Radiation-associated cardiovascular disease

Current evidence of integrative oncology modalities for managing adverse effects and survivorship issues among adolescents and young adult (AYA) cancer patients and survivors

PURPOSE OF REVIEW

Symptom burden of cancer diagnosis and treatment has led adolescents and young adult cancer patients (AYAC) and survivors to seek different self-management strategies including integrative oncology (IO) modalities. IO holds great promise to improve survivorship issues in adolescents and young adult (AYA) cancer survivors. This review aims to encompass the current evidence of IO modalities and to analyze the efficacy of IO for managing survivorship issues among AYA cancer patients and survivors.

RECENT FINDINGS

Nineteen randomized controlled trials included in this review evaluated mind and body modalities including both physical and psychological (74%) and psychological only (26%) modalities. Most assessed IO modalities were physical activity (PA) (37%) and structured exercise (10%). Most effective IO modalities found were PA, massage, mindfulness-based stress reduction (MBSR) and light therapy for treating AYA symptom burden. The Cochrane risk of bias (RoB-2) concluded 21% studies had high risk, 58% possessed some concerns and 21% had low risk.

SUMMARY

Although evidence has shown that a number of IO modalities may improve survivorship among AYA cancer survivors, more rigorous study designs are needed in order for these modalities to be routinely recommended for use in clinical practice.

Early Effects of Modern Radiotherapy for Lung Cancer on Endothelial Damage and Myocardial Fibrosis: A Prospective Single-Center Study

Radiotherapy (RT) may have a cardiotoxic effect on the heart and cardiovascular system. Postulated mechanisms mediating these complications include vascular endothelium damage and myocardial fibrosis. The aim of our study was to assess endothelial damage and myocardial fibrosis in the early period after RT on the basis of cardiac biomarkers and in relation to the radiation dose applied to individual heart structures in patients treated for non-small-cell lung cancer. This single-center prospective study included consecutive patients with lung cancer (LC) who were referred for treatment with radiochemotherapy (study group) or chemotherapy (control group). The study protocol included performing an echocardiographic examination, a standard ECG examination, and collecting blood samples for laboratory tests before starting treatment for lung cancer in the first week after completing RT (after four cycles of chemotherapy in the control group) and after 12 weeks from the end of treatment. The study included 23 patients in the study group and 20 patients in the control group. Compared to the baseline values, there was a significant increase in total cholesterol concentration in the study group immediately after the end of RT, which persisted for three months after the end of therapy. After taking into account the use of statins in the analysis, it was found that an increase in total cholesterol concentration after oncological treatment was observed only among patients who did not use statins. Taking into account the assessment of myocardial fibrosis markers, there were no significant changes in the concentration of matrix metallopeptidase 9 (MMP-9) and tissue inhibitors of metalloproteinases 1 (TIMP-1) in the study group. In patients treated with radiochemotherapy, there was a significant increase in the concentration of intercellular adhesion molecule 1 (ICAM-1) immediately after RT, when compared to the baseline. After taking into account the use of statins, an increase in ICAM-1 concentration immediately after RT was observed only in patients who did not use statins. There was also a significant correlation between the radiation dose received by the left anterior descending coronary artery (LAD) and left circumferential coronary artery, and vascular cell adhesion protein 1 (VCAM-1) concentration measured at three months after the end of RT. Immediately after completion of radiotherapy, a significant increase in the level of ICAM-1 is observed indicating endothelial damage. The radiation dose to coronary arteries should be minimized, as it correlates with the concentration of VCAM-1. The use of statins may prevent the increase in total cholesterol and ICAM-1 concentration after irradiation for lung cancer; however, further studies designed for this specific purpose are necessary to confirm the effectiveness of statins in this area.

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.

Clinical Efficacy of Percutaneous Osteoplasty Under Fluoroscopy and Cone-Beam CT Guidance for Painful Sternal Metastases: A Case Series

Background

Although percutaneous osteoplasty (POP) has been widely accepted and is now being performed for the treatment of painful bone metastases outside the spine. It is emerging as one of the most promising procedures for patients with painful bone metastasis who are unsuitable for surgery or who show resistance to radiotherapy and/or analgesic therapies. However, there are only scarce reports regarding osteoplasty in painful sternal metastases.

Subjects and Method

We report four patients with sternal metastases suffered with severe pain of anterior chest wall. The original tumors included lung cancer and thyroid cancer. For the initially pain medication failing, all the four patients received POP procedure under fluoroscopic and cone-beam CT (CBCT) guidance, and obtained satisfying resolution of painful symptoms at 6-month postop follow-up.

Conclusion

POP is a safe and effective treatment for pain caused by metastatic bone tumors in the sternum. In practice, however, percutaneous puncture of pathologic sternal fractures can be a challenge because of the long flat contour and the defacement by lytic tumor of bony landmarks. We find that the use of fluoroscopic and CBCT can facilitate POP for flat bone fractures with displacing the trajectory planning, needle advancement, and cement delivery in time.

Proton Beam Therapy for Breast Cancer

Given the radiobiological and physical properties of the proton, proton beam therapy has the potential to be advantageous for many patients compared with conventional radiotherapy by limiting toxicity and improving patient outcomes in specific breast cancer scenarios.

Cardiovascular Toxicities of Radiation Therapy and Recommended Screening and Surveillance

Radiation therapy is a key part of treatment for many cancers. Vast advancements in the field of radiation oncology have led to a decrease in malignancy-related mortality, which has uncovered some of the long-term side effects of radiation therapy. Specifically, there has been an increase in research looking into the cardiovascular side effects of chest radiation therapy for cancers of the esophagus, breast, and lung tissue as well as lymphomas. The manifestations of cardiac injury from irradiation range from short-term complications, such as pericarditis, to long-term damage including cardiomyopathy, valvular disease, and conduction disturbances. The aims of this article are to describe the cardiovascular side effects and the associated risk factors, to discuss risk reduction strategies, and to provide guidance in pre-radiation screening, post-radiation surveillance, and the management of these conditions.

Novel simulation for dosimetry impact of diaphragm respiratory motion in four-dimensional volumetric modulated arc therapy for esophageal cancer

BACKGROUND AND PURPOSE

The diaphragm respiratory motion (RM) could impact the target dose robustness in the lower esophageal cancer (EC). We aimed to develop a framework evaluating the impact of different RM patterns quantitatively in one patient, by creating virtual four-dimensional computed-tomography (v4DCT) images, which could lead to tailored treatment for the breathing pattern. We validated virtual 4D radiotherapy (v4DRT) along with exploring the acceptability of free-breathing volumetric modulated arc therapy (FB-VMAT).

METHODS AND MATERIALS

We assessed 10 patients with superficial EC through their real 4DCT (r4DCT) scans. v4DCT images were derived from the end-inhalation computed tomography (CT) image (reference CT) and the v4DRT dose was accumulated dose over all phases. r4DRT diaphragm shifts were applied with magnitudes derived from r4DCT scans; clinical target volume (CTV) dose of v4DRT was compared with that of r4DRT to validate v4DRT. CTV dosage modifications and planning organ at risk volume (PRV) margins of the spinal cord were examined with the diaphragm movement. The percentage dose differences (ΔDx) were determined between the v4DRT and the dose calculated on the reference CT image.

RESULTS

The CTV ΔDx between the r4DRT and v4DRT were within 1% in cases with RM ≦ 15 mm. The average ΔD100% and ΔDmean of the CTV ranging from 5 to 15 mm of diaphragm motion was 0.3% to 1.7% and 0.1% to 0.4%, respectively. All CTV index changes were within 3% and ΔD1cc and ΔD2cc of Cord PRV were within 1%.

CONCLUSION

We postulate a novel method for evaluating the CTV robustness, comparable to the conventional r4DCT method under the diaphragm RM ≦ 15 mm permitting an impact of within 3% in FB-VMAT for EC on the CTV dose distribution.

Age-specific cardiovascular disease-related mortality among patients with major gastrointestinal cancers: A SEER population-based study

BACKGROUND

Studies have reported age as a risk factor for cardiovascular disease (CVD)-related mortality; however, only a few studies have focused on the relationship between age and CVD-related mortality, especially among major gastrointestinal cancers.

METHOD

The present retrospective cohort enrolled patients with colorectal, pancreatic, hepatocellular, gastric, and esophageal cancer between 2000 to 2015 from the Surveillance, Epidemiology and End Results Registry (SEER). Standardized mortality ratio (SMR), competing risk regression, and restricted cubic spline (RCS) analyses were used in our study.

RESULTS

We analyzed 576,713 patients with major gastrointestinal cancers (327,800 patients with colorectal cancer, 93,310 with pancreatic cancer, 69,757 with hepatocellular cancer, 52,024 with gastric cancer, and 33,822 with esophageal cancer). Overall, CVD-related mortality gradually decreased every year, and the majority were older patients. All cancer patients had a higher CVD-related mortality rate than the general U.S.

POPULATION

The adjusted sub-hazard ratios for middle-aged with colorectal cancer, pancreatic cancer, hepatocellular cancer, gastric cancer, and esophageal cancer were 2.55 (95% CI: 2.15-3.03), 1.77 (95% CI: 1.06-2.97), 2.64 (95% CI: 1.60-4.36), 2.15 (95% CI: 1.32-3.51), and 2.28 (95% CI: 1.17-4.44), respectively. The adjusted sub-hazard ratios for older patients with colorectal cancer, pancreatic cancer, hepatocellular cancer, gastric cancer, and esophageal cancer were 11.23 (95% CI: 9.50-13.27), 4.05 (95% CI: 2.46-6.66), 4.47 (95% CI: 2.72-7.35), 7.16 (95% CI: 4.49-11.41), and 4.40 (95% CI: 2.28-8.48), respectively. A non-linear relationship between age at diagnosis and CVD-related mortality was found in colorectal cancer, pancreatic cancer, and esophageal cancer; their reference ages were 67, 69, and 66 years old, respectively.

CONCLUSION

This study demonstrated that age was a risk factor for CVD-related mortality among major gastrointestinal cancers.

Accelerated Atherosclerosis and Cardiovascular Toxicity Induced by Radiotherapy in Breast Cancer

The number of patients diagnosed with breast cancer and cardiovascular disease is continuously rising. Treatment options for breast cancer have greatly evolved, but radiotherapy (RT) still has a key role in it. Despite many advances in RT techniques, cardiotoxicity is one of the most important side effects. The new cardio-oncology guidelines recommend a baseline evaluation, risk stratification and follow-up of these patients. Cardiotoxicity induced by RT can be represented by almost all forms of cardiovascular disease, with atherosclerosis being the most frequent. An interdisciplinary team should manage these patients, in order to have maximum therapeutic effect and minimum cardiovascular toxicity. This review will summarize the current incidence, risk factors, mechanisms and follow-up of RT-induced cardiovascular toxicity.

Quantitative assessment of radiotherapy-induced myocardial damage using MRI: a systematic review

PURPOSE

To determine the role of magnetic resonance imaging (MRI)-based metrics to quantify myocardial toxicity following radiotherapy (RT) in human subjects through review of current literature.

METHODS

Twenty-one MRI studies published between 2011-2022 were identified from available databases. Patients received chest irradiation with/without other treatments for various malignancies including breast, lung, esophageal cancer, Hodgkin's, and non-Hodgkin's lymphoma. In 11 longitudinal studies, the sample size, mean heart dose, and follow-up times ranged from 10-81 patients, 2.0-13.9 Gy, and 0-24 months after RT (in addition to a pre-RT assessment), respectively. In 10 cross-sectional studies, the sample size, mean heart dose, and follow-up times ranged from 5-80 patients, 2.1-22.9 Gy, and 2-24 years from RT completion, respectively. Global metrics of left ventricle ejection fraction (LVEF) and mass/dimensions of cardiac chambers were recorded, along with global/regional values of T1/T2 signal, extracellular volume (ECV), late gadolinium enhancement (LGE), and circumferential/radial/longitudinal strain.

RESULTS

LVEF tended to decline at >20 years follow-up and in patients treated with older RT techniques. Changes in global strain were observed after shorter follow-up (13±2 months) for concurrent chemoradiotherapy. In concurrent treatments with longer follow-up (8.3 years), increases in left ventricle (LV) mass index were correlated with LV mean dose. In pediatric patients, increases in LV diastolic volume were correlated with heart/LV dose at 2 years post-RT. Regional changes were observed earlier post-RT. Dose-dependent responses were reported for several parameters, including: increased T1 signal in high-dose regions, a 0.136% increase of ECV per Gy, progressive increase of LGE with increasing dose at regions receiving >30 Gy, and correlation between increases in LV scarring volume and LV mean/V10/V25 Gy dose.

CONCLUSION

Global metrics only detected changes over longer follow-up, in older RT techniques, in concurrent treatments, and in pediatric patients. In contrast, regional measurements detected myocardial damage at shorter follow-up and in RT treatments without concurrent treatment and had greater potential for dose-dependent response. The early detection of regional changes suggests the importance of regional quantification of RT-induced myocardial toxicity at early stages, before damage becomes irreversible. Further works with homogeneous cohorts are required to examine this matter.

Palliative Arterial Embolization for Metastases of the Sternum

BACKGROUND

To investigate the safety and efficacy of palliative arterial embolization for metastases of the sternum.

MATERIALS AND METHODS

This study included 10 consecutive patients (5 M, 5 F; mean age 58.1; range 37-70) with metastases of the sternum from different primary tumors, treated with palliative arterial embolization using NBCA-Lipiodol between January 2007 and June 2022. Four patients received a second embolization at the same site, for a total of 14 embolizations. Data on technical and clinical success, as well as changes in tumor size, were collected. All embolization-related complications were evaluated according to the CIRSE classification system for complications.

RESULTS

Post-embolization angiography showed occlusion of more than 90% of the pathological feeding vessels in all procedures. Pain score and analgesic drug consumption were reduced by 50% in all 10 patients (100%, p < 0.05). The mean duration of pain relief was 9.5 months (range 8 to 12 months, p < 0.05). Metastatic tumor size was reduced from a mean of 71.5 cm³ (range 41.6 to 90.3 cm³) pre-embolization to a mean of 67.9 cm³ (range 38.5 to 86.1 cm³) at the 12-month follow-up (p < 0.05). None of the patients experienced embolization-related complications.

CONCLUSION

Arterial embolization is safe and effective as a palliative treatment for patients with metastases of the sternum who did not benefit from radiation therapy or experienced recurrence in symptoms.

The Promise of Nanoparticles-Based Radiotherapy in Cancer Treatment

Radiation has been utilized for a long time for the treatment of cancer patients. However, radiotherapy (RT) has many constraints, among which non-selectivity is the primary one. The implementation of nanoparticles (NPs) with RT not only localizes radiation in targeted tissue but also provides significant tumoricidal effect(s) compared to radiation alone. NPs can be functionalized with both biomolecules and therapeutic agents, and their combination significantly reduces the side effects of RT. NP-based RT destroys cancer cells through multiple mechanisms, including ROS generation, which in turn damages DNA and other cellular organelles, inhibiting of the DNA double-strand damage-repair system, obstructing of the cell cycle, regulating of the tumor microenvironment, and killing of cancer stem cells. Furthermore, such combined treatments overcome radioresistance and drug resistance to chemotherapy. Additionally, NP-based RT in combined treatments have shown synergistic therapeutic benefit(s) and enhanced the therapeutic window. Furthermore, a combination of phototherapy, i.e., photodynamic therapy and photothermal therapy with NP-based RT, not only reduces phototoxicity but also offers excellent therapeutic benefits. Moreover, using NPs with RT has shown promise in cancer treatment and shown excellent therapeutic outcomes in clinical trials. Therefore, extensive research in this field will pave the way toward improved RT in cancer treatment.

Effects of Simulated 5-Ion Galactic Cosmic Radiation on Function and Structure of the Mouse Heart

Missions into deep space will expose astronauts to the harsh space environment, and the degenerative tissue effects of space radiation are largely unknown. To assess the risks, in this study, male BALB/c mice were exposed to 500 mGy 5-ion simulated GCR (GCRsim) at the NASA Space Radiation Laboratory. In addition, male and female CD1 mice were exposed to GCRsim and administered a diet containing Transforming Growth Factor-beta (TGF-β)RI kinase (ALK5) inhibitor IPW-5371 as a potential countermeasure. An ultrasound was performed to investigate cardiac function. Cardiac tissue was collected to determine collagen deposition, the density of the capillary network, and the expression of the immune mediator toll-like receptor 4 (TLR4) and immune cell markers CD2, CD4, and CD45. In male BALB/c mice, the only significant effects of GCRsim were an increase in the CD2 and TLR4 markers. In male CD1 mice, GCRsim caused a significant increase in total collagens and a decrease in the expression of TLR4, both of which were mitigated by the TGF-β inhibitor diet. In female CD1 mice, GCRsim caused an increase in the number of capillaries per tissue area in the ventricles, which may be explained by the decrease in the left ventricular mass. However, this increase was not mitigated by TGF-β inhibition. In both male and female CD1 mice, the combination of GCRsim and TGF-β inhibition caused changes in left ventricular immune cell markers that were not seen with GCRsim alone. These data suggest that GCRsim results in minor changes to cardiac tissue in both an inbred and outbred mouse strain. While there were few GCRsim effects to be mitigated, results from the combination of GCRsim and the TGF-β inhibitor do point to a role for TGF-β in maintaining markers of immune cells in the heart after exposure to GCR.

Ionising radiation and cardiovascular disease: systematic review and meta-analysis

OBJECTIVE

To systematically review and perform a meta-analysis of radiation associated risks of cardiovascular disease in all groups exposed to radiation with individual radiation dose estimates.

DESIGN

Systematic review and meta-analysis.

MAIN OUTCOME MEASURES

Excess relative risk per unit dose (Gy), estimated by restricted maximum likelihood methods.

DATA SOURCES

PubMed and Medline, Embase, Scopus, Web of Science Core collection databases.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Databases were searched on 6 October 2022, with no limits on date of publication or language. Animal studies and studies without an abstract were excluded.

RESULTS

The meta-analysis yielded 93 relevant studies. Relative risk per Gy increased for all cardiovascular disease (excess relative risk per Gy of 0.11 (95% confidence interval 0.08 to 0.14)) and for the four major subtypes of cardiovascular disease (ischaemic heart disease, other heart disease, cerebrovascular disease, all other cardiovascular disease). However, interstudy heterogeneity was noted (P<0.05 for all endpoints except for other heart disease), possibly resulting from interstudy variation in unmeasured confounders or effect modifiers, which is markedly reduced if attention is restricted to higher quality studies or those at moderate doses (<0.5 Gy) or low dose rates (<5 mGy/h). For ischaemic heart disease and all cardiovascular disease, risks were larger per unit dose for lower dose (inverse dose effect) and for fractionated exposures (inverse dose fractionation effect). Population based excess absolute risks are estimated for a number of national populations (Canada, England and Wales, France, Germany, Japan, USA) and range from 2.33% per Gy (95% confidence interval 1.69% to 2.98%) for England and Wales to 3.66% per Gy (2.65% to 4.68%) for Germany, largely reflecting the underlying rates of cardiovascular disease mortality in these populations. Estimated risk of mortality from cardiovascular disease are generally dominated by cerebrovascular disease (around 0.94-1.26% per Gy), with the next largest contribution from ischaemic heart disease (around 0.30-1.20% per Gy).

CONCLUSIONS

Results provide evidence supporting a causal association between radiation exposure and cardiovascular disease at high dose, and to a lesser extent at low dose, with some indications of differences in risk between acute and chronic exposures, which require further investigation. The observed heterogeneity complicates a causal interpretation of these findings, although this heterogeneity is much reduced if only higher quality studies or those at moderate doses or low dose rates are considered. Studies are needed to assess in more detail modifications of radiation effect by lifestyle and medical risk factors.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020202036.

Straining under the echoes of the past

The long‐term effects of cancer treatment on cardiovascular health have remained incompletely defined. Safer treatments, more accessible cardiovascular monitoring, and emerging cardio‐protective medication strategies are promising for avoiding adverse cardiovascular effects of cancer treatment.

Tissue Reactions and Mechanism in Cardiovascular Diseases Induced by Radiation

The long-term survival rate of cancer patients has been increasing as a result of advances in treatments and precise medical management. The evidence has accumulated that the incidence and mortality of non-cancer diseases have increased along with the increase in survival time and long-term survival rate of cancer patients after radiotherapy. The risk of cardiovascular disease as a radiation late effect of tissue damage reactions is becoming a critical challenge and attracts great concern. Epidemiological research and clinical trials have clearly shown the close association between the development of cardiovascular disease in long-term cancer survivors and radiation exposure. Experimental biological data also strongly supports the above statement. Cardiovascular diseases can occur decades post-irradiation, and from initiation and development to illness, there is a complicated process, including direct and indirect damage of endothelial cells by radiation, acute vasculitis with neutrophil invasion, endothelial dysfunction, altered permeability, tissue reactions, capillary-like network loss, and activation of coagulator mechanisms, fibrosis, and atherosclerosis. We summarize the most recent literature on the tissue reactions and mechanisms that contribute to the development of radiation-induced cardiovascular diseases (RICVD) and provide biological knowledge for building preventative strategies.

Experimental determination of breast skin dose using volumetric modulated arc therapy and field-in-field treatment techniques

Introduction:

The use of volumetric modulated arc therapy (VMAT) on the breast has several dosimetric advantages but its impact on skin dose should be evaluated and compared to well-established treatment techniques using tangential fields. The aim of this work is to contrast the skin dose for VMAT and field-in-field (FIF) and to estimate the magnitude of the skin dose involved.

Method:

The skin dose was measured, without build-up, using thermoluminescent dosimeter (TLD) and optically stimulated luminescence dosimeter (OSLD) in breast radiotherapy by an in-house anthropomorphic phantom. Two different treatment techniques were used: FIF and VMAT, based on the planning strategy proposed by Nicolini et al. The dose levels were 4300 cGy, 4600 cGy and 5600 cGy in 20 fractions. In vivo dosimetry with TLD for VMAT was performed for different breast sizes in the same locations as phantom measurements.

Results:

The ipsilateral phantom breast skin dose using both treatment techniques was equivalent. TLD measured doses by the VMAT technique were up to 5% higher than OSLD, although they agree if we consider the geometry uncertainty of the TLD. In accordance with in vivo dosimetry, the mean dose of the ipsilateral breast skin was 62 ± 6% (51%, 75%) relative to the prescribed dose, regardless of the breast size for the volumes considered with this small population (n = 9) as shown by Mann–Whitney U-test (Z = 1·9, 95% confidence). The uncertainty expected in this region due to geometry (volume) changes is up to 9% higher for volumes from 225·9 cc to 968·8 cc. According to the treatment techniques and in vivo dosimetry, the contralateral breast skin dose was 1·0% in FIF and 2·5% in VMAT concerning the prescribed dose.

Conclusion:

There is no difference in skin dosimetry between VMAT and FIF techniques on the ipsilateral breast. It provides useful support for the use of VMAT as a planning technique for breast irradiation. The work describes the importance of quantifying potential differences in skin dosimetry.

Advances and potential of optical surface imaging in radiotherapy

This article reviews the recent advancements and future potential of optical surface imaging (OSI) in clinical applications as a four-dimensional (4D) imaging modality for surface-guided radiotherapy (SGRT), including OSI systems, clinical SGRT applications, and OSI-based clinical research. The OSI is a non-ionizing radiation imaging modality, offering real-time 3D surface imaging with a large field of view (FOV), suitable for in-room interactive patient setup, and real-time motion monitoring at any couch rotation during radiotherapy. So far, most clinical SGRT applications have focused on treating superficial breast cancer or deep-seated brain cancer in rigid anatomy, because the skin surface can serve as tumor surrogates in these two clinical scenarios, and the procedures for breast treatments in free-breathing (FB) or at deep-inspiration breath-hold (DIBH), and for cranial stereotactic radiosurgery (SRS) and radiotherapy (SRT) are well developed. When using the skin surface as a body-position surrogate, SGRT promises to replace the traditional tattoo/laser-based setup. However, this requires new SGRT procedures for all anatomical sites and new workflows from treatment simulation to delivery. SGRT studies in other anatomical sites have shown slightly higher accuracy and better performance than a tattoo/laser-based setup. In addition, radiographical image-guided radiotherapy (IGRT) is still necessary, especially for stereotactic body radiotherapy (SBRT). To go beyond the external body surface and infer an internal tumor motion, recent studies have shown the clinical potential of OSI-based spirometry to measure dynamic tidal volume as a tumor motion surrogate, and Cherenkov surface imaging to guide and assess treatment delivery. As OSI provides complete datasets of body position, deformation, and motion, it offers an opportunity to replace fiducial-based optical tracking systems. After all, SGRT has great potential for further clinical applications. In this review, OSI technology, applications, and potential are discussed since its first introduction to radiotherapy in 2005, including technical characterization, different commercial systems, and major clinical applications, including conventional SGRT on top of tattoo/laser-based alignment and new SGRT techniques attempting to replace tattoo/laser-based setup. The clinical research for OSI-based tumor tracking is reviewed, including OSI-based spirometry and OSI-guided tumor tracking models. Ongoing clinical research has created more SGRT opportunities for clinical applications beyond the current scope.

Myocardial Deformation Imaging by Speckle Tracking Echocardiography for Assessment of Cardiotoxicity in Children During and After Chemotherapy: A Systematic Review and Meta-analysis

BACKGROUND

Childhood cancer patients and childhood cancer survivors (CCS) are at risk of developing chemotherapy-induced cardiomyopathy. Myocardial deformation imaging has shown potential in the early detection of subclinical myocardial damage with implications on therapeutic interventions and improvement of outcomes. We aimed to perform a systemic review and meta-analysis of literature on the assessment of left (LV) and right ventricular (RV) myocardial deformation by speckle tracking echocardiography (STE) at rest and during stress in childhood cancer patients during and in survivors after chemotherapy.

METHODS

A systematic review was performed through searching MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, and Scopus. Search hedges were created to cover the concepts of childhood cancer, chemotherapy, radiotherapy, anthracycline, cardiotoxicity, speckle tracking, myocardial strain, and myocardial deformation. Two independent investigators reviewed the eligibility of the articles for inclusion. Weighted mean difference in ventricular strain between pre-and post-chemotherapy treatment and that between long-term CCS and healthy subjects were estimated by random-effect models with 95% confidence intervals. Heterogeneity and publication bias were assessed by I2 statistics and Egger test, respectively.

RESULTS

Of the total of 8703 records initially identified, 42 studies with a total of 430 childhood cancer patients were included. Of these 42 studies that showed heterogeneities, 9 assessed early myocardial injury during chemotherapy, 30 assessed late myocardial injury after chemotherapy with no publication bias, and 3 studied myocardial mechanics during stress. The main findings were 1) impairment of LV systolic deformation in childhood cancer patients during the initial treatment phase and among long-term CCS, while data on changes in RV deformation are limited and inconclusive, 2) the predictive value of early reduction of myocardial strain imaging in forecasting subsequent development of cardiotoxicity is unknown as it has not been studied, 3) limited data suggest possibility of impaired LV contractile mechanics during stress in CCS, and 4) cumulative anthracycline dose and chest-directed radiotherapy are consistently identified as factors associated with impaired myocardial deformation.results CONCLUSIONS: Myocardial strain imaging by STE unveils early evidence of myocardial injury in childhood cancer patients and long-term CCS. To support its adoption for clinical use, more data are required for the better understating of myocardial deformation parameters in the risk stratification of childhood cancer patients and prediction of development of cardiomyopathy among CCS.

Cardiovascular complications of mantle field radiation: a case series

Background

Mantle field radiotherapy has been known to cause cardiovascular complications even years after therapy. Complications include pericardial disease, coronary artery disease, and conduction abnormalities.

Case summary

We present a case series of two patients who developed cardiovascular complications years after receiving mantle radiation. Patient 1 is a 52-year-old man who presented with symptoms of heart failure. He had a neurostimulator which precluded him from cardiac magnetic resonance imaging. Haemodynamic findings on right heart catheterization raised suspicion for constrictive pericarditis and pericardiectomy was performed. Histopathological analysis reported dense, sclerotic fibrous tissue consistent with radiation-related changes. Patient 2 is a 37-year-old man with a 2-month history of chest pain and exertional dyspnoea who was admitted for management of coronary artery disease. Coronary angiography demonstrated bilateral subclavian artery stenosis and an elevated left ventricular end-diastolic pressure (50 mmHg). He had bilateral percutaneous subclavian artery stenting. Both patients had complete resolution of symptoms on follow-up.

Discussion

Our case series emphasizes the need for an index of suspicion for radiation-related cardiovascular changes in patients who have a history of mantle radiation, especially in younger patients. This was especially pertinent in the case of our first patient who presented a diagnostic challenge due to certain patient factors. Our second patient is a case of subclavian artery stenosis which is less frequently reported as a complication of mantle radiation in the literature.

Inequity in Cardio-Oncology: Identifying Disparities in Cardiotoxicity and Links to Cardiac and Cancer Outcomes

Minority and underresourced communities experience disproportionately high rates of fatal cancer and cardiovascular disease. The intersection of these disparities within the multidisciplinary field of cardio‐oncology is in critical need of examination, given the risk of perpetuating health inequities in the growing vulnerable population of patients with cancer and cardiovascular disease. This review identifies 13 cohort studies and 2 meta‐analyses investigating disparate outcomes in treatment‐associated cardiotoxicity and situates these data within the context of oncologic disparities, preexisting cardiovascular disparities, and potential system‐level inequities. Black survivors of breast cancer have elevated risks of cardiotoxicity morbidity and mortality compared with White counterparts. Adolescent and young adult survivors of cancer with lower socioeconomic status experience worsened cardiovascular outcomes compared with those of higher socioeconomic status. Female patients treated with anthracyclines or radiation have higher risks of cardiotoxicity compared with male patients. Given the paucity of data, our understanding of these racial and ethnic, socioeconomic, and sex and gender disparities remains limited and large‐scale studies are needed for elucidation. Prioritizing this research while addressing clinical trial inclusion and access to specialist care is paramount to reducing health inequity.

Imaging of the Chest After Radiotherapy and Potential Pitfalls

Radiotherapy is one of the cornerstones for the treatment of thoracic malignancies. The goal of radiotherapy is to deliver maximal dose to the tumor while minimizing damage to surrounding normal anatomical structures. Although advances in radiotherapy technology have considerably improved radiation delivery, potential adverse effects are still common. Post radiation changes to the chest may include different structures such as the lung, heart, great vessels, and esophagus. The purpose of this manuscript is to illustrate the post radiotherapy changes to these anatomical structures resulting from external beam radiotherapy, as well as discuss imaging pitfalls to prevent radiologist's interpretation errors.

United States medical preparedness for nuclear and radiological emergencies

With the end of the Cold War in 1991, U.S. Government (USG) investments in radiation science and medical preparedness were phased out; however, the events of 11 September, which involved a terroristic attack on American soil, led to the re-establishment of funding for both radiation preparedness and development of approaches to address injuries. Similar activities have also been instituted worldwide, as the global threat of a radiological or nuclear incident continues to be a concern. Much of the USG's efforts to plan for the unthinkable have centred on establishing clear lines of communication between agencies with responsibility for triage and medical response, and external stakeholders. There have also been strong connections made between those parts of the government that establish policies, fund research, oversee regulatory approval, and purchase and stockpile necessary medical supplies. Progress made in advancing preparedness has involved a number of subject matter meetings and tabletop exercises, publication of guidance documents, assessment of available resources, clear establishment of anticipated concepts of operation for multiple radiation and nuclear scenarios, and identification/mobilization of resources. From a scientific perspective, there were clear research gaps that needed to be addressed, which included the need to identify accurate biomarkers and design biodosimetry devices to triage large numbers of civilians, develop decorporation agents that are more amenable for mass casualty use, and advance candidate products to address injuries caused by radiation exposure and thereby improve survival. Central to all these activities was the development of several different animal constructs, since efficacy testing of these approaches requires extensive work in research models that accurately simulate what would be expected in humans. Recent experiences with COVID-19 have provided an opportunity to revisit aspects of radiation preparedness, and leverage those lessons learned to enhance readiness for a possible future radiation public health emergency.

In-Hospital Complications in Pregnant Women With Current or Historical Cancer Diagnoses

OBJECTIVE

To assess the temporal trends, characteristics and comorbidities, and in-hospital cardiovascular and obstetric complications and outcomes of pregnant women with current or historical cancer diagnosis at the time of admission for delivery.

METHODS

We analyzed delivery hospitalizations with or without current or historical cancer between January 1, 2004, and December 31, 2014, from the US National Inpatient Sample database.

RESULTS

We included 43,132,097 delivery hospitalizations with no cancer, 39,118 with current cancer, and 67,336 with historical diagnosis of cancer. The 5 most common types of current cancer were hematologic, thyroid, cervical, skin, and breast cancer. Women with current and historical cancer were older (29 years and 32 years vs 27 years) and incurred higher hospital costs ($4131 and $4078 vs $3521) compared with women without cancer. Most of the cancer types were associated with preterm birth (hematologic: adjusted odds ratio [aOR], 1.48 [95% CI, 1.35 to 1.62]; cervical: aOR, 1.47 [95% CI, 1.32 to 1.63]; breast: aOR, 1.93 [95% CI, 1.72 to 2.16]). Current hematologic cancer was associated with the highest risk of peripartum cardiomyopathy (aOR, 12.19 [95% CI, 7.75 to 19.19]), all-cause mortality (aOR, 6.50 [95% CI, 2.22 to 19.07]), arrhythmia (aOR, 3.82 [95% CI, 2.04 to 7.15]), and postpartum hemorrhage (aOR, 1.31 [95% CI, 1.11 to 1.54]). Having a current or historical cancer diagnosis did not confer additional risk for stillbirth; however, metastases increased the risk of maternal mortality and preterm birth.

CONCLUSION

Women with a current or historical diagnosis of cancer at delivery have more comorbidities compared with women without cancer. Clinicians should communicate the risks of multisystem complications to these complex patients.

Radiation‑induced dysfunction of energy metabolism in the heart results in the fibrosis of cardiac tissues

Thoracic radiotherapy increases the risk of radiation‑induced heart damage (RIHD); however, the molecular mechanisms underlying these changes are not fully understood. The aim of the present study was to investigate the effects of radiation on the mouse heart using high‑throughput proteomics. Male C57BL/6J mice were used to establish a model of RIHD by exposing the entire heart to 16 Gy high‑energy X‑rays, and cardiac injuries were verified using a cardiac echocardiogram, as well as by measuring serum brain natriuretic peptide levels and conducting H&E and Masson staining 5 months after irradiation. Proteomics experiments were performed using the heart apex of 5‑month irradiated mice and control mice that underwent sham‑irradiation. The most significantly differentially expressed proteins were enriched in 'cardiac fibrosis' and 'energy metabolism'. Next, the cardiac fibrosis and changes to energy metabolism were confirmed using immunohistochemistry staining and western blotting. Extracellular matrix proteins, such as collagen type 1 α 1 chain, collagen type III α 1 chain, vimentin and CCCTC‑binding factor, along with metabolism‑related proteins, such as fatty acid synthase and solute carrier family 25 member 1, exhibited upregulated expression following exposure to ionizing radiation. Additionally, the myocardial mitochondria inner membranes were injured, along with a decrease in ATP levels and the accumulation of lactic acid in the irradiated heart tissues. These results suggest that the high doses of ionizing radiation used lead to structural remodeling, functional injury and fibrotic alterations in the mouse heart. Radiation‑induced mitochondrial damage and metabolic alterations of the cardiac tissue may thus be a pathogenic mechanism of RIHD.

Mean heart dose-based normal tissue complication probability model for pericardial effusion: a study in oesophageal cancer patients

We investigated the normal tissue complication probability (NTCP) of the incidence of pericardial effusion (PCE) based on the mean heart dose (MHD) in patients with oesophageal cancer treated with definitive chemoradiotherapy. The incidences of PCE in any grade (A-PCE) and symptomatic PCE (S-PCE) were evaluated separately. To identify predictors for PCE, several clinical and dose-volume parameters were analysed using a receiver operating characteristic (ROC) curve and multivariate regression analysis. To validate its clinical applicability, the generated NTCP model was compared to the Lyman–Kutcher–Burman (LKB) model. Among 229 eligible patients, A-PCE and S-PCE were observed in 100 (43.7%) and 18 (7.9%) patients, respectively. MHD showed a preferable area under the curve (AUC) value for S-PCE (AUC = 0.821) and A-PCE (AUC = 0.734). MHD was the only significant predictor for A-PCE; MHD and hypertension were selected as significant factors for S-PCE. The estimated NTCP, using the MHD-based model, showed excellent correspondence to the LKB model in A-PCE and S-PCE. The NTCP curve of A-PCE was gentler than that of S-PCE and had no threshold. The MHD-based NTCP model was simple but comparable to the LKB model for both A-PCE and S-PCE. Therefore, the estimated NTCP may provide clinically useful parameters for predicting PCE.

Quantitative Bias Analysis of the Association between Occupational Radiation Exposure and Ischemic Heart Disease Mortality in UK Nuclear Workers

The scientific question of whether protracted low-dose or low-dose-rate exposure to external radiation is causally related to the risk of circulatory disease continues to be an important issue for radiation protection. Previous analyses of a matched case-control dataset nested in a large cohort of UK nuclear fuel cycle workers indicated that there was little evidence that observed associations between external radiation dose and ischemic heart disease (IHD) mortality risk [OR = 1.35 (95% CI: 0.99-184) for 15-year-lagged exposure] could alternatively be explained by confounding from pre-employment tobacco smoking, BMI or blood pressure, or from socioeconomic status or occupational exposure to excessive noise or shiftwork. To improve causal inference about the observed external radiation dose and IHD mortality association, we estimated the potential magnitude and direction of non-random errors, incorporated sensitivity analyses and simulated bias effects under plausible scenarios. We conducted quantitative bias analyses of plausible scenarios based on 1,000 Monte Carlo samples to explore the impact of exposure measurement error, missing information on tobacco smoking, and unmeasured confounding, and assessed whether observed associations were reliant on the inclusion of specific matched pairs using bootstrapping with 10% of matched pairs randomly excluded in 1,000 samples. We further explored the plausibility that having been monitored for internal exposure, which was an important confounding factor in the case-control analysis for which models were adjusted, was indeed a confounding factor or whether it might have been the result of some form of selection bias. Consistent with the broader epidemiological evidence-base, these analyses provide further evidence that the dose-response association between cumulative external radiation exposure and IHD mortality is non-linear in that it has a linear shape plateauing at an excess risk of 43% (95% CI: 7-92%) on reaching 390 mSv. Analyses of plausible scenarios of patterns of missing data for tobacco smoking at start of employment indicated that this resulted in relatively little bias towards the null in the original analysis. An unmeasured confounder would have had to have been highly correlated (rp > 0.60) with cumulative external radiation dose to importantly bias observed associations. The confounding effect of "having been monitored for internal dose" was unlikely to have been a true confounder in a biological sense, but instead may have been some unknown factor related to differences over time and between sites in selection criteria for internal monitoring, possibly resulting in collider bias. Plausible patterns of exposure measurement error negatively biased associations regardless of the modeled scenario, but did not importantly change the shape of the observed dose-response associations. These analyses provide additional support for the hypothesis that the observed association between external radiation exposure and IHD mortality may be causal.

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.

Population-Based Long-term Cardiac-Specific Mortality Among Patients With Major Gastrointestinal Cancers

IMPORTANCE

Patients with major gastrointestinal (GI) cancers are at long-term risk for cardiac disease and mortality.

OBJECTIVE

To investigate the cardiac-specific mortality rate among individuals with major GI cancers and the association of radiation and chemotherapy with survival outcomes in the United States.

DESIGN, SETTING, AND PARTICIPANTS

This US cohort study included individual patient-level data of men and women older than 18 years with 5 major gastrointestinal cancers, including colorectal, esophageal, gastric, pancreatic, and hepatocellular cancer from 1990 to 2016. Data was extracted from the Surveillance, Epidemiology, and End Results (SEER) national cancer database. Data cleaning and analyses were conducted between November 2020 and March 2021.

EXPOSURES

Patients received chemotherapy, radiotherapy, or a combination of adjuvant therapy for major GI cancers.

MAIN OUTCOMES AND MEASURES

The primary outcome was cardiac-specific mortality. Examined factors associated with cardiac mortality included age, sex, race, tumor location, tumor grade, SEER stage, TNM (seventh edition) staging criteria, cancer treatment (ie, the use of radiation, chemotherapy, or surgery), survival months, and cause of death.

RESULTS

A total of 359 032 patients (mean [SD] age at baseline, 65.1 [12.9] years; 186 921 [52.1%] men) with GI cancers were analyzed, including 313 940 patients (87.4%) with colorectal cancer, 7613 patients (2.1%) with esophageal cancer, 21 048 patients (5.9%) with gastric cancer, 7227 patients (2.0%) with pancreatic cancer, and 9204 patients (2.6%) with hepatocellular cancer. Most cancers were localized except pancreatic cancer, which presented with regional and distant involvement (3680 cancers [50.9%]). Overall, all major gastrointestinal tumors were associated with increased risk of cardiac mortality compared with noncardiac mortality (median survival time: 121 [95% CI, 120-122] months vs 287 [95% CI, 284.44-290] months). Patients with hepatocellular cancer had the lowest cardiac-specific median survival time (98 [95% CI, 90-106] months), followed by pancreatic cancer (105 [95% CI, 98-112] months), esophageal cancer (113 [95% CI, 107-119] months), gastric cancer (113 [95% CI, 110-116] months), and colorectal cancer (122 [95% CI, 121-123] months). At 15 years of follow up, the use of only chemotherapy, only radiation, or radiation and chemotherapy combined was associated with poor survival rates from cardiac causes of death (eg, colorectal: chemotherapy, 0 patients; radiation, 1 patient [1.9%]; radiation and chemotherapy, 3 patients [2.7%]).

CONCLUSIONS AND RELEVANCE

These findings suggest that among patients with major gastrointestinal cancers, cardiac disease is a significant cause of mortality. The use of only chemotherapy, only radiation, or both was associated with higher cardiac mortality.

Telomere Length Dynamics and Chromosomal Instability for Predicting Individual Radiosensitivity and Risk via Machine Learning

The ability to predict a cancer patient's response to radiotherapy and risk of developing adverse late health effects would greatly improve personalized treatment regimens and individual outcomes. Telomeres represent a compelling biomarker of individual radiosensitivity and risk, as exposure can result in dysfunctional telomere pathologies that coincidentally overlap with many radiation-induced late effects, ranging from degenerative conditions like fibrosis and cardiovascular disease to proliferative pathologies like cancer. Here, telomere length was longitudinally assessed in a cohort of fifteen prostate cancer patients undergoing Intensity Modulated Radiation Therapy (IMRT) utilizing Telomere Fluorescence in situ Hybridization (Telo-FISH). To evaluate genome instability and enhance predictions for individual patient risk of secondary malignancy, chromosome aberrations were assessed utilizing directional Genomic Hybridization (dGH) for high-resolution inversion detection. We present the first implementation of individual telomere length data in a machine learning model, XGBoost, trained on pre-radiotherapy (baseline) and in vitro exposed (4 Gy γ-rays) telomere length measurements, to predict post radiotherapy telomeric outcomes, which together with chromosomal instability provide insight into individual radiosensitivity and risk for radiation-induced late effects.

Appropriate use criteria for cardiovascular magnetic resonance imaging (CMR): SIC-SIRM position paper part 1 (ischemic and congenital heart diseases, cardio-oncology, cardiac masses and heart transplant)

Cardiac magnetic resonance (CMR) has emerged as new mainstream technique for the evaluation of patients with cardiac diseases, providing unique information to support clinical decision-making. This document has been developed by a joined group of experts of the Italian Society of Cardiology and Italian society of Radiology and aims to produce an updated consensus statement about the current state of technology and clinical applications of CMR. The writing committee consisted of members and experts of both societies who worked jointly to develop a more integrated approach in the field of cardiac radiology. Part 1 of the document will cover ischemic heart disease, congenital heart disease, cardio-oncology, cardiac masses and heart transplant.

Low- and moderate-dose non-cancer effects of ionizing radiation in directly exposed individuals, especially circulatory and ocular diseases: a review of the epidemiology

PURPOSE

There are well-known correlations between high and moderate doses (>0.5 Gy) of ionizing radiation exposure and circulatory system damage, also between radiation and posterior subcapsular cataract. At lower dose correlations with circulatory disease are emerging in the Japanese atomic bomb survivors and in some occupationally exposed groups, and are still to some extent controversial. Heterogeneity in excess relative risks per unit dose in epidemiological studies at low (<0.1 Gy) and at low-moderate (>0.1 Gy, <0.5 Gy) doses may result from confounding and other types of bias, and effect modification by established risk factors. There is also accumulating evidence of excess cataract risks at lower dose and low dose rate in various cohorts. Other ocular endpoints, specifically glaucoma and macular degeneration have been little studied. In this paper, we review recent epidemiological findings, and also discuss some of the underlying radiobiology of these conditions. We briefly review some other types of mainly neurological nonmalignant disease in relation to radiation exposure.

CONCLUSIONS

We document statistically significant excess risk of the major types of circulatory disease, specifically ischemic heart disease and stroke, in moderate- or low-dose exposed groups, with some not altogether consistent evidence suggesting dose-response non-linearity, particularly for stroke. However, the patterns of risk reported are not straightforward. We also document evidence of excess risks at lower doses/dose-rates of posterior subcapsular and cortical cataract in the Chernobyl liquidators, US Radiologic Technologists and Russian Mayak nuclear workers, with fundamentally linear dose-response. Nuclear cataracts are less radiogenic. For other ocular endpoints, specifically glaucoma and macular degeneration there is very little evidence of effects at low doses; radiation-associated glaucoma has been documented only for doses >5 Gy, and so has the characteristics of a tissue reaction. There is some evidence of neurological detriment following low-moderate dose (∼0.1-0.2 Gy) radiation exposure in utero or in early childhood.

Trifascicular Block and Ventricular Standstill: A Late Complication of Mediastinal Radiotherapy in a Cancer Survivor

Over the last half-century, radiation therapy has evolved to become one of the cornerstones of treatment for various types of cancers. It is estimated that more than 50% of patients with cancer are treated with radiotherapy. Patients with early stages of some cancers can even achieve a cure with radiotherapy alone. Radiation-induced heart disease is a well-recognized cause of mortality and morbidity in cancer survivors as a late complication of radiotherapy, often occurring more than a decade after radiotherapy. We describe a case of a middle-aged female who presented to the hospital with syncopal episodes. She was in remission from non-Hodgkin's lymphoma having received mediastinal radiotherapy 20 years, previously. Her initial workup such as laboratory investigations and 12 lead electrocardiogram were largely unremarkable. Cardiac monitoring over the course of the next few days was consistent with complete heart block with evidence of ventricular standstill. Her symptoms resolved following the implantation of a dual-chamber cardiac pacemaker. This case highlights the significance of clinical history taking and putting together all relevant facts to come to a differential diagnosis. In our case, this could have been easily overlooked as radiation therapy was given many years previously. We review and present an up-to-date albeit brief literature review on long-term cardiovascular complications of radiotherapy. Radiation-induced cardiac complications are an important cause of mortality and morbidity in cancer survivors. This article aims to raise awareness amongst clinicians of cardiac adverse effects occurring several years after the radiation therapy. This case also highlights the need for further research to better understand the pathophysiology of cardiovascular disease post-radiotherapy in order to develop effective prevention strategies and improve clinical outcomes.

Ionizing radiation-induced circulatory and metabolic diseases

Risks to health are the prime consideration in all human situations of ionizing radiation exposure and therefore of relevance to radiation protection in all occupational, medical, and public exposure situations. Over the past few decades, advances in therapeutic strategies have led to significant improvements in cancer survival rates. However, a wide range of long-term complications have been reported in cancer survivors, in particular circulatory diseases and their major risk factors, metabolic diseases. However, at lower levels of exposure, the evidence is less clear. Under real-life exposure scenarios, including radiotherapy, radiation effects in the whole organism will be determined mainly by the response of normal tissues receiving relatively low doses, and will be mediated and moderated by systemic effects. Therefore, there is an urgent need for further research on the impact of low-dose radiation. In this article, we review radiation-associated risks of circulatory and metabolic diseases in clinical, occupational or environmental exposure situations, addressing epidemiological, biological, risk modelling, and systems biology aspects, highlight the gaps in knowledge and discuss future directions to address these gaps.

Noninvasive Radioablation of Ventricular Tachycardia

Ventricular tachycardia (VT) occurs most commonly in the presence of structural heart disease or myocardial scarring from prior infarction. It is associated with increased mortality, especially when it results in cardiac arrest outside of a hospital. When not due to reversible causes (such as acute ischemia/infarction), placement of an implantable cardioverter-defibrillator for prevention of future sudden death is indicated. The current standard of care for recurrent VT is medical management with antiarrhythmic agents followed by invasive catheter ablation for VT that persists despite appropriate medical therapy. Stereotactic arrhythmia radioablation (STAR) is a novel, noninvasive method of treating VT that has been shown to reduce VT burden for patients who are refractory to medical therapy and/or catheter ablation, or who are unable to tolerate catheter ablation. STAR is the term applied to the use of stereotactic body radiation therapy for the treatment of arrhythmogenic cardiac tissue and requires collaboration between an electrophysiologist and a radiation oncologist. The process involves identification of VT substrate through a combination of electroanatomic mapping and diagnostic imaging (computed tomography, magnetic resonance imaging, positron emission tomography) followed by carefully guided radiation therapy. In this article, we review currently available literature describing the utilization, efficacy, safety profile, and potential future applications of STAR for the management of VT.

Comparison of time and dose dependent gene expression and affected pathways in primary human fibroblasts after exposure to ionizing radiation

Background

Exposure to ionizing radiation induces complex stress responses in cells, which can lead to adverse health effects such as cancer. Although a variety of studies investigated gene expression and affected pathways in human fibroblasts after exposure to ionizing radiation, the understanding of underlying mechanisms and biological effects is still incomplete due to different experimental settings and small sample sizes. Therefore, this study aims to identify the time point with the highest number of differentially expressed genes and corresponding pathways in primary human fibroblasts after irradiation at two preselected time points.

Methods

Fibroblasts from skin biopsies of 15 cell donors were exposed to a high (2Gy) and a low (0.05Gy) dose of X-rays. RNA was extracted and sequenced 2 h and 4 h after exposure. Differentially expressed genes with an adjusted p-value < 0.05 were flagged and used for pathway analyses including prediction of upstream and downstream effects. Principal component analyses were used to examine the effect of two different sequencing runs on quality metrics and variation in expression and alignment and for explorative analysis of the radiation dose and time point of analysis.

Results

More genes were differentially expressed 4 h after exposure to low and high doses of radiation than after 2 h. In experiments with high dose irradiation and RNA sequencing after 4 h, inactivation of the FAT10 cancer signaling pathway and activation of gluconeogenesis I, glycolysis I, and prostanoid biosynthesis was observed taking p-value (< 0.05) and (in) activating z-score (≥2.00 or ≤ − 2.00) into account. Two hours after high dose irradiation, inactivation of small cell lung cancer signaling was observed. For low dose irradiation experiments, we did not detect any significant (p < 0.05 and z-score ≥ 2.00 or ≤ − 2.00) activated or inactivated pathways for both time points.

Conclusions

Compared to 2 h after irradiation, a higher number of differentially expressed genes were found 4 h after exposure to low and high dose ionizing radiation. Differences in gene expression were related to signal transduction pathways of the DNA damage response after 2 h and to metabolic pathways, that might implicate cellular senescence, after 4 h. The time point 4 h will be used to conduct further irradiation experiments in a larger sample.

Exposure to Air Pollution and Particle Radioactivity With the Risk of Ventricular Arrhythmias

BACKGROUND

Individuals are exposed to air pollution and ionizing radiation from natural sources through inhalation of particles. This study investigates the association between cardiac arrhythmias and short-term exposures to fine particulate matter (particulate matter ≤2.5 µm aerodynamic diameter; PM2.5) and particle radioactivity.

METHODS

Ventricular arrhythmic events were identified among 176 patients with dual-chamber implanted cardioverter-defibrillators in Boston, Massachusetts between September 2006 and June 2010. Patients were assigned exposures based on residential addresses. Daily PM2.5 levels were estimated at 1-km×1-km grid cells from a previously validated prediction model. Particle gross β activity was used as a surrogate for particle radioactivity and was measured from several monitoring sites by the US Environmental Protection Agency's monitoring network. The association of the onset of ventricular arrhythmias (VA) with 0- to 21-day moving averages of PM2.5 and particle radioactivity (2 single-pollutant models and a 2-pollutant model) before the event was examined using time-stratified case-crossover analyses, adjusted for dew point and air temperatures.

RESULTS

A total of 1,050 VA were recorded among 91 patients, including 123 sustained VA among 25 of these patients. In the single-pollutant model of PM2.5, each interquartile range increase in daily PM2.5 levels for a 21-day moving average was associated with 39% higher odds of a VA event (95% CI, 12%-72%). In the single-pollutant model of particle radioactivity, each interquartile range increase in particle radioactivity for a 2-day moving average was associated with 13% higher odds of a VA event (95% CI, 1%-26%). In the 2-pollutant model, for the same averaging window of 21 days, each interquartile range increase in daily PM2.5 was associated with an 48% higher odds of a VA event (95% CI, 15%-90%), and each interquartile range increase of particle radioactivity with a 10% lower odds of a VA event (95% CI, -29% to 14%). We found that with higher levels of particle radioactivity, the effect of PM2.5 on VAs is reduced.

CONCLUSIONS

In this high-risk population, intermediate (21-day) PM2.5 exposure was associated with higher odds of a VA event onset among patients with known cardiac disease and indication for implanted cardioverter-defibrillator implantation independently of particle radioactivity.

The use of cardiovascular magnetic resonance as an early non-invasive biomarker for cardiotoxicity in cardio-oncology

Contemporary cancer therapy has resulted in significant survival gains for patients. However, many current and emerging cancer therapies have an associated risk of cardiotoxicity, either acutely or later in life. Regular cardiac screening and surveillance is recommended for patients undergoing treatment for cancer, with emphasis on the early detection of cardiotoxicity before irreversible complications develop. Cardiovascular magnetic resonance imaging is able to accurately assess cardiac structure, function, and perform advanced myocardial tissue characterisation, including perfusion, features which may facilitate the diagnosis and management of cardiotoxicity in cancer survivors. This review outlines the current standards for the diagnosis and screening of cardiotoxicity, with particular focus on current and future applications of cardiovascular magnetic resonance imaging.

Cardio-oncology, the myth of Sisyphus, and cardiovascular disease in breast cancer survivors

The number of breast cancer (BC) survivors has been increasing lately, due to the improvement in early detection strategies and oncological treatments. However, BC survivors are 3 times as likely to develop heart failure (HF) within 5 years of cancer diagnosis, and 7/100 of them will develop HF in a median follow-up of 8.5 years. Furthermore, HF in BC survivors has a worse prognosis compared to other causes of HF. Anthracyclines and trastuzumab have been proven to improve survival. However, they are also considered as the main causative factors of HF in BC survivors. Old patients, those with a pre-existing cardiovascular (CV) risk factors/disease, prior exposure to chemotherapy and radiotherapy are at increased risk. Serial evaluation of troponins and cardiac imaging parameters using echocardiography and cardiovascular magnetic resonance can significantly contribute to the early diagnosis of cardiac involvement before overt HF will develop. Assessment and immediate treatment of traditional CV risk factors is the first step for cardiotoxicity prevention. In BC survivors with known heart disease, the clinical stabilization is strongly recommended for cardiotoxicity prevention. Finally, in high-risk CV patients, primary prevention including cardioprotectants and/or CV drugs should be applied. According to recent studies, the early start of ACE inhibitors and β-blockers and the modification of anti-cancer treatment can prevent the decline in left ventricular ejection fraction. However, further multicenter studies are needed to establish both prevention and treatment protocols to successfully overcome HF development in BC survivors.

Radix Angelica Sinensis and Radix Hedysari Ultrafiltration Extract Protects against X-Irradiation-Induced Cardiac Fibrosis in Rats

Radiation-induced myocardial fibrosis (RIMF) is the main pathological change associated with radiation-induced heart toxicity after radiation therapy in patients with thoracic tumors. There is an antifibrosis effect of Radix Angelica Sinensis and Radix Hedysari (RAS-RH) ultrafiltration extract from Danggui Buxue decoction (DBD) in X-irradiation-induced rat myocardial fibrosis, and this study aimed to investigate whether that effect correlated with apoptosis and oxidative stress damage in primary rat cardiac fibroblasts; further, the potential mechanisms were also explored. In this study, we first found that the RAS-RH antifibrosis effect was associated with the upregulation of microRNA-200a and the downregulation of TGF-β1/smad3 and COL1α. In addition, we also found that the antifibrosis effect of RAS-RH was related to the induction of apoptosis in primary rat cardiac fibroblasts and to the prevention of damage caused by reactive oxygen species (ROS). Interestingly, primary rat cardiac fibroblasts exposed to X-ray radiation underwent apoptosis less frequently in the absence of RAS-RH. Therefore, RAS-RH has the ability to protect against fibrosis, which could be occurring through the induction of apoptosis and the resistance to oxidative stress in rats with X-irradiation-induced myocardial fibrosis; thus, in a model of RIMF, RAS-RH acts against X-irradiation-induced cardiac toxicity.

Chronic irradiation of human cells reduces histone levels and deregulates gene expression

Over the past decades, there have been huge advances in understanding cellular responses to ionising radiation (IR) and DNA damage. These studies, however, were mostly executed with cell lines and mice using single or multiple acute doses of radiation. Hence, relatively little is known about how continuous exposure to low dose ionising radiation affects normal cells and organisms, even though our cells are constantly exposed to low levels of radiation. We addressed this issue by examining the consequences of exposing human primary cells to continuous ionising γ-radiation delivered at 6-20 mGy/h. Although these dose rates are estimated to inflict fewer than a single DNA double-strand break (DSB) per hour per cell, they still caused dose-dependent reductions in cell proliferation and increased cellular senescence. We concomitantly observed histone protein levels to reduce by up to 40%, which in contrast to previous observations, was not mainly due to protein degradation but instead correlated with reduced histone gene expression. Histone reductions were accompanied by enlarged nuclear size paralleled by an increase in global transcription, including that of pro-inflammatory genes. Thus, chronic irradiation, even at low dose-rates, can induce cell senescence and alter gene expression via a hitherto uncharacterised epigenetic route. These features of chronic radiation represent a new aspect of radiation biology.