Cardiac Toxicity After Radiotherapy for Stage III Non-Small-Cell Lung Cancer: Pooled Analysis of Dose-Escalation Trials Delivering 70 to 90 Gy

Prediction for cardiac and pulmonary toxicity in a multicentric cohort of advanced stage NSCLC patients using sub-regions of the heart

Purpose

Follow-up investigations in locally advanced stage non-small cell lung cancer (NSCLC) patients treated with radiochemotherapy (RCHT) regularly focus around lung toxicity. However, Cardiac Adverse Events (CAE) can occur much earlier in patients than originally anticipated with serious repercussions for patient quality-of-life and survival.Therefore, here we investigated spatial dependencies of dose within the heart and their correlation with toxicity, with dosimetric parameters of sub-regions of the heart at the focus of this analysis.Additionally, we aimed to explore the connection between cardiac toxicity and pulmonary toxicity.

Methods

Patient treatment plans with dosimetric data for the lungs and the heart, as well as toxicity data for 502 NSCLC patients treated with either passively scattered proton therapy (PSPT), intensity modulated radiation therapy (IMRT), three-dimensional conformal radiation therapy (3DCRT) or volumetric arc therapy (VMAT) with or without chemotherapy was retrospectively retrieved from prospective clinical studies of three international centers. Cardiac toxicity data was not available for all patients. Data was randomly split into a training set (336) and validation set (166). Statistical analyses were performed using binomial logistic regression.

Results

In univariate modeling, the Mean Lung Dose (MLD) significantly predicted CAE grade ≥ 3 in the training-set (pMLD = 0.02, AUCtrain = 0.69), which was confirmed in validation (AUCval, = 0.77). No suitable candidates for the construction of multivariate models could be identified. Parameters of the heart and its subregions did not significantly predict CAE grade ≥ 3 in the investigated cohorts. No parameters were found to significantly predict CAE grade ≥ 2 or RP. Finally, no spatial dependency was found in the investigated toxicity data.

Conclusion

The pulmonary dosimetric parameter MLD successfully predicted CAE grade ≥ 3 in a cohort treated with either photons or protons. Cardiac dosimetric parameters as well as spatial parameters did not perform similarly. No parameters were found to significantly predict RP in the investigated cohorts.

Optimizing Dose Reduction to the Left Anterior Descending Artery in Patients With Locally Advanced Lung Cancer Treated With Definitive Radiation Therapy: A Feasibility Study of Coplanar Treatments Using Double-Stacked Multileaf Collimator

Purpose

Recent studies have shown that cardiac substructures and particularly left anterior descending artery (LAD) dose strongly correlates with the incidence of late adverse cardiac events. We evaluated whether greater cardiac and, importantly, LAD dose sparing could be achieved using a newly introduced closed bore (O-ring gantry) linac with a double-stacked multileaf collimator (Varian Ethos) relative to conventional linacs.

Methods and Materials

Twenty patients with locally advanced non-small cell lung cancer previously treated with definitive chemoradiotherapy were retrospectively evaluated. Volumetric modulated arc therapy plans were retrospectively generated for the Ethos system using optimization criteria focused on reducing overall heart and LAD doses (Heart_Ethos). Plans were also reoptimized using the same optimization criteria on a conventional C-arm linac (Heart_TB). Investigational plans were compared with the original plans and with each other using standard dose-volume histogram metrics such as percentage (V) volume receiving a specific dose (x) in Gy (Vx) or mean dose (Dmean) in Gy.

Results

Statistically significant decreases existed between the Heart_Ethos and original plans for mean heart dose (11.3 vs 14.8 Gy; P < .001) and V5, V30, and V50 (63.6% vs 75.2%; P < .001, 7.1% vs 12.3%; P < .001, 2.1% vs 2.9%; P = .03, respectively) and also for LAD mean dose (4.8 Gy vs 12.0 Gy [P < .001]) and V15 (4.9% vs 21.5%; P < .001). Compared with Heart_TB, Heart_Ethos plans had significantly less mean heart dose (11.6 vs 12.2 Gy; P = .006), and less heart V5 (64.4% vs 67.2%; P = .049) and V30 (7.7% vs 8.8%; P = .03), whereas other parameters were not significant. Optimal target coverage and other organs at risk constraints were maintained for all generated plans.

Conclusions

Heart_Ethos plans showed significant reduction in cardiac and LAD doses in comparison to the original plans while maintaining target and organ at risk goals. Our findings suggest that Ethos technology has the potential for better cardiac toxicity safety because Heart_Ethos plans were still able to reduce cardiac dose compared with Heart_TB plans.

Association between dose to cardiac structures and overall survival: A multivariable analysis in a large, multi-institutional database of stage III NSCLC patients with external validation

BACKGROUND AND PURPOSE

Inconsistencies in identifying dose-limiting cardiovascular substructures for treating stage III non-small cell lung cancer (NSCLC) have hindered the implementation of cardiac sparing treatment planning guidelines. This study aims to address these inconsistencies by performing a multivariable survival analysis with overall survival as the endpoint using a large, multinational database, followed by external validation.

MATERIALS AND METHODS

Clinical and dosimetric parameters from 1587 stage III NSCLC patients treated at five institutes were analyzed. The whole heart, four cardiac chambers, great vessels and their combinations were considered. The dataset was divided into a training set (four institutes) and a test set (one institute). The optimal parameter set was identified through cross-validation, and the resulting multivariable Cox regression model was externally validated using the test set. Adjusted hazard ratios (aHRs) for all cardiovascular parameters were evaluated.

RESULTS

The strongest associations were found for low Dx% parameters. However, their incremental contribution to model performance, compared to clinical and lung dosimetric parameters only, was low, with small effect sizes. Specifically, the cardiovascular parameter identified by parameter selection was Left Side D5% (aHR: 1.007 Gy-1, 95 % CI: 1.004 - 1.010 Gy-1, p < 0.0001), which provided a slight improvement in model concordance index of 0.0062 (95 % CI: 0.0000-0.0127) in the training set and 0.0037 (95 % CI: -0.0200-0.0280) in the test set.

CONCLUSIONS

Although significant associations between cardiovascular parameters and survival were found, their small effect sizes should be considered when prioritizing cardiac sparing in stage III NSCLC treatment.

Radiation-Induced Coronary Artery Disease in Lung and Breast Cancer Patients: Insights from PET Imaging and Long-Term Risk Assessment

Radiation-induced coronary artery disease (RI-CAD) is a significant cardiovascular complication for cancer survivors treated with thoracic radiation therapy (RT). Despite advances in RT techniques, exposure to the heart during treatment remains a critical factor influencing long-term cardiac outcomes, particularly in patients with breast and lung cancer. RI-CAD develops due to radiation-induced endothelial injury, inflammation, and accelerated atherosclerosis, presenting a unique and aggressive disease profile. This review explores the pathophysiology, risk factors, and diagnostic advancements for RI-CAD, emphasizing the role of PET in improving patient outcomes.

Global Longitudinal Strain: A Potential Noninvasive Tool for Early Detection of Radiation-Induced Cardiac Dysfunction in Patients With Lung Cancer Receiving Thoracic Radiation Therapy

PURPOSE

Radiation-induced cardiac dysfunction (RICD) is a competing cause of morbidity and mortality in patients receiving thoracic radiation therapy (RT). Currently, there are no clinically-validated approaches for early detection of RICD at a time point that affords the potential for mitigation. The goal of this study was to evaluate the potential of global longitudinal strain (GLS) derived from standard-of-care echocardiogram (ECHO) for the early detection of RICD and to assess the association between adverse GLS changes and survival in patients receiving thoracic RT.

METHODS AND MATERIALS

A retrospective review of changes in GLS was carried out in patients with primary or secondary lung cancer who received standard-of-care thoracic RT with a mean heart dose of ≥5 Gy and had measurable GLS on ECHOs performed before and after RT. Changes in 2-chamber (2C), 3-chamber (3C), and 4-chamber (4C) GLS and peak average GLS after RT (relative to pre-RT baseline) were quantified. Survival probabilities were estimated in patients with normal versus abnormal GLS.

RESULTS

Thirty-eight patients had measurable GLS before and after RT. Abnormal GLS (defined as <18% or >15% relative decline in GLS after RT from a normal baseline value) was present in 31.6% of patients before RT and 57.9% of patients after RT (P = .012). On paired comparisons, the absolute median reduction (IQR) in 2-chamber, 3-chamber, 4-chamber, and average GLS after RT relative to pre-RT baseline was 1.90 (4.43), 3.00 (3.83), 2.50 (3.63), and 2.25 (3.53), respectively, all P < .001. No statistically significant change in left ventricular ejection fraction was noted after RT. Patients with abnormal GLS after RT had significantly worse survival than those with normal GLS on univariable analysis (P = .049). Despite the small sample size of the study, the survival detriment in patients with abnormal GLS after RT strongly trended toward significance on multivariable analysis (P = .063).

CONCLUSIONS

Adverse changes in GLS are detectable on standard-of-care ECHOs and precede significant changes in left ventricular ejection fraction in this cohort of high-risk patients with primary and secondary lung cancer receiving thoracic RT. Thus, ECHO-derived GLS has the potential to serve as an early and noninvasive marker of RICD in this patient population and may enable early adoption of GLS-guided cardioprotective therapy, which has been shown to mitigate cardiac dysfunction in patients with cancer receiving cardiotoxic treatments.

Multidisciplinary management of N2 stage III non-small cell lung cancer: opportunities and challenges for radiation oncology

Stage III non-small cell lung cancer (NSCLC) constitutes a heterogeneous ailment, with optimal treatment evolving. This is especially true in N2 disease, where definitive treatment is often a discussion of surgery versus definitive chemoradiotherapy (CRT). New developments in neoadjuvant and adjuvant systemic therapeutics have shifted treatment paradigms, emphasizing the importance of multidisciplinary team discussions. The recent revisions to the ninth edition of the American Joint Commission on Cancer (AJCC) staging system have prompted a realignment in nodal stage categorization, introducing refined subcategories of N2 disease (N2a and N2b), which enhance prognostic accuracy. Critical questions including defining resectability and operability, feasibility of definitive CRT for operable patients, radiotherapy in operative and non-operative disease, and advanced radiation technology for definitive CRT are needed to be considered and answered in clinical practice. The current review aims to present a comprehensive overview of radiation oncology in management of N2 stage NSCLC by summarizing key clinical trials as well as most advanced evidence, including defining resectability and operability, feasibility of definitive CRT for operable patients, radiotherapy in operative and non-operative disease, and advanced radiation technology for definitive CRT. The review summarizes the most recent evidence and insights for radiation oncologists and other specialists involved in the multidisciplinary thoracic oncology team, to provide a better understanding of the opportunities and challenges for radiotherapy in the management of N2 stage III NSCLC.

Patient selection, ventricular tachycardia substrate delineation, and data transfer for stereotactic arrhythmia radioablation: a clinical consensus statement of the European Heart Rhythm Association of the European Society of Cardiology and the Heart Rhythm Society

Stereotactic arrhythmia radioablation (STAR) is a novel, non-invasive, and promising treatment option for ventricular arrhythmias (VAs). It has been applied in highly selected patients mainly as bailout procedure, when (multiple) catheter ablations, together with anti-arrhythmic drugs, were unable to control the VAs. Despite the increasing clinical use, there is still limited knowledge of the acute and long-term response of normal and diseased myocardium to STAR. Acute toxicity appeared to be reasonably low, but potential late adverse effects may be underreported. Among published studies, the provided methodological information is often limited, and patient selection, target volume definition, methods for determination and transfer of target volume, and techniques for treatment planning and execution differ across studies, hampering the pooling of data and comparison across studies. In addition, STAR requires close and new collaboration between clinical electrophysiologists and radiation oncologists, which is facilitated by shared knowledge in each collaborator's area of expertise and a common language. This clinical consensus statement provides uniform definition of cardiac target volumes. It aims to provide advice in patient selection for STAR including aetiology-specific aspects and advice in optimal cardiac target volume identification based on available evidence. Safety concerns and the advice for acute and long-term monitoring including the importance of standardized reporting and follow-up are covered by this document. Areas of uncertainty are listed, which require high-quality, reliable pre-clinical and clinical evidence before the expansion of STAR beyond clinical scenarios in which proven therapies are ineffective or unavailable.

Development of heart-sparing VMAT radiotherapy technique incorporating heart substructures for advanced NSCLC patients

OBJECTIVE

To investigate the feasibility of active heart sparing (AHS) planning in patients with locally advanced and centrally located NSCLC receiving standard definitive radiotherapy (RT), while maintaining or improving appropriate lung, esophagus, and spinal cord constraints and planning target volume (PTV) coverage intent.

METHODS AND MATERIALS

A total of 27 patients with stage IIIA/B NSCLC treated with curative intent RT were selected for this analysis. All existing radiation plans were revised and 27 further new equivalent plans were calculated using AHS for the same cohort of patients. Primary end-point was feasibility of AHS using constraints for heart substructures. The secondary end point was to calculate the difference in terms of dosimetric parameters of heart substructures and principal OARs as well as PTV-coverage parameters within the current patient group.

RESULTS

AHS was feasible in the entire group of patients. An optimal coverage of the target volume was obtained and all mandatory constraints for OARs have been met. The median value of the mean heart dose (MHD) was 8.18 Gy and 6.71 Gy in the standard planning group and AHS-group, respectively (p = 0.000). Other heart parameters such as V5Gy (40.57% vs. 27.7%; p = 0.000) and V30Gy (5.39% vs. 3.86%; p = 0.000) were significantly worse in the standard planning group. The following relevant dosimetric parameters regarding heart substructures were found to be significantly worse in the standard planning group compared to the AHS-group: median dose to heart base (16.97 Gy vs. 6.37 Gy, p = 0.000), maximum dose (18.64 Gy vs. 6.05 Gy, p = 0.000) and V15Gy (11.11% vs. 0% p = 0.000) to LAD; mean dose; V5Gy (9.55% vs. 0.94%, p = 0.000) and V23Gy (0.00% vs. 0.00% maximum 45.68% vs. 6.57%, p = 0.002 to the left ventricle.

CONCLUSION

Our analysis showed an improvement of dosimetric parameters of the heart and heart substructures in patients affected by locally advanced and centrally located NSCLC treated with curative RT using AHS optimization. This approach could lead to a possible reduction of heart events and a prolonged survival. New clinical studies regarding RT in advanced NSCLC should include cardiologic evaluations and biomarkers as well as the contouring of cardiac substructures.

Cardioprotective Effects of Dapagliflozin Against Radiotherapy Induced Cardiac Damage

BACKGROUND

With the increasing incidence of cancer among the adult population, radiotherapy (RT) is frequently used as a critical component in the treatment of various cancer types. Due to the nature of ionizing radiation, damage usually occurs within the tissues in anatomical neighborhood with the primary tumor localization. Dapagliflozin (DAPA), originally developed as an oral anti-diabetic medication, has been shown to have potent cardioprotective effects in the DAPA-HF trial. The cardioprotective effects of DAPA against RT induced cardiac cellular damage were investigated in this study.

METHODS

A total of 40 male Wistar albino rats were obtained and were subjected to a 10-day pretreatment period to accommodate laboratory settings. Afterwards, the rats were divided into 4 groups consisting of 10 each (control = 10, DAPA = 10, RT = 10, RT + DAPA = 10). Meanwhile, the RT and RT + DAPA groups received a single dose of 20 Gray (Gy) x-ray to 4 × 4 cm area at 0.60 Gy/min, and DAPA and RT + DAPA groups were gavaged daily with 10 mg/kg DAPA. In the second week of the study, rats were examined by echocardiography and electrocardiogram. Furthermore, histopathological method was used to evaluate the level of cardiotoxicity.

RESULTS

The ejection fraction value decreased by 17.3% lower in the DAPA + RT group compared with the RT group (P < .001). In addition, corrected QT interval prolongation and QRS widening were 11.5% and 17.4% higher in the RT group compared with the DAPA + RT group, respectively (P < .001 for both values). While sarcomyolysis, inflammatory cell infiltration, and necrotic changes were found to be severe in the RT group, the DAPA + RT group had 68% less sarcomyolysis, 64% less inflammatory cell infiltration, and 55% less necrosis (P < .001 for all values).

CONCLUSIONS

The protective effects of DAPA against left ventricular remodeling and dysfunction in RT-induced cardiomyopathy model were observed in this study.

Impact of Different Mediastinal Staging Modalities on Target Volume Delineation in Locally Advanced Non-Small Cell Lung Cancer: A Secondary Analysis of the Multicenter Randomized PET-Plan Trial

PURPOSE

To evaluate the role of different invasive and noninvasive mediastinal staging methods in patients with locally advanced non-small cell lung cancer treated with definitive chemoradiation therapy in the prospective PET-Plan trial (ARO-2009-09; NCT00697333) and to evaluate the impact of endobronchial ultrasound-guided transbronchial needle aspiration and mediastinoscopy on target volume definition.

METHODS AND MATERIALS

Patients treated per protocol (n = 172), all receiving isotoxically dose-escalated chemoradiation therapy, were included in this unplanned secondary analysis. Radiation treatment planning was based on an 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) targeting all CT-positive lymph nodes (ie, short-axis diameter > 10 mm), even if PET-negative, plus elective nodal irradiation (arm A) or targeting only PET-positive nodes (arm B). The concordance rate between different staging modalities and their impact on target volume delineation was calculated.

RESULTS

The median follow-up time (95% confidence interval) was 41.1 (33.8-50.4) months. A total of 2752 lymph node stations were evaluated noninvasively, whereas 330 were examined invasively. Of 172 patients, 87 (50.6%) underwent ≥1 invasive staging modality. The number of different staging procedures per patient did not correlate with any of the primary endpoints (overall survival, progression-free survival, or freedom from local progression). The sensitivity of 18F-FDG PET/CT was 89.7% (78/87) and the specificity was 67.5% (112/166) based on histology as assessed by endobronchial ultrasound. When using the results from mediastinoscopy, the sensitivity of PET was 82.6% (19/23) and the specificity was 66.7% (36/54). On the basis of invasive staging methods, 13 lymph node stations in 9 patients (10.3%) were PET-negative while positive on invasive staging, thus leading to a significant adjustment in the target volume.

CONCLUSIONS

In this unplanned secondary analysis of the PET-Plan trial, the additional use of invasive staging resulted in relevant changes to the target volume in a tenth of patients. Invasive staging did not, however, have an effect on outcome in this trial, with a low rate of isolated out-of-field recurrences (6 in arm A vs 3 in arm B). Radiation treatment planning can thus be based on invasive staging in addition to noninvasive PET in patients undergoing definitive chemoradiation therapy for locally advanced non-small cell lung cancer. Prospective randomized data are required to confirm these findings.

Cardiotoxicity following thoracic radiotherapy for lung cancer

Radiotherapy is the standard of care treatment for unresectable NSCLC, combined with concurrent chemotherapy and adjuvant immunotherapy. Despite technological advances in radiotherapy planning and delivery, the risk of damage to surrounding thoracic tissues remains high. Cardiac problems, including arrhythmia, heart failure and ischaemic events, occur in 20% of patients with lung cancer who undergo radiotherapy. As survival rates improve incrementally for this cohort, minimising the cardiovascular morbidity of RT is increasingly important. Problematically, the reporting of cardiac endpoints has been poor in thoracic radiotherapy clinical trials, and retrospective studies have been limited by the lack of standardisation of nomenclature and endpoints. How baseline cardiovascular profile and cardiac substructure radiation dose distribution impact the risk of cardiotoxicity is incompletely understood. As Thoracic Oncology departments seek to expand the indications for radiotherapy, and as the patient cohort becomes older and more comorbid, there is a pressing need for cardiotoxicity to be comprehensively characterised with sophisticated oncology, physics and cardio-oncology evaluations. This review synthesises the evidence base for cardiotoxicity in conventional radiotherapy, focusing on lung cancer, including current data, unmet clinical needs, and future scientific directions.

Predictive Value of Changes in Basal Myocardial 18F-Fluorodeoxyglucose Uptake for Cardiotoxicity in Patients With Locally Advanced Esophageal Cancer Receiving Definitive Radiation Therapy

PURPOSE

To investigate the predictive value of changes in segmental myocardial 18F-fluorodeoxyglucose (FDG) uptake for major adverse cardiac events (MACEs) in patients with locally advanced esophageal cancer undergoing definitive radiation therapy (RT).

METHODS AND MATERIALS

Between August 2012 and January 2019, 482 patients with stages II and III esophageal cancer from 2 institutions were enrolled and divided into the training (n = 285) and external validation (n = 197) cohorts. All patients underwent 18F-FDG positron emission tomography within 1 week before treatment and within 3 months of treatment. Myocardial delineation was performed using the Carimas software based on the American Heart Association 17-segment model and was automatically divided into basal, middle, and apical regions. The main endpoint was the occurrence of MACEs, including unstable angina, myocardial infarction, coronary revascularization, hospitalization for heart failure or urgent visits, and cardiac death. Analyses included competing risk and Cox regression. Model performance was assessed using the area under the receiver operating characteristic curve and Brier score.

RESULTS

Thirty-four patients (11.9%) developed MACEs at a median follow-up of 78 months. The basal region (median, 19.44 Gy) of the myocardium received the highest radiation dose, followed by the middle (median, 13.02 Gy) and apical regions (median, 9.32 Gy). Multivariate analysis showed that the change ratio in pretreatment and posttreatment basal myocardial mean standardized uptake value (SUV) remained significant after adjusting for age, pre-existing cardiac disease, and dosimetric parameters. The area under the receiver operating characteristic curves and Brier scores demonstrated favorable predictive accuracies of models integrating variables with significant differences in the multivariate analysis when predicting MACEs in the training and validation cohorts.

CONCLUSIONS

The basal change ratio of mean SUV was an independent predictor of MACEs in patients with locally advanced esophageal cancer receiving definitive RT. Changes in basal myocardial FDG uptake are promising biomarkers for predicting radiation-induced cardiotoxicity.

Cardiac Complications of Radiation Therapy

Radiation therapy is a critical component in managing many malignancies by improving local control and survival. The benefits of radiation may come at the expense of unintended radiation injury to the surrounding normal tissues, with the heart being one of the most affected organs in thoracic radiation treatments. As cancer survivors live longer, radiation-induced cardiotoxicity (RICT) is now increasingly recognized. In this review, we highlight the spectrum and pathophysiology of RICT. We summarize contemporary recommendations for risk stratification, screening, prevention, and management of RICT. We briefly highlight novel applications for radiation to treat some cardiac conditions such as resistant arrhythmias.

Risk Assessment Prior to Cardiotoxic Anticancer Therapies in 7 Steps

The burdens of cardiovascular (CV) diseases and cardiotoxic side effects of cancer treatment in oncology patients are increasing in parallel. The European Society of Cardiology (ESC) 2022 Cardio-Oncology guidelines recommend the use of standardized risk stratification tools to determine the risk of cardiotoxicity associated with different anticancer treatment modalities and the severity of their complications. The use of the Heart Failure Association-International Cardio-Oncology Society (HFA-ICOS) is essential for assessing risk prior to starting cancer treatment, and validation of these methods has been performed in patients receiving anthracyclines, human epidermal receptor 2 (HER2)-targeted therapies and breakpoint cluster region-abelson oncogene locus (BCR-ABL) inhibitors. The benefits of performing baseline CV risk assessment and stratification include early recognition of cardiotoxicities, personalisation of cancer treatment and monitoring strategies, and allocation of cardioprotection to those at the highest risk. This review summarizes the key points of risk stratification in these patients. The steps include identifying the target population, assessing nonmodifiable and modifiable CV risk factors, reviewing previous oncologic therapies and CV histories, and performing baseline investigations. In summary, this review aims to provide general physicians with a simple 7-step guide that will help steer and navigate them through cardiac risk evaluation of potentially cardiotoxic oncologic treatment strategies.

Dosimetric impact of sparing base of heart on organ at risk doses during lung radiotherapy

BACKGROUND

Minimising heart exposure during lung radiotherapy (RT) is important due to association between increased cardiac dose and adverse outcomes such as cardiac toxicity and reduced overall survival. This study evaluated the impact of incorporating a cardiac avoidance area (CAA) located at the base of the heart on the dose received by cardiac subregions and thoracic organs at risk.

METHODS

A comparative analysis was conducted on patients treated with lung RT at a single centre before and after the CAA was introduced as an anatomical region at risk (ARR) in April 2023. Two patient cohorts were analysed: those treated prior to CAA implementation (April 2021-March 2023, 923 patients) and those treated post implementation (April 2023-March 2024, 477 patients). For the second group, plans were optimised to keep CAA maximum dose to 1 cc below 19.5 Gy in 20 fractions (or equivalent biologically effective dose). Key dose metrics for the CAA, heart, lungs, oesophagus, and spinal canal were compared between the cohorts.

RESULTS

The introduction of the CAA as an ARR resulted in significant reductions in CAA and overall heart dose, with median CAA maximum dose (EQD2) decreasing from 32.0 Gy3 to 16.9 Gy3 (p < 0.001). No significant increases in dose were observed for other thoracic organs at risk.

CONCLUSIONS

Implementing a cardiac avoidance area in lung RT planning significantly reduces doses to critical heart regions without compromising the safety of other organs. This approach holds promise for reducing cardiac-related adverse events and improving overall survival in patients with lung cancer undergoing RT.

Feasibility of Left Anterior Descending Coronary Artery Sparing Radiation Therapy for Locally Advanced Lung Cancer

Efforts to mitigate radiation therapy (RT)-associated cardiotoxicity have focused on constraining mean heart dose. However, recent studies have shown greater predictive power with cardiac substructure dose metrics, such as the left anterior descending (LAD) coronary artery volume (V) receiving 15 Gy (V15Gy) ≥10%. Herein, we investigated the feasibility of LAD radiation sparing in contemporary intensity modulated RT (IMRT)/volumetric modulated arc therapy (VMAT) lung cancer plans. Single institution retrospective analysis of 54 patients with locally advanced lung cancer treated with thoracic RT was conducted between February 2018 and August 2021. After excluding 33 (5 = non-IMRT/VMAT or intentionally LAD-optimized; 28 = LAD V15Gy <10%), 21 plans with LAD V15Gy ≥10% were identified for LAD reoptimization with intent to meet LAD V15Gy <10% while maintaining meeting organ at risk (OAR) metrics and target coverage with original plan parameters. Dosimetric variables were compared using paired t tests. Most patients (57.1%, 12/21) were treated with definitive RT, 8 of 21 patients (38.1%) with postoperative RT, and 1 with neoadjuvant RT. The median prescribed RT dose was 60 Gy (range, 50.4-66 Gy) in 30 fractions (range, 28-33 fractions). LAD reoptimized plans (vs original) led to significant reductions in mean LAD V15Gy (39.4% ± 13.9% vs 9.4% ± 13.0%; P < .001) and mean LAD dose (12.9 Gy ± 4.6 Gy vs 7.6 Gy ± 2.8 Gy; P < .001). Most (85.7%; 18/21) LAD reoptimized plans achieved LAD V15Gy <10%. There were no statistically significant differences in overall lung, esophageal, or spinal cord dose metrics. Only 1 reoptimization (1/21) exceeded an OAR constraint that was initially met in the original plan. To our knowledge, this is the first report describing the feasibility of LAD-optimized lung cancer RT planning using the newly identified LAD V15Gy constraint. We observed that LAD V15Gy <10% is achievable in more than 85% of plans initially exceeding this constraint, with minimal dosimetric tradeoffs. Our results support the feasibility of routine incorporation of the LAD as an OAR in modern thoracic IMRT/VMAT planning.

Dose-volume predictors of cardiac adverse events after high-dose thoracic radiation therapy for lung cancer: a systematic review and meta-analysis

BACKGROUND

Lung cancer is a leading cause of cancer mortality and may require high-dose thoracic radiation therapy (RT). However, RT significantly increases the risk of radiation-induced cardiac events, such as pericarditis, cardiomyopathy, and ischemic heart diseases. Despite evidence from clinical trials showing that higher RT doses are associated with poorer survival outcomes due to these cardiac effects, data on dose-volume predictors of such events in lung cancer remain sparse.

OBJECTIVE

To systematically synthesize the incidence of cardiac events following radiation therapy for lung cancer treatment and dose-volume metrics predictors of radiation therapy-induced cardiac events in lung cancer treatment.

METHODS

This systematic review, registered on PROSPERO (CRD42024565103), adhered to PRISMA guidelines to investigate cardiac events and its dose-volume predictors following high-dose radiation therapy in adults with lung cancer. Data were extracted from longitudinal observational studies and randomized controlled trials. A comprehensive literature search was conducted across MEDLINE, Cochrane CENTRAL, and Embase, with studies selected based on predefined criteria, focusing on clinical cardiac outcomes. Data extraction followed CHARMS guidelines, and study quality was reported using the PROBAST tool. Results were synthesized narratively, with meta-analyses performed where appropriate using R software to estimate pooled effect sizes, heterogeneity, and publication bias.

RESULTS

The systematic review included 21 studies and identified a significant association between high-dose thoracic radiation therapy (RT) and an increased incidence of cardiac adverse events in lung cancer patients. The review revealed that higher dose-volume parameters, notably higher mean heart doses (MHD), were predictive of major cardiac events such as pericardial effusion, arrhythmias, and acute coronary syndrome. The meta-analysis showed a significant 4% (95% confidence interval: 3%-6%) increased probability of the occurrence of cardiac events per additional Gray of MHD, with low heterogeneity among studies (I2 = 23%). No publication bias was evidenced.

CONCLUSION

This study underscores the importance of dose-volume parameters as predictors of cardiac adverse events following high-dose thoracic RT in lung cancer treatment. The findings highlight the need for careful consideration of heart dose constraints in RT planning to mitigate the risk of radiation-induced cardiotoxicity, thereby improving the therapeutic ratio for lung cancer patients. Future research should focus on refining these dose constraints and exploring cardioprotective strategies during lung cancer radiotherapy.

Overview of cardiac toxicity from radiation therapy

Radiotherapy is an essential part of treatment for many patients with thoracic cancers. However, proximity of the heart to tumour targets can lead to cardiac side effects, with studies demonstrating link between cardiac radiation dose and adverse outcomes. Although reducing cardiac dose can reduce associated risks, most cardiac constraint recommendations in clinical use are generally based on dose to the whole heart, as dose assessment at cardiac substructure levels on individual patients has been limited historically. Furthermore, estimation of an individual's cardiac risk is complex and multifactorial, which includes radiation dose alongside baseline risk factors, and the impact of systemic therapies. This review gives an overview of the epidemiological impact of cancer and cardiac disease, risk factors contributing to radiation-related cardiotoxicity, the evidence for cardiac side effects and future directions in cardiotoxicity research. A better understanding of the interactions between risk factors, balancing treatment benefit versus toxicity and the ongoing management of cardiac risk is essential for optimal clinical care. The emerging field of cardio-oncology is thus a multidisciplinary collaborative effort to enable better understanding of cardiac risks and outcomes for better-informed patient management decisions.

American Radium Society Appropriate Use Criteria on Cardiac Toxicity Prevention and Management After Thoracic Radiotherapy

INTRODUCTION

The multidisciplinary American Radium Society Thoracic Committee was assigned to create appropriate use criteria on cardiac toxicity prevention and management for patients undergoing radiotherapy.

METHODS

A systematic review of the current literature was conducted. Case variants of patients with thoracic malignancies undergoing radiation were created based on presence or absence of cardiovascular risk factors and treatment-related risks assessed by dose exposure to the heart and cardiac substructures. Modified Delphi methodology was used to evaluate the variants and procedures, with less than or equal to three rating points from median defining agreement/consensus.

RESULTS

A total of six variants were evaluated. The panel felt that patients with cardiac comorbidities at high risk for radiation-related cardiac toxicity should undergo a prescreening cardiac-focused history and physical (H&P) examination, electrocardiogram, cardiac imaging including an echocardiogram, and referral to a cardiologist/cardio-oncologist. Recommendations for those without cardiac comorbidities at low risk for cardiac toxicity were to undergo a baseline H&P examination only. Conversely, those without cardiac comorbidities but at high risk for radiation-related cardiac toxicity were recommended to undergo a prescreening electrocardiogram, in addition to a H&P examination. For patients with cardiac comorbidities at low risk for cardiac toxicity, the panel felt that prescreening and postscreening tests may be appropriate.

CONCLUSIONS

The American Radium Society Thoracic appropriate use criteria panel has developed multidisciplinary consensus guidelines for cardiac toxicity prevention, surveillance, and management after thoracic radiotherapy based on cardiac comorbidities at presentation and risk of radiation-related cardiac toxicity.

Dosimetric Planning Comparison for Left Ventricle Avoidance in Non-small Cell Lung Cancer Radiotherapy

INTRODUCTION

Radiation may unintentionally injure myocardial tissue, potentially leading to radiation-induced cardiac disease (RICD), with the net benefit of non-small cell lung cancer (NSCLC) radiotherapy (RT) due to the proximity of the lung and heart. RTOG-0617 showed a greater reduction in overall survival (OS) comparing higher doses to standard radiation doses in NSCLC RT. V5GyHeart has been reported as an OS predictor in the first- and fifth-year follow-ups. A worsening OS trend was reported in another study where the mean left ventricle dose (mean LV) was ≥14.5 Gy. It is therefore important to spare the heart, specifically the LV, from radiation. Furthermore, dose-limiting factors toward the normal lung should be accounted for to prevent radiation-induced lung injury.

METHODS

The LV and left anterior descending artery (LAD) were also contoured on the average four-dimensional computed tomography (4D-CT) dataset that contained clinically defined targets and normal structures for stage III NSCLC RT. The prescribed treatment plans (n=15) were retrospectively optimized with the clinical goals of minimizing the mean LV and mean heart dose while maintaining the dose constraint of V20GyLung ≤30% and V95%PTV ≥95%. Dose-volume histograms were used to compare the heart and lung dosimetric parameters between the delivered and reoptimized RT plans.

RESULTS

A significant reduction (p≤0.044) was observed in the mean LV, mean heart dose, mean LAD dose, max LAD dose, and V5GyHeart from the reoptimized RT plans. V20GyLung ≤30% and V95%PTV ≥95% were maintained, and no differences were observed in the mean lung, V5GyLung, V20GyLung, mean esophagus, and max cord.

CONCLUSION

Minimizing the LV dose in NSCLC RT plans is achievable and dosimetrically advantageous for the heart while maintaining dose constraints to the normal lung and maximizing tumor control. Radiation dose reduction to cardiac substructures may decrease the RICD risk in NSCLC patients.

Consequences of ionizing radiation exposure to the cardiovascular system

Ionizing radiation is widely used in various industrial and medical applications, resulting in increased exposure for certain populations. Lessons from radiation accidents and occupational exposure have highlighted the cardiovascular and cerebrovascular risks associated with radiation exposure. In addition, radiation therapy for cancer has been linked to numerous cardiovascular complications, depending on the distribution of the dose by volume in the heart and other relevant target tissues in the circulatory system. The manifestation of symptoms is influenced by numerous factors, and distinct cardiac complications have previously been observed in different groups of patients with cancer undergoing radiation therapy. However, in contemporary radiation therapy, advances in treatment planning with conformal radiation delivery have markedly reduced the mean heart dose and volume of exposure, and these variables are therefore no longer sole surrogates for predicting the risk of specific types of heart disease. Nevertheless, certain cardiac substructures remain vulnerable to radiation exposure, necessitating close monitoring. In this Review, we provide a comprehensive overview of the consequences of radiation exposure on the cardiovascular system, drawing insights from various cohorts exposed to uniform, whole-body radiation or to partial-body irradiation, and identify potential risk modifiers in the development of radiation-associated cardiovascular disease.

Radiation Oncology Opinions and Practice on Cardiotoxicity in Lung Cancer: A Cross-sectional Study by the International Cardio-oncology Society

AIMS

Symptomatic radiation cardiotoxicity affects up to 30% patients with lung cancer and several heart substructure doses are associated with reduced overall survival. A greater focus on minimising cardiotoxicity is now possible due to advancements in radiotherapy technology and the new discipline of cardio-oncology, but uptake of emerging data has not been ascertained. A global cross-sectional analysis of Radiation Oncologists who treat lung cancer was therefore conducted by the International Cardio-Oncology Society in order to establish the impact of recently published literature and guidelines on practice.

MATERIALS AND METHODS

A bespoke questionnaire was designed following an extensive review of the literature and from recurring relevant themes presented at Radiation Oncology and Cardio-Oncology research meetings. Six question domains were retained following consensus discussions among the investigators, comprising 55 multiple choice stems: guidelines, cardiovascular assessment, cardiology investigations, radiotherapy planning strategies, primary prevention prescribing and local cardio-oncology service access. An invitation was sent to all Radiation Oncologists registered with ICOS and to Radiation Oncology colleagues of the investigators.

RESULTS

In total 118 participants were recruited and 92% were consultant physicians. The ICOS 2021 expert consensus statement was rated as the most useful position paper, followed by the joint ESC-ESTRO 2022 guideline. The majority (80%) of participants indicated that a detailed cardiovascular history was advisable. Although 69% of respondents deemed the availability of cardiac substructure auto-segmentation to be very/quite important, it was implemented by only a few, with the most common being the left anterior descending coronary artery V15. A distinct cardio-oncology service was available to 39% participants, while the remainder utilised general cardiology services.

CONCLUSION

The uptake of recent guidelines on cardiovascular optimisation is good, but access to cardiology investigations and consultations, and auto-segmentation, represent barriers to modifying radiotherapy practices in lung cancer to reduce the risk of radiation cardiotoxicity.

Development of learning-based predictive models for radiation-induced atrial fibrillation in non-small cell lung cancer patients by integrating patient-specific clinical, dosimetry, and diagnostic information

BACKGROUND AND PURPOSE

Radiotherapy (RT) in non-small cell lung cancer (NSCLC) can induce cardiac adverse events, including atrial fibrillation (AF), despite advanced RT. This study integrates patient-specific information to develop learning-based models to predict the incidence of AF following NSCLC chemoradiotherapy (CRT) and evaluates these models using institutional and external datasets.

MATERIALS AND METHODS

Institutional and external patient cohorts consisted of 321 and 187 NSCLC datasets who received definitive CRT, including 17 and 6 AF incidences, respectively. The network input had 159 features with clinical, dosimetry, and diagnostic. The class imbalance was mitigated by synthetic minority oversampling technique. To handle various types of input features, machine learning-based model adopted an intervention technique that chose one feature with the largest weight at each dosimetry sub-group in feature selection process, while deep learning-based model employed a hybrid architecture assigning different types of networks to corresponding input paths. Performance was assessed by area under the curve (AUC). The key features were investigated for the machine and deep learning-based models.

RESULTS

The hybrid deep learning model outperformed the machine learning-based algorithm in internal validation (AUC: 0.817 vs. 0.801) and produced more consistent performance in external validation (AUC: 0.806 vs. 0.776). Importantly, maximum dose to heart and sinoatrial node (SAN) were found to be the key features for both learning-based models in external and internal validations.

CONCLUSIONS

The learning-based predictive models showed consistent prediction performance across internal and external cohorts, identifying maximum heart and SAN dose as key features for the incidence of AF.

A roadmap for modelling radiation-induced cardiac disease

Cardiac risk mitigation is a major priority in improving outcomes for cancer survivors as advances in cancer screening and treatments continue to decrease cancer mortality. More than half of adult cancer patients will be treated with radiotherapy (RT); therefore it is crucial to develop a framework for how to assess and predict radiation-induced cardiac disease (RICD). Historically, RICD was modelled solely using whole heart metrics such as mean heart dose. However, data over the past decade has identified cardiac substructures which outperform whole heart metrics in predicting for significant cardiac events. Additionally, non-RT factors such as pre-existing cardiovascular risk factors and toxicity from other therapies contribute to risk of future cardiac events. In this review, we aim to discuss the current evidence and knowledge gaps in predicting RICD and provide a roadmap for the development of comprehensive models based on three interrelated components, (1) baseline CV risk assessment, (2) cardiac substructure radiation dosimetry linked with cardiac-specific outcomes and (3) novel biomarker development.

Predictors of Atrial Fibrillation After Thoracic Radiotherapy

Background

Atrial fibrillation (AF) has been associated with thoracic radiotherapy, but the specific risk with irradiating different cardiac substructures remains unknown.

Objectives

This study sought to examine the relationship between irradiation of cardiac substructures and the risk of clinically significant (grade ≥3) AF.

Methods

We analyzed data from patients who underwent definitive radiotherapy for localized cancers (non-small cell lung, breast, Hodgkin lymphoma, or esophageal) at our institution between 2004 and 2022. The 2-Gy fraction equivalent dose was calculated for cardiac substructures, including the pulmonary veins (PVs), left atrium, sinoatrial node, and left coronary arteries (the left main, left anterior descending, and left circumflex arteries). Competing risk models (subdistribution HRs [sHRs]) for AF incidence were adjusted for the Mayo AF risk score (MAFRS).

Results

Among 539 patients, the median follow-up was 58.8 months. The 5-year cumulative incidence of AF was 11.1% for non-small cell lung cancer, 8.3% for esophageal cancer, 1.3% for breast cancer, and 0.8% for Hodgkin lymphoma. Increased AF risk was associated with a higher PV maximum dose (dmax) (sHR: 1.22; P < 0.001), larger left atrial volume (sHR: 1.01; P = 0.002), greater smoking history in pack-years (sHR: 1.01; P = 0.010), and higher MAFRS (sHR: 1.16; P < 0.001). PV dmax remained a significant predictor of AF across different MAFRS subgroups (P interaction = 0.11), and a PV dmax >39.7 Gy was linked to a higher AF risk, even when stratified by MAFRS.

Conclusions

PV dmax is a significant predictor of grade ≥3 AF regardless of underlying risk factors. These findings highlight the importance of cardiac substructures in radiation toxicity and suggest that various PV dose metrics should be further validated in clinical settings.

Can We Offset Local Recurrence in Locally Advanced Non-Small Cell Lung Cancer? The Merry-Go-Round of Radiation Dose Escalation and Stubborn Outcomes

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.

Coronary artery calcium on lung cancer radiation planning CT aids cardiovascular risk assessment

BACKGROUND

Patients with non-small cell lung cancer (NSCLC) undergoing thoracic radiation are at high cardiovascular risk. Semiquantitative assessment of coronary artery calcification (CAC) on baseline planning non-gated chest computed tomography (CT) scans may help further risk stratify patients.

OBJECTIVES

This study aimed to characterize the association between CAC and major adverse cardiovascular events (MACE; myocardial infarction or stroke) and assess the utility of semiquantitative assessment of CAC.

METHODS

Patients with NSCLC with non-contrast planning chest CT scans were evaluated for CAC. Planning scans were visually graded using the CAC-DRS method, stratifying patients into no, mild, moderate, and severe CAC groups. Demographics, comorbidities, and radiation treatment characteristics were gathered, and CAC groups were assessed for the incidence of MACE after initiation of radiation therapy.

RESULTS

Out of 137 patients, 39 patients had no CAC, and 98 patients had any CAC (38 with mild CAC, 34 with moderate CAC, and 26 with severe CAC). There was 1 MACE event in the no CAC group and 11 in patients with any CAC. The presence of CAC was associated with increased MACE compared to no CAC (p = 0.034). Semiquantitative CAC analysis correlated with formal CAC scoring.

CONCLUSION

There is a significantly lower incidence of MACE in patients with no CAC on planning CT compared to patients with higher burdens of CAC. CAC burden is an important risk factor for adverse cardiovascular events in patients with NSCLC undergoing thoracic radiation. Semiquantitative CAC scoring may be a useful proxy when formal CAC scoring is unavailable.

Novel risk score for predicting acute cardiovascular and cerebrovascular events after chest radiotherapy in patients with breast or lung cancer

AIMS

Radiation therapy (RT) is an integral component of cancer therapy but associated with adverse events. Our goal was to establish risk prediction models for major adverse cardiovascular and cerebrovascular events (MACCE) after chest RT.

METHODS AND RESULTS

A retrospective study of lung/breast cancer patients who had chest RT with planning CT at Mayo Clinic between 01/2010 and 01/2014. Predictive models were developed based on weighted independent predictors using a derivation (406 lung and 711 breast cancer) and validation cohort (179 lung and 234 breast cancer). Patient characteristics, pre-RT CT for coronary artery calcification (CAC), and post-RT MACCE data were reviewed. Post-RT MACCE occurred in 6.1 and 5.6% in the derivation and validation cohort over a mean follow-up of 42 ± 13 months. Post-therapy model (C2AD2) included CAC (two points), MACCE history (two points), age ≥74 (three points), DM (two points), and mean heart radiation dose ≥ 850 mGy (two points), and pre-therapy model (C2AD) included post-therapy model parameters minus mean heart radiation dose. Both models stratified patients into three risk groups: low (0-2), intermediate (3-5), and high (≥6). Post-RT MACCE across these groups were 2.7, 8.9, and 19.8% in the derivation, and 3.9, 6.6, and 16.4% in the validation cohort for post-therapy model (C2AD2) and 2.8, 9.2, and 20.4% in the derivation and 3.7, 9.2, and 13.2% in the validation cohort for pre-therapy model. Both models showed statistically significant graded survival outcome.

CONCLUSION

Post-therapy (C2AD2) and pre-therapy (C2AD) models are simple, easy to use and effective tools to stratify breast and lung cancer patients undergoing chest radiation for post-RT MACCE.

The influence of cardiac substructure dose on survival in a large lung cancer stereotactic radiotherapy cohort using a robust personalized contour analysis

BACKGROUND/PURPOSE

Radiation-induced cardiac toxicity in lung cancer patients has received increased attention since RTOG 0617. However, large cohort studies with accurate cardiac substructure (CS) contours are lacking, limiting our understanding of the potential influence of individual CSs. Here, we analyse the correlation between CS dose and overall survival (OS) while accounting for deep learning (DL) contouring uncertainty, α / β uncertainty and different modelling approaches.

MATERIALS/METHODS

This single institution, retrospective cohort study includes 730 patients (early-stage tumours (I or II). All treated: 2009-2019), who received stereotactic body radiotherapy (≥ 5 Gy per fraction). A DL model was trained on 70 manually contoured patients to create 12 cardio-vascular structures. Structures with median dice score above 0.8 and mean surface distance (MSD) <2 mm during testing, were further analysed. Patientspecific CS dose was used to find the correlation between CS dose and OS with elastic net and random survival forest models (with and without confounding clinical factors). The influence of delineation-induced dose uncertainty on OS was investigated by expanding/contracting the DL-created contours using the MSD ± 2 standard deviations.

RESULTS

Eight CS contours met the required performance level. The left atrium (LA) mean dose was significant for OS and an LA mean dose of 3.3 Gy (in EQD2) was found as a significant dose stratum.

CONCLUSION

Explicitly accounting for input parameter uncertainty in lung cancer survival modelling was crucial in robustly identifying critical CS dose parameters. Using this robust methodology, LA mean dose was revealed as the most influential CS dose parameter.

S6K1 Controls DNA Damage Signaling Modulated by the MRN Complex to Induce Radioresistance in Lung Cancer

Radiation is a mainstay of lung cancer treatment; however, resistance frequently develops. Identifying novel therapeutic targets to increase radiation sensitivity is crucial. S6K1 is a serine/threonine kinase known to regulate protein translation which is associated with radioresistance, but the mechanisms involved are unknown. We proposed to determine whether S6K1 promotes radioresistance by regulating DNA repair in lung cancer. Colony formation, protein expression and proliferation were assessed. S6K1 was modulated pharmacologically by either PF-4708671 or genetically by Crispr-Cas9. Higher radioresistance levels in lung cancer cells were associated with lower phosphoactivation of MRN complex members, a key activator of radiation-induced DNA repair signaling. We also found lower levels of p-ATM, a target of the MRN complex, in more radioresistant cells, which was associated with a lower expression of γ-H2AX cafter radiation. Further, genetic and pharmacological S6K1 targeting sensitized lung cancer cells to low doses of radiation (p ≤ 0.01). Additionally, S6K1-/- deletion increased the phosphoactivation of MRN complex members, indicating that S6K1 itself can shut down DNA damage regulated by MRN signaling. This is the first report showing that S6K1 inhibition radiosensitizes lung cancer cells by decreasing MRN complex-regulated DNA repair signaling. Future studies should evaluate the role of S6K1 as a target to overcome radioresistance.

Risk Stratification by Combination of Heart and Lung Dose in Locally Advanced Non-Small-Cell Lung Cancer after Radiotherapy

Background/Objectives: Despite advancements in treatment for patients with unresectable locally advanced non-small cell lung cancer (LA-NSCLC), overall survival (OS) remains poor. The specific effects of varying heart and lung doses on OS in LA-NSCLC patients have not been thoroughly investigated, especially their combined impact on survival. This study aimed to examine the impact on OS of both individual and combined heart and lung doses in patients with LA-NSCLC treated with radiotherapy over a three-year follow-up period. Methods: A total of 120 patients who received definitive radiotherapy for LA-NSCLC (stage III, 92.5%) from January 2015 to January 2020 were retrospectively reviewed. The endpoint in this study was OS. Each patient was followed for a fixed period of three years. Results: Univariate Cox regression analysis showed that OS was significantly related to mean heart dose (MHD, hazard ratio [HR], 3.4 [1.8-6.3]; p < 0.001), pericardium V40 (HR, 3.2 [1.7-6.0]; p < 0.001), and total lung V20 (HR, 2.6 [1.4-5.0]; p = 0.003), and these were independent predictors for worse OS in multivariate analysis. Kaplan-Meier curve analysis with log-rank tests revealed that survival was significantly worse in patients with higher MHD (p < 0.001), pericardium V40 (p < 0.001), and total lung V20 (p = 0.002). Combining MHD and total lung V20, and pericardium V40 and total lung V20 provided enhanced risk stratification for OS (p < 0.001 for both combinations). Conclusions: The combination of heart and lung doses provided enhanced and more detailed risk stratification in prediction of OS for a fixed period of three years in LA-NSCLC patients treated with radiotherapy.

Treatment of unresectable stage III non-small cell lung cancer for patients who are under-represented in clinical trials

Concurrent chemoradiotherapy (cCRT) followed by one year of consolidation durvalumab is the current standard-of-care for patients with unresectable stage III non-small cell lung cancer (NSCLC), of good functional status. However, cCRT and consolidation durvalumab may be challenging to administer for selected patient populations underrepresented or even excluded in clinical trials: older and/or frail patients; those with cardiovascular or respiratory comorbidities in which treatment-related adverse events may be higher, and patients with pre-existing autoimmune disorders for whom immunotherapy use is controversial. In this narrative review, we discuss the current evidence, challenges, ongoing clinical trials and potential future treatment scenarios in relevant subgroups of patients with locally advanced NSCLC, who are underrepresented in clinical trials.

A Historical Survey of Key Epidemiological Studies of Ionizing Radiation Exposure

In this article we review the history of key epidemiological studies of populations exposed to ionizing radiation. We highlight historical and recent findings regarding radiation-associated risks for incidence and mortality of cancer and non-cancer outcomes with emphasis on study design and methods of exposure assessment and dose estimation along with brief consideration of sources of bias for a few of the more important studies. We examine the findings from the epidemiological studies of the Japanese atomic bomb survivors, persons exposed to radiation for diagnostic or therapeutic purposes, those exposed to environmental sources including Chornobyl and other reactor accidents, and occupationally exposed cohorts. We also summarize results of pooled studies. These summaries are necessarily brief, but we provide references to more detailed information. We discuss possible future directions of study, to include assessment of susceptible populations, and possible new populations, data sources, study designs and methods of analysis.

Cardiac Substructure Radiation Dose and Associations With Tachyarrhythmia and Bradyarrhythmia After Lung Cancer Radiotherapy

Background

Arrhythmias are common following radiotherapy for non-small cell lung cancer.

Objectives

The aim of this study was to analyze the association of distinct arrhythmia classes with cardiac substructure radiotherapy dose.

Methods

A retrospective analysis was conducted of 748 patients with locally advanced non-small cell lung cancer treated with radiotherapy. Cardiac substructure dose parameters were calculated. Receiver-operating characteristic curve analyses for predictors of Common Terminology Criteria for Adverse Events grade ≥3 atrial fibrillation (AF), atrial flutter, non-AF and non-atrial flutter supraventricular tachyarrhythmia (SVT), bradyarrhythmia, and ventricular tachyarrhythmia (VT) or asystole were calculated. Fine-Gray regression models were performed (with noncardiac death as a competing risk).

Results

Of 748 patients, 128 (17.1%) experienced at least 1 grade ≥3 arrhythmia, with a median time to first arrhythmia of 2.0 years (Q1-Q3: 0.9-4.2 years). The 2-year cumulative incidences of each arrhythmia group were 8.0% for AF, 2.7% for atrial flutter, 1.8% for other SVT, 1.4% for bradyarrhythmia, and 1.1% for VT or asystole. Adjusting for baseline cardiovascular risk, pulmonary vein (PV) volume receiving 5 Gy was associated with AF (subdistribution HR [sHR]: 1.04/mL; 95% CI: 1.01-1.08; P = 0.016), left circumflex coronary artery volume receiving 35 Gy with atrial flutter (sHR: 1.10/mL; 95% CI: 1.01-1.19; P = 0.028), PV volume receiving 55 Gy with SVT (sHR: 1.03 per 1%; 95% CI: 1.02-1.05; P < 0.001), right coronary artery volume receiving 25 Gy with bradyarrhythmia (sHR: 1.14/mL; 95% CI: 1.00-1.30; P = 0.042), and left main coronary artery volume receiving 5 Gy with VT or asystole (sHR: 2.45/mL; 95% CI: 1.21-4.97; P = 0.013).

Conclusions

This study revealed pathophysiologically distinct arrhythmia classes associated with radiotherapy dose to discrete cardiac substructures, including PV dose with AF and SVT, left circumflex coronary artery dose with atrial flutter, right coronary artery dose with bradyarrhythmia, and left main coronary artery dose with VT or asystole, guiding potential risk mitigation approaches.

Radiosensitization effect of quinoline-indole-schiff base derivative 10E on non-small cell lung cancer cells in vitro and in tumor xenografts

Radioresistance is an inevitable obstacle in the clinical treatment of inoperable patients with non-small cell lung cancer (NSCLC). Combining treatment with radiosensitizers may improve the efficacy of radiotherapy. Previously, the quinoline derivative 10E as new exporter of Nur77 has shown superior antitumor activity in hepatocellular carcinoma. Here, we aimed to investigate the radiosensitizing activity and acting mechanisms of 10E. In vitro, A549 and H460 cells were treated with control, ionizing radiation (IR), 10E, and 10E + IR. Cell viability, apoptosis, and cycle were examined using CCK-8 and flow cytometry assays. Protein expression and localization were examined using western blotting and immunofluorescence. Tumor xenograft models were established to evaluate the radiosensitizing effect of 10E in vivo. 10E significantly inhibited cell proliferation and increased their radiosensitivity while reducing level of p-BCRA1, p-DNA-PKs, and 53BP1 involved in the DNA damage repair pathway, indicating that its radiosensitizing activity is closely associated with repressing DNA damage repair. A549 cells showed low level of Nur77 and a low response to IR but 10E-treated A549 cells showed high level of Nur77 indicating that Nur77 is a core radiosensitivity factor and 10E restores the expression of Nur77. Nur77 and Ku80 extranuclear co-localization in the 10E-treated A549 cells suggested that 10E-modulated Nur77 nuclear exportation inhibits DNA damage repair pathways and increases IR-triggered apoptosis. The combination of 10E and IR significantly inhibits tumor growth in a tumor xenograft model. Our findings suggest that 10E acts as a radiosensitizer and that combining 10E with radiotherapy may be a potential strategy for NSCLC treatment.

Comparing Dosimetry of Heart and Left Anterior Descending Artery Exposure in Carcinoma Esophagus Patients: Volumetric Arc Therapy Versus Intensity-Modulated Radiotherapy

Introduction Esophageal cancer remains a leading cause of cancer-related mortality worldwide, with chemoradiotherapy being a cornerstone of its treatment. Ensuring precise radiation delivery is critical, as it minimizes exposure to surrounding healthy tissues, particularly vital structures like the heart and the left anterior descending artery (LAD). Volumetric arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) are two advanced radiotherapy techniques that offer enhanced dose conformity and reduced toxicity. This study conducts a retrospective dosimetric analysis to compare the effectiveness of VMAT and IMRT in sparing cardiac substructures and the LAD in patients with carcinoma of the esophagus. Methods Ten patients with middle-third esophageal cancer were treated using the VMAT technique with two coplanar arcs. These patients were retrospectively re-planned with IMRT using 7-9 fields on the Varian TrueBeam linear accelerator between June 2023 and December 2023. VMAT planning involved a two-phase approach: 45 Gy in 25 fractions followed by a boost of 5.4 Gy in three fractions. Dose-volume histograms were analyzed and compared for the planning target volume (PTV), heart and its substructures (including the right atrium, right ventricle, left atrium, and left ventricle), and the LAD. Statistical significance was determined using paired t-tests with a significance level set at P < 0.05. Results PTV coverage was comparable between VMAT and IMRT. VMAT resulted in higher low-dose exposure (V5 and V10) but offered better sparing at moderate doses (V20 and V40) for the heart. The LAD benefited from reduced high-dose exposure with VMAT. For other cardiac substructures, VMAT generally showed higher low-dose exposure but provided superior sparing at moderate doses compared to IMRT. Conclusions VMAT offers notable dosimetric advantages in sparing critical cardiac structures compared to IMRT for treating patients with middle third esophageal cancer. Long-term follow-up studies are needed to assess how these dosimetric benefits influence coronary artery disease and other cardiac complications.

Baseline Cardiac Parameters as Biomarkers of Radiation Cardiotoxicity in Lung Cancer: An NI-HEART Analysis

Background

Radiation-induced cardiotoxicity poses a significant challenge in lung cancer management because of the close anatomical proximity of the heart to the lungs, compounded by a high prevalence of cardiovascular risk factors among patients.

Objectives

The aim of this study was to assess the predictive value of routinely available clinical and imaging-based cardiac parameters in identifying "high risk" patients for major adverse cardiac events (MACE) and mortality following radiation therapy (RT).

Methods

The medical records of patients who underwent definitive RT for non-small cell lung cancer using modern planning techniques at a single center between 2015 and 2020 were retrospectively reviewed. Cardiac events were verified by cardiologists, and mortality data were confirmed with the national registry. Cardiac substructures were autosegmented on RT planning scans for retrospective structure and dose analysis, and their correlation with clinical factors was examined. Fine-Gray models were used to analyze relationships while considering the competing risk for death.

Results

Among 478 patients included in the study, 77 (16%) developed 88 MACE, with a median time to event of 16.3 months. A higher burden of pre-existing cardiac diseases was associated with an increased cumulative incidence of MACE (55% [95% CI: 12%-20%] vs 16% [95% CI: 35%-71%]; P < 0.001). Left atrial and left ventricular enlargement on RT planning scans was associated with cumulative incidence of atrial arrhythmia (14% [95% CI: 9%-20%] vs 4% [95% CI: 2%-8%]; P = 0.001) and heart failure (13% [95% CI: 8%-18%] vs 6% [95% CI: 3%-10%]; P = 0.007) at 5 years, respectively. However, myocardial infarction was not associated with the presence of coronary calcium (4.2% [95% CI: 2%-7%] vs 0% [95% CI: 0%-0%]; P = 0.094). No cardiac imaging metrics were found to be both clinically and statistically associated with survival.

Conclusions

The present findings suggest that cardiac history and RT planning scan parameters may offer potential utility in prospectively evaluating cardiotoxicity risk following RT for patients with lung cancer.

Dosimetric comparison of nodal clinical target volume for locally advanced non‑small cell lung cancer: Options for geometric expansion vs. lymph node stations

The purpose of the present retrospective study was to evaluate whether dosimetric differences existed in nodal clinical target volume (CTV) using options for geometric expansion and lymph node (LN) stations based on the European Society for Radiotherapy and Oncology guideline for locally advanced non-small cell lung cancer (NSCLC). In the treatment planning computed tomographic images of 17 patients with cT4N2M0 NSCLC, nodal CTVs were contoured based on the guideline options of: i) Geometric expansion, with CTV including the nodal gross tumor volume plus 5 mm margin; and ii) LN stations, with CTV including the affected LN stations. Treatment planning of 60 Gy in 30 fractions was performed using volumetric modulated arc therapy; Dmean was the mean irradiated dose to the structure; and VnGy was the volume of the structure receiving ≥n Gy. Dose-volume parameters were compared between the two options. Consequently, the option of geometric expansion was associated with a significantly lower V60Gy and Dmean of the esophagus, V20Gy, V5Gy and Dmean of the lungs, and Dmean of the heart than the option of LN stations in all patients (P=0.017, P<0.001, P<0.001, P<0.001, P<0.001 and P=0.029, respectively). For the V20Gy of the lungs, the 8 patients (47%) with LN metastases in stations 2 or 3 had significantly larger differences in the values between the two options than the 9 patients (53%) without those metastases; the median values of the difference of V20Gy of the lungs between the two options were 2.8% (range, 0.2 to 9.6%) with LN metastases in stations 2 or 3 and 0.5% (range, -0.2 to 5.0%) without these metastases (P=0.027). In conclusion, using the option for geometric expansion might help reduce the V60Gy and Dmean of the esophagus, V20Gy, V5Gy and Dmean of the lungs, and Dmean of the heart in all patients, and the V20Gy of the lungs in patients with LN metastases in stations 2 or 3.

Antithrombotic Therapy in Cancer Patients with Cardiovascular Diseases: Daily Practice Recommendations by the Hemostasis Working Party of the German Society of Hematology and Medical Oncology (DGHO) and the Society for Thrombosis and Hemostasis Research (GTH e.V.)

Active cancer by itself but also chemotherapy is associated with an increased risk of cardiovascular disease (CVD) and especially coronary artery disease (CAD) and atrial fibrillation (AF). The frequency of CVD, CAD, and AF varies depending on comorbidities (particularly in older patients), cancer type, and stage, as well as the anticancer therapeutic being taken. Many reports exist for anticancer drugs being associated with CVD, CAD, and AF, but robust data are often lacking. Because of this, each patient needs an individual structured approach concerning thromboembolic and bleeding risk, drug-drug interactions, as well as patient preferences to evaluate the need for anticoagulation therapy and targeting optimal symptom control. Interruption of specific cancer therapy should be avoided to reduce the potential risk of cancer progression. Nevertheless, additional factors like thrombocytopenia and anticoagulation in the elderly and frail patient with cancer cause additional challenges which need to be addressed in daily clinical management. Therefore, the aim of these recommendations is to summarize the available scientific data on antithrombotic therapy (both antiplatelet and anticoagulant therapy) in cancer patients with CVD and in cases of missing data providing guidance for optimal careful decision-making in daily routine.

FLASH Proton Radiation Therapy Mitigates Inflammatory and Fibrotic Pathways and Preserves Cardiac Function in a Preclinical Mouse Model of Radiation-Induced Heart Disease

PURPOSE

Studies during the past 9 years suggest that delivering radiation at dose rates exceeding 40 Gy/s, known as "FLASH" radiation therapy, enhances the therapeutic index of radiation therapy (RT) by decreasing normal tissue damage while maintaining tumor response compared with conventional (or standard) RT. This study demonstrates the cardioprotective benefits of FLASH proton RT (F-PRT) compared with standard (conventional) proton RT (S-PRT), as evidenced by reduced acute and chronic cardiac toxicities.

METHODS AND MATERIALS

Mice were imaged using cone beam computed tomography to precisely determine the heart's apex as the beam isocenter. Irradiation was conducted using a shoot-through technique with a 5-mm diameter circular collimator. Bulk RNA-sequencing was performed on nonirradiated samples, as well as apexes treated with F-PRT or S-PRT, at 2 weeks after a single 40 Gy dose. Inflammatory responses were assessed through multiplex cytokine/chemokine microbead assay and immunofluorescence analyses. Levels of perivascular fibrosis were quantified using Masson's Trichrome and Picrosirius red staining. Additionally, cardiac tissue functionality was evaluated by 2-dimensional echocardiograms at 8- and 30-weeks post-PRT.

RESULTS

Radiation damage was specifically localized to the heart's apex. RNA profiling of cardiac tissues treated with PRT revealed that S-PRT uniquely upregulated pathways associated with DNA damage response, induction of tumor necrosis factor superfamily, and inflammatory response, and F-PRT primarily affected cytoplasmic translation, mitochondrion organization, and adenosine triphosphate synthesis. Notably, F-PRT led to a milder inflammatory response, accompanied by significantly attenuated changes in transforming growth factor β1 and α smooth muscle actin levels. Critically, F-PRT decreased collagen deposition and better preserved cardiac functionality compared with S-PRT.

CONCLUSIONS

This study demonstrated that F-PRT reduces the induction of an inflammatory environment with lower expression of inflammatory cytokines and profibrotic factors. Importantly, the results indicate that F-PRT better preserves cardiac functionality, as confirmed by echocardiography analysis, while also mitigating the development of long-term fibrosis.

Advances in bacteria-based drug delivery systems for anti-tumor therapy

In recent years, bacteria have gained considerable attention as a promising drug carrier that is critical in improving the effectiveness and reducing the side effects of anti-tumor drugs. Drug carriers can be utilised in various forms, including magnetotactic bacteria, bacterial biohybrids, minicells, bacterial ghosts and bacterial spores. Additionally, functionalised and engineered bacteria obtained through gene engineering and surface modification could provide enhanced capabilities for drug delivery. This review summarises the current studies on bacteria-based drug delivery systems for anti-tumor therapy and discusses the prospects and challenges of bacteria as drug carriers. Furthermore, our findings aim to provide new directions and guidance for the research on bacteria-based drug systems.

Effects of confounding and effect-modifying lifestyle, environmental and medical factors on risk of radiation-associated cardiovascular disease

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death worldwide. It has been known for some considerable time that radiation is associated with excess risk of CVD. A recent systematic review of radiation and CVD highlighted substantial inter-study heterogeneity in effect, possibly a result of confounding or modifications of radiation effect by non-radiation factors, in particular by the major lifestyle/environmental/medical risk factors and latent period.

METHODS

We assessed effects of confounding by lifestyle/environmental/medical risk factors on radiation-associated CVD and investigated evidence for modifying effects of these variables on CVD radiation dose-response, using data assembled for a recent systematic review.

RESULTS

There are 43 epidemiologic studies which are informative on effects of adjustment for confounding or risk modifying factors on radiation-associated CVD. Of these 22 were studies of groups exposed to substantial doses of medical radiation for therapy or diagnosis. The remaining 21 studies were of groups exposed at much lower levels of dose and/or dose rate. Only four studies suggest substantial effects of adjustment for lifestyle/environmental/medical risk factors on radiation risk of CVD; however, there were also substantial uncertainties in the estimates in all of these studies. There are fewer suggestions of effects that modify the radiation dose response; only two studies, both at lower levels of dose, report the most serious level of modifying effect.

CONCLUSIONS

There are still large uncertainties about confounding factors or lifestyle/environmental/medical variables that may influence radiation-associated CVD, although indications are that there are not many studies in which there are substantial confounding effects of these risk factors.

Predictors of Early Hospice or Death in Patients With Inoperable Lung Cancer Treated With Curative Intent

INTRODUCTION

Treatment for inoperable stage II to III non-small cell lung cancer (NSCLC) involves chemo-radiotherapy (CRT). However, some patients transition to hospice or die early during their treatment course. We present a model to prognosticate early poor outcomes in NSCLC patients treated with curative-intent CRT.

METHODS AND MATERIALS

Across a statewide consortium, data was prospectively collected on stage II to III NSCLC patients who received CRT between 2012 and 2019. Early poor outcomes included hospice enrollment or death within 3 months of completing CRT. Logistic regression models were used to assess predictors in prognostic models. LASSO regression with multiple imputation were used to build a final multivariate model, accounting for missing covariates.

RESULTS

Of the 2267 included patients, 128 experienced early poor outcomes. Mean age was 71 years and 59% received concurrent chemotherapy. The best predictive model, created parsimoniously from statistically significant univariate predictors, included age, ECOG, planning target volume (PTV), mean heart dose, pretreatment lack of energy, and cough. The estimated area under the ROC curve for this multivariable model was 0.71, with a negative predictive value of 95%, specificity of 97%, positive predictive value of 23%, and sensitivity of 16% at a predicted risk threshold of 20%.

CONCLUSIONS

This multivariate model identified a combination of clinical variables and patient reported factors that may identify individuals with inoperable NSCLC undergoing curative intent chemo-radiotherapy who are at higher risk for early poor outcomes.

Effect of Radiotherapy on the Right Ventricular Function in Lung Cancer Patients

BACKGROUND

Anticancer treatment is associated with many side effects, including those involving the cardiovascular system. While many studies are available on the effects of radiotherapy (RT) on the left ventricle (LV), studies are lacking on the early effects of RT on the structure and function of the right ventricle (RV). Our study aims to assess, using modern echocardiographic techniques, the effect of irradiation on RV systolic function in the mid-term follow-up of patients undergoing RT for lung cancer (LC).

METHODS

This single-center, prospective study included consecutive patients with LC who were referred for treatment with definite radiotherapy and chemotherapy (study group) or chemotherapy only (control group).

RESULTS

The study included 43 patients with a mean age of 64.9 ± 8.1 years. Cancer treatment-related RV toxicity (CTR-RVT) was found in 17 patients (40%). Early reductions in TAPSE values were observed among patients in the study group (20.3 mm vs. 22.1 mm, p = 0.021). Compared to baseline, there was a significant reduction in RV global longitudinal strain (RV GLS) in the study group immediately after the treatment (-21.1% vs. -18.4%, p = 0.02) and also at 3 months after RT (-21.1% vs. -19.1%, p = 0.021). A significant reduction in the RV FWLS value was also observed at 3 months after the end of the treatment (-23.8% vs. -21.8, p = 0.046). There were no significant changes in the three-dimensional right ventricular ejection fraction (3DRVEF) during the follow-up. We found a correlation (p = 0.003) between the mean dose of radiation to the RV and 3DRVEF when assessed immediately after RT. The mean dose of radiation to the heart correlated with RV free-wall longitudinal strain (RV FWLS) immediately after RT (p = 0.03).

CONCLUSIONS

RV cardiotoxicity occurs in nearly half of patients treated for lung cancer. TAPSE is an important marker of deterioration of RV function under LC treatment. Compared to 3DRVEF, speckle tracking echocardiography is more useful in revealing deterioration of RV systolic function after radiotherapy.

Survival outcomes and toxicity of adjuvant immunotherapy after definitive concurrent chemotherapy with proton beam radiation therapy for patients with inoperable locally advanced non-small cell lung carcinoma

INTRODUCTION

Adjuvant immunotherapy (IO) following concurrent chemotherapy and photon radiation therapy confers an overall survival (OS) benefit for patients with inoperable locally advanced non-small cell lung carcinoma (LA-NSCLC); however, outcomes of adjuvant IO after concurrent chemotherapy with proton beam therapy (CPBT) are unknown. We investigated OS and toxicity after CPBT with adjuvant IO versus CPBT alone for inoperable LA-NSCLC.

MATERIALS AND METHODS

We analyzed 354 patients with LA-NSCLC who were prospectively treated with CPBT with or without adjuvant IO from 2009 to 2021. Optimal variable ratio propensity score matching (PSM) matched CPBT with CPBT + IO patients. Survival was estimated with the Kaplan-Meier method and compared with log-rank tests. Multivariable Cox proportional hazards regression evaluated the effect of IO on disease outcomes.

RESULTS

Median age was 70 years; 71 (20%) received CPBT + IO and 283 (80%) received CPBT only. After PSM, 71 CPBT patients were matched with 71 CPBT + IO patients. Three-year survival rates for CPBT + IO vs CPBT were: OS 67% vs 30% (P < 0.001) and PFS 59% vs 35% (P = 0.017). Three-year LRFS (P = 0.137) and DMFS (P = 0.086) did not differ. Receipt of adjuvant IO was a strong predictor of OS (HR 0.40, P = 0.001) and PFS (HR 0.56, P = 0.030), but not LRFS (HR 0.61, P = 0.121) or DMFS (HR 0.61, P = 0.136). There was an increased incidence of grade ≥3 esophagitis in the CPBT-only group (6% CPBT + IO vs 17% CPBT, P = 0.037).

CONCLUSION

This study, one of the first to investigate CPBT followed by IO for inoperable LA-NSCLC, showed that IO conferred survival benefits with no increased rates of toxicity.

Heart and Lung Dose as Predictors of Overall Survival in Patients With Locally Advanced Lung Cancer. A National Multicenter Study

Introduction

It is an ongoing debate how much lung and heart irradiation impact overall survival (OS) after definitive radiotherapy for lung cancer. This study uses a large national cohort of patients with locally advanced NSCLC to investigate the association between OS and irradiation of lung and heart.

Methods

Treatment plans were acquired from six Danish radiotherapy centers, and patient characteristics were obtained from national registries. A hybrid segmentation tool automatically delineated the heart and substructures. Dose-volume histograms for all structures were extracted and analyzed using principal component analyses (PCAs). Parameter selection for a multivariable Cox model for OS prediction was performed using cross-validation based on bootstrapping.

Results

The population consisted of 644 patients with a median survival of 26 months (95% confidence interval [CI]: 24-29). The cross-validation selected two PCA variables to be included in the multivariable model. PCA1 represented irradiation of the heart and affected OS negatively (hazard ratio, 1.14; 95% CI: 1.04-1.26). PCA2 characterized the left-right balance (right atrium and left ventricle) irradiation, showing better survival for tumors near the right side (hazard ratio, 0.92; 95% CI: 0.84-1.00). Besides the two PCA variables, the multivariable model included age, sex, body-mass index, performance status, tumor dose, and tumor volume.

Conclusions

Besides the classic noncardiac risk factors, lung and heart doses had a negative impact on survival, while it is suggested that the left side of the heart is a more radiation dose-sensitive region. The data indicate that overall heart irradiation should be reduced to improve the OS if possible.

Antitumour mechanisms of traditional Chinese medicine elicited by regulating tumour-associated macrophages in solid tumour microenvironments

Tumour-associated macrophages (TAMs), particularly M2-TAMs, constitute the largest proportion of immune cells in the solid tumour microenvironment, playing a crucial role in tumour progression and correlating with poor prognosis. TAMs promote the proliferation, invasion, and metastasis of tumour cells by remodelling the extracellular matrix, inhibiting immunity, promoting immune escape and tumour angiogenesis, and affecting cell metabolism. Traditional Chinese medicine (TCM) has been used clinically in China for millennia. Chinese herbs exhibit potent antitumour effects with minimal to no toxicity, substantially contributing to prolonging the lives of patients with cancer and improving their quality of life. TCM has unique advantages in improving the solid tumour microenvironment, particularly in regulating TAMs to further inhibit tumour angiogenesis, reduce drug resistance, reverse immunosuppression, and enhance antitumour immunity. This review highlights the TAM-associated mechanisms within the solid tumour microenvironment, outlines the recent advancements in TCM targeting TAMs for antitumour effects, emphasises the superiority of combining TCM with standard treatments or new nano-drug delivery systems, and evaluates the safety and efficacy of TCM combined with conventional treatments via clinical trials to provide insights and strategies for future research and clinical treatment.