Radiotherapy For Non-small Cell Lung Cancer Research Articles

BIBR1532 combined with radiotherapy induces ferroptosis in NSCLC cells and activates cGAS-STING pathway to promote anti-tumor immunity

BackgroundTelomerase, by safeguarding damaged telomeres and bolstering DNA damage repair, has the capacity to heighten the radioresistance of tumour cells. Thus, in turn, can compromise the efficacy of radiotherapy (RT) and radioimmunotherapy. Our previous studies have revealed that the highly selective telomerase inhibitor, BIBR1532, possesses the potential to enhance the radiosensitivity of Non-small cell lung cancer (NSCLC). In this study, we delve further into the impact of BIBR1532 on the immune activation induced by RT and elucidate the underlying mechanisms.MethodsBiological information analyses, immunofluorescence assays, western blot assays, flow cytometry analysis were conducted to elucidate the functions of the combination of BIBR1532 with radiotherapy in NSCLC. Intracellular levels of lipid peroxides, glutathione, malondialdehyde, and Fe2+ were measured as indicators of ferroptosis status. Both in vitro and in vivo studies were conducted to examine the antitumor effects.ResultsOur findings indicate that the confluence of BIBR1532 with RT significantly augments the activation of the cGAS-STING pathway in both in vivo and in vitro settings, thereby fostering an effective anti-tumoral immune response. The effects can be ascribed to two key processes. Firstly, ionizing radiation, in precipitating DNA double-strand breaks (DSBs), prompts the release of tumour-derived double-stranded DNA (dsDNA) into the cytoplasm. Subsequently, BIBR1532 amplifies the activation of antigen-presenting cells by dsDNA post-RT and instigates the cGAS-STING pathway. Secondly, BIBR1532 enhances the ferroptosis response in NSCLC following RT, thereby promoting unrestrained lipid peroxidation and elevated levels of reactive oxygen species (ROS) within tumour cells. This ultimately leads to mitochondrial stress and the release of endogenous mitochondrial DNA (mtDNA) into the cytoplasm, thus facilitating the activation of the STING pathway and the induction of a type I interferon (IFN)-linked adaptive immune response.ConclusionThis study underscores the potential of BIBR1532 as an efficacious and safe radiosensitizer and radioimmunotherapy synergist, providing robust preclinical research evidence for the treatment of NSCLC.

T790M mutation sensitizes non-small cell lung cancer cells to radiation via suppressing SPOCK1

BackgroundApproximately 50% of patients harbor the T790M mutation after developing first-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) resistance. Evidence has showed the major treatment failure is local relapses and limited metastases. Several studies have demonstrated the value of radiotherapy in metastatic non-small cell lung cancer (NSCLC) with the EGFR T790M mutation after the development of TKI resistance. The aim of this study was to explore the role of radiation in T790M-mutant NSCLC and the value of early radiotherapy for NSCLC with T790M-mediated EGFR-TKI resistance. MethodsGefitinib-resistant NSCLC cell lines were established via stepwise exposure to increasing concentrations of gefitinib (PC-9-GR). Droplet digital PCR was used to determine the relative T790M subclone abundance. In vitro and in vivo models were established using different mixtures of PC-9-GR and PC-9 cells. Differentially expressed genes were identified using RNA sequencing. Two research models were constructed (salvage and prophylactic radiotherapy) to determine the effects of early radiotherapy on gefitinib-resistant cells. ResultsPC-9-GR cells exhibited higher radiosensitivity than PC-9 cells (sensitivity enhancement ratio = 1.5). Salvage radiation reduced the number of T790M-mutant subclones, and the relative T790M abundance was significantly lower than that without radiation at 90 days (10.94% vs. 21.54%). Prophylactic radiation prevented the development of T790M subclones. These results were also confirmed in vivo. qRT-PCR revealed threefold elevation of miR-1243 in PC-9-GR cells, and the increased radiosensitivity of PC-9-GR cells was inhibited when miR-1243 was knocked down. RNA sequencing revealed that SPOCK1 was downregulated in PC-9-GR cells. Interestingly, bioinformatic analysis showed that SPOCK1 was a target gene of miR-1243. SPOCK1 knockdown markedly increased the radiosensitivity of PC-9 cells. ConclusionGefitinib-resistant NSCLC with the T790M mutation had higher radiosensitivity than that without the mutation, possibly mediated by SPOCK1. Early radiotherapy can eliminate T790M subclones, providing evidence for the benefit of early local treatment in patients with TKI-resistant NSCLC.

Mogrol-mediated enhancement of radiotherapy sensitivity in non-small cell lung cancer: a mechanistic study.

This study investigated mogrol's impact on non-small cell lung cancer (NSCLC) radiosensitivity and underlying mechanisms, using various methods including assays, bioinformatics, and xenograft models. CCK-8, clonogenic, flow cytometry, TUNEL, and Western blot assays evaluated mogrol and radiation effects on NSCLC viability and apoptosis. Ubiquitin-specific protease 22 (USP22) expression in NSCLC patient tissues was determined by RT-qPCR and Western blot. A xenograft model validated mogrol's effects on tumor growth. Bioinformatics identified four ubiquitin-specific proteases, including USP22, in NSCLC. Kaplan-Meier analysis confirmed USP22's value in lung cancer survival. Human Protein Atlas (HPA) database analysis indicated higher USP22 expression in lung cancer tissues. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis implicated ERK1/2 in NSCLC progression, and molecular docking showed stability between mogrol and ERK1/2. Further in vivo and in vitro experiments have demonstrated that mogrol enhances the inhibitory effect of radiation on NSCLC cell viability and clonogenic capacity. Cell viability and clonogenic capacity are reduced by >50%, and an increase in cellular apoptosis is observed, with apoptotic levels reaching 10%. USP22 expression was significantly elevated in NSCLC tissues, particularly in radiotherapy-resistant patients. Mogrol downregulated USP22 expression by inhibiting the ERK/CREB pathway, lowering COX2 expression. Mogrol also enhanced radiation's inhibition of tumor growth in mice. Mogrol enhances NSCLC radiosensitivity by downregulating USP22 via the ERK/CREB pathway, leading to reduced COX2 expression.NEW & NOTEWORTHY Mogrol enhances non-small cell lung cancer (NSCLC) cell sensitivity to radiotherapy by downregulating USP22 through the ERK/CREB pathway, reducing COX2 expression. These findings highlight mogrol's potential as an adjunct to improve NSCLC radiotherapy and open avenues for further research and clinical applications.

Abstract 695: Enhancing radiotherapy with lenvatinib by targeting the CXCL13/CXCR5/NF-ΚB axis

Abstract Lung cancer is the leading cause of cancer death worldwide, with non-small cell lung cancer (NSCLC) accounting for approximately 85% of all lung cancers. At the time of diagnosis, it is often already advanced or metastatic, resulting in poor treatment outcomes. Treatment of NSCLC mainly relies on surgery, radiation and chemotherapy, but the survival rate has not increased significantly in the past decade. Therefore, finding appropriate treatment methods is necessary and crucial. Radiotherapy (RT) is a frequently employed approach for tumor treatment and serves as the primary local treatment for NSCLC. However, it often results in a poor prognosis and severe side effects when administered at high-dose irradiation. Existing literature suggests that RT may trigger the expression of nuclear factor kappa B (NF-ΚB), potentially compromising its therapeutic efficacy. Consequently, the question remains: Can targeting NF-ΚB signaling enhance the sensitivity of RT in NSCLC Furthermore, studies have indicated that elevated levels of CXCR5 in NSCLC contribute to tumor growth. CXCR5 is situated upstream of the NF-ΚB pathway. As a result, it becomes imperative and indispensable to develop strategies targeting the CXCL13/CXCR5/NF-ΚB signaling axis to counteract NSCLC growth. Lenvatinib is a multi-kinase inhibitor targeted drug. It has been proven to inhibit VEGFR1-3, FGFR1-4 and PDGFR, inhibiting tumor growth. Lenvatinib has received clinical approval from the US FDA for the treatment of advanced hepatocellular carcinoma (HCC) and has been shown to inhibit NF-ΚB expression in HCC. However, the potential radiation-sensitizing mechanism of Lenvatinib in lung cancer remains unexplored. This study is dedicated to investigating the effects and molecular mechanisms of combining Lenvatinib with radiotherapy in NSCLC. Our results suggest that lenvatinib may enhance the sensitivity of NSCLC to RT. Furthermore, evidence from both the intrinsic and extrinsic apoptosis pathways (Caspase-3/Caspase-8/Caspase-9) and TUNEL experiments supports the idea that the combined treatment of lenvatinib with RT induces a more pronounced apoptotic response compared to individual treatments. Additionally, silencing CXCR5 in NSCLC also appears to enhance its responsiveness to RT. In our western blot (p-ATM, p-CHK2), flow cytometry (p-ATM), we showed that the combination of lenvatinib and RT may effective induce DNA damage. Our in vivo data demonstrates that the combination of Lenvatinib and RT exhibits superior tumor growth inhibition. Immunohistochemistry (IHC) staining of tumor tissue also revealed an upregulation of apoptosis-related proteins and the downregulation of CXCL13/CXCR5/NF-ΚB related proteins. In conclusion, our findings suggest that Lenvatinib can serve as a radiosensitizer, enhancing the sensitivity of NSCLC patients to radiotherapy by targeting the CXCL13/CXCR5/NF-ΚB signaling pathway. Citation Format: Tsai-Lan Liao, I-Tsang Chiang, Bo-Han Huang, Fei-Ting Hsu, Ming-Hsien Chan. Enhancing radiotherapy with lenvatinib by targeting the CXCL13/CXCR5/NF-ΚB axis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 695.

Abstract 703: GABA(A) receptor activation drives GABARAP-Nix mediated autophagy to radiosensitize primary and metastatic lung adenocarcinoma tumors

Abstract In non-small cell lung cancer (NSCLC) treatment, targeted therapies help a subset of patients, and radiotherapy responses are not durable and toxicity limits therapy. Most advanced-stage NSCLC patients have brain metastases that render an abysmal prognosis. Standard-of-care radiation therapy for NSCLC brain metastasis includes stereotactic radiosurgery (SRS) if the number of lesions is less than ten, otherwise whole brain radiation therapy (WBRT) is administered. Challenges in applying radiotherapy include overcoming radiation resistance and reducing significant associated co-morbidities. Cancer neuroscience is an evolving area, and the purpose of this study is to determine if activation of GABA(A) receptors intrinsic to NSCLC cells can improve radiation efficacy in primary NSCLC and its brain metastasis. We find that a GABA(A) receptor activator, AM-101, impairs the viability and clonogenicity of NSCLC primary and brain metastatic cells. Employing a human-relevant ex vivo ‘chip’, AM-101 is as efficacious as docetaxel, a chemotherapeutic used with radiotherapy for advanced-stage NSCLC. In vivo, AM-101 potentiates radiation, including conferring a significant survival benefit to mice bearing NSCLC intracranial tumors generated using a patient-derived metastatic line. GABA(A) receptor activation stimulates a selective-autophagic response via multimerization of GABA(A) Receptor-Associated Protein (GABARAP), stabilization of mitochondrial receptor Nix, utilization of ubiquitin-binding protein p62, and upregulation of Beclin-1. A high-affinity peptide disrupting Nix binding to GABARAP inhibits the cytotoxicity of AM-101. This supports a model of GABA(A) receptor activation driving a GABARAP-Nix multimerization axis that triggers autophagy. In NSCLC brain metastases patients, GABA(A) receptor activation may improve radiation efficacy and tumor control while allowing radiation dose de-intensification to reduce toxicity. Citation Format: Debanjan Bhattacharya, Riccardo Barrile, Donatien Kamdem Toukam, Vaibhavkumar S. Gawali, Laura Kallay, Taukir Ahmed, Hawley Brown, Sepideh Rezvanian, Aniruddha Karve, Pankaj B. Desai, Mario Medvedovic, Kyle Wang, Dan Ionascu, Nusrat Harun, Chenran Wang, Andrew M. Baschnagel, Joshua A. Kritzer, James Cook, Daniel A. Pomeranz Krummel, Soma Sengupta. GABA(A) receptor activation drives GABARAP-Nix mediated autophagy to radiosensitize primary and metastatic lung adenocarcinoma tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 703.

Enhancing non-small cell lung cancer radiotherapy planning: A deep learning-based multi-modal fusion approach for accurate GTV segmentation

In the treatment of non-small cell lung cancer (NSCLC), radiotherapy is pivotal. However, manual segmentation of the gross target volume (GTV) is both time-consuming and prone to errors. This study presents an automated solution using deep learning-based multi-modal fusion for efficient GTV segmentation. The method integrates data from CT, and PET images, enhancing GTV segmentation precision. Key features include intensity normalization and random cropping, which ensure data integration and variety. The system's core is the 3D U-Net, extracting detailed features from CT images, and the DeepLab network managing multi-modal fusion. The 3D Unet-DeepLab model demonstrates superior performance with a Dice Similarity Coefficient (DSC) of 0.7502, outperforming the 3D ResSE-Unet. Additionally, the 3D Unet_4B model surpasses existing techniques, with a DSC of 0.7502 and a Hausdorff Distance 95 mm (HD95) of 19.78 mm. These results confirm the method's capability in improving GTV segmentation precision and spatial consistency. Automating segmentation through this innovative method not only refines tumor targeting but also minimizes potential damage to healthy tissues, offering implications for personalized radiotherapy planning and enhanced NSCLC treatment outcomes.

Pulmonary vein dose and risk of atrial fibrillation in patients with non-small cell lung cancer following definitive radiotherapy: An NI-HEART analysis

Background and purposeSymptomatic arrhythmia is common following radiotherapy for non-small cell lung cancer (NSCLC), frequently resulting in morbidity and hospitalization. Modern treatment planning technology theoretically allows sparing of cardiac substructures. Atrial fibrillation (AF) comprises the majority of post-radiotherapy arrhythmias, but efforts to prevent this cardiotoxicity have been limited as the causative cardiac substructure is not known. In this study we investigated if incidental radiation dose to the pulmonary veins (PVs) is associated with AF. Material and methodsA single-centre study of patients completing contemporary (chemo)radiation for NSCLC, with modern planning techniques. Oncology, cardiology and death records were examined, and AF events were verified by a cardiologist. Cardiac substructures were contoured on planning scans for retrospective dose analysis. ResultsIn 420 eligible patients with NSCLC treated with intensity-modulated (70%) or 3D-conformal (30%) radiotherapy with a median OS of 21.8 months (IQR 10.8–35.1), there were 26 cases of new AF (6%). All cases were grade 3 except two cases of grade 4. Dose metrics for both the left (V55) and right (V10) PVs were associated with the incidence of new AF. Metrics remained statistically significant after accounting for the competing risk of death and cardiovascular covariables for both the left (HR 1.02, 95%CI 1.00–1.03, p = 0.005) and right (HR 1.01 (95%CI 1.00–1.02, p = 0.033) PVs. ConclusionRadiation dose to the PVs during treatment of NSCLC was associated with the onset of AF. Actively sparing the PVs during treatment planning could reduce the incidence of AF during follow-up, and screening for AF may be warranted for select cases.

Deep Learning-based Lung dose Prediction Using Chest X-ray Images in Non-small Cell Lung Cancer Radiotherapy.

This study aimed to develop a deep learning model for the prediction of V20 (the volume of the lung parenchyma that received ≥20 Gy) during intensity-modulated radiation therapy using chest X-ray images. The study utilized 91 chest X-ray images of patients with lung cancer acquired routinely during the admission workup. The prescription dose for the planning target volume was 60 Gy in 30 fractions. A convolutional neural network-based regression model was developed to predict V20. To evaluate model performance, the coefficient of determination (R2), root mean square error (RMSE), and mean absolute error (MAE) were calculated with conducting a four-fold cross-validation method. The patient characteristics of the eligible data were treatment period (2018-2022) and V20 (19.3%; 4.9%-30.7%). The predictive results of the developed model for V20 were 0.16, 5.4%, and 4.5% for the R2, RMSE, and MAE, respectively. The median error was -1.8% (range, -13.0% to 9.2%). The Pearson correlation coefficient between the calculated and predicted V20 values was 0.40. As a binary classifier with V20 <20%, the model showed a sensitivity of 75.0%, specificity of 82.6%, diagnostic accuracy of 80.6%, and area under the receiver operator characteristic curve of 0.79. The proposed deep learning chest X-ray model can predict V20 and play an important role in the early determination of patient treatment strategies.

The Correlation Between Low-Dose Radiotherapy Area of the Mediastinum and CD8+T Cells and the Efficacy of Radiotherapy for Non-Small Cell Lung Cancer.

Radiation therapy (RT) can cause changes in peripheral blood immune cells. The relationship between the efficacy of radiation therapy for non-small cell lung cancer (NSCLC) and immune cell changes and the study of how mediastinal radiation dose parameters affect immune cell changes is still unclear. This study aims to analyze the relationship between immune cell changes induced by radiotherapy and the efficacy of NSCLC radiotherapy, as well as the relationship between radiotherapy dose parameters and immune cell changes. We retrospectively analyzed the data of NSCLC patients receiving mediastinal radiation therapy from 2020 to 2022. Collect lymphocytes and circulating immune cells within one week before and after radiotherapy and collect the dose-volume parameters of the whole mediastinum in the patient's RT planning system. Analyze the changes in lymphocytes and radiotherapy effects after radiotherapy, and explore the relationship between radiotherapy dose parameters and immune cell changes. A total of 72 patients were enrolled. Compared with before radiotherapy, the proportion of CD3+T cells, CD8+T cells, and CD8/Treg in peripheral blood significantly increased after radiotherapy (P<0.05). The increase in CD8+T cells and CD8/Treg after radiotherapy was correlated with Objective response rate (ORR) (P<0.05). Based on binary logistic univariate and multivariate regression analysis, an increase in CD8+T cells after radiotherapy is an independent predictor of objective tumor response after radiotherapy (OR=12.71, 95% CI=3.64-44.64, P=0.01), and Volume of 200 cGy irradiation (V2) is an independent positive predictor of an increase in CD8+T lymphocyte ratio after radiotherapy (high group, OR=3.40, 95% CI=1.13-10.36, P=0.03). The increase in CD8+T cells after radiotherapy can positively predict the short-term efficacy of radiotherapy. Mediastinal low-dose radiation therapy can increase CD8+T cells, thereby improving the short-term efficacy of radiotherapy. These potentially related mechanisms are worth further verification and exploration.

The Association of Incidental Radiation Dose to the Heart Base with Overall Survival and Cardiac Events after Curative-intent Radiotherapy for Non-small Cell Lung Cancer: Results from the NI-HEART Study

AimsCardiac disease is a dose-limiting toxicity in non-small cell lung cancer radiotherapy. The dose to the heart base has been associated with poor survival in multiple institutional and clinical trial datasets using unsupervised, voxel-based analysis. Validation has not been undertaken in a cohort with individual patient delineations of the cardiac base or for the endpoint of cardiac events. The purpose of this study was to assess the association of heart base radiation dose with overall survival and the risk of cardiac events with individual heart base contours. Materials and methodsPatients treated between 2015 and 2020 were reviewed for baseline patient, tumour and cardiac details and both cancer and cardiac outcomes as part of the NI-HEART study. Three cardiologists verified cardiac events including atrial fibrillation, heart failure and acute coronary syndrome. Cardiac substructure delineations were completed using a validated deep learning-based autosegmentation tool and a composite cardiac base structure was generated. Cox and Fine–Gray regressions were undertaken for the risk of death and cardiac events. ResultsOf 478 eligible patients, most received 55 Gy/20 fractions (96%) without chemotherapy (58%), planned with intensity-modulated radiotherapy (71%). Pre-existing cardiovascular morbidity was common (78% two or more risk factors, 46% one or more established disease). The median follow-up was 21.1 months. Dichotomised at the median, a higher heart base Dmax was associated with poorer survival on Kaplan–Meier analysis (20.2 months versus 28.3 months; hazard ratio 1.40, 95% confidence interval 1.14–1.75, P = 0.0017) and statistical significance was retained in multivariate analyses. Furthermore, heart base Dmax was associated with pooled cardiac events in a multivariate analysis (hazard ratio 1.75, 95% confidence interval 1.03–2.97, P = 0.04). ConclusionsHeart base Dmax was associated with the rate of death and cardiac events after adjusting for patient, tumour and cardiovascular factors in the NI-HEART study. This validates the findings from previous unsupervised analytical approaches. The heart base could be considered as a potential sub-organ at risk towards reducing radiation cardiotoxicity.

Impact of declared wildfire disasters on survival of lung cancer patients undergoing radiation treatment.

302 Background: In recent years, the frequency and severity of climate-driven disasters, including wildfires, have posed significant challenges to the delivery of oncology care. Among various treatment modalities, radiotherapy stands is particularly vulnerable due to its reliance on consistent electrical power and daily treatment sessions. For patients receiving radiation treatment for locally advanced non-small cell lung cancer (NSCLC), even minor disruptions in treatment continuity have been shown to have a detrimental impact on overall survival. Methods: Patients undergoing definitive radiotherapy for nonoperative locally advanced NSCLC between 2004 and 2019 were selected from the hospital-based National Cancer Database, which captures approximately 70% of all cases in the United States. Disaster declarations were identified from the Federal Emergency Management Agency from 2004 to 2019. Exposed patients (n = 1,419) were defined as those who had a wildfire disaster declared in the county of the treatment facility during the exposure window (within 12 weeks of radiotherapy start date), while unexposed patients (n = 226,719) had no disasters declared within the same timeframe. Overall survival was defined as age when radiation therapy started and age of death, last contact, or study end. Cox proportional hazards was used for estimating hazard ratios (HRs) adjusted for sex, region, health insurance, comorbidities, facility type, lymph node involvement and concomitant chemotherapy. Survival estimates were weighted by the inverse of the probability of remaining uncensored at the end of the exposure window. Results: A total of 228,138 individuals were included in the study. Our preliminary data shows that exposed individuals were more likely to receive treatment in facilities located in western states, have no comorbidities, and have private health insurance coverage. Individuals whose facility had a wildfire disaster declared within 12 weeks of the radiation start date had worse overall survival (HR = 1.03; 95% Confidence Interval = 1.01, 1.06) compared to unexposed individuals with sensitivity analyses pending. Conclusions: Our study highlights the vulnerability of individuals undergoing radiotherapy for NSCLC to the hazards posed by wildfires. These findings underscore the urgent need for oncology institutions to prioritize the climate adaptation efforts aimed at safeguarding the needs of this vulnerable population.

Dissecting Systemic T Cell Responses after Stereotactic Ablative Radiotherapy in NSCLC by Single-Cell RNA and T Cell Receptor Sequencing

There is accumulating evidence that stereotactic ablative radiotherapy (SABR) modulates immune responses to cancer; combining SABR and immunotherapy could promote the abscopal effect, but the precise effects of SABR on patients' systemic T cells is unclear. Here, we investigated SABR-induced systemic T cell response in early-stage non-small cell lung cancer (NSCLC) by single-cell RNA and T cell receptor sequencing. We performed single-cell RNA and T cell receptor sequencing on 29,439 T cells from four pairs of peripheral blood before and after SABR in early-stage NSCLC patients. Cell clustering and dimensionality reduction, SingleR, feature genes score, and TCR profiling analyses were used to investigate the heterogeneity of T cells and their changes following SABR. We identified fourteen T cell subtypes using unsupervised graph-based clustering of uniform manifold approximation and projection. By comparing the gene set scores of CD8_TE and CD8_EM pre- and post-SABR, we found both cytotoxic and inhibitory scores were significantly elevated in CD8_TE (both P < 0.001), while cytotoxic score was significantly increased in CD8_EM (P < 0.001) after SABR. We also found that CD4_TE showed increased cytotoxic scores and decreased Treg scores (P < 0.001 and < 0.05, respectively), while Treg cells showed decreased inhibitory and Treg scores (P < 0.001 and <0.01, respectively) after SABR. The proportion of large TCR clones was higher after SABR, which was accompanied by a decrease in proportion of single clones. When we compared the transcriptomes of CD8_TE cells between the single, small and large clones post-SABR, we found high expression of GZMB and KLRC3 in cells with large clones, and GZMK, IL7R, and SELL in small and single clones. This suggested that T cells after SABR with large clones may have higher cytotoxicity than those with small and single clones. Our study identified systemic T cell activation after SABR at single-cell resolution, providing unprecedented insight into the immune-modulatory role of SABR in early-stage NSCLC.

Investigating Dosimetry and Imaging Biomarkers for Prediction of Major Adverse Cardiac Events Following Locally Advanced Non-Small Cell Lung Cancer Radiotherapy

Thoracic radiotherapy (RT) may confer major adverse cardiac events (MACE) following treatment. Mean heart dose positively associates with MACE and recent studies show cardiac substructure dosimetry improves MACE prediction. Use of imaging biomarkers with cardiac substructure dose has not been studied for prediction of MACE. We sought to develop an integrated model for cardiac substructure dose and baseline coronary artery calcium (CAC) scoring and establish its relationship to MACE. A retrospective cohort analysis was performed of consecutive patients with locally advanced non-small cell lung cancer (NSCLC) treated with definitive RT from 2006-2018 at a single institution. Demographics, medical history, cardiac events, and treatments received were recorded. Cardiac substructures were contoured, including the left descending artery (LAD), left main coronary artery (LMCA), left circumflex (LCX), right coronary artery (RCA), TotalLeft (LAD+LMCA+LCX), and TotalCor (TotalLeft+RCA). Doses were measured in 2 Gy equivalent dose. CAC was scored by visual assessment and compared to established automated Agatston scoring. Primary endpoint was MACE incidence. Receiver operating characteristic (ROC) curves assessed dose and CAC metric model performance. Threshold modeling was conducted using the log rank statistic with 95% confidence intervals measured using bootstrap resampling with 1000 iterations. Competing risk models adjusted for death were used to measure cumulative incidence of MACE as well as in univariable and multivariable risk regression modeling. Pearson correlations were used to validate CAC scoring. P-values were two tailed and considered significant at P≤0.05. Of 233 eligible patients, 61.4% were male with a 68.1 years (range 34.9-90.7) median age. Median follow-up was 73.7 months (range 1.6-153.9). Median overall survival was 34.8 months. Following RT, 22.3% experienced at least one cardiac event at a median time of 21.5 months (range 1.7-118.9). Visual CAC scoring showed significant correlation with automated Agatston scoring (r = 0.72, P=1e-5). While left sided coronary arteries (TotalLeft), mean heart dose (MHD) and CAC scores individually predicted for MACE (AUC = 0.56-0.59), a multivariable model of TotalLeft CAC had the highest ROC analysis performance (AUC = 0.69). On univariable and multivariable competing risk regression analyses, TotalLeft V15 Gy >2.53 cc and CAC score >5 independently associated with MACE (P<0.05). A model incorporating age, TotalLeft CAC>5 and V15>2.53cc, showed incrementally higher MACE incidences for low (9.3%), intermediate (18.4%), and high-risk groups (27.7%) (P<0.01). RT-induced MACE occurs in >20% of those undergoing thoracic RT in a median time of <2 years. We validate significant associations between TotalLeft RT dose and MACE and establish CAC as a predictive risk factor. These findings may serve to inform personalized RT and future cardiac risk in locally advanced NSCLC.

Dosimetric Comparison of Nodal Clinical Target Volume for Locally Advanced Non-Small Cell Lung Cancer: Options for Geometric Expansion vs. Lymph Node Stations

We investigated whether dosimetric differences existed in nodal clinical target volume (CTV) using options for geometric expansion and lymph node stations based on the European Society for Radiotherapy and Oncology (ESTRO) guideline for locally advanced non-small cell lung cancer (NSCLC). With treatment planning computed tomographic images in 17 patients who underwent radiotherapy for cT4N2M0 NSCLC from 2017 to 2022 at our institution, we retrospectively contoured nodal CTVs based on the guideline's options of: (1) geometric expansion, CTV including the nodal gross tumor volume plus 5 mm margin: (2) lymph node stations, CTV including the affected lymph node stations. The 5 mm margins for planning target volume (PTV) were added to the nodal and primary tumors' CTVs. Treatment planning of 60 Gy in 30 fractions to the PTV D50% was performed using volumetric modulated arc therapy; Dn% was irradiated dose to n% of volume of the structure; VnGy was percentage of volume of the structure at least irradiated n Gy. We compared dose-volume parameters between the two options using Wilcoxon rank sum test. Primary tumors were located in the right and left lobes in 12 and five patients, and in the upper and lower lobes in 13 and four patients, respectively. Median PTV size/D95% of the options for geometric expansion and lymph node stations were 569 cc (range, 149-2005 cc)/58.2 Gy (range, 57.5-58.7 Gy) and 635 cc (range, 184-2109 cc)/58.1 Gy (range, 57.5-58.7 Gy), respectively. Median mean dose of the esophagus/heart in the two options were 12.2 Gy (range, 6.6-24.9 Gy)/3.3 Gy (range, 0.6-19.1 Gy) and 16.1 Gy (range, 13.6-30.5 Gy)/4.6 Gy (range, 0.7-18.9 Gy), respectively. Median V20 Gy/mean dose of the lungs in the options for geometric expansion and lymph node stations were 20.5% (range, 14.8-33.9%)/12.2 Gy (range, 8.7-18.4 Gy) and 24.0% (range, 15.1-36.7%)/13.5 Gy (range, 9.5-19.4 Gy), respectively. In the eight patients (47%) with lymph node metastases in stations 2 or 3, a significant dosimetric difference between the two options existed on V20 Gy of the lungs; median values of the difference were 2.8% and 0.5% with and without lymph node metastases in stations 2 or 3, respectively (p = 0.027). Of the ESTRO guideline for the nodal CTV, using the option for geometric expansion might be able to reduce V20 Gy of the lungs in patients with lymph node metastases in stations 2 or 3.

Efficacy and Safety of PD-1/PD-L1 Inhibitors Combined with Radiotherapy in Patients with Brain Metastases Caused by Non-Small Cell Lung Cancer: A Multi-Center Retrospective Analysis

To investigate efficacy and safety of PD-1/PD-L1 inhibitors plus radiotherapy in patients that brain metastases (BMs) from non-small cell lung cancer (NSCLC). All 234 eligible patients were divided into PD-1/PD-L1 inhibitors plus intracranial radiotherapy (BM-RT) group and immunotherapy (non-BM-RT) group. 144 patients in BM-RT group were divided into patients received extracranial radiotherapy for NSCLC (extra-RT) group and had not (non-extra-RT) group. According to the Lung Immune Prognostic Index (LIPI), patients were stratified into good, intermediate, and poor groups. The toxicity was assessed with Common Terminology Criteria for Adverse Events (CTCAE) 5.0. Kaplan-Meier method and Log-rank test were used to analyze intracranial progression-free survival (iPFS) and overall survival (OS). The median iPFS (11.6 months vs. 9.9 months, P = 0.001) and median OS (17.3 months vs. 14.6 months, P = 0.029) had a significant difference in BM-RT group and non-BM-RT group. Meanwhile, median iPFS (15.7 months vs. 10.5 months, P<0.001) and median OS (20.2 months vs. 15.1 months, P = 0.024) in extra-RT group were longer than non-extra-RT group. The median iPFS (12.9 months vs. 10.4 vs. 8.4 months, P = 0.001) and median OS (20.1 months vs. 16.7 months vs. 12.6 months, P = 0.025) were longer in good group than intermediate group and poor group in LIPI. Our data suggested there was a significant difference in iPFS and OS with or without radiotherapy in patients of BMs from NSCLC, and with safety profiles. LIPI helped predict prognosis of BMs in NSCLC.

Optimal Radiation Therapy Fractionation Regimens for Early-Stage Non-Small Cell Lung Cancer

A series of radiobiological models were developed to study tumor control probability (TCP) for stereotactic body radiation therapy (SBRT) of early-stage non-small cell lung cancer (NSCLC) per the Hypofractionated Treatment Effects in the Clinic (HyTEC) working group. This study was conducted to further validate 3 representative models with the recent clinical TCP data ranging from conventional radiation therapy to SBRT of early-stage NSCLC and to determine systematic optimal fractionation regimens in 1 to 30 fractions for radiation therapy of early-stage NSCLC that were found to be model-independent. Recent clinical 1-, 2-, 3-, and 5-year actuarial or Kaplan-Meier TCP data of 9808 patients from 56 published papers were collected for radiation therapy of 2 to 4 Gy per fraction and SBRT of early-stage NSCLC. This data set nearly triples the original HyTEC sample, which was used to further validate the HyTEC model parameters determined from a fit to the clinical TCP data. TCP data from the expanded data set are well described by the HyTEC models with α/β ratios of about 20 Gy. TCP increases sharply with biologically effective dose and reaches an asymptotic maximal plateau, which allows us to determine optimal fractionation schemes for radiation therapy of early-stage NSCLC. The HyTEC radiobiological models with α/β ratios of about 20 Gy determined from the fits to the clinical TCP data for SBRT of early-stage NSCLC describe the recent TCP data well for both radiation therapy of 2 to 4 Gy per fraction and SBRT dose and fractionation schemes of early-stage NSCLC. A steep dose response exists between TCP and biologically effective dose, and TCP reaches an asymptotic maximum. This feature results in model-independent optimal fractionation regimens determined whenever safe for SBRT and hypofractionated radiation therapy of early-stage NSCLC in 1 to 30 fractions to achieve asymptotic maximal tumor control, and T2 tumors require slightly higher optimal doses than T1 tumors. The proposed optimal fractionation schemes are consistent with clinical practice for SBRT of early-stage NSCLC.

Anlotinib combined with whole-brain radiotherapy in non-small cell lung cancer with multiple brain metastases that progressed or developed after at least one lines of prior treatment.

Intracranial metastasis that failed standard systematic treatment is common in advanced non-small cell lung cancer (NSCLC), contributing significantly to morbidity and mortality. The aim of this study was to evaluate the efficacy and safety of anlotinib combined with whole-brain radiotherapy (WBRT) for NSCLC with brain metastases (BMs) that progressed or developed after at least one line of prior treatment and compare the outcomes with that of the contemporary institutional control. NSCLC patients with multiple BMs that progressed or developed after at least one line of prior systematic treatment and treated with WBRT subsequently between 2019 and 2021 were selected retrospectively for analysis. Based on whether concurrent anlotinib had been used in combination with WBRT, the cases were divided into the anlotinib group and control group. The primary endpoints were intracranial progression-free survival (iPFS) and safety. A total of 76 patients met the inclusion criteria of the study. Of the 76 patients, 34 received concurrent WBRT and anlotinib followed by anlotinib maintenance and 42 were treated with WBRT alone or in combination with other systemic agents at the physicians' discretion. The median follow-up for the entire cohort was 21 months. The median iPFS for the anlotinib and control group was 6.7 months (95% CI, 4.6-9.9) and 5.3 months (95% CI, 4.0-6.5), respectively (log-rank P = 0.04). There was no difference in overall survival between the two groups (log-rank P = 0.38). In the anlotinib group, treatment-related adverse events were reported in 15 patients (44.1%), with acute or late grade 3-5 adverse events identified in 14.7% of patients (n = 5). WBRT plus anlotinib, as a convenient chemo-free regimen, may represent an overall safe and effective procedure in advanced NSCLC with multiple BMs that progressed or developed after standard systematic treatment.

The institutional experience of the implementing 4DCT in NSCLC radiotherapy planning.

The study was to evaluate the effectiveness of dose distribution of four-dimensional computed tomography (4DCT) simulation. The gross tumor volume (GTV) and clinical target volume (CTV) were contoured in all 10 respiratory phases of 4DCT in 30 patients with non-small cell lung cancer (NSCLC). Both 3D and 4D treatment plans were made individually for each patient using the planning volume (PTV). The PTV3D was taken from a single CTV plus the recommended margin, and the PTV4D was taken from the 4D internal target volume, including all 10 CTVs plus the setup margins. The mean PTV was 460 ± 179 (69-820) cm3 for 3DCT and 401 ± 167 (127-854) cm3 for 4DCT (p = 0.0018). The dose distribution (DD) of organs at risk, especially the lungs, was lower for the 4DCT simulation. The V5%, V10%, and V20% of the total lung dose for 4DCT were significantly lower for the 3DCT. However, lung V30% the heart, esophagus, and spinal cord were not significantly different. In addition, the conformity index and the dose heterogeneity index of the PTV were not significantly different. The normal tissue complication probability (NTCP) of the lung and heart was significantly lower for 4DCT than for 3DCT. The 4DCT simulation gives better results on the NTCP. The organs at risk, especially the lungs, receive a significantly lower DD compared with the 3DCT. The conformity index (CI), heterogeneity index (HI) and the DD to the heart, spinal cord, and esophagus were not significantly different between the two techniques.

Applying a novel two-step deep learning network to improve the automatic delineation of esophagus in non-small cell lung cancer radiotherapy.

To introduce a model for automatic segmentation of thoracic organs at risk (OARs), especially the esophagus, in non-small cell lung cancer radiotherapy, using a novel two-step deep learning network. A total of 59 lung cancer patients' CT images were enrolled, of which 39 patients were randomly selected as the training set, 8 patients as the validation set, and 12 patients as the testing set. The automatic segmentations of the six OARs including the esophagus were carried out. In addition, two sets of treatment plans were made on the basis of the manually delineated tumor and OARs (Plan1) as well as the manually delineated tumor and the automatically delineated OARs (Plan2). The Dice similarity coefficient (DSC), 95% Hausdorff distance (HD95), and average surface distance (ASD) of the proposed model were compared with those of U-Net as a benchmark. Next, two groups of plans were also compared according to the dose-volume histogram parameters. The DSC, HD95, and ASD of the proposed model were better than those of U-Net, while the two groups of plans were almost the same. The highest mean DSC of the proposed method was 0.94 for the left lung, and the lowest HD95 and ASD were 3.78 and 1.16mm for the trachea, respectively. Moreover, the DSC reached 0.73 for the esophagus. The two-step segmentation method can accurately segment the OARs of lung cancer. The mean DSC of the esophagus realized preliminary clinical significance (>0.70). Choosing different deep learning networks based on different characteristics of organs offers a new option for automatic segmentation in radiotherapy.

Association between statin therapy dose intensity and radiation cardiotoxicity in non-small cell lung cancer: Results from the NI-HEART study

IntroductionRadiation cardiotoxicity is a dose-limiting toxicity and major survivorship issue for patients with non-small cell lung cancer (NSCLC) completing curative-intent radiotherapy, however patients’ cardiovascular baseline is not routinely optimised prior to treatment. In this study we examined the impact of statin therapy on overall survival and post-radiotherapy cardiac events. MethodsPatients treated between 2015–2020 at a regional center were identified. Clinical notes were interrogated for baseline patient, tumor and cardiac details, and both follow-up cancer control and cardiac events. Three cardiologists verified cardiac events. Radiotherapy planning scans were retrieved for application of validated deep learning-based autosegmentation. Pre-specified Cox regression analyses were generated with varying degrees of adjustment for overall survival. Fine and Gray regression for the risk of cardiac events, accounting for the competing risk of death and cardiac covariables was undertaken. ResultsStatin therapy was prescribed to 59% of the 478 included patients. The majority (88%) of patients not prescribed a statin had at least one indication for statin therapy according to cardiovascular guidelines. In total, 340 patients (71%) died and 79 patients (17%) experienced a cardiac event. High-intensity (HR 0.68, 95%CI 0.50–0.91, p = 0.012) and medium-intensity (HR 0.70, 95%CI 0.51–0.97, p = 0.033) statin therapy were associated with improved overall survival after adjustment for patient, cancer, treatment, response and cardiovascular clinical factors. There were no consistent differences in the rate or grade of cardiac events according to statin intensity. ConclusionsStatin therapy is associated with improved overall survival in patients receiving curative-intent radiotherapy for NSCLC, and there is evidence of a dose–response relationship. This study highlights the importance of a pre-treatment cardiovascular risk assessment in this cohort. Further studies are needed to examine if statin therapy is cardioprotective in patients undergoing treatment for NSCLC with considerable incidental cardiac radiation dose and a low baseline cardiac risk.