Radiotherapy-induced right ventricular remodelling: The missing piece of the puzzle

Application of two-dimensional speckle-tracking echocardiography in radiotherapy-related cardiac systolic dysfunction and analysis of its risk factors: a prospective cohort study

BACKGROUND

The cardiac toxicity of radiotherapy (RT) can affect cancer survival rates over the long term. This has been confirmed in patients with breast cancer and lymphoma. However, there are few studies utilizing the two-dimensional speckle-tracking echocardiography (2D-STE) to evaluate the risk factors affecting radiation induced heart disease (RIHD), and there is a lack of quantitative data. Therefore, we intend to explore the risk factors for RIHD and quantify them using 2D-STE technology.

METHODS

We ultimately enrolled 40 patients who received RT for thoracic tumors. For each patient, 2D-STE was completed before, during, and after RT and in the follow up. We analyzed the sensitivity of 2D-STE in predicting RIHD and the relationship between RT parameters and cardiac systolic function decline.

RESULTS

Left ventricle global longitudinal strain (LVGLS), LVGLS of the endocardium (LVGLS-Endo), LVGLS of the epicardium (LVGLS-Epi), and right ventricle free-wall longitudinal strain (RVFWLS) decreased mid- and post-treatment compared with pre-treatment, whereas traditional parameters such as left ventricular ejection fraction (LVEF), cardiac Tei index (Tei), and peak systolic velocity of the free wall of the tricuspid annulus (s') did not show any changes. The decreases in the LVGLS and LVGLS-Endo values between post- and pre-treatment and the ratios of the decreases to the baseline values were linearly correlated with mean heart dose (MHD) (all P values < 0.05). The decreases in the LVGLS-Epi values between post- and pre-treatment and the ratios of the decreases to the baseline values were linearly correlated with the percentage of heart volume exposed to 5 Gy or more (V5) (P values < 0.05). The decrease in RVFWLS and the ratio of the decrease to the baseline value were linearly related to MHD and patient age (all P values < 0.05). Endpoint events occurred more frequently in the right side of the heart than in the left side. Patients over 56.5 years of age had a greater probability of developing right-heart endpoint events. The same was true for patients with MHD over 20.2 Gy in both the left and right sides of the heart.

CONCLUSIONS

2D-STE could detect damages to the heart earlier and more sensitively than conventional echocardiography. MHD is an important prognostic parameter for LV systolic function, and V5 may also be an important prognostic parameter. MHD and age are important prognostic parameters for right ventricle systolic function.

Right Ventricle and Epigenetics: A Systematic Review

There is an increasing recognition of the crucial role of the right ventricle (RV) in determining the functional status and prognosis in multiple conditions. In the past decade, the epigenetic regulation (DNA methylation, histone modification, and non-coding RNAs) of gene expression has been raised as a critical determinant of RV development, RV physiological function, and RV pathological dysfunction. We thus aimed to perform an up-to-date review of the literature, gathering knowledge on the epigenetic modifications associated with RV function/dysfunction. Therefore, we conducted a systematic review of studies assessing the contribution of epigenetic modifications to RV development and/or the progression of RV dysfunction regardless of the causal pathology. English literature published on PubMed, between the inception of the study and 1 January 2023, was evaluated. Two authors independently evaluated whether studies met eligibility criteria before study results were extracted. Amongst the 817 studies screened, 109 studies were included in this review, including 69 that used human samples (e.g., RV myocardium, blood). While 37 proposed an epigenetic-based therapeutic intervention to improve RV function, none involved a clinical trial and 70 are descriptive. Surprisingly, we observed a substantial discrepancy between studies investigating the expression (up or down) and/or the contribution of the same epigenetic modifications on RV function or development. This exhaustive review of the literature summarizes the relevant epigenetic studies focusing on RV in human or preclinical setting.

Radiation Treatment Mechanisms of Cardiotoxicity: A Systematic Review

Radiotherapy may be used alone or in combination with chemotherapy for cancer treatment. There are many mechanisms of radiation treatment exposure to toxicities. Our aim was to summarize the literature about known mechanisms of radiation-induced cardiac toxicities. We performed a systematic review of the literature on the PubMed database until October 2022 about cardiovascular toxicities and radiation therapy exposure. Only systematic reviews, meta-analyses, and reviews were selected. Out of 1429 publications screened, 43 papers met inclusion criteria and were selected for the umbrella review process. Microvascular and macrovascular complications could lead to adverse cardiac effects. Many radiotherapy-associated risk factors were responsible, such as the site of radiation treatment, beam proximity to heart tissues, total dosage, the number of radiotherapy sessions, adjuvant chemotherapeutic agents used, and patient traditional cardiovascular risk factors, patient age, and gender. Moreover, important dosage cutoff values could increase the incidence of cardiac toxicities. Finally, the time from radiation exposure to cardiac side effects was assessed. Our report highlighted mechanisms, radiation dosage values, and the timeline of cardiovascular toxicities after radiation therapy. All of the above may be used for the assessment of cardiovascular risk factors and the development of screening programs for cancer patients.

Dosimetric evaluation of the benefit of deep inspiration breath hold (DIBH) for locoregional irradiation of right breast cancer with volumetric modulated arctherapy (VMAT)

INTRODUCTION

Right-lateralized cardiac substructures can be substantially exposed during right breast cancer (R-BC) radiotherapy. The cardiac benefit of deep inspiration breath hold (DIBH) is established in combination with volumetric modulated arctherapy (VMAT) for left breast cancer with regional node irradiation but is unknown for R-BC. This study evaluated the dosimetric benefit of DIBH for locoregional irradiation of R-BC with VMAT.

MATERIAL AND METHODS

All patients treated for R-BC with adjuvant locoregional DIBH-VMAT in the Department of Radiation Oncology of the Institut Curie (Paris, France) until December 2022 were included, corresponding to 15 patients. FB- and DIBH-VMAT plans were compared both for a normofractionated regimen (50 Gy/25fx) used for treatment and a replanned hypofractionated regimen (40 Gy/15fx). Dose to the heart, cardiac substructures (sinoatrial node (SAN), atrio-ventricular node (AVN), right coronary artery, left anterior descending coronary artery, left ventricle), ipsilateral lung and liver were retrieved and compared.

RESULTS

Mean heart dose (MHD) was 3.33 Gy with FB vs. 3.10 Gy with DIBH on normofractionated plans (p = 0.489), and 2.58 Gy with FB vs. 2.41 Gy with DIBH on hypofractionated plan (p = 0.489). The benefit of DIBH was not significant for any cardiac substructure. The most exposed cardiac substructure were the SAN (mean dose of 6.62 Gy for FB- and 5.64 Gy for DIBH-VMAT on normofractionated plans) and the RCA (mean dose of 4.21 Gy for FB- and 4.06 Gy for DIBH-VMAT on normofractionated plans). The maximum benefit was observed for the RCA with a median individual dose reduction of 0.84 Gy on normofractionated plans (p = 0.599). No significant dosimetric difference were observed for right lung. Liver mean dose was significantly lower with DIBH with median values decreasing from 2.54 Gy to 0.87 Gy (p = 0.01).

CONCLUSION

Adding DIBH to efficient cardiac-sparing radiotherapy techniques, such as VMAT, is not justified in the general case for locoregional R-BC irradiation. Specific R-BC patient subpopulations who could benefit from additional DIBH combination with locoregional VMAT are yet to be identified.

Radiation-induced cardiac side-effects: The lung as target for interacting damage and intervention

Radiotherapy is part of the treatment for many thoracic cancers. During this treatment heart and lung tissue can often receive considerable doses of radiation. Doses to the heart can potentially lead to cardiac effects such as pericarditis and myocardial fibrosis. Common side effects after lung irradiation are pneumonitis and pulmonary fibrosis. It has also been shown that lung irradiation has effects on cardiac function. In a rat model lung irradiation caused remodeling of the pulmonary vasculature increasing resistance of the pulmonary vascular bed, leading to enhanced pulmonary artery pressure, right ventricle hypertrophy and reduced right ventricle performance. Even more pronounced effects are observed when both, lung and heart are irradiated.

The effects observed after lung irradiation show striking similarities with symptoms of pulmonary arterial hypertension. In particular, the vascular remodeling in lung tissue seems to have similar underlying features. Here, we discuss the similarities and differences of vascular remodeling observed after thoracic irradiation compared to those in pulmonary arterial hypertension patients and research models. We will also assess how this knowledge of similarities could potentially be translated into interventions which would be beneficial for patients treated for thoracic tumors, where dose to lung tissue is often unavoidable.

Stress Echo 2030: The Novel ABCDE-(FGLPR) Protocol to Define the Future of Imaging

With stress echo (SE) 2020 study, a new standard of practice in stress imaging was developed and disseminated: the ABCDE protocol for functional testing within and beyond CAD. ABCDE protocol was the fruit of SE 2020, and is the seed of SE 2030, which is articulated in 12 projects: 1-SE in coronary artery disease (SECAD); 2-SE in diastolic heart failure (SEDIA); 3-SE in hypertrophic cardiomyopathy (SEHCA); 4-SE post-chest radiotherapy and chemotherapy (SERA); 5-Artificial intelligence SE evaluation (AI-SEE); 6-Environmental stress echocardiography and air pollution (ESTER); 7-SE in repaired Tetralogy of Fallot (SETOF); 8-SE in post-COVID-19 (SECOV); 9: Recovery by stress echo of conventionally unfit donor good hearts (RESURGE); 10-SE for mitral ischemic regurgitation (SEMIR); 11-SE in valvular heart disease (SEVA); 12-SE for coronary vasospasm (SESPASM). The study aims to recruit in the next 5 years (2021-2025) ≥10,000 patients followed for ≥5 years (up to 2030) from ≥20 quality-controlled laboratories from ≥10 countries. In this COVID-19 era of sustainable health care delivery, SE2030 will provide the evidence to finally recommend SE as the optimal and versatile imaging modality for functional testing anywhere, any time, and in any patient.

Case Report: Adjuvant Radiotherapy Can Be an Effective Treatment for Intimal Sarcoma of the Heart

Intimal sarcoma of the heart is a sporadic disease, which involves symptoms of cardiac insufficiency due to a fast-growing intraluminal mass. Tumor resection is the first-line treatment, although its location precludes excision with wide uninvolved margins. Despite the aggressiveness of this neoplasm and a high risk of recurrence even after removal by microscopically radical surgery, no standard adjuvant therapy has been established. Chemotherapy is used either as an adjuvant treatment or in cases of advanced disease. In contrast, the use of radiotherapy is rare and usually considered in a palliative setting because the risk of radiation-induced heart disease after high-dose radiotherapy to the heart is significant. Herein, we present the cases of two patients, both diagnosed with cardiac intimal sarcoma, who received irradiation after tumor resection. In both cases, radiotherapy was effective, providing long-lasting local disease control. We regularly monitored cardiac function in both patients to assess the impact of radiotherapy on tumor-free heart structures. The excellent local control of the disease with only mild long-term cardiac dysfunction in both patients suggests that radiotherapy can be a useful treatment modality in this indication.

Evaluating cardiac substructure radiation exposure in breast rotational intensity modulated radiation therapy: Effects of cancer laterality, fractionation and deep inspiration breath-hold

PURPOSE

Rotational intensity-modulated radiation therapy currently has a growing role in breast cancer radiation therapy, since this radiation technique reduces cardiac radiation exposure while homogeneously covering target volumes. This study aims to evaluate radiation exposure of cardiac substructures across a broad spectrum of breast cancer cases differing by cancer laterality, fractionation regimen and addition of deep-inspiration breath hold.

MATERIALS AND METHODS

Cardiac substructures were delineated following guidelines endorsed by the European Society for Radiotherapy and Oncology (ESTRO) for forty-four breast cancer patients having undergone conserving surgery and adjuvant rotational intensity-modulated radiation therapy. Target volumes consisted of the whole breast with a boost, axillary and internal mammary nodes. Patients were treated using free-breathing technique for left-sided or right-sided, normofractionated or hypofractionated helical tomotherapy or volumetric modulated arc therapy, or using deep-inspiration breath hold for left-sided normofractionated volumetric modulated arc therapy. Mean and maximum doses to cardiac substructures were retrieved. Correlations were performed between mean- and maximum radiation doses to cardiac substructures.

RESULTS

Left-sided and right-sided irradiations were associated with different cardiac substructure exposure patterns despite comparable mean heart dose: 7.21Gy for left-sided normofractionated regimen, 6.28Gy for right-sided normofractionated regimen. Deep-inspiration breath hold reduced mean doses to almost all cardiac substructures for left-sided irradiation, but did not decrease maximum doses to coronary arteries. Correlations between mean- and maximum doses to cardiac substructures were usually moderate, but stronger for right-sided irradiation.

CONCLUSION

Despite comparable mean heart dose, cardiac substructure radiation exposure patterns with rotational intensity-modulated radiation therapy strongly depend on the breast side, which could trigger clinically different long-term cardiotoxicity events. Deep-inspiration breath hold improves cardiac substructure dosimetry. Mean- and maximum heart dose could probably not be used as surrogate markers for precise cardiac substructure evaluation. In a near future, clinical practice and cardiotoxicity studies could possibly gain by considering cardiac substructure in a more systematic manner, possibly relying on cardiac autosegmentation algorithms.

The Role of NLRP3 Inflammasome in Radiation-Induced Cardiovascular Injury

The increasing risk of long-term adverse effects from radiotherapy on the cardiovascular structure is receiving increasing attention. However, the mechanisms underlying this increased risk remain poorly understood. Recently, the nucleotide-binding domain and leucine-rich-repeat-containing family pyrin 3 (NLRP3) inflammasome was suggested to play a critical role in radiation-induced cardiovascular injury. However, the relationship between ionizing radiation and the NLRP3 inflammasome in acute and chronic inflammation is complex. We reviewed literature detailing pathological changes and molecular mechanisms associated with radiation-induced damage to the cardiovascular structure, with a specific focus on NLRP3 inflammasome-related cardiovascular diseases. We also summarized possible therapeutic strategies for the prevention of radiation-induced heart disease (RIHD).

Right ventricular involvement in cancer therapy-related cardiotoxicity: the emerging role of strain echocardiography

The involvement of the right ventricle (RV) in various cardiovascular pathologies is usually explored and demonstrated after thorough research of the left ventricle (LV). This is also true in cardio-oncology, where multimodality imaging with cardiac magnetic resonance and nuclear imaging is essential, but echocardiography plays pivotal role in everyday clinical practice. Chemotherapy and radiotherapy effect on RV has been studied mainly in breast cancer patients and survivors from childhood cancer. Right ventricular geometry and shape limit the ability of classical echocardiographic indices like RV ejection fraction (RVEF), RV fractional area change (FAC), and tricuspid annular plane systolic excursion (TAPSE) to identify reliably subtle changes in RV systolic function in cancer patients. The assessment of diastolic function of the RV in various timepoints during or after chemotherapy leads to conflicting results too. However, longitudinal strain of the RV (RV LS) seems to detect myocardial injury with consistent results. Remarkably, cardiotoxicity of the RV is identified by RV LS almost simultaneously with LV cardiotoxicity and with similar cutoff percent change suggesting the uniform effect of cancer and its treatments on myocardium. The prognostic value of cardiotoxic effects on the RV needs to be investigated by large prospective studies.

Radiotherapy-induced heart disease: a review of the literature

Radiotherapy as one of the four pillars of cancer therapy plays a critical role in the multimodal treatment of thoracic cancers. Due to significant improvements in overall cancer survival, radiotherapy-induced heart disease (RIHD) has become an increasingly recognized adverse reaction which contributes to major radiation-associated toxicities including non-malignant death. This is especially relevant for patients suffering from diseases with excellent prognosis such as breast cancer or Hodgkin's lymphoma, since RIHD may occur decades after radiotherapy. Preclinical studies have enriched our knowledge of many potential mechanisms by which thoracic radiotherapy induces heart injury. Epidemiological findings in humans reveal that irradiation might increase the risk of cardiac disease at even lower doses than previously assumed. Recent preclinical studies have identified non-invasive methods for evaluation of RIHD. Furthermore, potential options preventing or at least attenuating RIHD have been developed. Ongoing research may enrich our limited knowledge about biological mechanisms of RIHD, identify non-invasive early detection biomarkers and investigate potential treatment options that might attenuate or prevent these unwanted side effects. Here, we present a comprehensive review about the published literature regarding clinical manifestation and pathological alterations in RIHD. Biological mechanisms and treatment options are outlined, and challenges in RIHD treatment are summarized.

Purine versus non-purine xanthine oxidase inhibitors against cyclophosphamide-induced cardiac and bone marrow toxicity in rats

BACKGROUND AND AIM

Cancer is a fatal and serious disease. Cyclophosphamide (CYC) is a commonly used anticancer drug. Cardiotoxicity and myelotoxicity are life-threatening side effects of CYC treatment. We aimed to evaluate the effect of the xanthine oxidase (XO) inhibitors, allopurinol (ALL) and febuxostat (FEB), on CYC-induced cardio- and hematopoietic toxicity in rats.

METHODS

ALL (100 mg/kg/day) or FEB (10 mg/kg/day) were administered orally to rats in the presence and absence of CYC (200 mg/kg kg i.p. single dose) treatment. Serum creatine kinase-MB creatine kinase myocardial band (CK-MB) and lactate dehydrogenase (LDH) activities were estimated. Complete blood counting (CBC), cardiac and bone marrow XO activity, malondialdehyde level, and superoxide dismutase activity were determined. Cardiac and bone marrow histopathological changes were also evaluated.

RESULTS

ALL and FEB significantly decreased CK-MB and LDH induced by CYC. Disturbed levels of XO, oxidative stress parameters, and CBC were also corrected by both XO inhibitors tested, with amelioration of cardiac histopathological changes caused by CYC. Treatment with FEB, but not ALL, prior to CYC challenges normalized bone marrow histopathological changes.

CONCLUSION

These results suggest that both XO inhibitors tested; ALL and FEB can ameliorate CYC-induced cardiotoxicity. However, only FEB can protect against CYC-induced myelotoxicity, whereas ALL, to the contrary, might aggravate it.

Cardiovascular complications after radiotherapy

Over the past decades, effective cancer therapies have resulted in a significant improvement in the survival rates for a number of cancers and an increase in the number of cancer survivors. Radiation therapy is widely used in the treatment of cancer, and it can induce various cardiotoxicities that differ considerably from chemotherapy-induced cardiotoxicity. They occur primarily as late radiation-induced complications, several years from the end of anticancer treatment and present as coronary artery disease, heart failure, pericardial disease, valvular heart disease and arrhythmias. Patients who recovered from cancer disease suffer from cardiac complications of anticancer treatment, it affects the quality of their lives and life expectancy, especially if the diagnosis is delayed. These patients may present distinct symptoms of cardiac injury, resulting from radiation-induced neurotoxicity and altered pain perception, which makes diagnosis difficult. This review highlights the need for a screening programme for patients who have undergone radiation therapy and which will subsequently have a potentially profound impact on morbidity and mortality.

Image-guided adaptive radiotherapy in patients with locally advanced non-small cell lung cancer: the art of PET

With a worldwide annual incidence of 1.8 million cases, lung cancer is the most diagnosed form of cancer in men and the third most diagnosed form of cancer in women. Histologically, 80-85% of all lung cancers can be categorized as non-small cell lung cancer (NSCLC). For patients with locally advanced NSCLC, standard of care is fractionated radiotherapy combined with chemotherapy. With the aim of improving clinical outcome of patients with locally advanced NSCLC, combined and intensified treatment approaches are increasingly being used. However, given the heterogeneity of this patient group with respect to tumor biology and subsequent treatment response, a personalized treatment approach is required to optimize therapeutic effect and minimize treatment induced toxicity. Medical imaging, in particular positron emission tomography (PET), before and during the course radiotherapy is increasingly being used to personalize radiotherapy. In this setting, PET imaging can be used to improve delineation of target volumes, employ molecularly-guided dose painting strategies, early response monitoring, prediction and monitoring of treatment-related toxicity. The concept of PET image-guided adaptive radiotherapy (IGART) is an interesting approach to personalize radiotherapy for patients with locally advanced NSCLC, which might ultimately contribute to improved clinical outcomes and reductions in frequency of treatment-related adverse events in this patient group. In this review, we provide a comprehensive overview of available clinical data supporting the use of PET imaging for IGART in patients with locally advanced NSCLC.

Right ventricular function and mechanics in chemotherapy- and radiotherapy-naïve cancer patients

The present research evaluated right ventricular (RV) structure, function and mechanics in the cancer patients before initiation of chemo- or radiotherapy, and the association between cancer and decreased RV longitudinal strain. This retrospective investigation included 101 chemo- and radiotherapy-naïve patients with solid cancer and 38 age- and gender-matched controls with similar cardiovascular risk profile. Echocardiographic examination and strain evaluation was performed in all participants. RV structure and RV systolic and diastolic function estimated with conventional echocardiographic parameters were similar between the cancer patients and controls. However, RV global longitudinal strain (- 22.7 ± 2.6% vs. - 21.1 ± 2.4%, p < 0.001) was significantly decreased in the cancer patients than in controls. The same was revealed for RV free wall endocardial (- 33.6 ± 4.3% vs. - 31.4 ± 4.0%, p = 0.006) and mid-myocardial (- 25.2 ± 3.6% vs. - 23.7 ± 3.8%, p = 0.035) longitudinal RV strains, whereas difference was not found in RV free wall epicardial longitudinal strain. The presence of cancer was independently of age, gender, body mass index, left ventricular hypertrophy, diabetes, hypertension and pulmonary pressure associated with reduced RV global longitudinal strain (OR 3.79; 95% CI 2.18-10.92, p < 0.001), as well as with decreased free wall RV longitudinal strain (OR 5.73; 95% CI 3.17-9.85, p < 0.001). RV strain is deteriorated in the chemo- and radiotherapy-naïve cancer patients. Endocardial and mid-myocardial layers are more affected than epicardial strain in the cancer patients. The presence of cancer is independently of other clinical parameters associated with reduced RV longitudinal strain.