Risk of developing cardiovascular disease after involved node radiotherapy versus mantle field for Hodgkin lymphoma

Long-term cardiac effects of modern treatment for Hodgkin's lymphoma

BACKGROUND

Hodgkin's lymphoma (HL) is a hematological malignancy that affects both children and young adults. Traditional treatment is associated with a life-time prevalence of cardiac disease exceeding 50%. In the late 1990s protocols were modified to reduce cancer therapy-related adverse cardiac effects. This study aimed to assess the long-term impact of advances in treatment protocols on the cardiac health of HL survivors (HLS).

METHODS

HLS (n = 246) treated between 1997 and 2007 with anthracycline-based chemotherapy in three centers in Norway were included. Of these, 132 (53%) had also received mediastinal radiotherapy. HLS were compared to controls (n = 58) recruited from the general population and matched for sex, age, smoking status, and heredity for coronary artery disease. All subjects underwent echocardiography, clinical assessment, and blood sampling.

RESULTS

The HLS were 46 ± 9 years old and had been treated 17 ± 3 years before inclusion in the study. There was no significant difference between HLS and controls in ejection fraction (EF) (58%±5 vs. 59%±4, p = 0.08) or prevalence of heart failure. HLS treated with both anthracyclines and mediastinal radiotherapy (AC + MRT) had slightly worse left ventricular global longitudinal strain than controls (-19.3 ± 2.5% vs. -20.8 ± 2.0%, p < 0.001), but those treated with only anthracyclines did not. HLS treated with AC + MRT had a higher prevalence of valve disease than those treated only with anthracyclines (12% vs. 4%, p < 0.05).

CONCLUSIONS

HLS treated with anthracyclines after the late 1990s have similar cardiac function and morphology as age-matched controls, apart from higher rates of valvular disease in those who also underwent mediastinal radiotherapy.

Cardiovascular Risk in Patients with Hematological Malignancies: A Systematic Review and Meta-Analysis

Patients with hematologic malignancies (HMs) are at risk of future cardiovascular (CV) events. We therefore conducted a systematic review and meta-analysis to quantify their risk of future CV events. We searched Medline and EMBASE databases from inception until January 31, 2023 for relevant articles using a combination of keywords and medical subject headings. Studies examining CV outcomes in patients with HM versus controls without HM were included. The outcomes of interest included acute myocardial infarction (AMI), heart failure (HF), and stroke. The outcomes were expressed as hazard ratios (HRs) and their 95% confidence intervals (CIs). This study is registered with PROSPERO at CRD42022307814. A total of 15 studies involving 1,960,144 cases (178,602 patients with HM and 1,781,212 controls) were included in the quantitative analysis. A total of 10 studies examined the risk of AMI, 5 examined HF, and 11 examined stroke. Compared with the control group, the HRs for HM for AMI, HF, and stroke were 1.65 (95% CI 1.29 to 2.09, p <0.001), 4.82 (95% CI 3.72 to 6.25, p <0.001), and 1.60 (95% CI 1.30 to 1.97, p <0.001), respectively. The sensitivity analysis of stroke risk based on lymphoma type showed an increased risk of stroke in patients with non-Hodgkin lymphoma compared with controls (HR 1.31, 95% CI 1.04 to 1.64, p = 0.03) but no significant difference for Hodgkin lymphoma (HR 1.67, 95% CI 0.86 to 3.23, p = 0.08). Patients with HM are at increased risk of future AMI, HF, and stroke, and these findings suggest that CV care of patients with HM should be considered as a growing priority.

Radiotherapy dose de-escalation in patients with high grade non-Hodgkin lymphoma in a real-world clinical practice

PURPOSE

The standard treatment of non-Hodgkin lymphoma (NHL) comprises combined modality treatment, radiotherapy (RT), and chemotherapy with rituximab which has significantly improved both disease-free survival (DFS) and overall survival (OS). However, there is no uniformity in radiation dose usage in these patients. In this retrospective study, we compared lower radiation dose with higher in patients with aggressive NHL.

MATERIALS AND METHODS

From 2007 to 2017, treatment records of all high-grade NHL or diffuse large B-cell lymphoma and non-central nervous system NHL were included. We compared response rates, OS and DFS of patients who received ≤30 Gy RT to those with >30 Gy. Univariate and multivariate analyses were done to determine factors affecting prognosis, i.e., age, sex, stage, International Prognostic Index (IPI), adding rituximab, and radiation dose.

RESULTS

A total of 184 NHL patients treated with combined modality or radiation alone having complete follow-up details were analyzed. At median follow-up of 66.8 months, 5-year OS was 72.8% in high-dose group versus 69.9% in low-dose group (p = 0.772) and 5-year DFS 64.7% versus 64.1% (p = 0.871). Patients having early-stage disease receiving low dose and those with advanced disease treated with >30 Gy had better OS and DFS though not statistically significant. Adding rituximab was associated with significantly better OS and DFS irrespective of radiation dose delivered. High IPI score and omitting rituximab were the only factors that significantly worsened both OS and DFS. Acute radiation toxicities were comparable in both groups (p = 0.82). Among late toxicities, no patient developed a second malignancy and 5% died due to cardiovascular complications (p = 0.595) though only two patients (1.1%) had received thoracic radiation.

CONCLUSION

The two groups had comparable response rates, acute toxicities, DFS and OS. This study suggests that RT dose reduction may be possible in high-grade NHL without compromising the DFS and OS.

Development of a comprehensive cardiac atlas on a 1.5 Tesla Magnetic Resonance Linear Accelerator

Background and purpose

The 1.5 Tesla (T) Magnetic Resonance Linear Accelerator (MRL) provides an innovative modality for improved cardiac imaging when planning radiation treatment. No MRL based cardiac atlases currently exist, thus, we sought to comprehensively characterize cardiac substructures, including the conduction system, from cardiac images acquired using a 1.5 T MRL and provide contouring guidelines.

Materials and methods

Five volunteers were enrolled in a prospective protocol (NCT03500081) and were imaged on the 1.5 T MRL with Half Fourier Single-Shot Turbo Spin-Echo (HASTE) and 3D Balanced Steady-State Free Precession (bSSFP) sequences in axial, short axis, and vertical long axis. Cardiac anatomy was contoured by (AS) and confirmed by a board certified cardiologist (JR) with expertise in cardiac MR imaging.

Results

A total of five volunteers had images acquired with the HASTE sequence, with 21 contours created on each image. One of these volunteers had additional images obtained with 3D bSSFP sequences in the axial plane and additional images obtained with HASTE sequences in the key cardiac planes. Contouring guidelines were created and outlined. 15-16 contours were made for the short axis and vertical long axis. The cardiac conduction system was demonstrated with eleven representative contours. There was reasonable variation of contour volume across volunteers, with structures more clearly delineated on the 3D bSSFP sequence.

Conclusions

We present a comprehensive cardiac atlas using novel images acquired prospectively on a 1.5 T MRL. This cardiac atlas provides a novel resource for radiation oncologists in delineating cardiac structures for treatment with radiotherapy, with special focus on the cardiac conduction system.

Revisiting treatment-related cardiotoxicity in patients with malignant lymphoma-a review and prospects for the future

Treatment of malignant lymphoma has for years been represented by many cardiotoxic agents especially anthracyclines, cyclophosphamide, and thoracic irradiation. Although they are in clinical practice for decades, the precise mechanism of cardiotoxicity and effective prevention is still part of the research. At this article we discuss most routinely used anti-cancer drugs in chemotherapeutic regiments for malignant lymphoma with the focus on novel insight on molecular mechanisms of cardiotoxicity. Understanding toxicity at molecular levels may unveil possible targets of cardioprotective supportive therapy or optimization of current therapeutic protocols. Additionally, we review novel specific targeted therapy and its challenges in cardio-oncology.

Reappraisal of the role of radiation therapy in lymphoma treatment

Radiation therapy (RT) for lymphomas has improved dramatically with modern imaging and treatment techniques, encompassing only the necessary volume with minimal doses to normal structures. Prescribed radiation doses are reduced, and fractionation schedules are under revision. With effective systemic treatment only initial macroscopic disease is irradiated. With no or less effective systemic treatment, possible microscopic disease is also included. Risks of long-term side effects of RT have diminished dramatically and should be weighed against risks from more systemic treatment or increased risk of relapse. Lymphoma patients are often elderly, they tolerate modern limited RT very well. Lymphomas refractory to systemic treatments often remain radioresponsive, and brief, mild RT may offer effective palliation. New roles for RT are emerging with immune therapies. RT for "bridging," keeping the lymphoma under control while waiting for immune therapy, is well established. Enhancement of the immune response to lymphomas, so-called "priming," is being intensively researched.

A Phase 2 trial of deep-inspiration breath hold in radiotherapy of gastric lymphomas

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A Bayesian method is developed for the uncertainty quantification of FE models.

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Expectation-Maximization strategies are combined with asymptotic approximations.

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Identification uncertainty and test-to-test variability of parameters are included.

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A new rationale to optimally weight the modal parameters is introduced.

Background and purpose

Radiotherapy (RT) is an important part in the treatment of gastric lymphomas and the prognosis after radiotherapy is very good with a good chance of long-term survival, so prevention of long-term adverse effects is important. In patients with gastric lymphomas cardiac late effects are of most concern. The aim of this study was to assess if the dose to the heart could be reduced with deep inspiration breath-hold (DIBH) without compromising the dose to the target or increasing the risk of other late effects.

Methods and patients

Fifteen patients with gastric lymphoma were included. RT plans were made using DIBH and Free breathing (FB) scans. Clinical target volume (CTV) was the stomach plus 1 cm margin. The heart and surrounding organs at risk (OAR) were contoured. Two sets of plan comparisons were made, one with 1 cm CTV to planning target volume (PTV) margin in both DIBH and FB and one set with an additional 5 mm CTV to PTV margin in cranio-caudal direction with FB. Datasets were analysed with Wilcoxon signed rank test for non-parametric paired data.

Results

All patients tolerated the procedures and were treated with volumetric arc therapy technique in DIBH. Target coverage was kept equal between FB and DIBH, while a statistically significant reduction of the estimated does to the heart was seen with DIBH. Median mean heart dose was reduced from 7.1 Gy (5.7–12) to a median of 3.2 Gy (1.2–7.0) and heart V20 from a median of 54 (17–106) cm³ to 15. (0.0–78) cm³. The estimated mean doses to the liver, duodenum, pancreas and spinal cord were at the same level.

Conclusion

This clinical trial of RT with DIBH for gastric lymphomas showed that the heart dose could be reduced without compromising PTV coverage. The doses to abdominal OARs were similar with FB and DIBH.

Vital organ sparing with proton therapy for pediatric Hodgkin lymphoma: Toxicity and outcomes in 50 patients

BACKGROUND AND PURPOSE

With high survival rates for pediatric Hodgkin lymphoma (HL), attention has turned to minimizing treatment-related morbidity and mortality. Chemotherapy and dose of radiation to organs at risk (OARs) contribute to elevated risks of secondary malignancy and cardiopulmonary disease. We sought to characterize the radiation dose to OARs, toxicities, and outcomes for pediatric HL patients treated with proton therapy (PT).

MATERIALS AND METHODS

Fifty patients aged 11-21 with HL consecutively treated with PT were evaluated 1-2 months following completion of PT and every 6 months thereafter. Acute and late toxicities were captured retrospectively using CTCAE v5. Patterns of relapse were characterized, and survival was assessed using Kaplan-Meier method.

RESULTS

Most (47, 94%) patients received PT to the mediastinum. Median mean heart dose was 4.3 Gy (RBE) and median bilateral lung V20Gy was 5.8%. Median integral dose was 1.7 Gy. For the 27 female patients, a median mean dose of 0.4 and 0.3 Gy (RBE) was delivered to ipsilateral and contralateral breast tissue, respectively. No on-treatment grade 3-5 toxicities were seen. At a median follow-up of 5.3 years, no PT-related grade 3-5 toxicities or secondary malignancies developed. Five patients relapsed at a median time of 9.2 months after PT (range 2.5-24.9 months; 5-year recurrence free survival 90%). Recurrences were both in- and out-of-field in all 5 cases with no marginal failures. All relapsed patients were successfully salvaged (5-year overall survival 100%).

CONCLUSION

For pediatric HL patients, proton treatment resulted in marked dose sparing of OARs with low rates of toxicity, no marginal failures, and excellent 5-year survival.

Radiation-Induced Cardiovascular Disease: Mechanisms, Prevention, and Treatment

PURPOSE OF REVIEW

Despite the advancements of modern radiotherapy, radiation-induced cardiovascular disease (RICVD) remains a common cause of morbidity and mortality among cancer survivors.

RECENT FINDINGS

Proposed pathogenetic mechanisms of RICVD include endothelial cell damage with accelerated atherosclerosis, pro-thrombotic alterations in the coagulation pathway as well as inflammation and fibrosis of the myocardial, pericardial, valvular, and conduction tissues. Prevention of RICVD can be achieved by minimizing the exposure of the cardiovascular system to radiation, by treatment of underlying cardiovascular risk factors and cardiovascular disease, and possibly by prophylactic pharmacotherapy post exposure. Herein we summarize current knowledge on the mechanisms underlying the pathogenesis of RICVD and propose prevention and treatment strategies.

Impact of lung block shape on cardiac dose for total body irradiation

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Partial cardiac shielding in TBI is not commonly reported and varies among clinics.

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We evaluated the effects of cardiac shielding in TBI using 3D beam modeling in a commercial TPS.

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Partial cardiac shielding can reduce mean heart dose and reduce LAD dose up to 30%.

Evaluating cardiac dose during total body irradiation (TBI) is of increasing interest. A three-dimensional beam model for TBI was commissioned and lung shielding was simulated in a treatment planning system with the cardiac silhouette partially blocked and unblocked. When blocked, the median heart dose decreased by 6% (IQR = 6%) and the median cardiac V12Gy decreased by 27% (IQR = 17%). The median left anterior descending artery dose decreased 20% (IQR = 12%) for blocked cases. Because using partial heart shielding may result in considerable changes in dose to cardiac structures, TBI protocols should explicitly consider lung block design parameters and their potential effects.

Predicted Risks of Cardiovascular Disease Following Chemotherapy and Radiotherapy in the UK NCRI RAPID Trial of Positron Emission Tomography-Directed Therapy for Early-Stage Hodgkin Lymphoma

PURPOSE

The contemporary management of early-stage Hodgkin lymphoma (ES-HL) involves balancing the risk of late adverse effects of radiotherapy against the increased risk of relapse if radiotherapy is omitted. This study provides information on the risk of radiation-related cardiovascular disease to help personalize the delivery of radiotherapy in ES-HL.

METHODS

We predicted 30-year absolute cardiovascular risk from chemotherapy and involved field radiotherapy in patients who were positron emission tomography (PET)-negative following three cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy within a UK randomized trial of PET-directed therapy for ES-HL. Cardiac and carotid radiation doses and chemotherapy exposure were combined with established dose-response relationships and population-based mortality and incidence rates.

RESULTS

Average mean heart dose was 4.0 Gy (range 0.1-24.0 Gy) and average bilateral common carotid artery dose was 21.5 Gy (range 0.6-38.1 Gy), based on individualized cardiovascular dosimetry for 144 PET-negative patients receiving involved field radiotherapy. The average predicted 30-year radiation-related absolute excess overall cardiovascular mortality was 0.56% (range 0.01%-6.79%; < 0.5% in 67% of patients and > 1% in 15%), whereas average predicted 30-year excess incidence was 6.24% (range 0.31%-31.09%; < 5% in 58% of patients and > 10% in 24%). For cardiac disease, the average predicted 30-year radiation-related absolute excess mortality was 0.42% (0.79% with mediastinal involvement and 0.05% without) and for stroke, it was 0.14%.

CONCLUSION

Predicted excess cardiovascular risk is small for most patients, so radiotherapy may provide net benefit. However, for a minority of patients receiving high doses of radiation to cardiovascular structures, it may be preferable to consider advanced radiotherapy techniques to reduce doses or to omit radiotherapy and accept the increased relapse risk. Individual assessment of cardiovascular and other risks before treatment would allow personalized decision making about radiotherapy in ES-HL.

[Impact of thoracic irradiation on cardiac structures]

Thoracic irradiation requires protection of the heart as an organ at risk of complications. The mean heart dose is the most studied dosimetric parameter in the literature. Recent studies question its relevance in view of the multiplicity of cardiac injuries, the heterogeneity of the cardiac dose distribution and the current technical possibilities to refine cardiac dosimetric protection. The objective of this literature review is to analyze the available scientific data on the impact of the dose received by the cardiac substructures. A search of articles using the PubMed search engine was used to select the most relevant studies. A total of 19 articles were selected according to pre-established criteria to answer the issue. Several studies found significant associations between dosimetric parameters of substructures and clinical cardiological impact. Some proposed dose constraints for substructures.

Cardiovascular Manifestations From Therapeutic Radiation: A Multidisciplinary Expert Consensus Statement From the International Cardio-Oncology Society

Radiation therapy is a cornerstone of cancer therapy, with >50% of patients undergoing therapeutic radiation. As a result of widespread use and improved survival, there is increasing focus on the potential long-term effects of ionizing radiation, especially cardiovascular toxicity. Radiation therapy can lead to atherosclerosis of the vasculature as well as valvular, myocardial, and pericardial dysfunction. We present a consensus statement from the International Cardio-Oncology Society based on general principles of radiotherapy delivery and cardiovascular risk assessment and risk mitigation in this population. Anatomical-based recommendations for cardiovascular management and follow-up are provided, and a priority is given to the early detection of atherosclerotic vascular disease on imaging to help guide preventive therapy. Unique management considerations in radiation-induced cardiovascular disease are also discussed. Recommendations are based on the most current literature and represent a unanimous consensus by the multidisciplinary expert panel.

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Radiation therapy leads to short- and long-term cardiovascular adverse effects of the vasculature and the heart, including valvular, myocardial, and pericardial disease.

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Computed tomography scans conducted for radiation planning or cancer staging provide an available opportunity to detect asymptomatic atherosclerosis and direct preventive therapies.

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Additional practical screening recommendations for cardiovascular disease based on anatomical exposure are provided.

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There are unique considerations in the management of radiation-induced cardiovascular disease; contemporary percutaneous treatment is often preferred over surgical options.

Past, Present, and Future of Radiation-Induced Cardiotoxicity: Refinements in Targeting, Surveillance, and Risk Stratification

Radiation therapy is an important component of cancer therapy for many malignancies. With improvements in cardiac-sparing techniques, radiation-induced cardiac dysfunction has decreased but remains a continued concern. In this review, we provide an overview of the evolution of radiotherapy techniques in thoracic cancers and associated reductions in cardiac risk. We also highlight data demonstrating that in some cases radiation doses to specific cardiac substructures correlate with cardiac toxicities and/or survival beyond mean heart dose alone. Advanced cardiac imaging, cardiovascular risk assessment, and potentially even biomarkers can help guide post-radiotherapy patient care. In addition, treatment of ventricular arrhythmias with the use of ablative radiotherapy may inform knowledge of radiation-induced cardiac dysfunction. Future efforts should explore further personalization of radiotherapy to minimize cardiac dysfunction by coupling knowledge derived from enhanced dosimetry to cardiac substructures, post-radiation regional dysfunction seen on advanced cardiac imaging, and more complete cardiac toxicity data.

On the Importance of Individualized, Non-Coplanar Beam Configurations in Mediastinal Lymphoma Radiotherapy, Optimized With Automated Planning

Background and Purpose

Literature is non-conclusive regarding selection of beam configurations in radiotherapy for mediastinal lymphoma (ML) radiotherapy, and published studies are based on manual planning with its inherent limitations. In this study, coplanar and non-coplanar beam configurations were systematically compared, using a large number of automatically generated plans.

Material and Methods

An autoplanning workflow, including beam configuration optimization, was configured for young female ML patients. For each of 25 patients, 24 plans with different beam configurations were generated with autoplanning: 11 coplanar CP_x plans and 11 non-coplanar NCP_x plans with x = 5 to 15 IMRT beams with computer-optimized, patient-specific configurations, and the coplanar VMAT and non-coplanar Butterfly VMAT (B-VMAT) beam angle class solutions (600 plans in total).

Results

Autoplans compared favorably with manually generated, clinically delivered plans, ensuring that beam configuration comparisons were performed with high quality plans. There was no beam configuration approach that was best for all patients and all plan parameters. Overall there was a clear tendency towards higher plan quality with non-coplanar configurations (NCP_x≥12 and B-VMAT). NCP_x≥12 produced highly conformal plans with on average reduced high doses in lungs and patient and also a reduced heart Dmean, while B-VMAT resulted in reduced low-dose spread in lungs and left breast.

Conclusions

Non-coplanar beam configurations were favorable for young female mediastinal lymphoma patients, with patient-specific and plan-parameter-dependent dosimetric advantages of NCP_x≥12 and B-VMAT. Individualization of beam configuration approach, considering also the faster delivery of B-VMAT vs. NCP_x≥12, can importantly improve the treatments.

Topographic variability of the normal circle of Willis anatomy on a paediatric population

Long-term sequelae are major limitations of radiation therapy use, especially for childhood brain tumour. Circle of Willis irradiation strongly increases the long-term risk of stroke, but to establish dose-response relationship, anticipating long-term effects of new techniques, requires to perform accurate and reproducible dosimetric estimations in large cohorts of patients having received radiotherapy decades ago. For the accuracy of retrospective dose reconstruction, the topographic variability of the Circle of Willis arteries is crucial. In order to improve retrospective dosimetric studies and dose-volume estimates to the typical Circle of Willis arteries, we aim to study the inter-individual topographic variability of these structures. Thirty-eight time of flight MRI sequences of children aged 2–17 years in both genders were investigated. A region growth algorithm was used for the segmentation of the cerebral arteries. A rigid registration in a common skull was performed following the anatomy of skull base foramina. The Posterior clinoid processes of the sella turcica were used as reference landmark (R0), and 5 key landmarks were chosen in each segmented Circle of Willis, then distances between the 5 landmarks and R0 were calculated for each of the 38 subjects. The distance between R0 and each landmark of the Circle of Willis followed a normal distribution, the average values ranging from 13.6 to 17.0 mm, and the standard deviations ranged from 2.6 to 3.0 mm, i.e. less than a fifth of the average value. The perimeter of the Circle of Willis was longer in older subjects, this increase being isotropic. Our study shows a remarkably low topographic variability of the typical Circle of Willis. An important result, allowing reliable anthropomorphic phantoms-based retrospective estimations of the radiation doses delivered to these arterial structures during radiotherapy treatment.

A Pilot Study of Safer Radiation Dosage to the Heart and Its Subregions

Background and Objectives: The real impact of ionizing radiation on the heart and poorer overall survival for patients with non small cell lung cancer (NSCLC) remains unclear. This study aims to determine the safe dose constraints to the heart’s subregions that could prevent patients’ early non-cancerous death and improve their quality of life. Methods and Materials: A retrospective cohort study was performed containing 51 consecutive patients diagnosed with stage III NSCLC and treated using 3D, Intensity-modulated radiation therapy (IMRT), and Volumetric modulated arc therapy (VMAT) radiotherapy. For a dosimetric analysis, these structures were chosen: heart, heart base (HB), and region of great blood vessels (GBV). Dose–volume histograms (DVH) were recorded for all mentioned structures. Maximum and mean doses to the heart, HB, the muscle mass of the HB, and GBV were obtained. V10–V60 (%) parameters were calculated from the DVH. After performed statistical analysis, logistic regression models were created, and critical doses calculated. Results: The critical dose for developing a fatal endpoint for HB was 30.5 Gy, while for GBV, it was 46.3 Gy. Increasing the average dose to the HB or GBV by 1 Gy from the critical dose further increases the possibility of early death by 22.0% and 15.8%, respectively. Conclusions: We suggest that the non-canonical sub-regions of the heart (HB and GBV) should be considered during the planning stage. Additional constraints of the heart subregions should be chosen accordingly, and we propose that the mean doses to these regions be 30.5 Gy and 46.3 Gy, respectively, or less. Extrapolated DVH curves for both regions may be used during the planning stage with care.

Modern Radiotherapy and Risk of Cardiotoxicity

Despite the advancements of modern radiotherapy, radiation-induced heart disease remains a common cause of morbidity and mortality amongst cancer survivors. This review outlines the basic mechanism, clinical presentation, risk stratification, early detection, possible mitigation, and treatment of this condition.

Adoption of Expansion Margins to Reduce the Dose Received by the Coronary Arteries and the Risk of Cardiovascular Events in Lymphoma Patients

PURPOSE

Mediastinal radiation therapy (RT) in patients with lymphoma implies involuntary coronary artery (CA) exposure, resulting in an increased risk of coronary artery disease (CAD). Accurate delineation of CAs may spare them from higher RT doses. However, heart motion affects the estimation of the dose received by CAs. An expansion margin (planning organ at risk volume [PRV]), encompassing the nearby area where CAs displace, may compensate for these uncertainties, reducing CA dose and CAD risk. Our study aimed to evaluate if a planning process optimized on CA-specific PRVs, rather than just on CAs, could provide any dosimetric or clinical benefit.

METHODS AND MATERIALS

Forty patients receiving RT for mediastinal lymphomas were included. We contoured left main trunk, left anterior descending, left circumflex, and right coronary arteries. An isotropic PRV was then applied to all CAs, in accordance with literature data. A comparison was then performed by optimizing treatment plans either on CAs or on PRVs, to detect any difference in CA sparing in terms of maximum (D_max), median (D_med), and mean (D_mean) dose. We then investigated, through risk modeling, if any dosimetric benefit obtained with the PRV-related optimization process could translate to a lower risk of ischemic complications.

RESULTS

Plan optimization on PRVs demonstrated a significant dose reduction (range, 7%-9%) in D_max, D_med, and D_mean for the whole coronary tree, and even higher dose reductions when vessels were located 5- to 20-mm from PTV (range, 13%-15%), especially for left main trunk and left circumflex (range, 16%-21%). This translated to a mean risk reduction of developing CAD of 12% (P < .01), which increased to 17% when CAs were located 5- to 20-mm from PTV.

CONCLUSIONS

Integration of CA-related PRVs in the optimization process reduces the dose received by CAs and translates to a meaningful prevention of CAD risk in patients with lymphoma treated with mediastinal RT.

Delineation of whole heart and substructures in thoracic radiation therapy: National guidelines and contouring atlas by the Danish Multidisciplinary Cancer Groups

BACKGROUND AND PURPOSE

This study presents Danish consensus guidelines for delineation of the heart and cardiac substructures across relevant Danish Multidisciplinary Cancer Groups.

MATERIAL AND METHODS

Consensus guidelines for the heart and cardiac substructures were reached among 15 observers representing the radiotherapy (RT) committees of four Danish Multidisciplinary Cancer Groups. The guidelines were validated on CT scans of 12 patients, each with five independent contour sets. The Sørensen-Dice similarity coefficient (DSC), the distance between the centers of the arteries and the mean surface distance were used to evaluate the inter-observer variation.

RESULTS

National guidelines for contouring the heart and cardiac substructures were achieved. The median DSC was 0.78-0.96 for the heart and the four cardiac chambers. For the four substructures of the left ventricle, the median DSC was 0.35-0.57. The coronary arteries were contoured in ten segments, with the best agreement for the left anterior descending coronary artery segments, with a median distance between the arteries ranging from 2.4-4.4 mm. The median variation was 3.7-12.8 mm for the right coronary artery segments and 3.7-6.2 mm for the left circumflex coronary artery segments, with the most pronounced inter-observer variation in the distal segment for all three coronary arteries.

CONCLUSION

National guidelines for contouring the heart and cardiac substructures were developed across relevant Danish Multidisciplinary Cancer Groups, where RT dose to the heart is of concern. The inter-observer contour overlap was best for the heart and chambers and decreased for smaller structures.

Harnessing data science to advance radiation oncology

Radiation oncology, a major treatment modality in the care of patients with malignant disease, is a technology‐ and computer‐intensive medical specialty. As such, it should lend itself ideally to data science methods, where computer science, statistics, and clinical knowledge are combined to advance state‐of‐the‐art care. Nevertheless, data science methods in radiation oncology research are still in their infancy and successful applications leading to improved patient care remain scarce. Here, we discuss data interoperability issues within and across organizational boundaries that hamper the introduction of big data and data science techniques in radiation oncology. At the semantic level, creating common underlying models and codification of the data, including the use of data elements with standardized definitions, an ontology, remains a work in progress. Methodological issues in data science and in the use of large population‐based health data registries are identified. We show that data science methods and big data cannot replace randomized clinical trials in comparative effectiveness research by reviewing a series of instances where the outcomes of big data analyses and randomized trials are at odds. We also discuss the modern wave of machine learning and artificial intelligence as represented by deep learning and convolutional neural networks. Finally, we identify promising research avenues and remain optimistic that the data sources in radiation oncology can be linked to yield important insights in the near future. We argue that data science will be a valuable complement to, but not a replacement of, the traditional hypothesis‐driven translational research chain and the randomized clinical trials that form the backbone of evidence‐based medicine.

Fondazione Italiana Linfomi (FIL) expert consensus on the use of intensity-modulated and image-guided radiotherapy for Hodgkin's lymphoma involving the mediastinum

Aim

Advances in therapy have resulted in improved cure rates and an increasing number of long-term Hodgkin's lymphoma (HL) survivors. However, radiotherapy (RT)-related late effects are still a significant issue, particularly for younger patients with mediastinal disease (secondary cancers, heart diseases). In many Centers, technological evolution has substantially changed RT planning and delivery. This consensus document aims to analyze the current knowledge of Intensity-Modulated Radiation Therapy (IMRT) and Image-Guided Radiation Therapy (IGRT) for mediastinal HL and formulate practical recommendations based on scientific evidence and expert opinions.

Methods

A dedicated working group was set up within the Fondazione Italiana Linfomi (FIL) Radiotherapy Committee in May 2018. After a first meeting, the group adopted a dedicated platform to share retrieved articles and other material. Two group coordinators redacted a first document draft, that was further discussed and finalized in two subsequent meetings. Topics of interest were: 1) Published data comparing 3D-conformal radiotherapy (3D-CRT) and IMRT 2) dose objectives for the organs at risk 3) IGRT protocols and motion management.

Results

Data review showed that IMRT might allow for an essential reduction in the high-dose regions for all different thoracic OAR. As very few studies included specific dose constraints for lungs and breasts, the low-dose component for these OAR resulted slightly higher with IMRT vs. 3D-CRT, depending on the technique used. We propose a set of dose objectives for the heart, breasts, lungs, and thyroid. The use of IGRT is advised for margin reduction without specific indications, such as the use of breath-holding techniques. An individual approach, including comparative planning and considering different risk factors for late morbidity, is recommended for each patient.

Conclusions

As HL therapy continues to evolve, with an emphasis on treatment reduction, radiation oncologists should use at best all the available tools to minimize the dose to organs at risk and optimize treatment plans. This document provides indications on the use of IMRT/IGRT based on expert consensus, providing a basis for clinical implementation and future development.

Cardiotoxicity of mediastinal radiotherapy

Aim

To explore available recent literature related to cardiotoxicity following mediastinal radiation.

Background

Radiotherapy-related heart injury is well documented, with no apparent safety threshold dose. The number of long-term cancer survivors exposed to mediastinal radiotherapy at some point of their treatment is increasing. Heart dosimetric parameters are of great importance in developing a treatment plan, but few data are available regarding radiosensitivity and dose-volume constraints for specific heart structures.

Materials and Methods

In October 2018, we identified articles published after 1990 through a PubMed/MEDLINE database search. The authors examined rough search results and manuscripts not relevant for the topic were excluded. We extracted clinical outcomes following mediastinal radiotherapy of childhood cancers, lymphoma, medulloblastoma, thymic cancers and hematopoietic cell transplantation survivors and evaluated treatment planning data, whenever available.

Results

A total of 1311 manuscripts were identified in our first-round search. Of these manuscripts, only 115 articles, matching our selection criteria, were included.

Conclusions

Studies uniformly show a linear radiation dose-response relationship between mean absorbed dose to the heart (heart-D_mean) and the risk of dying as a result of cardiac disease, particularly when heart-D_mean exceeds 5 Gy. Limited data are available regarding dose-volume predictors for heart substructures and the risk of subsequent cardiac toxicity. An individual patient's cardiotoxicity risk can be modified with advanced treatment planning techniques, including deep inspiration breath hold. Proton therapy is currently showing advantages in improving treatment planning parameters when compared to advanced photon techniques in lymphoma, thymic malignancies, malignant mesothelioma and craniospinal irradiation.

Radiation-Associated Pericardial Disease

PURPOSE OF REVIEW

This review highlights the literature related to pericardial injury following radiation for oncologic diseases.

RECENT FINDINGS

Radiation-associated pericardial disease can have devastating consequences. Unfortunately, there is considerably less evidence regarding pericardial syndromes following thoracic radiation as compared to other cardiovascular outcomes. Pericardial complications of radiation may arise acutely or have an insidious onset several decades after treatment. Transthoracic echocardiography is the screening imaging modality of choice, while cardiac magnetic resonance imaging further characterizes the pericardium and guides treatment decision-making. Cardiac CT can be useful for assessing pericardial calcification. Ongoing efforts to lessen inadvertent cardiac injury are directed towards the revision of radiation techniques and protocols. As survival of mediastinal and thoracic malignancies continues to improve, radiation-associated pericardial disease is increasingly relevant. Though advances in radiation oncology demonstrate promise in curtailing cardiotoxicity, the long-term effects pertaining to pericardial complications remain to be seen.

Improvements in Imaging of Hodgkin Lymphoma: Positron Emission Tomography

18-Fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG PET/CT) is currently the criterion standard of lymphoma imaging and recommended through all stages of Hodgkin lymphoma management. Accurate staging is important for risk stratification and initial choice of therapy and also for the planning of postchemoradiotherapy. 18-Fluoro-2-deoxy-D-glucose PET/CT frequently leads to upstaging and potentially a more intensive treatment. Visual-only assessment of staging and interim scans is being accompanied by quantitative and semiquantitative methods to measure metabolic tumor volume, total lesion glycolysis, and so on. It is still unclear if these methods significantly improve the value of FDG PET/CT by visual assessment only. Because of the good prognostic value of FDG PET/CT, a large number of studies have used interim FDG PET to tailor treatment to the individual patients, according to their early metabolic response rather than according to their pretreatment prognostic features. 18-Fluoro-2-deoxy-D-glucose PET/CT is standard of care for posttreatment response assessment but has no place in routine follow-up of Hodgkin lymphoma patients in remission.

Protontherapy versus best photon for mediastinal Hodgkin lymphoma: Dosimetry comparison and treatment using ILROG guidelines

The purpose of this work was reducing treatment-related toxicity for Hodgkin lymphomas using practical procedure inspired by the ILROG guidelines. Reporting the first case of localized Hodgkin lymphoma treated with protontherapy in France. A 24-year-old female with mediastinal, bulky, localized, mixed-cellularity, classic Hodgkin lymphoma required an involved-site radiation therapy after complete response following polychemotherapy. Three-dimensional conformal radiation therapy was not acceptable due to high doses to breasts, heart and lungs. We realized a four-dimensional computed tomography (CT) to evaluate target movements and another CT with gating and breath-hold technique. Delineation was performed on both CT using the initial fluorodeoxyglucose positron-emission tomography/CT. One dosimetric plan with rotational intensity-modulated radiation therapy with a helical Tomotherapy© was realized and compared to another one with conformational protontherapy. Ninety-five percent of the planning target volume was covered by 98 and 99% of the prescribed dose with protontherapy and helical Tomotherapy©. Protontherapy provided the best organ at risk protection. Lung and heart protections were better with protontherapy: lung mean dose (3.7Gy vs. 8.4Gy) and median dose (0.002Gy vs. 6.9Gy), heart mean dose (2.6Gy vs. 3.7Gy). Breast sparing was better for both breasts using protontherapy: right breast mean dose (2.4Gy vs. 4.4Gy) and left (1.9Gy vs. 4.6Gy). The biggest difference was seen with low doses, which were better with protontherapy: volume of lung receiving 5Gy was 17.5% vs. 54.2% with Helical Tomotherapy©. In view of these results, we decided to treat our patient with protontherapy using respiratory assessment. We delivered 30Gy (15 fractions) using protontherapy with one direct anterior field using pencil beam scanning and deep inspiration breath-hold technique. We observed only grade 1 skin erythema during treatment and no toxicity during early follow-up.

Radiation-Associated Cardiac Disease: From Molecular Mechanisms to Clinical Management

PURPOSE OF REVIEW

Radiation-associated cardiac disease (RACD) is an increasingly recognized latent manifestation of chest and mediastinal radiation therapy. The delayed presentation reflects increased survival rates from malignancies successfully treated decades previously. However, individuals are now presenting with multiple coexistent manifestations of RACD and pulmonary disease as a consequence of high-dose radiation administered prior to the routine institution of modern dose-modulating regimens. Increased awareness of RACD is critical for implementation of appropriate screening algorithms and for specific management strategies involving the timing and strategies of intervention in these patients.

RECENT FINDINGS

Recent advances in multimodality cardiac imaging have demonstrated pathognomonic findings of RACD, which can predict outcomes including mortality. Accurate diagnosis of these typically concurrent manifestations is critical and should prompt referral to a center experienced in managing RACD as surgical risk is significantly increased for this patient cohort, particularly for those undergoing redo operation. The latent effect of RACD and its unique combination of manifestations means that these patients will increasingly present with challenging management issues, resulting in increased rates of morbidity and mortality. Timing of treatment intervention must be carefully considered, although percutaneous options may provide alternative future strategies for this higher risk cohort.

Radiation-associated epithelial-myoepithelial carcinoma among five secondary malignancies: A case report and review of literature

BACKGROUND

Epithelial-myoepithelial carcinoma (EMC) is a rare, low-grade, malignant tumor that constitutes less than one percent of all salivary gland tumors. To date, only one other case report has described radiation-associated EMC in the English language medical literature.

CASE SUMMARY

In this report, we describe the case of a 56-year-old male patient who presented with a neck mass diagnosed as EMC of the left submandibular gland approximately 30 years after mantle field radiation and chemotherapy for Hodgkin lymphoma. Treatment included resection, re-resection with nodal dissection, and adjuvant chemoradiotherapy. This patient was also diagnosed with 4 other secondary malignancies, including stage IV diffuse large B cell lymphoma in the abdomen with subsequent brain metastases, low-grade neuroendocrine carcinoma of the lung, Hurthle cell adenoma, and small B cell lymphoma before the patient expired. This case provides important information regarding the pathology, clinical sequelae, and management of a patient diagnosed with radiation-associated EMC amidst four concurrent malignancies.

CONCLUSION

Further investigation is needed on the efficacy of adjuvant radiotherapy in EMC, especially atypical EMC.

Cardiac Structure Injury After Radiotherapy for Breast Cancer: Cross-Sectional Study With Individual Patient Data

Purpose Incidental cardiac irradiation can cause cardiac injury, but little is known about the effect of radiation on specific cardiac segments. Methods For 456 women who received breast cancer radiotherapy between 1958 and 2001 and then later experienced a major coronary event, information was obtained on the radiotherapy regimen they received and on the location of their cardiac injury. For 414 women, all with documented location of left ventricular (LV) injury, doses to five LV segments were estimated. For 133 women, all with documented location of coronary artery disease with ≥ 70% stenosis, doses to six coronary artery segments were estimated. For each segment, numbers of women with left-sided and right-sided breast cancer were compared. Results Of women with LV injury, 243 had left-sided breast cancer and 171 had right-sided breast cancer (ratio of left v right, 1.42; 95% CI, 1.17 to 1.73), reflecting the higher typical LV radiation doses in left-sided cancer (average dose left-sided, 8.3 Gy; average dose right-sided, 0.6 Gy; left minus right dose difference, 7.7 Gy). For individual LV segments, the ratios of women with left- versus right-sided radiotherapy were as follows: inferior, 0.94 (95% CI, 0.70 to 1.25); lateral, 1.42 (95% CI, 1.04 to 1.95); septal, 2.09 (95% CI, 1.37 to 3.19); anterior, 1.85 (95% CI, 1.39 to 2.46); and apex, 4.64 (95% CI, 2.42 to 8.90); corresponding left-minus-right dose differences for these segments were 2.7, 4.9, 7.2, 10.4, and 21.6 Gy, respectively ( Ptrend < .001). For women with coronary artery disease, the ratios of women with left- versus right-radiotherapy for individual coronary artery segments were as follows: right coronary artery proximal, 0.48 (95% CI, 0.26 to 0.91); right coronary artery mid or distal, 1.69 (95% CI, 0.85 to 3.36); circumflex proximal, 1.46 (95% CI, 0.72 to 2.96); circumflex distal, 1.11 (95% CI, 0.45 to 2.73); left anterior descending proximal, 1.89 (95% CI, 1.07 to 3.34); and left anterior descending mid or distal, 2.33 (95% CI, 1.19 to 4.59); corresponding left-minus-right dose differences for these segements were -5.0, -2.5, 1.6, 3.5, 9.5, and 38.8 Gy ( Ptrend = .002). Conclusion For individual LV and coronary artery segments, higher radiation doses were strongly associated with more frequent injury, suggesting that all segments are sensitive to radiation and that doses to all segments should be minimized.

Cardiovascular effects of radiation therapy

Radiation therapy (RT) plays a prominent role in the treatment of many cancers. With increasing use of RT and high overall survival rates, the risks associated with RT must be carefully considered. Of these risks, the cardiovascular and autonomic toxicities have been of significant concern. In fact, cardiovascular disease is the leading cause of nonmalignancy-related death in cancer survivors. The manifestations of radiation induced cardiac injury include the acute toxicities of myopericarditis and late toxicities including constrictive pericarditis, restrictive cardiomyopathy, coronary artery disease, valvular heart disease, heart failure, and conduction abnormalities. Neck and cranial RT have also been associated with significant long-term toxicities including accelerated occlusive carotid artery disease, autonomic dysfunction due to baroreceptor damage, and development of metabolic syndromes due to damage to the hypothalamic-pituitary axis. The clinical manifestations of radiation induced disease may not present until several years following the delivery of radiation. We review the adverse effects of RT on these organ systems and discuss risk reduction strategies that may effectively mitigate some of these adverse outcomes.

Reduced Mortality Risk in the Recent Era in Early-Stage Hodgkin Lymphoma Patients Treated With Radiation Therapy With or Without Chemotherapy

PURPOSE

To determine the effect of treatment changes over time on all-cause mortality risk in patients with early-stage Hodgkin lymphoma (HL) after radiation therapy. The long-term survivorship of those with HL necessitates quantification of the late risk of mortality from HL and other causes.

METHODS AND MATERIALS

An institutional review board-approved retrospective study was conducted using a multi-institutional database of 1541 stage I and II HL patients treated from 1968 to 2007 with radiation therapy alone or combined-modality treatment. The analytic methods included cumulative incidence function, Kaplan-Meier estimates and log-rank tests for overall survival (OS) differences, and Cox proportional hazards modeling.

RESULTS

The median age at diagnosis was 27 years. At a median follow-up of 15.2 years (35% of patients with >20 years of follow-up), 395 patients had died of all causes, including 85 HL, 168 second malignancy (25 hematologic and 143 nonhematologic), 70 cardiovascular, and 21 pulmonary deaths. The cumulative incidence of non-HL mortality had surpassed HL mortality at 8.3 years. For patients treated from 1968 to 1982, 1983 to 1992, and 1993 to 2007, the 15-year OS rates were 78%, 85%, and 88%, respectively (P=.0016). On Cox proportional hazards analysis, age, B symptoms, and number of disease sites were significantly associated with all-cause mortality in the first decade of follow-up, with a trend toward significance for radiation field extent.

CONCLUSIONS

The all-cause mortality risk was significantly lower for patients treated in the most recent era during the first decade of follow-up, likely due to improved HL therapy resulting in a higher cure rate and lower treatment-related toxicity from smaller radiation fields. Current efforts toward radiation treatment reduction might further reduce the long-term mortality risk for these patients.

Clinical outcome of patients with early stage favorable Hodgkin lymphoma treated with ABVD × two cycles followed by FDG-PET/CT restaging and 20 Gy of involved-site radiotherapy

Our purpose was to assess outcome of patients with early-stage, favorable (per GHSG criteria) Hodgkin Lymphoma (HL) staged with FDG-PET/CT and treated with two cycles of adriamycin, bleomycin, vincristine, and dacarbazine (ABVD) followed by PET/CT assessment and involved-site radiotherapy (ISRT) to 20 Gy. Records of 23 patients who met eligibility criteria, treated between 2008 and 2016, were reviewed. PET response after two cycles of ABVD was independently assessed by a nuclear medicine physician. After two cycles of ABVD, 91.3% of patients had a Deauville score of 1-2; 1 patient had a score of 3. Median follow-up was 45.3 months. As of this analysis, all patients are alive without disease. One patient had an out-of-field relapse, yielding a 4-year relapse-free survival rate of 92.9% (95%CI [59.1, 99.0]). Our results showed that with careful patient selection by initial disease characteristics and FDG-PET response to chemotherapy, the use of a more restricted treatment volume of ISRT to 20 Gy following ABVD × 2 is associated with excellent outcomes.

Are heart toxicities in breast cancer patients important for radiation oncologists? A practice pattern survey in German speaking countries

Background

To assess the personal beliefs of radiation oncologists regarding heart sparing techniques in breast cancer patients.

Methods

Between August 2015 and September 2015, a survey was sent to radiation oncology departments in Germany, Austria and Switzerland. 82 radiation oncology departments answered the questionnaire: 16 university clinics and 66 other departments. Most (87.2%) of the participants had >10 years of radiation oncology experience.

Results

89.2% of the participants felt that there is enough evidence to support heart sparing for breast cancer patients. The most important dose parameter was considered the mean heart dose (69.1%). The personal “safe” dose to the heart was considered to be 5 Gy (range: 0–40 Gy). The main impediment in offering all breast cancer patients heart-sparing techniques seems to be the fact that these techniques are time/ resource consuming (46.5% of the participants).

Conclusions

Most radiation oncologists believe that there is enough evidence to support heart sparing for breast cancer patients. But translating this belief into a wide practice will need better dosimetric and clinical data on what patients are expected to profit most, specific guidelines for which patients’ heart sparing techniques should be performed, as well as recognition of the time/resource consumption of these techniques.

Valvular Heart Disease in Cancer Patients: Etiology, Diagnosis, and Management

OPINION STATEMENT

Cardiac valvular disease as consequence of radiation and chemotherapy during treatment for malignancy is growing in its awareness. While the overwhelming emphasis in this population has been on the monitoring and preservation of left ventricular systolic function, we are now developing a greater appreciation for the plethora of cardiac sequelae beyond this basic model. To this end many institutions across the country have developed cardio-oncology programs, which are collaborative practices between oncologists and cardiologists in order to minimize a patient's cardiovascular risk while allowing them to receive the necessary treatment for their cancer. These programs also help to recognize early nuanced treatment complications such as valvular heart disease, and provide consultation for the most appropriate course of action. In this article we will discuss the etiology, prevalence, diagnosis, and current treatment options of valvular heart disease as the result of chemotherapy and radiation.

Heart-sparing radiotherapy in patients with breast cancer: What are the techniques used in the clinical routine?: A pattern of practice survey in the German-speaking countries

The aim of this study was to understand the practice of care in German-speaking countries with regard to heart-sparing radiotherapy techniques. Between August 2015 and September 2015, an e-mail/fax-based survey was sent to radiation oncology departments in Germany, Austria, and the German-speaking Switzerland. The questionnaire was divided into 3 chapters: a general chapter on the department, a chapter specific for heart-sparing techniques in patients with breast cancer, and a third chapter on personal beliefs on the topic of heart sparing in patients with breast cancer. A total of 82 radiation oncology departments answered the questionnaire: 16 university clinics and 66 other departments. In general, heart-sparing techniques are being offered by 90.2% of departments for radiation oncology in the German-speaking countries. However, in the clinical routine, 87.7% of institutions use heart-sparing techniques in less than 50% of patients with breast cancer. Heart-sparing techniques are especially provided for patients with left-sided breast cancer (80%), patients after mastectomy (52.5%), and when the mammaria interna lymph drainage vessels are irradiated (41.3%). In 46.3% of departments, there are written internal guidelines for heart sparing in patients with breast cancer. Breathing-adapted radiotherapy is used as the most frequent heart-sparing technique in 64.7% of the institutions, followed by intensity-modulated radiation therapy, which is most frequently used by 22.1%. The only significant difference between university hospitals and other departments was seen for the offering of partial breast irradiation. The most commonly used heart-sparing technique is breathing-adapted radiotherapy, but there is no coherent approach for heart sparing in patients with breast cancer in the German-speaking countries. Overall, all options for cardiac protection/cardiac avoidance have their advantages and disadvantages, with deep inspiration breath-hold radiotherapyhaving the most clear data, which should be the preferred choice when using heart-sparing techniques.

Risk of heart failure in survivors of Hodgkin lymphoma: effects of cardiac exposure to radiation and anthracyclines

Hodgkin lymphoma (HL) survivors treated with radiotherapy and/or chemotherapy are known to have increased risks of heart failure (HF), but a radiation dose-response relationship has not previously been derived. A case-control study, nested in a cohort of 2617 five-year survivors of HL diagnosed before age 51 years during 1965 to 1995, was conducted. Cases (n = 91) had moderate or severe HF as their first cardiovascular diagnosis. Controls (n = 278) were matched to cases on age, sex, and HL diagnosis date. Treatment and follow-up information were abstracted from medical records. Mean heart doses and mean left ventricular doses (MLVD) were estimated by reconstruction of individual treatments on representative computed tomography datasets. Average MLVD was 16.7 Gy for cases and 13.8 Gy for controls (Pdifference = .003). HF rate increased with MLVD: relative to 0 Gy, HF rates following MVLD of 1-15, 16-20, 21-25, and ≥26 Gy were 1.27, 1.65, 3.84, and 4.39, respectively (Ptrend < .001). Anthracycline-containing chemotherapy increased HF rate by a factor of 2.83 (95% CI: 1.43-5.59), and there was no significant interaction with MLVD (Pinteraction = .09). Twenty-five-year cumulative risks of HF following MLVDs of 0-15 Gy, 16-20 Gy, and ≥21 Gy were 4.4%, 6.2%, and 13.3%, respectively, in patients treated without anthracycline-containing chemotherapy, and 11.2%, 15.9%, and 32.9%, respectively, in patients treated with anthracyclines. We have derived quantitative estimates of HF risk in patients treated for HL following radiotherapy with or without anthracycline-containing chemotherapy. Our results enable estimation of HF risk for patients before treatment, during radiotherapy planning, and during follow-up.

Late Cardiac Toxicity After Mediastinal Radiation Therapy for Hodgkin Lymphoma: Contributions of Coronary Artery and Whole Heart Dose-Volume Variables to Risk Prediction

PURPOSE

Mediastinal radiation therapy (RT) for Hodgkin lymphoma (HL) is associated with late cardiotoxicity, but there are limited data to indicate which dosimetric parameters are most valuable for predicting this risk. This study investigated which whole heart dosimetric measurements provide the most information regarding late cardiotoxicity, and whether coronary artery dosimetry was more predictive of this outcome than whole heart dosimetry.

METHODS AND MATERIALS

A random sample of 125 HL patients treated with mediastinal RT was selected, and 3-dimensional cardiac dose-volume data were generated from historical plans using validated methods. Cardiac events were determined by linking patients to population-based datasets of inpatient and same-day hospitalizations and same-day procedures. Variables collected for the whole heart and 3 coronary arteries included the following: Dmean, Dmax, Dmin, dose homogeneity, V5, V10, V20, and V30. Multivariable competing risk regression models were generated for the whole heart and coronary arteries.

RESULTS

There were 44 cardiac events documented, of which 70% were ischemic. The best multivariable model included the following covariates: whole heart Dmean (hazard ratio [HR] 1.09, P=.0083), dose homogeneity (HR 0.94, P=.0034), male sex (HR 2.31, P=.014), and age (HR 1.03, P=.0049). When any adverse cardiac event was the outcome, models using coronary artery variables did not perform better than models using whole heart variables. However, in a subanalysis of ischemic cardiac events only, the model using coronary artery variables was superior to the whole heart model and included the following covariates: age (HR 1.05, P<.001), volume of left anterior descending artery receiving 5 Gy (HR 0.98, P=.003), and volume of left circumflex artery receiving 20 Gy (HR 1.03, P<.001).

CONCLUSION

In addition to higher mean heart dose, increasing inhomogeneity in cardiac dose was associated with a greater risk of late cardiac effects. When all types of cardiotoxicity were evaluated, the whole heart variable model outperformed the coronary artery models. However, when events were limited to ischemic cardiotoxicity, the coronary artery-based model was superior.

Prevention and Monitoring of Cardiac Dysfunction in Survivors of Adult Cancers: American Society of Clinical Oncology Clinical Practice Guideline

Purpose

Cardiac dysfunction is a serious adverse effect of certain cancer-directed therapies that can interfere with the efficacy of treatment, decrease quality of life, or impact the actual survival of the patient with cancer. The purpose of this effort was to develop recommendations for prevention and monitoring of cardiac dysfunction in survivors of adult-onset cancers.

Methods

Recommendations were developed by an expert panel with multidisciplinary representation using a systematic review (1996 to 2016) of meta-analyses, randomized clinical trials, observational studies, and clinical experience. Study quality was assessed using established methods, per study design. The guideline recommendations were crafted in part using the Guidelines Into Decision Support methodology.

Results

A total of 104 studies met eligibility criteria and compose the evidentiary basis for the recommendations. The strength of the recommendations in these guidelines is based on the quality, amount, and consistency of the evidence and the balance between benefits and harms.

Recommendations

It is important for health care providers to initiate the discussion regarding the potential for cardiac dysfunction in individuals in whom the risk is sufficiently high before beginning therapy. Certain higher risk populations of survivors of cancer may benefit from prevention and screening strategies implemented during cancer-directed therapies. Clinical suspicion for cardiac disease should be high and threshold for cardiac evaluation should be low in any survivor who has received potentially cardiotoxic therapy. For certain higher risk survivors of cancer, routine surveillance with cardiac imaging may be warranted after completion of cancer-directed therapy, so that appropriate interventions can be initiated to halt or even reverse the progression of cardiac dysfunction.

A cardiac contouring atlas for radiotherapy

BACKGROUND AND PURPOSE

The heart is a complex anatomical organ and contouring the cardiac substructures is challenging. This study presents a reproducible method for contouring left ventricular and coronary arterial segments on radiotherapy CT-planning scans.

MATERIAL AND METHODS

Segments were defined from cardiology models and agreed by two cardiologists. Reference atlas contours were delineated and written guidelines prepared. Six radiation oncologists tested the atlas. Spatial variation was assessed using the DICE similarity coefficient (DSC) and the directed Hausdorff average distance (d→H,avg). The effect of spatial variation on doses was assessed using six different breast cancer regimens.

RESULTS

The atlas enabled contouring of 15 cardiac segments. Inter-observer contour overlap (mean DSC) was 0.60-0.73 for five left ventricular segments and 0.10-0.53 for ten coronary arterial segments. Inter-observer contour separation (mean d→H,avg) was 1.5-2.2mm for left ventricular segments and 1.3-5.1mm for coronary artery segments. This spatial variation resulted in <1Gy dose variation for most regimens and segments, but 1.2-21.8Gy variation for segments close to a field edge.

CONCLUSIONS

This cardiac atlas enables reproducible contouring of segments of the left ventricle and main coronary arteries to facilitate future studies relating cardiac radiation doses to clinical outcomes.

Cardiac atlas development and validation for automatic segmentation of cardiac substructures

PURPOSE

To develop and validate a set of atlases for auto-contouring cardiac substructures.

METHODS

Eight radiation oncologists manually and independently delineated 15 cardiac substructures from noncontrast CT images of 6 patients by referring to their respective fused contrast CT images. Individual contours were fused together for each structure, edited by 2 physicians, and became atlases to delineate other 6 patients. The auto-delineated contours of the 6 additional patients became templates for manual contouring. These 12 patients with well-defined contours composed the final atlases for multi-atlas segmentation.

RESULTS

The average time for manually contouring the 15 cardiac substructures was about 40min. Inter-observer variability was small for the heart, the chambers, and the aorta compared with that for other structures that were not clearly distinguishable in CT images. The mean dice similarity coefficient and mean surface distance of auto-segmented contours were within one standard deviation of expert contouring variability. Good agreement between auto-segmented and manual contours was observed for the heart, the chambers, and the great vessels. Independent validation on other 19 patients showed reasonable agreement for the heart chambers.

CONCLUSIONS

A set of cardiac atlases was created for auto-contouring from noncontrast CT images. The accuracy of auto-contouring for the heart, chambers, and great vessels was validated for potential clinical use.

Radiation Toxicity to the Cardiovascular System

Radiation therapy is an important component of cancer treatment, and today, it is applied to approximately 50% of malignancies, including valvular, myocardial, pericardial, coronary or peripheral vascular disease, and arrhythmias. An increased clinical suspicion and knowledge of those mechanisms is important to initiate appropriate screening for the optimal diagnosis and treatment. As the number of cancer survivors has been steadily increasing over the last decades, cardio-oncology, an evolving subspecialty of cardiology, will soon play a pivotal role in raising awareness of the increased cardiovascular risk and formulate strategies to optimally manage patients in this unique population.