immunotherapy were retrospectively reviewed. Among 240 patients, poor Eastern Cooperative Oncology Group (ECOG) score, high PD-L1 expression, and ICI-related adverse events (AE) were significantly associated with progression-free survival (PFS) (HR, 2.654; 95% CI, 1.484–4.749; p = 0.001; HR, 0.645; 95% CI, 0.449–0.926, p = 0.017; HR, 0.430; 95% CI, 0.229–0.808; p = 0.009, respectively). Among patients who received both RT and immunotherapy, poor ECOG status, squamous cell carcinoma, and ICI-related AE were significant factors associated with poor PFS (HR, 2.430; 95% CI, 1.464–4.034; p = 0.001; HR, 0.667; 95% CI, 0.455–0.978, p = 0.038; HR, 0.520; 95% CI, 0.284–0.953, p = 0.034, respectively). The present study showed that prior RT showed no significant independent association with primary outcomes in patients with advanced NSCLC receiving immunotherapy. In patients who received both RT and immunotherapy, clinical parameters, including ICI-related AEs, were independently predictive of PFS.

Downstaging and resection of hepatocellular carcinoma in patients with extrahepatic metastases after stereotactic therapy

BACKGROUND

A combination of tyrosine kinase inhibitors (TKIs) and anti-PD-1 antibodies with local regional therapy has elicited yield substantial clinical benefits in patients who have hepatocellular carcinoma (HCC) with extrahepatic metastases. Using this treatment strategy to convert HCC patients with extrahepatic metastases from unresectable to resectable has not yet been reported.

METHODS

Consecutive hepatocellular carcinoma patients with extrahepatic metastases who received first-line therapy with a combination of TKIs and anti-PD-1 antibodies and at least one local regional therapy were analysed.

RESULTS

Nine patients with localized disease who received first-line systemic therapy were enrolled. At baseline, all of them had oligometastatic disease, namely, Barcelona Clinic Liver Cancer stage C (or Chinese Liver Cancer stage IIIB). The most common treatment administered was lenvatinib plus anti-PD-1 antibody and transarterial chemoembolization, and the median time span from systemic therapy to surgery was 3.2 (IQR, 2.8-6.2) months. Three patients achieved a pathological complete response. Six patients underwent laparoscopic surgery, and the other 3 patients underwent open surgery. After a median follow-up of 10.2 (IQR, 8.6-20.0) months, 7 patients survived without disease recurrence, and 2 experienced tumour recurrence. All patients had any-grade AEs, and 55.6% of the patients experienced grade 3 AEs. Fatigue was the most common AE, followed by elevated aminotransferase levels and hypertension.

CONCLUSIONS

Stereotactic therapy is a feasible conversion therapy for HCC patients with extrahepatic metastases to become resectable. This is the first study to analyse therapeutic outcomes of patients receiving these therapies for HCC with extrahepatic metastases.

Ferroptosis in the tumor microenvironment: perspectives for immunotherapy

Targeting ferroptosis, which provokes lipid peroxidation in cancer cells, presents potentially new avenues for anticancer therapy. Recent studies have begun to explore how immune cells in the tumor microenvironment (TME) respond and adapt to lethal lipid peroxides (LPOs). A better understanding of this process in the TME is likely to uncover another side of ferroptosis in cancer immunity and promote the development of ferroptosis-targeted therapy. This Opinion article overviews the main metabolic processes in ferroptosis, summarizes the emerging roles of ferroptosis not only in immune cells in the TME but also in the crosstalk between tumor cells and immune cells, and presents a perspective on the targeting of ferroptosis in cancer immunotherapy.

Radiotherapy and immunotherapy converge on elimination of tumor-promoting erythroid progenitor cells through adaptive immunity

Tumor-induced CD45^-Ter119⁺CD71⁺ erythroid progenitor cells, termed "Ter cells," promote tumor progression by secreting artemin (ARTN), a neurotrophic peptide that activates REarranged during Transfection (RET) signaling. We demonstrate that both local tumor ionizing radiation (IR) and anti-programmed death ligand 1 (PD-L1) treatment decreased tumor-induced Ter cell abundance in the mouse spleen and ARTN secretion outside the irradiation field in an interferon- and CD8⁺ T cell-dependent manner. Recombinant erythropoietin promoted resistance to radiotherapy or anti-PD-L1 therapies by restoring Ter cell numbers and serum ARTN concentration. Blockade of ARTN or potential ARTN signaling partners, or depletion of Ter cells augmented the antitumor effects of both IR and anti-PD-L1 therapies in mice. Analysis of samples from patients who received radioimmunotherapy demonstrated that IR-mediated reduction of Ter cells, ARTN, and GFRα3, an ARTN signaling partner, were each associated with tumor regression. Patients with melanoma who received immunotherapy exhibited favorable outcomes associated with decreased expression of GFRα3. These findings demonstrate an out-of-field, or "abscopal," effect mediated by adaptive immunity, which is induced during local tumor irradiation. This effect, in turn, governs the therapeutic effects of radiation and immunotherapy. Therefore, our results identify multiple targets to potentially improve outcomes after radiotherapy and immunotherapy.

How to optimize the incorporation of immunotherapy in trials for oligometastatic non-small cell lung cancer: a narrative review

Patients with oligometastatic disease (OMD) non-small cell lung cancer (NSCLC) are considered as a subgroup of metastatic NSCLC that can obtain long-term survival or even cure. Oligometastatic refers to a state of a limited number of metastases in a limited number of organs. In clinical guidelines it is stated that patients with oligometastatic NSCLC can benefit from the addition of local radical therapy (LRT) to systemic therapy. With the introduction of minimally invasive surgery, advances in interventional radiology and stereotactic radiotherapy (SRT), LRT is becoming feasible for more and more patients. Furthermore, the introduction of immune checkpoint inhibitors (ICI) in the treatment landscape of advanced NSCLC has improved the survival of these patients. Importantly, the use of ICI in combination with LRT is also of interest in the subgroup of NSCLC patients with OMD. For example, it has been suggested that SRT may synergize with ICI as several preclinical studies reported an increased tumor antigen release, improved antigen presentation, and T-cell infiltration in irradiated tumors. In this narrative review, we describe the current evidence of immunotherapy treatment in OMD NSCLC, with a focus on future trial design and problems that need to be addressed.