Radiation-induced heart disease: an update

Cardiac surgery in patients irradiated for Hodgkin's lymphoma

Background/Objectives. Therapy for Hodgkin's lymphoma is disease specific and cannot be compared with treatment for other diseases. It often includes more extensive radiotherapy on the mediastinum than for other malignancies. Cardiac morbidity is known to occur in patients previously irradiated. This study describes the postoperative course after cardiac surgery of patients previously irradiated for Hodgkin's lymphoma.Methods. From January 1990 until June 2008, 12 patients underwent cardiac surgery in the University Medical Center Utrecht after previous irradiation for Hodgkin's lymphoma. Data on radiotherapy, surgery and follow-up were collected retrospectively. The postoperative functional status was assessed by a telephone questionnaire.Results. Atrial fibrillation (33%) and pleural effusion (25%) were the most common postoperative complications. After a mean followup of 2.6+/-2.9 years four patients had died. The remaining patients were all in a favourable New York Heart Association and Canadian Cardiothoracic Society class. The estimated one-, two- and four-year survival rates were 83, 69 and 46% respectively.Conclusion. The early postoperative outcome of cardiac surgery in this population is reasonably good. The long-term results may prove to be disappointing, but the cohort is small. (Neth Heart J 2010;18:61-5.).

Bilateral coronary ostial disease following mediastinal irradiation: a case report

Introduction

Ostial coronary artery disease is rare with a reported incidence of 0.07 to 0.25% in all patients undergoing angiography. It has a strong association with previous mediastinal irradiation, which induces specific histological changes distinct from atherosclerotic lesions. The radiation also affects the myocardium and surrounding structures, which can alter the surgical approach.

Case presentation

We present a case of a 62-year-old female who developed bilateral ostial coronary artery stenosis 32 years following therapeutic radiotherapy for Hodgkin’s disease. She underwent successful coronary artery bypass surgery using a combination of arterial and venous conduits. Postoperatively she developed a clinical picture of diastolic impairment not detected pre-operatively. She was managed appropriately and made a successful recovery.

Conclusions

This case highlights the cardiac pathology associated with mediastinal irradiation, which should be suspected during surgical assessment, especially in long-term survivors. It heightens the surgeon’s awareness so a more thorough evaluation of coronary anatomy, ventricular function and potential conduits is made prior to surgery.

Primary cardiac angiosarcoma: a fatal disease

A 42-year-old man with a cardiac tamponade underwent an urgent pericardiotomy that showed tumoral tissue, covering the surface of the right atrium. The tumor was then partially excised, and the histological examination revealed the presence of a moderately-differentiated angiosarcoma. The patient was then referred to the oncology unit and scheduled for a chemotherapy schedule including Epirubicin (60 mg/m(2), on days 1 and 2) plus Ifosfamide (2000 mg/m(2), on days 1 to 3) and Uromitexan (2000 mg/m(2) at hours 0, 4, 8 after IFO). All drugs were administered every three weeks. After two cycles, a restaging work-up revealed a partial remission. The treatment was continued for another two cycles. A new evaluation by cardiac MRI evidenced a local and distant (lung) progression of disease. The patient died after three months. This paper confirms that cardiac angiosarcoma is a fatal disease, and the prognosis is usually 6-11 months from time of diagnosis.

Effects of multiple doses of ionizing radiation on cytokine expression in rat and human cells

PURPOSE

To determine the effect of daily fractionated irradiation on the expression of growth factors and cytokines in different cardiac and vascular cell types.

MATERIALS AND METHODS

Cell cultures of rat cardiac myocytes, fibroblasts, a rat cardiac microvascular endothelial cell line and human artery endothelial cells were irradiated with doses of 2 Gy, given daily during 5 consecutive days. Twenty-four hours after each fraction, gene expression was determined by competitive or semiquantitative polymerase chain reaction. Protein secretion into culture media was determined by enzyme-linked immunoabsorbant assay.

RESULTS

Of all investigated mRNA levels, transforming growth factor (TGF)-ss1 and fibroblast growth factor (FGF)-2 were slightly upregulated in the rat cardiac endothelial cell line after irradiation. TGF-ss1 protein secretion by these cells was slightly, but non-significantly, elevated. Interleukin 1ss protein levels in myocyte culture media were decreased in control cultures at days 3 and 4 compared with day 2. No significant changes were observed in expression of FGF-2 in either of the four cell types. Moreover, no changes were observed in gene expression of platelet-derived growth factors A, B and interleukin 8 in the human artery endothelial cells.

CONCLUSIONS

Fractionated irradiation leads to minor changes in the expression of specific cytokines in cardiac myocytes, fibroblasts and endothelial cells.

The diagnosis and management of cardiovascular disease in cancer patients

Cardiovascular disease is commonly found in cancer patients. The co-existence of heart disease and cancer in a patient often complicates treatment, because therapy for one disease may negatively affect the outcome of the other disease. In addition, guidelines for the treatment of cardiovascular disease are often based on studies, which exclude patients who have cancer. In this review we will discuss the diagnosis and management of cardiovascular disease in cancer patients. We will focus on cancer-related causes of cardiovascular disease and special treatment options for cardiovascular disease in cancer patients. The cardiac complications of cancer therapy will be discussed according to common syndromes: left ventricular dysfunction, myocardial ischemia, blood pressure changes, thromboembolism, bradyarrhythmias, and prolonged QT interval.

Monitoring for cardiovascular disease in survivors of childhood cancer: report from the Cardiovascular Disease Task Force of the Children's Oncology Group

Curative therapy for childhood cancer has improved significantly in the last 2 decades such that, at present, approximately 80% of all children with cancer are likely to survive > or = 5 years after diagnosis. Prevention, early diagnosis, and treatment of long-term sequelae of therapy have become increasingly more significant as survival rates continue to improve. Cardiovascular disease is a well-recognized cause of increased late morbidity and mortality among survivors of childhood cancer. The Children's Oncology Group Late Effects Committee and Nursing Discipline and Patient Advocacy Committee have recently developed guidelines for follow-up of long-term survivors of pediatric cancer. A multidisciplinary task force critically reviewed the existing literature to evaluate the evidence for the cardiovascular screening recommended by the Children's Oncology Group guidelines. In this review we outline the clinical manifestations of late cardiovascular toxicities, suggest modalities and frequency of monitoring, and address some of the controversial and unresolved issues regarding cardiovascular disease in childhood cancer survivors.

Three-Vessel Coronary Artery Disease, Aortic Stenosis, and Constrictive Pericarditis 27 Years after Chest Radiation Therapy: A Case Report

A patient with a history of Hodgkin's lymphoma presented with recurrent left pleural effusions and dyspnea on exertion 27 years after radiation therapy. Further evaluation disclosed suspected radiation-induced constrictive pericarditis, aortic stenosis and regurgitation, and severe coronary artery disease. He underwent successful 3-vessel coronary artery bypass grafting, aortic valve replacement, and pericardiectomy.

Diastolic dysfunction after mediastinal irradiation

BACKGROUND

Mediastinal irradiation is known to cause cardiac disease, but its effect on left ventricular diastolic function is unknown. The purpose of this study was to determine the prevalence of diastolic dysfunction and its association with prognosis in asymptomatic patients after mediastinal irradiation.

METHODS

We recruited 294 patients who had received at least 35 Gy to the mediastinum for treatment of Hodgkin disease. Each patient underwent resting echocardiography, stress echocardiography, and nuclear scintigraphy. Survival free from cardiac events was determined during 3.2 years of follow-up.

RESULTS

The mean age of the included patients was 42 years, and 49% were male. Adequate measurements of diastolic function were obtained in 282 (97%) patients. Diastolic dysfunction was considered mild in 26 (9%) and moderate in 14 (5%). Exercise-induced ischemia was more common in patients with diastolic dysfunction (23%) than those with normal diastolic function (11%, P = .008). After adjustment for patient demographics, clinical characteristics, and radiation history, patients with diastolic dysfunction had worse event-free survival than patients with normal function (hazard ratio 1.66, 95% CI 1.06-2.4).

CONCLUSIONS

There is a high prevalence of diastolic dysfunction in asymptomatic patients after mediastinal irradiation, and the presence of diastolic dysfunction is associated with stress-induced ischemia and a worse prognosis. Screening with Doppler echocardiography may be helpful in identifying patients at risk for subsequent cardiac events.

Cardiac Morbidity of Adjuvant Radiotherapy for Breast Cancer

Purpose

Adjuvant breast irradiation has been associated with an increase in cardiac mortality, because left-sided breast radiation can produce cardiac damage. The purpose of this study was to determine whether modern adjuvant radiotherapy is associated with increased risk of cardiac morbidity.

Patients and Methods

Data from the Surveillance, Epidemiology, and End Results–Medicare database were used for women who were diagnosed with nonmetastatic breast cancer from 1986 to 1993, had known disease laterality, underwent breast surgery, and received adjuvant radiotherapy. The Cox proportional-hazards model was used to compare patients with left- versus right-sided breast cancer for the end points of hospitalization with the following discharge diagnoses (International Classification of Diseases, 9th Revision codes): ischemic heart disease (410-414, 36.0, and 36.1), valvular heart disease (394-397, 424, 35), congestive heart failure (428, 402.01, 402.11, 402.91, and 425), and conduction abnormalities (426, 427, 37.7-37.8, and 37.94-37.99).

Results

Eight thousand three hundred sixty-three patients had left-sided breast cancer, and 7,907 had right-sided breast cancer. Mean follow-up was 9.5 years (range, 0 to 15 years). There were no significant differences in patients with left- versus right-sided cancers for hospitalization for ischemic heart disease (9.9% v 9.7%), valvular heart disease (2.9% v 2.8%), conduction abnormalities (9.7% v 9.6%), or heart failure (9.7% v 9.7%). The adjusted hazard ratio for left- versus right-sided breast cancer was 1.05 (95% CI, 0.94 to 1.16) for ischemic heart disease, 1.07 (95% CI, 0.89 to 1.30) for valvular heart disease, 1.07 (95% CI, 0.96 to 1.19) for conduction abnormalities, and 1.05 (95% CI, 0.95 to 1.17) for heart failure.

Conclusion

With up to 15 years of follow-up there were no significant differences in cardiac morbidity after radiation for left- versus right-sided breast cancer.

Cardiovascular effects of radiation therapy: practical approach to radiation therapy-induced heart disease

Radiation induced heart diseases (RIHD) are increasingly recognized as more patients who received radiation therapy survive their diseases with improved management of various malignancies. Radiation affects every component of the heart, ranging from subclinical histopathologic changes to overt clinical disease. Pericardial involvement is the most common and includes asymptomatic pericardial effusion and constrictive pericarditis. The diseases involving the myocardium, valvular apparatus, and conduction system are often subclinical. When symptomatic, they are often the harbinger of more lethal, but treatable, radiation-induced coronary artery disease (CAD). Improvements in the modern radiation delivery systems have minimized irradiation of the heart. However, with increased and emerging indications for radiation therapy for various malignancies in the chest, as a part of bone marrow transplantations, and as the main agent of brachytherapy for advanced preexisting CAD, the incidence of RIHD is likely to increase. Appropriate management of RIHD, either overt or occult, must include understanding the natural history of RIHD, recognition of symptoms by careful history, and vigilant search for treatable causes of the RIHD or other diseases that might mimic RIHD. This article focuses on providing practical yet comprehensive clinical information for general internal medicine and cardiology practices.

Long-term medical effects of childhood and adolescent rhabdomyosarcoma: a report from the childhood cancer survivor study

BACKGROUND

This study was conducted to evaluate the incidence of adverse medical conditions and to assess the risk of developing these conditions in a cohort of long-term survivors of rhabdomyosarcoma (RMS) diagnosed before age 21.

PROCEDURE

Using data from the Childhood Cancer Survivor Study (CCSS), we evaluated the incidence of self-reported adverse medical conditions for 606 RMS survivors and 3,701 siblings of cancer survivors. Cancer and treatment data abstracted from medical records were used to evaluate the effects of primary tumor site and combined modality therapy on the risk of developing sequelae in survivors.

RESULTS

The relative risk (RR) for developing sequelae among survivors compared with siblings was greatest within 5 years after diagnosis. RR was elevated more than 5 years after diagnosis for several conditions (RR, 95% CI) as follows: eye impairment (cataract: 7.4, 2.9-18.9; visual disturbances: 3.2, 2.0-5.1; very dry eyes: 2.0, 1.2-3.3), endocrine impairment (growth hormone deficiency: 83.9, 33.0-213.6; hypothyroidism: 6.9, 4.1-11.3; need for medications to induce puberty: 90.4, 30.2-270.5), cardiopulmonary impairment (congestive heart failure: 43.0, 12.7-145.5; angina-like symptoms: 2.0, 1.3-2.9), neurosensory impairment (legal blindness: 9.8, 4.8-20.0; abnormal sensations: 1.5, 1.0-2.2), and neuromotor impairment (repeated seizures: 2.3, 1.2-4.4; motor problems: 3.7, 2.2-6.4; problems chewing or swallowing: 3.8, 1.9-7.5).

CONCLUSIONS

Survivors are at risk for developing sequelae many years after their initial diagnosis and treatment. Continued medical surveillance is necessary to ensure the long-term health and well-being of RMS survivors.

Pathophysiology of anthracycline- and radiation-associated cardiomyopathies: implications for screening and prevention

Great progress has been made in treating childhood cancers over the past 40 years. Along with second malignancies, a major complication of anti-cancer therapies is adverse cardiovascular effects, especially cardiomyopathy and coronary artery disease. The pathophysiology and characteristics of cardiomyopathy associated with radiation therapy and anthracycline therapy are distinctive. We describe each type of cardiomyopathy, along with its risk factors. These distinctive cardiomyopathies require different screening tests. Appropriate screening of the entire cardiovascular system should be performed because radiation and chemotherapy affect the entire system. Prevention recommendations focus on cardiomyopathy and coronary artery disease.

Coronary heart disease after radiotherapy for peptic ulcer disease

PURPOSE

To evaluate the risk of coronary heart disease (CHD) and cerebrovascular disease after radiotherapy (RT) for peptic ulcer disease.

METHODS AND MATERIALS

Peptic ulcer disease patients treated with RT (n = 1859) or by other means (n = 1860) at the University of Chicago Medical Center between 1936 and 1965, were followed through 1997. The observed numbers of cause-specific deaths were compared with the expected numbers from the general population rates. During RT, 5% of the heart was in the treatment field and the remainder of the heart mostly received scattered radiation. A volume-weighted cardiac dose was computed to describe the average tissue dose to the entire organ. We used Cox proportional hazards regression analysis to analyze the CHD and cerebrovascular disease risk associated with RT, adjusting for confounding factors.

RESULTS

Greater than expected CHD mortality was observed among the irradiated patients. The irradiated patients received volume-weighted cardiac doses ranging from 1.6 to 3.9 Gy and the portion of the heart directly in the field received doses of 7.6-18.4 Gy. The CHD risk increased with the cardiac dose (p trend = 0.01). The cerebrovascular disease risk was not associated with the surrogate carotid dose.

CONCLUSION

The excess CHD risk in patients undergoing RT for peptic ulcer disease decades previously indicates the need for long-term follow-up for cardiovascular disease after chest RT.

A systolic murmur is a common presentation of aortic regurgitation detected by echocardiography

BACKGROUND

The finding of aortic regurgitation at a classical examination is a diastolic murmur.

HYPOTHESIS

Aortic regurgitation is more likely to be associated with a systolic than with a diastolic murmur during routine screening by a noncardiologist physician.

METHODS

In all, 243 asymptomatic patients (mean age 42 +/- 10 years) with no known cardiac disease but at risk for aortic valve disease due to prior mediastinal irradiation (> or = 35 Gy) underwent auscultation by a noncardiologist followed by echocardiography. A systolic murmur was considered benign if it was grade < or = II/VI, not holosystolic, was not heard at the apex, did not radiate to the carotids, and was not associated with a diastolic murmur.

RESULTS

Of the patients included, 122 (49%) were male, and 86 (35%) had aortic regurgitation, which was trace in 20 (8%), mild in 52 (21%), and moderate in 14 (6%). A systolic murmur was common in patients with aortic regurgitation, occurring in 12 (86%) with moderate, 26 (50%) with mild, 6 (30%) with trace, and 27 (17%) with no aortic regurgitation (p < 0.0001). The systolic murmurs were classified as benign in 21 (78%) patients with mild and 8 (67%) with moderate aortic regurgitation. Diastolic murmurs were rare, occurring in two (14%) with moderate, two (4%) with mild, and three (2%) with no aortic regurgitation (p=0.15).

CONCLUSIONS

An isolated systolic murmur is a common auscultatory finding by a noncardiologist in patients with moderate or milder aortic regurgitation. A systolic murmur in patients at risk for aortic valve disease should prompt a more thorough physical examination for aortic regurgitation.

β-Radiation for the Creation of Linear Lesions in the Canine Atrium

Background— Creating linear lesions is important for the treatment of arrhythmias such as atrial flutter and fibrillation. Making these lesions with standard radiofrequency catheters can be difficult and may result in charring and thrombosis. The purpose of this study was to evaluate β-radiation as a novel energy source for creating linear myocardial lesions.

Methods and Results— Eight dogs with intact conduction across the cavotricuspid isthmus were studied. The isthmus was irradiated (25 to 50 Gy) with strontium/yttrium-90 delivered via a deflectable 7F catheter (Novoste Corporation). There were no immediate effects, but bidirectional conduction block developed during follow-up studies in 7 of 8 dogs. The dog without conduction block received 25 Gy. After the animals were euthanized, histology revealed transmural, linear areas of fibrosis without any thrombus.

Conclusions— β-Radiation can safely and effectively create linear lesions that are contiguous and nonthrombogenic. This energy source may become an interesting adjunct to radiofrequency for the treatment of atrial flutter and fibrillation.

Expressão da proteína tgfbeta1 em coração irradiado in vivo

OBJETIVO: Avaliar, no coração, por imuno-histoquímica, a localização das proteínas TGFbeta1 latente e TGFbeta1 ativa, se ocorre ativação radioinduzida da proteína TGFbeta1 latente, e a distribuição das fibras colágenas em diversos períodos de tempo após irradiação. MATERIAIS E MÉTODOS: Trinta e dois camundongos isogênicos (C57BL) foram divididos em dois grupos: GI (não irradiado), com 12 animais, e GII (irradiado), com 20 animais. Os animais do GII receberam radiação gama (telecobaltoterapia, 60Co, com rendimento de 0,97 Gy/min., dose única de 7 Gy em corpo inteiro). Os camundongos dos grupos I e II foram sacrificados por estiramento cervical nos períodos de 1, 14, 30 e 90 dias após irradiação. RESULTADOS: Os corações irradiados apresentaram: 1) alterações nucleares e diminuição das estriações das células musculares cardíacas; 2) aumento significante da deposição de fibras colágenas aos 90 dias depois da irradiação; 3) ativação da proteína TGFbeta1 latente em cardiomiócitos e células do conjuntivo depois da irradiação. CONCLUSÃO: Nossos resultados mostram a importância da proteína TGFbeta1 no processo de fibrose cardíaca radioinduzida e sugerem que células do parênquima (cardiomiócitos) e do conjuntivo podem participar deste mecanismo atuando como fontes da proteína TGFbeta1 ativa.

Radiation-induced cardiomyopathy as a function of radiation beam gating to the cardiac cycle

Portions of the heart are often unavoidably included in the primary treatment volume during thoracic radiotherapy, and radiation-induced heart disease has been observed as a treatment-related complication. Such complications have been observed in humans following radiation therapy for Hodgkin's disease and treatment of the left breast for carcinoma. Recent attempts have been made to prevent re-stenosis following angioplasty procedures using external beam irradiation. These attempts were not successful, however, due to the large volume of heart included in the treatment field and subsequent cardiac morbidity. We suggest a mechanism for sparing the heart from radiation damage by synchronizing the radiation beam with the cardiac cycle and delivering radiation only when the heart is in a relatively hypoxic state. We present data from a rat model testing this hypothesis and show that radiation damage to the heart can be altered by synchronizing the radiation beam with the cardiac cycle. This technique may be useful in reducing radiation damage to the heart secondary to treatment for diseases such as Hodgkin's disease and breast cancer.

Asymptomatic cardiac disease following mediastinal irradiation

OBJECTIVES

This study was designed to evaluate the potential benefit of screening previously irradiated patients with echocardiography.

BACKGROUND

Mediastinal irradiation is known to cause cardiac disease. However, the prevalence of asymptomatic cardiac disease and the potential for intervention before symptom development are unknown.

METHODS

We recruited 294 asymptomatic patients (mean age 42 +/- 9 years, 49% men, mean mantle irradiation dose 43 +/- 0.3 Gy) treated with at least 35 Gy to the mediastinum for Hodgkin's disease. After providing written consent, each patient underwent electrocardiography and transthoracic echocardiography. Valvular disease was common and increased with time following irradiation. Patients who had received irradiation more than 20 years before evaluation had significantly more mild or greater aortic regurgitation (60% vs. 4%, p < 0.0001), moderate or greater tricuspid regurgitation (4% vs. 0%, p = 0.06), and aortic stenosis (16% vs. 0%, p = 0.0008) than those who had received irradiation within 10 years. The number needed to screen to detect one candidate for endocarditis prophylaxis was 13 (95% confidence interval [CI] 7 to 44) for patients treated within 10 years and 1.6 (95% CI 1.3 to 1.9) for those treated at least 20 years ago. Compared with the Framingham Heart Study population, mildly reduced left ventricular fractional shortening (<30%) was more common (36% vs. 3%), and age- and gender-adjusted left ventricular mass was lower (90 +/- 27 g/m vs. 117 g/m) in irradiated patients.

CONCLUSIONS

There is a high prevalence of asymptomatic heart disease in general, and aortic valvular disease in particular, following mediastinal irradiation. Screening echocardiography should be considered for patients with a history of mediastinal irradiation.

A combined modality approach to recurrent cardiac sarcoma resulting in a prolonged remission: a case report

We report a case of cardiac fibrosarcoma that was treated with cardiac tumor resection, chemotherapy, cardiac explantation, tumor repeat resection, and autotransplantation followed by external beam irradiation. The patient was able to achieve clinical remission and remained disease free > 2 years after the initial diagnosis. This case report demonstrates that a sustained remission from cardiac sarcoma is possible with an aggressive combined modality approach.

Antioxidants attenuate atherosclerotic plaque development in a balloon-denuded and -radiated hypercholesterolemic rabbit

BACKGROUND

Oxidation of lipoproteins is considered to be a key contributor to atherogenesis. Antioxidants are potential antiatherogenic agents because they can inhibit lipoprotein oxidation. Radiation has been shown to increase oxidative stress leading to increased atherogenesis. This study is designed to test the potential of antioxidants to inhibit atherosclerotic plaque progression in balloon-denuded and -radiated rabbits.

METHODS AND RESULTS

Two groups of New Zealand white rabbits (n=36) were fed with 1% cholesterol diet (control diet) or with 1% cholesterol diet containing a mixture of various antioxidants for 1 week. Iliac arteries in all the animals were balloon denuded and continued to fed with 0.15% cholesterol diet or 0.15% cholesterol diet containing antioxidants (antioxidant diet). Four weeks after balloon denudation one iliac artery in 12 animals from each group was radiated and all the animals were continued to be fed with the same diet. Four weeks after radiation animals were sacrificed and morphometric analysis of iliac arteries (n=12) in nonradiated and radiated animals were performed. Plaque area (PA) in the rabbits that were fed with cholesterol diet is 0.2+/-0.12 mm2, and it is increased by 2.75-fold (P<.05) in the radiated arteries of animals fed with cholesterol diet. Plaque area in the animals fed with antioxidant diet is 50% less then the one in the animals fed with cholesterol diet. Similarly, plaque area in radiated arteries of the animals fed with antioxidant diet is 50% less then the animals fed with cholesterol diet.

CONCLUSION

Antioxidants significantly attenuate atherosclerotic plaque progression in balloon-injured and -radiated hypercholesterolemic rabbits.

Radiation-associated cardiovascular disease

As the number of cancer survivors grows because of advances in therapy, it has become more important to understand the long-term complications of these treatments. This article presents the current knowledge of adverse cardiovascular effects of radiotherapy to the chest. Emphasis is on clinical presentations, recommendations for follow-up, and treatment of patients previously exposed to irradiation. Medline literature searches were performed, and abstracts related to this topic from oncology and cardiology meetings were reviewed. Potential adverse effects of mediastinal irradiation are numerous and can include coronary artery disease, pericarditis, cardiomyopathy, valvular disease and conduction abnormalities. Damage appears to be related to dose, volume and technique of chest irradiation. Effects may initially present as subclinical abnormalities on screening tests or as catastrophic clinical events. Estimates of relative risk of fatal cardiovascular events after mediastinal irradiation for Hodgkin's disease ranges between 2.2 and 7.2 and after irradiation for left-sided breast cancer from 1.0 to 2.2. Risk is life long, and absolute risk appears to increase with length of time since exposure. Radiation-associated cardiovascular toxicity may in fact be progressive. Long-term cardiac follow-up of these patients is therefore essential, and the range of appropriate cardiac screening is discussed, although no specific, evidence-based screening regimen was found in the literature.

Pathophysiological effects of radiation on atherosclerosis development and progression, and the incidence of cardiovascular complications

Radiation therapy while important in the management of several diseases, is implicated in the causation of atherosclerosis and other cardiovascular complications. Cancer and atherosclerosis go through the same stages of initiation, promotion, and complication, beginning with a mutation in a single cell. Clinical observations before the 1960s lead to the belief that the heart is relatively resistant to the doses of radiation used in radiotherapy. Subsequently, it was discovered that the heart is sensitive to radiation and many cardiac structures may be damaged by radiation exposure. A significantly higher risk of death due to ischemic heart disease has been reported for patients treated with radiation for Hodgkin's disease and breast cancer. Certain cytokines and growth factors, such as TGF-beta1 and IL-1 beta, may stimulate radiation-induced endothelial proliferation, fibroblast proliferation, collagen deposition, and fibrosis leading to advanced lesions of atherosclerosis. The treatment for radiation-induced ischemic heart disease includes conventional pharmacological therapy, balloon angioplasty, and bypass surgery. Endovascular irradiation has been shown to be effective in reducing restenosis-like response to balloon-catheter injury in animal models. Caution must be exercised when radiation therapy is combined with doxorubicin because there appears to be a synergistic toxic effect on the myocardium. Damage to endothelial cells is a central event in the pathogenesis of damage to the coronary arteries. Certain growth factors that interfere with the apoptotic pathway may provide new therapeutic strategies for reducing the risk of radiation-induced damage to the heart. Exposure to low level occupational or environmental radiation appears to pose no undue risk of atherosclerosis development or cardiovascular mortality. But, other radiation-induced processes such as the bystander effects, abscopal effects, hormesis, and individual variations in radiosensitivity may be important in certain circumstances.

The clinical value of nuclear medicine in the assessment of irradiation-induced and anthracycline-associated cardiac damage

Two groups of patients, those treated for Hodgkin's disease and breast cancer, are particularly at risk of developing late myocardial damage, since radiotherapy (RT) techniques for both patient groups may include (large) parts of the heart, and adjuvant systemic therapy is frequently administered to these patients, in particular anthracycline-containing chemotherapy. Available literature on the monitoring and prediction of RT-induced and anthracycline-associated cardiac damage using nuclear medicine techniques is presented. Based on relevant studies, the risk of overall cardiac disease post-RT and overt congestive heart failure during anthracycline-containing chemotherapy is probably low. Conventional nuclear medicine imaging, i.e. myocardial perfusion scintigraphy, may be of complementary use to echocardiographical evaluation for routine follow-up after RT with modern techniques, in a subgroup of patients with known cardiovascular risk factors. Left ventricle ejection fraction (LVEF) measurements, as assessed by radionuclide angiography for the monitoring of anthracycline-associated cardiac injury, are not very sensitive and early detection will probably be enhanced by combining LVEF measurements with other cardiac function parameters. Also, it may be expected that nuclear medicine techniques using molecular radioligands will constitute an essential future step in the evaluation of subclinical cardiac injury afforded by the combined effect of RT and cardiotoxic chemotherapy.

Long-term follow-up after total lymphoid irradiation in pediatric heart transplant recipients

BACKGROUND

Total lymphoid irradiation (TLI) is used to treat recurrent allograft rejection. Short-term success and complication rates have been reported in pediatric and adult cardiac transplant populations. We report the long-term efficacy and safety of TLI in treating intractable rejection in pediatric patients.

METHODS

Eight pediatric patients were treated with TLI (7 for recurrent rejection, 1 for risk of medication non-compliance). Therapy consisted of a mid-plane dose of 8 Gy administered with a 6-MeV linear accelerator using an anterior-posterior opposed technique. We reviewed outcomes for a total of 40 patient-years of follow-up.

RESULTS

We encountered rejection (>Grade 2 by International Society for Heart and Lung Transplantation criteria) in 56.7% +/- 34.7% of biopsies performed within 90 days before TLI. Rejection rates dropped to 3.1% +/- 8.8% within the first 90 days (p < 0.005) after therapy and remained low at 5.6% +/- 1.3% (p < 0.05) during the first year after completion of TLI. Median time from TLI to the first subsequent rejection episode was 305 days (range, 77-1,920 days). Long-term follow-up (>3 years) of 5 patients demonstrated a continuing low incidence of rejection. Non-Hodgkin's lymphoma was diagnosed in 1 of 8 patients, graft coronary artery disease in 4 of 8 patients, and restrictive cardiomyopathy in 1 of 8 patients after TLI.

CONCLUSIONS

Total lymphoid irradiation is an effective treatment for recurrent rejection and has short- and long-term efficacy. Morbid events may include cancer, graft coronary artery disease, and restrictive cardiomyopathy.

Partial irradiation of the heart

Radiation-induced heart disease (RIHD) includes pericarditis, ischemic heart disease, and myocardial infarction and leads in some cases to fatal complications. It has been shown that the increased survival due to radiotherapy could be negated by excess deaths from RIHD in breast cancer radiotherapy for left-sided tumors. Subclinical effects following irradiation have been detected in several studies both of breast cancer and Hodgkin's irradiation. The dose-volume response relationships describing cardiac complications have been studied for pericarditis and cardiac mortality by means of biologic models, including the well-known Lyman-Kutcher-Burman (LKB) model and Källman's relative seriality model. Studies by Martel and coworkers on pericarditis and by Gagliardi and coworkers on cardiac mortality are reviewed. The anatomical and functional definition of the heart represents a key issue in modeling, as it affects strongly the dosimetrical data to be used as input data in the models. Several treatment strategies to decrease heart irradiation, based on models and/or based on dose-distribution evaluations, are reviewed. It is concluded that left-sided breast cancer patients should always be 3-dimensional (3D) dose planned.

Prognostic role of pericardial fluid cytology in cardiac tamponade associated with non-small cell lung cancer

BACKGROUND AND STUDY OBJECTIVES

Cardiac tamponade is a life-threatening complication of non-small cell lung cancer (NSCLC). Malignant pericardial effusion signifies advanced disease, but the significance of a negative pericardial fluid cytology in patients with advanced lung cancer is still controversial. The differential diagnosis of cytology-negative pericardial effusion is difficult and sometimes impossible. The purpose of this study is to determine the prognostic role of pericardial fluid cytology in patients with NSCLC and cardiac tamponade.

DESIGN

Retrospective review of patients with concurrent NSCLC and cardiac tamponade over a 10-year period.

METHODS AND RESULTS

Eighty-two patients were included in this study. Pericardial fluid cytology was positive in 60 patients and negative in 22 patients. The overall median survival was 74.5 days, and 1-year survival was 7.3%, with no survival difference between the two groups (p = 0.2506). However, there was a significant survival difference after different treatment strategies. Patients receiving systemic chemotherapy survived longer than those receiving local therapy (p<0.001), and these patients, in turn, survived longer than those receiving supportive treatment (p<0.001).

CONCLUSIONS

When patients have concurrent advanced NSCLC and cardiac tamponade, the most likely cause of the pericardial effusion is the cancer itself, regardless of the results of the cytologic examination. Our results suggest that systemic chemotherapy might prolong survival in such patients, but further prospective, randomized study is necessary.

Cardiac systolic function before and after hematopoietic stem cell transplantation

In order to examine the effect of hematopoietic stem cell transplantation (HSCT) on cardiac systolic function, we measured left ventricular ejection fraction (LVEF) by radioventriculography (RVG) before and after the transplantation procedure. One hundred and forty-eight patients were examined, 96 undergoing allogeneic grafting and 52 autologous. Fifty patients had CML, 48 AML, 21 ALL, 18 multiple myeloma and 11 breast cancer. The second RVG examination was performed 22 to 227 days (median 60 days) after HSCT. The mean LVEF value in the whole patient group was 60.2% (range 39-81%) before and 61.1% (35-86%) after transplantation. Patients with CML had significantly higher LVEF before transplantation than patients with acute leukemia (P = 0.007) and multiple myeloma (P = 0.005). No significant changes in mean LVEF between the pre- and post-transplant measurements were seen in any of the diagnostic subgroups or in allogeneic or autologous recipients. None of the 148 patients in the study has shown any signs of clinical heart failure at 2, 5 to 10 years follow-up. Patients who had received anthracyclines in the previous treatment had significantly lower LVEF before transplantation but showed no increased risk of decline in cardiac function. In conclusion, the HSCT procedure does not seem to affect myocardial function 1-7 months after transplantation.

Cardiac disease late after chest radiotherapy for Hodgkin's disease: a case report

This report presents a case of occult constrictive pericarditis and mitral valve insufficiency following chest radiotherapy. A 44-year-old man had received radiotherapy for the treatment of Hodgkin's disease 8 years ago. At age 40 years, effusive pericarditis occurred and he was treated with intrapericardial drainage. Biopsy revealed a fibrotic and thickened pericardium. He developed congestive heart failure 3 years later. The patient was found to have occult constrictive pericarditis and mitral valve insufficiency. He underwent mitral valve replacement, tricuspid annul plasty, and pericardiectomy. Although there is the benefit of cure for the Hodgkin's disease, the prognosis after treatment is affected by radiotherapy-induced heart disease. After radiotherapy of the chest and mediastinum, long-term cardiological follow-up is recommended in order to detecting patients with radiation-induced heart disease, such as the present case.

Theoretical assessment of late cardiac complication from endovascular brachytherapy for restenosis prevention

PURPOSE

In this study, a theoretical assessment of late cardiac complication from endovascular brachytherapy is performed using the integrated logistic model.

MATERIALS AND METHODS

Calculation were performed for various lengths of Ir-192 sources using alpha/beta = 3.2 for the endpoint of chronic ischemia, TD50/5 = 7,000 cGy, and TD5/5 = 5,000 cGy. The dose distribution over a standard heart was divided into volume elements with uniform dose (dose-volume histogram). Using linear-quadratic equation, the dose in each of the volume elements was converted into dose equivalent to standard fractionation external beam irradiation. The normal tissue complication probability (NTCP) for each volume element was calculated and combined together to arrive at the cumulative risk of late cardiac complication. The NTCP was plotted against the dose prescribed at 2-mm radial distance for four treatment lengths.

RESULTS

(1) The overall risk of late cardiac toxicity (chronic ischemia within 5 years) was estimated to be less than 1% for current clinical trials using Ir-192. (2) There is a volume effect with higher risk for larger irradiated volume, which can come from longer treatment time, the same dose prescribed at a greater radial distance, and a longer source train. (3) The NTCP vs. dose demonstrates a sigmoidal relationship. There is a threshold dose (about 500 cGy), below which the risk is minimal; the gradient of the curve is greater for longer treatment length.

CONCLUSION

If the prediction from this model is validated with clinical data, it will contribute to guidelines for dose prescription, dose escalation, evaluation of new source design, and multivessel treatment.

Effectiveness of fractionated external beam radiation in the inhibition of vascular restenosis

BACKGROUND

From the clinical oncologic experience, fractionation of the radiation dose offers a better therapeutic window, both with respect to effectiveness and unwanted side effects. Thus, we undertook a pilot study in a rodent model, using a single dose of 15 Gy compared with fractionation schedules of 5 or 10 daily applications of 3 Gy.

MATERIALS AND METHODS

Using a previously described rat angioplasty model, animals were randomly assigned to one of four groups: unilateral balloon injury, sham irradiation; unilateral balloon injury, bilateral 15 Gy single dose irradiation; unilateral balloon injury, bilateral 3 Gy x 5 daily fractions; or unilateral balloon injury, bilateral 3 Gy x 10 daily fractions.

RESULTS AND CONCLUSIONS

All three radiation groups demonstrated a clear inhibition of neointimal hyperplasia. We therefore offer evidence for the effectiveness of fractionated radiation as a means to inhibit vascular restenosis in a rat carotid model. However, the 3 Gy x 5 schedule was less effective than either the 3 Gy x 10 schedule or the 15 Gy single dose. This study must be repeated using longer time points to provide proof of principle.

Ionizing radiation accelerates aortic lesion formation in fat-fed mice via SOD-inhibitable processes

Ionizing radiation promotes formation of reactive oxygen species, including the superoxide anion (O2-). To evaluate whether O2- or O2--mediated perturbations may contribute to the known atherogenic effects of radiation, we examined aortic lesion formation in irradiated C57BL/6 mice and evaluated the effects of CuZn-superoxide dismutase (CuZn-SOD) overexpression. Ten-week-old mice were exposed to a 2-, 4-, or 8-Gy dose of 250-keV x-rays to the upper thorax and then placed on a high-fat diet for 18 weeks. Based on quantitative lipid staining of serial sections of the proximal aorta, mean lesion area was increased with increasing radiation dose and was 3-fold greater in 8-Gy-irradiated than sham-irradiated mice (7800+/-2140 versus 2635+/-709 micrometer(2), P<0.05). These effects were absolutely dependent on a high-fat diet, which had to be introduced within 1 to 2 weeks of the radiation exposure, suggesting the early involvement of atherogenic lipoproteins that were elevated in response to the diet. The importance of radiation-induced oxidative stress was supported by the observation of a 2-fold lower mean lesion area in irradiated CuZn-SOD transgenic mice than in their irradiated, nontransgenic littermates (3026+/-1590 versus 6102+/-1834 micrometer(2), P<0.05). Lucigenin-enhanced chemiluminescence, used as an index of aortic O2- concentrations, was significantly elevated in the postradiation period, and this response was reduced in CuZn-SOD transgenics. On the basis of these results, we propose that radiation may be a useful tool for initiating oxidative or redox-regulated events that promote atherogenesis and for testing the antiatherogenic properties of antioxidants.

Surveillance for stage I testicular seminoma. Is it a good option?

Postorchidectomy treatment options in patients with stage I seminoma include surveillance (reserving treatment for patients who relapse), adjuvant radiation therapy (RT), and adjuvant chemotherapy. Adjuvant retroperitoneal RT remains the treatment of choice in most centers; however, the success of surveillance in stage I nonseminomatous germ cell testis tumors, the establishment of curative chemotherapy for advanced disease, and the improvements in CT have led to re-examination of the standard treatment approach. The available data from the surveillance and adjuvant RT series suggest that almost 100% of patients with stage I testicular seminoma are cured, whichever approach is chosen. This article presents an overview of the available information on all treatment options, the pros and cons of each approach, and indications for where surveillance fits into the armamentarium of clinicians dealing with this disease.

Long-term cardiac morbidity and mortality in a randomized trial of pre- and postoperative radiation therapy versus surgery alone in primary breast cancer

BACKGROUND AND PURPOSE

Some types of radiation therapy have been associated with an increased risk of cardiac mortality and morbidity in patients with early-stage breast cancer. A relationship has been observed between cardiac radiation dose-volume and the level of excess risk of cardiac mortality. However, relatively few data are available on the morbidity from myocardial infarction associated with adjuvant radiotherapy.

PATIENTS AND METHODS

From 1971 to 1976, a total of 960 patients with operable breast cancer were randomly allocated to preoperative radiation therapy, postoperative radiation therapy or to surgery alone. A previous analysis of the cardiac dose-volumes with the treatment techniques used in the trial indicated that the irradiated patients could roughly be divided into three groups. Information on the number of myocardial infarctions was obtained through computerized record linkage with a population-based registry of myocardial infarctions in Stockholm County. Information on cause-specific mortality was obtained from the Swedish Cause-of-Death Registry. The median follow-up was 20 years (range 17-23 years).

RESULTS

A total of 58 patients developed an acute myocardial infarction during the period of follow-up. The number of myocardial infarction cases was not significantly different between the three treatment groups. When analyzed according to estimated cardiac radiation dose-volumes, patients in the highest dose-volume subgroup exhibited a hazard of myocardial infarction of 1.3 (95% CI 0.7-2.6) relative to that of the surgical controls, whereas the corresponding relative hazard for the intermediate and low dose-volume subgroups was below unity. Data on death due to cardiovascular disease showed that patients in the high dose-volume group exhibited a hazard of 2.0 (95% CI 1.0-3.9, P = 0.04) relative to that of the surgical controls. Concerning death due to ischemic heart disease, the relative hazard for the same subgroup was 2.5 (95% CI 1.1-5.7, P = 0.03). The difference between the groups was established after 4-5 years. The cumulative incidence curves continued to diverge up to about 10-12 years. No further divergence appeared after 12 years, but the number of events was low.

CONCLUSIONS

This analysis confirms and extends previous results from the trial. Cardiac mortality was positively correlated with the cardiac dose-volume. Patients receiving high dose-volumes exhibited an increased mortality of ischemic heart disease, but not of myocardial infarction, which implies another mechanism, e.g. radiation-induced microvascular damage to the heart.

Radiation-induced ischemic heart disease in breast cancer--a review

It is well established that adjuvant radiotherapy (RT) reduces loco-regional recurrences in breast cancer. The effect on overall survival, on the other hand, is a much-debated issue. Some old trials with a long follow-up as well as the first report on the overview of the randomized RT trials initiated before 1975 showed a reduced survival among irradiated patients compared with the surgical controls. In the update of the overview this proved to be due to cardiac deaths. In two more recent studies, adjuvant RT in the postmastectomy setting improved the survival of node-positive premenopausal patients who were also treated with chemotherapy. In one of these trials it was indicated that cardiac mortality was not increased. There are few data concerning the cardiac side effects of RT after conservative surgery. Some studies suggest that radiation-induced heart disease may be a potential problem also among these patients. Therefore, the search for both the causes of radiation-induced heart disease and preventive measures is crucial issues in breast cancer radiation oncology.