Increased C-reactive protein is associated with the severity of thoracic radiotherapy-induced cardiomyopathy

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.

Early reduction in cardiorespiratory fitness and diastolic reserve following radiation therapy for lung cancer

BACKGROUND

Contemporary radiotherapy for the treatment of lung cancer is effective in targeting tumor tissue while limiting heart exposure, yet cardiac toxicity still occurs, often becoming clinically apparent years later. Cardiorespiratory fitness (CRF) is an independent predictor of cardiovascular, cancer-related, and overall mortality and may serve as a sensitive measure of subclinical cardiac toxicity following anti-cancer treatments. Prior work has demonstrated a significant relationship between reduced CRF and impaired left-ventricular (LV) diastolic reserve in cancer survivors following thoracic radiotherapy. The purpose of this study was to assess early longitudinal changes in CRF and cardiac function in patients with lung cancer following radiotherapy.

METHODS

Ten patients (69 [61-76] years, 70% female) with lung cancer without known cardiovascular disease scheduled to receive radiotherapy involving a clinically-relevant heart dose (≥ 5 Gy to > 10% of heart volume) were evaluated prior to and following treatment. Changes in CRF (peak oxygen consumption [VO2peak], oxygen uptake efficiency slope [OUES]), cardiac function (LV ejection fraction [LVEF], rest and exercise diastolic function [diastolic functional reserve index (DFRI)]), cardiac biomarkers (N-terminal pro-brain natriuretic peptide [NT-proBNP], high-sensitivity C-reactive protein [hsCRP]), and health-related quality of life (HRQOL; Functional Assessment of Cancer Therapy-General-7 [FACT-G7]) were measured.

RESULTS

The VO2peak was reduced at baseline (1.245 [0.882-1.605] L·min- 1; 70 [62-86] %-predicted) and significantly declined (1.095 [0.810-1.448] L·min- 1, P = 0.047; 62 [56-76] %-predicted, P = 0.005) at 6.0 [3.0-6.0] months post-radiotherapy. Similarly, a significant decline in the OUES was observed (1.63 [1.27-1.88] to 1.57 [1.12-1.75], P = 0.032). Systolic cardiac function was normal at baseline and did not change following radiotherapy (LVEF; 62 [56-65]% to 66 [57-68]%, P = 0.475). The DFRI significantly declined following radiotherapy (34.9 [22.7-41.6] vs. 12.8 [3.1-35.9]). The hsCRP increased significantly from 4.4 [1.4-5.8] to 6.1 [3.7-20.7] g/L, P = 0.047 with a trend towards higher levels of NT-proBNP (65 [49-125] to 121 [88-191] pg/mL, P = 0.110). Health-related quality of life significantly decreased (FACT-G7; 21.5 [18.8-25] to 15.5 [11.5-20]; P = 0.021) post-radiotherapy.

CONCLUSIONS

Patients with lung cancer receiving radiotherapy with a clinically-significant heart dose experience reductions in CRF (VO2peak, OUES) as early as six months following treatment with concurrent reductions in diastolic reserve (DFRI), HRQOL, and increases in cardiac biomarkers (NT-proBNP, hsCRP).

Radiation-induced circulating microRNAs linked to echocardiography parameters after radiotherapy

Introduction

Patients treated with radiotherapy to the chest region are at risk of cardiac sequelae, however, identification of those with greatest risk of complications remains difficult. Here, we sought to determine whether short-term changes in circulating miRNA expression are related to measures of cardiac dysfunction in follow-up.

Materials and methods

Two parallel patient cohorts were enrolled and followed up for 3 years after completion of RT to treat left-sided breast cancer. In the primary group (N=28) we used a a panel of 752 miRNAs to identify miRNAs associated with radiation and cardiac indices at follow up. In the second, independent cohort (N=56) we validated those candidate miRNAs with a targeted qPCR panel. In both cohorts. serum samples were collected before RT, 24h after the last dose and 1 month after RT; cardiac echocardiography was performed 2.5-3 year after RT.

Results

Seven miRNAs in the primary group showed marked changes in serum miRNAs immediately after RT compared to baseline and associations with cardiopulmonary dose-volume histogram metrics. Among those miRNAs: miR-15b-5p, miR-22-3p, miR-424-5p and miR-451a were confirmed to show significant decrease of expression 24 hours post-RT in the validation cohort. Moreover, miR-29c, miR-451 and miR-424 were correlated with the end-diastolic diameter of the left ventricle, which was also confirmed in multivariable analysis adjusting for RT-associated factors.

Conclusion

We identified a subset of circulating miRNAs predictive for cardiac function impairment in patients treated for left-sided breast cancer, although longer clinical observation could determine if these can be used to predict major clinical endpoints.

Influence of extracellular volume fraction on peak exercise oxygen pulse following thoracic radiotherapy

Background

Radiation-induced myocardial fibrosis increases heart failure (HF) risk and is associated with a restrictive cardiomyopathy phenotype. The myocardial extracellular volume fraction (ECVF) using contrast-enhanced cardiac magnetic resonance (CMR) quantifies the extent of fibrosis which, in severe cases, results in a noncompliant left ventricle (LV) with an inability to augment exercise stroke volume (SV). The peak exercise oxygen pulse (O₂Pulse), a noninvasive surrogate for exercise SV, may provide mechanistic insight into cardiac reserve. The relationship between LV ECVF and O₂Pulse following thoracic radiotherapy has not been explored.

Methods

Patients who underwent thoracic radiotherapy for chest malignancies with significant incidental heart dose (≥5 Gray (Gy), ≥10% heart) without a pre-cancer treatment history of HF underwent cardiopulmonary exercise testing to determine O₂Pulse, contrast-enhanced CMR, and N-terminal pro-brain natriuretic peptide (NTproBNP) measurement. Multivariable-analyses were performed to identify factors associated with O₂Pulse normalized for age/gender/anthropometrics.

Results

Thirty patients (median [IQR] age 63 [57–67] years, 18 [60%] female, 2.0 [0.6–3.8] years post-radiotherapy) were included. The peak VO₂ was 1376 [1057–1552] mL·min^− 1, peak HR = 150 [122–164] bpm, resulting in an O₂Pulse of 9.2 [7.5–10.7] mL/beat or 82 (66–96) % of predicted. The ECVF, LV ejection fraction, heart volume receiving ≥10 Gy, and NTproBNP were independently associated with %O₂Pulse (P < .001).

Conclusions

In patients with prior radiotherapy heart exposure, %-predicted O₂Pulse is inversely associated markers of diffuse fibrosis (ECVF), ventricular wall stress (NTproBNP), radiotherapy heart dose, and positively related to LV function. Increased LV ECVF may reflect a potential etiology of impaired LV SV reserve in patients receiving thoracic radiotherapy for chest malignancies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40959-021-00127-6.

Transcriptomes of Wet Skin Biopsies Predict Outcomes after Ionizing Radiation Exposure with Potential Dosimetric Applications in a Mouse Model

Countermeasures for radiation diagnosis, prognosis, and treatment are trailing behind the proliferation of nuclear energy and weaponry. Radiation injury mechanisms at the systems biology level are not fully understood. Here, mice skin biopsies at h2, d4, d7, d21, and d28 after exposure to 1, 3, 6, or 20 Gy whole-body ionizing radiation were evaluated for the potential application of transcriptional alterations in radiation diagnosis and prognosis. Exposure to 20 Gy was lethal by d7, while mice who received 1, 3, or 6 Gy survived the 28-day time course. A Sammon plot separated samples based on survival and time points (TPs) within lethal (20 Gy) and sublethal doses. The differences in the numbers, regulation mode, and fold change of significantly differentially transcribed genes (SDTGs, p < 0.05 and FC > 2) were identified between lethal and sublethal doses, and down and upregulation dominated transcriptomes during the first post-exposure week, respectively. The numbers of SDTGs and the percentages of upregulated ones revealed stationary downregulation post-lethal dose in contrast to responses to sublethal doses which were dynamic and largely upregulated. Longitudinal up/downregulated SDTGs ratios suggested delayed and extended responses with increasing IR doses in the sublethal range and lethal-like responses in late TPs. This was supported by the distributions of common and unique genes across TPs within each dose. Several genes with potential dosimetric marker applications were identified. Immune, fibrosis, detoxification, hematological, neurological, gastric, cell survival, migration, and proliferation radiation response pathways were identified, with the majority predicted to be activated after sublethal and inactivated after lethal exposures, particularly during the first post-exposure week.

Early Detection of Cardiac Damage by Two-Dimensional Speckle Tracking Echocardiography After Thoracic Radiation Therapy: Study Protocol for a Prospective Cohort Study

Background

As one of the important treatment methods for cancer patients, radiotherapy may lead to incidental irradiation of the heart, resulting in radiotherapy-induced heart disease (RIHD) arising many years after radiotherapy. While, there are few studies on early subclinical cardiac damage, which may be essential for the protection of late RIHD. To detect and predict RIHD and early subclinical cardiac damage induced by thoracic radiation therapy, based on two-dimensional speckle tracking echocardiography (2D STE) combined with multiple circulating biomarkers and accurate heart dosimetry.

Methods and Analysis

This is a monocentric prospective cohort study in which 104 patients treated for malignant tumors and with cardiac radiation exposure will be included. All participants will be followed for 12 months after radiotherapy. Echocardiography, 2D STE, and blood samples will be underwent at 5-time points (baseline; after completion of RT; 2, 6, and 12 months after RT). Left ventricular ejection fraction (LVEF); global longitudinal, radial, and circumferential strain; diastolic function parameters; creatine kinase (CK); creatine kinase isoenzyme (CK-MB); cardiac troponin T (cTnT); N-terminal pro-B-type natriuretic peptide (NT-proBNP) and hypersensitive C-reactive protein (hs-CRP) will be measured at baseline and every follow-up time. The incidence of major adverse cardiovascular events will be recorded.

Discussion

This study details the protocol and presents the primary limits and advantages of this single-center project. The inclusion of patients began in 2021, and the results are expected to be published in 2023. This study will be allowed to enhance knowledge on detection and prediction of early subclinical cardiac dysfunction induced by thoracic radiation therapy, based on two-dimensional speckle tracking echocardiography (2D STE) combined with circulating biomarkers and accurate heart dosimetry. Furthermore, we will evaluate risk factors of subtle cardiac damage and identify high-risk groups for early heart damage.

Clinical Trial Registration

ClinicalTrials.gov, identifier: NCT04443400.

Advances in Biomarkers for Detecting Early Cancer Treatment-Related Cardiac Dysfunction

With the gradual prolongation of the overall survival of cancer patients, the cardiovascular toxicity associated with oncology drug therapy and radiotherapy has attracted increasing attention. At present, the main methods to identify early cancer treatment-related cardiac dysfunction (CTRCD) include imaging examination and blood biomarkers. In this review, we will summarize the research progress of subclinical CTRCD-related blood biomarkers in detail. At present, common tumor therapies that cause CTRCD include: (1) Chemotherapy—The CTRCD induced by chemotherapy drugs represented by anthracycline showed a dose-dependent characteristic and most of the myocardial damage is irreversible. (2) Targeted therapy—Cardiovascular injury caused by molecular-targeted therapy drugs such as trastuzumab can be partially or completely alleviated via timely intervention. (3) Immunotherapy—Patients developed severe left ventricular dysfunction who received immune checkpoint inhibitors have been reported. (4) Radiotherapy—CTRCD induced by radiotherapy has been shown to be significantly associated with cardiac radiation dose and radiation volume. Numerous reports have shown that elevated troponin and B-type natriuretic peptide after cancer treatment are significantly associated with heart failure and asymptomatic left ventricular dysfunction. In recent years, a few emerging subclinical CTRCD potential biomarkers have attracted attention. C-reactive protein and ST2 have been shown to be associated with CTRCD after chemotherapy and radiation. Galectin-3, myeloperoxidas, placental growth factor, growth differentiation factor 15 and microRNAs have potential value in predicting CTRCD. In this review, we will summarize CTRCD caused by various tumor therapies from the perspective of cardio-oncology, and focus on the latest research progress of subclinical CTRCD biomarkers.

Diastolic Dysfunction Contributes to Impaired Cardiorespiratory Fitness in Patients with Lung Cancer and Reduced Lung Function Following Chest Radiation

Cardiorespiratory fitness (CRF) is a robust and independent predictor of cardiovascular health and overall mortality. Patients with lung cancer often have chronic lung disease, contributing to impaired CRF. Radiation to the heart during lung cancer treatment may further reduce CRF. The determinants of CRF in this population are not well understood. We prospectively evaluated 12 patients with lung cancer without known cardiovascular disease with reduced lung function receiving curative intent thoracic radiotherapy to determine whether cardiac diastolic function, as assessed by Doppler echocardiography and N-terminal pro-brain natriuretic peptide (NTproBNP) levels, correlate with CRF measured by peak oxygen consumption (VO₂). Doppler-derived measures of diastolic function and serum NTproBNP levels inversely correlated with peak VO_2. In a multivariate regression model, NTproBNP was the strongest independent variable associated with peak VO₂. These results suggest that diastolic dysfunction further contributes to reduced CRF in patients with lung cancer who have received radiotherapy.

Data-Independent Acquisition Proteomics Reveals Long-Term Biomarkers in the Serum of C57BL/6J Mice Following Local High-Dose Heart Irradiation

Background and Purpose: Cardiotoxicity is a well-known adverse effect of radiation therapy. Measurable abnormalities in the heart function indicate advanced and often irreversible heart damage. Therefore, early detection of cardiac toxicity is necessary to delay and alleviate the development of the disease. The present study investigated long-term serum proteome alterations following local heart irradiation using a mouse model with the aim to detect biomarkers of radiation-induced cardiac toxicity.

Materials and Methods: Serum samples from C57BL/6J mice were collected 20 weeks after local heart irradiation with 8 or 16 Gy X-ray; the controls were sham-irradiated. The samples were analyzed by quantitative proteomics based on data-independent acquisition mass spectrometry. The proteomics data were further investigated using bioinformatics and ELISA.

Results: The analysis showed radiation-induced changes in the level of several serum proteins involved in the acute phase response, inflammation, and cholesterol metabolism. We found significantly enhanced expression of proinflammatory cytokines (TNF-α, TGF-β, IL-1, and IL-6) in the serum of the irradiated mice. The level of free fatty acids, total cholesterol, low-density lipoprotein (LDL), and oxidized LDL was increased, whereas that of high-density lipoprotein was decreased by irradiation.

Conclusions: This study provides information on systemic effects of heart irradiation. It elucidates a radiation fingerprint in the serum that may be used to elucidate adverse cardiac effects after radiation therapy.

Cardiac MRI utilizing late gadolinium enhancement (LGE) and T1 mapping in the detection of radiation induced heart disease

Background and purpose

Radiotherapy has been associated with late dose-dependent cardiovascular toxicity. In this cross-sectional pilot study, radiation dose distributions were correlated with areas of localized and diffuse myocardial fibrosis as measured by novel cardiac MRI (CMR) sequences including late gadolinium enhancement (LGE) and T1 mapping with the goal to identify early markers of myocardial damage.

Materials and methods

Twenty-eight patients with chest tumors including lung, breast, esophagus, and lymphoma underwent CMR per study protocol on average 46.4 months (range 1.7–344.5) after radiotherapy. Patients without pretreatment cardiac history were included if the volume of heart receiving 5 Gy or more was at least 10% (V5Gy ≥ 10%). The association of LGE with cardiac dosimetric factors, clinical factors (e.g., tumor type, smoking history, BMI), and T1 values was analyzed.

Results

Cardiac maximum (Dmax) and mean dose (Dmean) equivalent to doses delivered in 2 Gy fractions (EQD2) were on average 50.9 Gy (range 6.2–108.0) and 8.2 Gy (range 1.0–35.7), respectively, compared to 60.8 Gy (40.8–108.0) and 6.8 Gy (1.8–21.8) among the 9 patients with LGE. Doses were not different between patients with and without LGE (p = 0.16 and 0.56, respectively). The average T1 value of the left ventricle myocardium was 1009 ms (range 933–1117). No significant correlation was seen for heart Dmax and Dmean and T1 values (p = 0.14 and 0.58, respectively). In addition, no significant association between clinical factors and the development of LGE was identified.

Conclusions

No relation between cardiac doses, the presence of LGE or T1 values was observed. Further study is needed to determine the benefit of CMR for detecting radiotherapy-related myocardial fibrosis.