Cardiac Morbidity of Adjuvant Radiotherapy for Breast Cancer

Modern Radiation Therapy and Cardiac Outcomes in Breast Cancer

PURPOSE

Adjuvant radiation therapy, which has proven benefit against breast cancer, has historically been associated with an increased incidence of ischemic heart disease. Modern techniques have reduced this risk, but a detailed evaluation has not recently been conducted. The present study evaluated the effect of current radiation practices on ischemia-related cardiac events and procedures in a population-based study of older women with nonmetastatic breast cancer.

METHODS AND MATERIALS

A total of 29,102 patients diagnosed from 2000 to 2009 were identified from the Surveillance, Epidemiology, and End Results-Medicare database. Medicare claims were used to identify the radiation therapy and cardiac outcomes. Competing risk models were used to assess the effect of radiation on these outcomes.

RESULTS

Patients with left-sided breast cancer had a small increase in their risk of percutaneous coronary intervention (PCI) after radiation therapy-the 10-year cumulative incidence for these patients was 5.5% (95% confidence interval [CI] 4.9%-6.2%) and 4.5% (95% CI 4.0%-5.0%) for right-sided patients. This risk was limited to women with previous cardiac disease. For patients who underwent PCI, those with left-sided breast cancer had a significantly increased risk of cardiac mortality with a subdistribution hazard ratio of 2.02 (95% CI 1.23-3.34). No other outcome, including cardiac mortality for the entire cohort, showed a significant relationship with tumor laterality.

CONCLUSIONS

For women with a history of cardiac disease, those with left-sided breast cancer who underwent radiation therapy had increased rates of PCI and a survival decrement if treated with PCI. The results of the present study could help cardiologists and radiation oncologists better stratify patients who need more aggressive cardioprotective techniques.

Long-term outcomes of ductal carcinoma in situ of the breast: a systematic review, meta-analysis and meta-regression analysis

BACKGROUND

To summarize data on long-term ipsilateral local recurrence (LR) and breast cancer death rate (BCDR) for patients with ductal carcinoma in situ (DCIS) who received different treatments.

METHODS

Systematic review and study-level meta-analysis of prospective (n = 5) and retrospective (n = 21) studies of patients with pure DCIS and with median or mean follow-up time of ≥10 years. Meta-regression was performed to assess and adjust for effects of potential confounders - the average age of women, period of initial treatment, and of bias - follow-up duration on recurrence- and death-rates in each treatment group. LR and BCDR rates by local treatment used were reported. Outside of randomized trials, remaining studies were likely to have tailored patient treatment according to the clinical situation.

RESULTS

Nine thousand four hundred and four DCIS cases in 9391 patients with 10-year follow-up were included. The adjusted meta-regression LR rate for mastectomy was 2.6 % (95 % CI, 0.8-4.5); breast-conserving surgery with radiotherapy (RT), 13.6 % (95 % CI, 9.8-17.4); breast-conserving surgery without RT, 25.5 % (95 % CI, 18.1-32.9); and biopsy-only (residual predominately low-grade DCIS following inadequate excision), 27.8 % (95 % CI, 8.4-47.1). RT + tamoxifen (TAM) in conservation surgery (CS) patients resulted in lower LR compared to one or no adjuvant treatments: LR rate for CS + RT + TAM, 9.7 %; CS + RT(no TAM), 14.1 %; CS + TAM(no RT), 24.7 %; CS(alone), 25.1 % (linear trend for treatment P < 0.0001). Compared to CS + RT + TAM, a significantly higher invasive LR was observed for CS(alone), odds ratio (OR) 2.61 (P < 0.0001); CS + TAM(no RT), OR 2.52 (P = 0.001); CS + RT(no TAM), OR 1.59 (P = 0.022). BCDR was similar for mastectomy, breast-conserving surgery with or without RT (1.3-2.0 %) and non-significantly higher for biopsy-only (2.7 %). Additionally, the 15-year follow-up was reported where all like-studies had ≥ 15-year data sets; the biopsy-only patients had a meta-analysed total LR rate of 40.2 % and the invasive LR rate was 28.1 %. The biopsy-only patients had a ≥ 15-year BCDR (that included women with metastatic disease) of 17.9 %; the ≥ 15-year BCDR was 55.2 % for those with invasive LR.

CONCLUSIONS

More local intervention was associated with greater local control for patients with DCIS at long-term follow-up. For patients undergoing breast-conservation, invasive LR was significantly lower when two rather than one adjuvant treatment modalities were given.

Late cardiac morbidity of adjuvant radiotherapy for early breast cancer - A population-based study

PURPOSE

The purpose of this study was to assess the long-term cardiac morbidity and mortality after breast irradiation using contemporary irradiation techniques.

METHODS

We used the Catastrophic Illness dataset from the National Health Insurance Research Database to explore the possible association between late cardiotoxicity and women with early breast cancer treated with breast conservation therapy from 2000 to 2010. The Cox proportional-hazards model was used to compare breast cancer patients who received adjuvant radiotherapy versus without adjuvant radiotherapy for the end points with the following primary diagnoses (International Classification of Diseases, 9th Revision codes): ischemic heart disease (410-414, 36.0, 36.1), valvular heart disease (394-397, 424, 35), congestive heart failure (428, 402.01, 402.11, 402.91), and conduction abnormalities (426, 37.7-37.8, 37.94-37.99).

RESULTS

Three hundred and thirty patients received adjuvant radiotherapy and 4802 patients did not receive radiotherapy. Median follow-up was 3.5 years. There was no difference in overall morbidity and mortality from any cardiac cause (p=0.13) in breast cancer patients who received adjuvant radiotherapy versus without radiotherapy by using modern radiotherapy techniques.

CONCLUSION

There were no significant differences in cardiac morbidity and mortality after radiotherapy for breast cancer with a 9-year follow-up period in our population.

Contemporary Breast Radiotherapy and Cardiac Toxicity

Long-term cardiac effects are an important component of survivorship after breast radiotherapy. The pathophysiology of cardiotoxicity, history of breast radiotherapy, current methods of cardiac avoidance, modern outcomes, context of historical outcomes, quantifying cardiac effects, and future directions are reviewed in this article. Radiation-induced oxidative stress induces proinflammatory cytokines and is a process that potentiates late effects of fibrosis and intimal proliferation in endothelial vasculature. Breast radiation therapy has changed substantially in recent decades. Several modern technologies exist to improve cardiac avoidance such as deep inspiration breath hold, gating, accelerated partial breast irradiation, and use of modern 3-dimensional planning. Modern outcomes may vary notably from historical long-term cardiac outcomes given the differences in cardiac dose with modern techniques. Methods of quantifying radiation-related cardiotoxicity that correlate with future cardiac risks are needed with current data exploring techniques such as measuring computed tomography coronary artery calcium score, single-photon emission computed tomography imaging, and biomarkers. Placing historical data, dosimetric correlations, and relative cardiac risk in context are key when weighing the benefits of radiotherapy in breast cancer control and survival. Estimating present day cardiac risk in the modern treatment era includes challenges in length of follow-up and the use of confounding cardiotoxic agents such as evolving systemic chemotherapy and targeted therapies. Future directions in both multidisciplinary management and advancing technology in radiation oncology may provide further improvements in patient risk reduction and breast cancer survivorship.

Diastolic Dysfunction Occurs Early in HER2-Positive Breast Cancer Patients Treated Concurrently With Radiation Therapy and Trastuzumab

BACKGROUND

Left ventricular ejection fraction (LVEF) is used routinely to monitor cardiac dysfunction associated with breast cancer treatment. In this study the prevalence of early left ventricular diastolic dysfunction (LVDD) and its relationship to the dose-volume of the heart irradiated were evaluated in HER2-positive breast cancer patients undergoing concurrent trastuzumab and adjuvant radiotherapy (RT).

MATERIALS AND METHODS

Data from 40 breast cancer patients treated with concurrent trastuzumab and left-sided adjuvant RT between September 2011 and October 2012 were collected prospectively. For comparison, 32 patients treated with concurrent trastuzumab and right-sided adjuvant RT and 71 patients treated with left-sided RT alone were collected retrospectively. Echocardiography was obtained before RT, immediately following RT, and 3 and 6 months after RT. Doses to the heart and left ventricle (LV) were quantified.

RESULTS

Prior to RT with concurrent trastuzumab, 11 of 29 (left) and 8 of 25 (right) patients with normal baseline left ventricular diastolic function (LVDF) developed LVDD. In patients receiving left-sided RT alone, 12 of 61 patients with normal baseline LVDF developed LVDD. Dmean, D15-D40, D60-D70, and V3-V10 of the LV were significantly higher in patients who developed LVDD after concurrent trastuzumab and left-sided RT. In contrast, only two patients developed grade 1 LVEF decrease after both concurrent treatment and left-sided RT alone.

CONCLUSION

Changes in LVDF compared with LVEF are more sensitive for early detection of cardiotoxicity. The dose-volume of the heart contributes significantly to the risk of LVDD in patients with left-sided breast cancer treated concurrently with trastuzumab.

IMPLICATIONS FOR PRACTICE

Abnormalities in diastolic function are more sensitive than changes in the left ventricular ejection fraction for detecting acute cardiotoxicity and are related to the dose-volume of the heart irradiated in patients with left-sided breast cancer receiving radiotherapy concurrently with trastuzumab. This result highlights the importance of decreasing the dose-volume of heart irradiated as a protective strategy in the treatment setting of concurrent trastuzumab and radiotherapy. Diastolic dysfunction may serve as a more sensitive tool for the early detection of cardiac damage and should be incorporated as a routine parameter in the functional monitoring of cardiotoxicity.

Comparison of doses and NTCP to risk organs with enhanced inspiration gating and free breathing for left-sided breast cancer radiotherapy using the AAA algorithm

Background

The purpose of this study was to investigate the potential dose reduction to the heart, left anterior descending (LAD) coronary artery and the ipsilateral lung for patients treated with tangential and locoregional radiotherapy for left-sided breast cancer with enhanced inspiration gating (EIG) compared to free breathing (FB) using the AAA algorithm. The radiobiological implication of such dose sparing was also investigated.

Methods

Thirty-two patients, who received tangential or locoregional adjuvant radiotherapy with EIG for left-sided breast cancer, were retrospectively enrolled in this study. Each patient was CT-scanned during FB and EIG. Similar treatment plans, with comparable target coverage, were created in the two CT-sets using the AAA algorithm. Further, the probability of radiation induced cardiac mortality and pneumonitis were calculated using NTCP models.

Results

For tangential treatment, the median V_25Gy for the heart and LAD was decreased for EIG from 2.2% to 0.2% and 40.2% to 0.1% (p < 0.001), respectively, whereas there was no significant difference in V_20Gy for the ipsilateral lung (p = 0.109). For locoregional treatment, the median V_25Gy for the heart and LAD was decreased for EIG from 3.3% to 0.2% and 51.4% to 5.1% (p < 0.001), respectively, and the median ipsilateral lung V_20Gy decreased from 27.0% for FB to 21.5% (p = 0.020) for EIG. The median excess cardiac mortality probability decreased from 0.49% for FB to 0.02% for EIG (p < 0.001) for tangential treatment and from 0.75% to 0.02% (p < 0.001) for locoregional treatment. There was no significant difference in risk of radiation pneumonitis for tangential treatment (p = 0.179) whereas it decreased for locoregional treatment from 6.82% for FB to 3.17% for EIG (p = 0.004).

Conclusions

In this study the AAA algorithm was used for dose calculation to the heart, LAD and left lung when comparing the EIG and FB techniques for tangential and locoregional radiotherapy of breast cancer patients. The results support the dose and NTCP reductions reported in previous studies where dose calculations were performed using the pencil beam algorithm.

Operable breast cancer of the inner hemisphere is associated with poor survival

Purpose

This study investigated the clinicopathological features of operable breast cancer lesions located in different hemispheres of the breast and determined related survival outcomes.

Methods

Data from 5,330 patients with invasive ductal carcinoma were retrospectively analyzed based on tumor location.

Results

The median follow-up time was 68 months (range, 18-176 months). Patients with breast cancer located in the outer hemisphere of the breast had lesions with more advanced nodal stages and more frequently received adjuvant chemotherapy than patients with breast cancer in the inner hemisphere. The 5-year disease-free survival (DFS) rates of patients with tumors located in outer versus inner hemispheres were 81.5% and 77.0%, respectively (p=0.004); the overall survival (OS) rates were 90.7% and 88.8%, respectively (p<0.001). The association between tumor location and the 5-year DFS rate was most apparent in node-positive patients (73.1% vs. 65.8% for outer vs. inner hemisphere lesions, p<0.001) and in patients with primary tumors greater than 2 cm in diameter (78.2% vs. 72.3%, p=0.002). Multivariate analysis showed that tumor location was an independent predictor of DFS (hazard ratio [HR], 1.23; p=0.002) and OS (HR, 1.28; p=0.006). There were no significant differences in 5-year DFS or OS rates between patients with outer versus inner hemisphere tumors when internal mammary node irradiation was performed.

Conclusion

This study demonstrated that tumor location was an independent prognostic factor for operable breast cancer. Internal mammary node irradiation is recommended for patients with breast cancer of the inner hemisphere and positive axillary lymph nodes or large primary tumors.

Long-term cardiac abnormalities after cranial radiotherapy in childhood cancer survivors

BACKGROUND

Cardiac morbidity is an important late effect in long-term childhood cancer survivors (CCS) treated with cardiotoxic agents or radiotherapy (RT) on the chest. However, there is limited data on the long-term cardiac sequelae in CCS who only received cranial RT. We hypothesized that cranial RT might negatively influence cardiac structure and function.

METHODS AND RESULTS

We studied 13 CCS [mean age 30.8 (18.1-39.3) years, 7 males] who received RT only on the head for a cranial tumor and 36 age- and sex-matched healthy sibling controls. Echocardiographic follow-up was performed at median 21.7 (12.6-30.8) years after diagnosis. CCS had lower indexed diastolic LV volumes [56.0 (31.4-68.3) vs. 60.5 (41.9-94.3) mL/m(2), p = 0.024]. CCS also had reduced LV systolic and diastolic function, reflected by lower systolic LV myocardial velocities (5.3 ± 0.9 vs. 7.1 ± 1.7 cm/s, p = 0.001) and longitudinal deformation (- 17.3 ± 3.1 vs. - 20.7 ± 2.0%, p < 0.001), as well as lower diastolic LV myocardial velocities (- 10.7 ± 1.7 vs. - 12.2 ± 1.5 cm/s, p = 0.006) and deformation speed (1.1 ± 0.3 vs. 1.5 ± 0.2 1/s, p = 0.005). Additionally, in CCS insulin-like growth factor levels [15.4 (9.2-34.6) vs. 24.4 (14.8-55.5) nmol/L, p = 0.007] were lower.

CONCLUSION

Cranial RT in CCS is associated with smaller cardiac volumes and reduced systolic and diastolic LV function. This off target effect of RT might be related to lower insulin-like growth factor levels.

Dosimetric comparison of the simultaneous integrated boost in whole-breast irradiation after breast-conserving surgery: IMRT, IMRT plus an electron boost and VMAT

Objectives

To compare the target volume coverage and doses to organs at risks (OARs) using three techniques that simultaneous integrated boost (SIB) in whole-breast irradiation (WBI) after breast-conserving surgery, including intensity-modulated radiation therapy (IMRT), IMRT plus an electron boost (IMRT-EB), and volumetric-modulated arc therapy (VMAT).

Methods

A total of 10 patients with early-stage left-sided breast cancer after breast-conserving surgery were included in this study. IMRT, IMRT-EB and VMAT plans were generated for each patient.

Results

The conformity index (CI) of the planning target volumes evaluation (PTV-Eval) of VMAT was significantly superior to those of IMRT and IMRT-EB (P < 0.05). The CI of the PTV Eval-boost of VMAT was better than that of IMRT (P = 0.018) and IMRT-EB (P < 0.001), while the CI of the PTV Eval-boost of IMRT was better than that of IMRT-EB (P = 0.002). The V5, V10 and Dmean in ipsilateral lung with VMAT were significantly higher than IMRT (P < 0.05) and IMRT-EB (P < 0.05). The Dmean, V5 and V10 in heart with VMAT were significantly greater than those of IMRT and IMRT-EB (P < 0.05). There was no significant difference in the OARs between IMRT and IMRT-EB (P > 0.05).

Conclusions

Considered the target volume coverage and radiation dose delivered to the OARs (especially the heart and lung), IMRT may be more suitable for the SIB in WBI than IMRT-EB and VMAT. Additional clinical studies with a larger sample size will be needed to assess the long-term feasibility and efficacy of SIB using different radiotherapy techniques.

Growing Use of Mastectomy for Ductal Carcinoma-In Situ of the Breast Among Young Women in the United States

BACKGROUND

Ductal carcinoma-in situ (DCIS) is a preinvasive form of breast cancer associated with excellent outcomes after either mastectomy or breast conservation therapy. Previous studies have demonstrated declining rates of mastectomy. However, it is unclear how this pattern has changed in recent years.

METHODS

Women with DCIS were identified within the National Cancer Data Base. Patients treated with lumpectomy with or without radiotherapy were compared to women treated with mastectomy on the basis of demographic, clinicopathologic, and reporting facility details using χ (2) tests and multivariable logistic regression modeling to identify factors that may influence surgical choice. Changes in the proportion of women receiving contralateral prophylactic mastectomy (CPM) were assessed in a similar fashion.

RESULTS

We identified 212,936 women diagnosed with DCIS between 1998 and 2011. Lumpectomy was performed in 68 % (144,681) of patients. Mastectomy rates initially declined from 1998 (36 %) through 2004 (28 %), before increasing again through 2011 (33 %). Younger patient age, greater medical comorbidity, more extensive disease, higher tumor grade, treatment at an academic facility, and greater distance from the reporting facility were associated with heightened use of mastectomy (all p < 0.001). CPM also increased over time, particularly among younger patients, on multivariate analysis (p < 0.001).

CONCLUSIONS

Mastectomy utilization appears to be rising between 2004 and 2011, particularly among younger patients and those with higher-risk histopathologic features. CPM is increasing in a similar fashion. Further research is needed to understand the drivers of this change.

Deep inspiration breath-hold technique for left-sided breast cancer: An analysis of predictors for organ-at-risk sparing

To identify anatomic and treatment characteristics that correlate with organ-at-risk (OAR) sparing with deep inspiration breath-hold (DIBH) technique to guide patient selection for this technique. Anatomic and treatment characteristics and radiation doses to OARs were compared between free-breathing and DIBH plans. Linear regression analysis was used to identify factors independently predicting for cardiac sparing. We identified 64 patients: 44 with intact breast and 20 postmastectomy. For changes measured directly on treatment planning scans, DIBH plans decreased heart-chest wall length (6.5 vs 5.0cm, p < 0.001), and increased lung volume (1074.4 vs 1881.3cm(3), p < 0.001), and for changes measured after fields are set, they decreased maximum heart depth (1.1 vs 0.3cm, p < 0.001) and heart volume in field (HVIF) (9.1 vs 0.9cm(3), p < 0.001). DIBH reduced the mean heart dose (3.4 vs 1.8Gy, p < 0.001) and lung V20 (19.6% vs 15.3%, p < 0.001). Regression analysis found that only change in HVIF independently predicted for cardiac sparing. We identified patients in the bottom quartile of the dosimetric benefits seen with DIBH and categorized the cause of this "minimal benefit." Overall, 29% of patients satisfied these criteria for minimal benefit with DIBH and the most common cause was favorable baseline anatomy. Only the reduction in HVIF predicted for reductions in mean heart dose; no specific anatomic surrogate for the dosimetric benefits of DIBH technique could be identified. Most patients have significant dosimetric benefit with DIBH, and this technique should be planned and evaluated for all patients receiving left-sided breast/chest wall radiation.

Serum biomarkers for the detection of cardiac toxicity after chemotherapy and radiation therapy in breast cancer patients

Multi-modality cancer treatments that include chemotherapy, radiation therapy, and targeted agents are highly effective therapies. Their use, especially in combination, is limited by the risk of significant cardiac toxicity. The current paradigm for minimizing cardiac morbidity, based on serial cardiac function monitoring, is suboptimal. An alternative approach based on biomarker testing, has emerged as a promising adjunct and a potential substitute to routine echocardiography. Biomarkers, most prominently cardiac troponins and natriuretic peptides, have been evaluated for their ability to describe the risk of potential cardiac dysfunction in clinically asymptomatic patients. Early rises in cardiac troponin concentrations have consistently predicted the risk and severity of significant cardiac events in patients treated with anthracycline-based chemotherapy. Biomarkers represent a novel, efficient, and robust clinical decision tool for the management of cancer therapy-induced cardiotoxicity. This article aims to review the clinical evidence that supports the use of established biomarkers such as cardiac troponins and natriuretic peptides, as well as emerging data on proposed biomarkers.

Cardiovascular event-free survival after adjuvant radiation therapy in breast cancer patients stratified by cardiovascular risk

The objective of this study was to estimate the risk of a cardiovascular event or death associated with modern radiation in a population of elderly female breast cancer patients with varying baseline cardiovascular risk. The data used for this analysis are from the linked Surveillance, Epidemiology, and End-Results (SEER)-Medicare database. The retrospective cohort study included women aged 66 years and older with stage 0–III breast cancer diagnosed between 2000 and 2005. Women were grouped as low, intermediate, or high cardiovascular risk based on the presence of certain clinical diagnoses. The risk for the combined outcome of a hospitalization for a cardiovascular event or death within 6 months and 24 months of diagnosis was estimated using a multivariable Cox model. The median follow-up time was 24 months. Among the 91,612 women with American Joint Committee on Cancer (AJCC) stage 0–III breast cancer: 39,555 (43.2%) were treated with radiation therapy and 52,057 (56.8%) were not. The receipt of radiation therapy in the first 6 months was associated with a statistically significant increased risk for the combined outcome in women categorized as high risk (HR = 1.510; 95% CI, 1.396–1.634) or intermediate risk (HR = 1.415; 95% CI, 1.188–1.686) but not low risk (HR = 1.027; 95% CI, 0.798–1.321). Women with a prior medical history of cardiovascular disease treated with radiation therapy are at increased risk for an event and should be monitored for at least 6 months following treatment with radiation therapy.

[Postoperative radiotherapy of breast cancer and cardiotoxicity]

Cardiac complications may present a particular problem following radiation treatment applied to the mediastinum and thoracic wall (and especially to the left breast). Exposure of the heart during radiotherapy increases the risk of ischemic heart disease occurring generally years after the treatment. The incidence of radiation cardiotoxicity depends on various factors related to oncological therapies and the patient (details of radiotherapy, age, gender, comorbidities, smoking habits, etc.). Until recently the majority of clinical studies reported increased cardiac morbidity in patients receiving radiation treatment of the chest wall and the breast. Due to modern methods, however, postoperative chest wall and left breast irradiation is much safer today than previously. In order to avoid cardiotoxicity, adherence to clinical practice guidelines for chemo- and targeted therapy of breast cancer, use of the most advanced irradiation procedures, regular monitoring of patients, and close cooperation between cardiologists and oncologists are all recommended.

Cardiovascular disease after cancer therapy

Improvements in treatment and earlier diagnosis have both contributed to increased survival for many cancer patients. Unfortunately, many treatments carry a risk of late effects including cardiovascular diseases (CVDs), possibly leading to significant morbidity and mortality. In this paper we describe current knowledge of the cardiotoxicity arising from cancer treatments, outline gaps in knowledge, and indicate directions for future research and guideline development, as discussed during the 2014 Cancer Survivorship Summit organised by the European Organisation for Research and Treatment of Cancer (EORTC). Better knowledge is needed of the late effects of modern systemic treatments and of radiotherapy to critical structures of the heart, including the effect of both radiation dose and volume of the heart exposed. Research elucidating the extent to which treatments interact in causing CVD, and the mechanisms involved, as well as the extent to which treatments may increase CVD indirectly by increasing cardiovascular risk factors is also important. Systematic collection of data relating treatment details to late effects is needed, and great care is needed to obtain valid and generalisable results. Better knowledge of these cardiac effects will contribute to both primary and secondary prevention of late complications where exposure to cardiotoxic treatment is unavoidable. Also surrogate markers would help to identify patients at increased risk of cardiotoxicity. Evidence-based screening guidelines for CVD following cancer are also needed. Finally, risk prediction models should be developed to guide primary treatment choice and appropriate follow up after cancer treatment.

Advanced radiotherapy techniques for breast cancer to minimize cardiovascular risk

SUMMARY 

Radiotherapy plays an integral role in the management of breast cancer and has been demonstrated to reduce the risk of recurrence and improve overall survival. Recent reports in the literature have suggested a dose-dependent risk of cardiovascular disease following radiation treatment for breast cancer. This article highlights new advances in radiotherapy for breast cancer that may help minimize radiotherapy doses to the heart.

Cancer in heart disease patients: what are the limitations in the treatment strategy?

Cardiovascular disease and cancer are leading causes of morbidity and mortality, and can both be present in one patient. In patients with simultaneous disease, the most threatening disease should be treated first. This is usually heart disease, but this can pose specific problems. If percutaneous coronary intervention is preferred, bleeding and thrombotic tendencies have to be taken into account in the subsequent treatment of the malignancy. With coronary artery bypass grafting, the advantages and disadvantages of one- or two-stage procedures, and the use of extracorporeal circulation have to be balanced. Development of heart disease after treatment of malignancy could be due to radiotherapy and chemotherapy. The effects of these cancer treatments have to be taken into account for the treatment options of the heart disease and the postoperative prognosis.

Cardiotoxicity and oncological treatments

BACKGROUND

Cardiotoxic and other side effects limit the usefulness of treatments for cancer.

METHOD

This article is based on pertinent articles that were retrieved by a selective search in PubMed and other databases, and on the guidelines of the European Society of Cardiology, the Association of Scientific Medical Societies in Germany, and the European Society of Medical Oncology.

RESULTS

Prospective studies have shown that some treatments for cancer are cardiotoxic. The heart damage that they cause can manifest itself as arrhythmia, arterial hypertension, thromboembolism, angina pectoris, myocardial infarction, or heart failure. It has been observed that potentially lethal complications can arise as late as 40 years after treatment of the original cancer. The anthracycline drug doxorubicin, given in a dose of 500 mg/m2 of body surface area, has been found to cause cardiac complications in 4-36% of the patients treated with it. Trastuzumab and epirubicin cause dose-limiting cardiac events in 1.7-5% of patients, depending on the dosage. Paclitaxel causes bradycardia, intracardiac conduction block, or arrhythmia in 0.5% of patients. 18% of patients treated with sunitimib or sorafenib have clinical manifestations relating to the heart (angina pectoris, dyspnea). 5-fluorouracil can cause angina pectoris at the beginning of treatment and rarely causes myocardial infarction. Cardiac radiation therapy, a form of treatment practiced in earlier decades, can cause cardiac complications 20 years after the event. The opportunity to prevent cardiac complications of anthracycline drugs with dexrazoxane is decidedly limited, but initial studies have shown that treatment with beta-blockers and ACE inhibitors lessens the likelihood of cardiotoxic side effects. When cardiac complications arise, the generally applicable rules for the treatment of each type of cardiac problem should be followed. The oncological treatment protocol should be adjusted or switched to one that is less damaging to the heart.

CONCLUSION

Treating physicians need to be thoroughly acquainted with the cardiotoxic effects of anti-cancer drugs so that they can diagnose them early on and avoid jeopardizing the overall success of treatment.

Cancer, physical activity, and exercise

This review examines the relationship between physical activity and cancer along the cancer continuum, and serves as a synthesis of systematic and meta-analytic reviews conducted to date. There exists a large body of epidemiologic evidence that conclude those who participate in higher levels of physical activity have a reduced likelihood of developing a variety of cancers compared to those who engage in lower levels of physical activity. Despite this observational evidence, the causal pathway underlying the association between participation in physical activity and cancer risk reduction remains unclear. Physical activity is also a useful adjunct to improve the deleterious sequelae experienced during cancer treatment. These deleterious sequelae may include fatigue, muscular weakness, deteriorated functional capacity, and many others. The benefits of physical activity during cancer treatment are similar to those experienced after treatment. Despite the growing volume of literature examining physical activity and cancer across the cancer continuum, a number of research gaps exist. There is little evidence on the safety of physical activity among all cancer survivors, as most trials have selectively recruited participants. The specific dose of exercise needed to optimize primary cancer prevention or symptom control during and after cancer treatment remains to be elucidated.

Estimation of the displacement of cardiac substructures and the motion of the coronary arteries using electrocardiographic gating

Purpose

The aim of this study was to quantify the displacement of cardiac substructures, including the anterior myocardial territory (AMT), left ventricle, and coronary arteries during a normal cardiac cycle.

Materials and methods

Computed tomography (CT) images with retrospective electrocardiographic gating of 17 eligible patients were obtained. All images were reconstructed automatically for the end-diastolic and end-systolic phases. CT scanning without contrast at a random phase and a selected vertebral body were used as references to measure three-dimensionaldisplacements of the cardiac substructures.

Results

The displacement between the end-diastolic and end-systolic phases (D_d-s) was greater than that between the end-systolic and random phases and between the end-diastolic and random cardiac phases. The largest displacements for the heart were in the left, posterior, and inferior directions with an average D_d-s of approximately 4–6 mm. The average D_d-s for the AMT and left ventricle was 1.2–2.7 mm in the anterior and right directions, 4.3–7.8 mm in left and posterior directions, and 4.9–6.3 mm in superior and inferior directions. For the coronary arteries, the average D_d-s was 2.8–5.9 mm in the anterior-posterior direction, 3.5–6.6 mm in left-right direction, and 3.8–5.3 mm in the superior-inferior direction. Inter-observer agreement was excellent for the heart, AMT, and left ventricle (kappa coefficient, >0.75 for all) and good for most coronary arteries in three dimensions (kappa coefficient, 0.511–0.687). The D_d-s did not differ significantly between men and women.

Conclusion

Most average displacements of the cardiac substructures and coronary arteries were 3–8 mm in three dimensions. These findings will be useful to accurately estimate the radiation dose to cardiac substructures during thoracic radiation and to evaluate the risk of radiation-related heart disease.

Dosimetric comparison of normal structures associated with accelerated partial breast irradiation and whole breast irradiation delivered by intensity modulated radiotherapy for early breast cancer after breast conserving surgery

PURPOSE

To assess the heart and lung dosimetry results associated with accelerated partial breast irradiation intensity-modulated radiotherapy (APBI-IMRT) and whole breast field-in-field intensity-modulated radiotherapy (WBI-FIF-IMRT).

METHODS

A total of 29 patients with early-stage breast cancer after lumpectomy were included in this study. APBI-IMRT and WBI-FIF-IMRT plans were generated for each patient. The dosimetric parameters of ipsilateral lung and heart in both plans were then compared with and without radiobiological correction.

RESULTS

With and without radiobiological correction, the volume of ipsilateral lung showed a substantially lower radiation exposure in APBI-IMRT with moderate to high doses (P < 0.05) but non-significant increases in volume of ipsilateral lung in 2.5 Gy than WBI-FIF-IMRT (P > 0.905).There was no significant difference in volume of ipsilateral lung receiving 1, 2.5, and 5 Gy between APBI-IMRT and WBI (P > 0.05) in patients with medial tumor location, although APBI-IMRT exposed more lung to 2.5 and 5 Gy. APBI-IMRT significantly decreases the volume of heart receiving low to high doses in left-sided breast cancer (P < 0.05).

CONCLUSION

APBI-IMRT can significantly spare the volume of heart and ipsilateral lung receiving moderate and high dose. Non-significant increases in volume of the ipsilateral lung exposed to low doses of radiation were observed for APBI-IMRT in comparison to WBI-FIF-IMRT, particularly in patients with medial tumor location. With the increasing interest in APBI-IMRT, our data may help clinicians individualize patient treatment decisions.

[Radiotherapy of invasive breast cancer: French national guidelines]

The French National Cancer Institute (INCa) and Société française de sénologie et pathologie mammaire (SFSPM), in collaboration with a multidisciplinary experts group, have published the French national clinical practice guidelines on a selection of 11 currently debated questions regarding the management of invasive breast cancer. Those guidelines are based on a comprehensive analysis of the current published evidence dealing with those issues, secondly reviewed by 100 reviewers. Radiotherapy was concerned by five of the 11 questions: indications for the boost after whole gland irradiation; hypofractionated radiotherapy; partial breast irradiation; indications for mammary internal nodes irradiation, and indications of radiotherapy after neo-adjuvant chemotherapy.

Radiation-induced cardiac damage in early left breast cancer patients: risk factors, biological mechanisms, radiobiology, and dosimetric constraints

Today there is general awareness of the potential damage to the heart in left-sided (more than in right-sided) breast cancer radiotherapy (RT). Historical changes in tumor and heart doses are presented here along with the impact of different RT techniques and volumes. Individual and pharmacological risk factors are also examined with respect to radiation damage. The biological mechanisms of harm are only partially understood, such as the radiobiology of heart damage due to the presence of various radiosensitive structures and their topographic heterogeneity. Furthermore, individual variability may expose patients to higher or lower risks of late cardiac damage or death. Damage mechanisms and radiobiological characteristics in heart irradiation are presented in relation to dosimetric and biological parameters.

Incidence of heart disease in 35,000 women treated with radiotherapy for breast cancer in Denmark and Sweden

PURPOSE

To study incidence of radiation-related heart disease in a large population of breast cancer patients followed for up to 30 years.

MATERIAL AND METHODS

72,134 women diagnosed with breast cancer in Denmark or Sweden during 1976-2006 and followed prospectively. Radiation-related risk was studied by comparing women with left-sided and right-sided tumours.

RESULTS

34,825 women (48%) received radiotherapy. Among unirradiated women tumour laterality had little relevance to heart disease. Among irradiated women mean dose to the whole heart was 6.3 Gy for left-sided tumours and 2.7 Gy for right-sided tumours. Mortality was similar in irradiated women with left-sided and right-sided tumours, but incidence ratios, left-sided versus right-sided, were raised: acute myocardial infarction 1.22 (95% CI 1.06-1.42), angina 1.25 (1.05-1.49), pericarditis 1.61 (1.06-2.43), valvular heart disease 1.54 (1.11-2.13). Incidence ratios for all heart disease were as high for women irradiated since 1990 (1.09 [1.00-1.19]) as for women irradiated during 1976-1989 (1.08 [0.99-1.17]), and were higher for women diagnosed with ischaemic heart disease prior to breast cancer than for other women (1.58 [1.19-2.10] versus 1.08 [1.01-1.15], p for difference=0.01).

CONCLUSIONS

Breast cancer radiotherapy has, at least until recently, increased the risk of developing ischaemic heart disease, pericarditis and valvular disease. Women with ischaemic heart disease before breast cancer diagnosis may have incurred higher risks than others.

Distribution of coronary artery stenosis after radiation for breast cancer

PURPOSE

To study distribution of coronary artery stenosis among patients with breast cancer (BC) and to assess correlation between radiotherapy (RT) and location of stenosis.

PATIENTS AND METHODS

A Swedish BC cohort diagnosed from 1970 to 2003 was linked to registers of coronary angiography from 1990 to 2004, which yielded 199 patients. Stenoses of the coronary arteries were graded from 0 to 5, where 0 indicated a normal vessel and 5 indicated occlusion. Two hotspot areas for radiation were defined: proximal right coronary artery (prox RCA), mid and distal left anterior descending artery and distal diagonal (mdLAD + dD). RT regimens were categorized as high or low risk of irradiating the hotspot areas. Left breast/chest wall was considered high risk for mdLAD + dD; left internal mammary chain (IMC), high risk for prox RCA and mdLAD + dD from 1970 to 1995 and thereafter solely for mdLAD + dD; and right IMC, high risk for prox RCA. Other RT targets and no RT were considered low risk. Results were expressed in odds ratios (ORs) and 95% CIs.

RESULTS

For irradiated left- versus right-sided BC, the OR for grade 3 to 5 stenosis in mdLAD + dD was 4.38 (95% CI, 1.64 to 11.7), and for grade 4 to 5 stenosis, the OR was 7.22 (95% CI, 1.64 to 31.8). For high-risk RT versus low-risk or no RT, the OR for grade 3 to 5 stenosis in hotspot areas was 1.90 (95% CI, 1.11 to 3.24).

CONCLUSION

An increase of stenosis in mdLAD + dD in irradiated left-sided BC and an association between high-risk RT and stenosis in hotspot areas for radiation indicate a direct link between radiation and location of coronary stenoses.

Age, comorbidity, and breast cancer severity: impact on receipt of definitive local therapy and rate of recurrence among older women with early-stage breast cancer

BACKGROUND

The definitive local therapy options for early-stage breast cancer are mastectomy and breast-conserving surgery followed by radiation therapy. Older women and those with comorbidities frequently receive breast-conserving surgery alone. The interaction of age and comorbidity with breast cancer severity and their impact on receipt of definitive therapy have not been well-studied.

STUDY DESIGN

In a cohort of 1,837 women aged 65 years and older receiving treatment for early-stage breast cancer in 6 integrated health care delivery systems in 1990-1994 and followed for 10 years, we examined predictors of receiving nondefinitive local therapy and assessed the impact on breast cancer recurrence within levels of severity, defined as level of risk for recurrence.

RESULTS

Age and comorbidity were associated with receipt of nondefinitive therapy. Compared with those at low risk, women at the highest risk were less likely to receive nondefinitive therapy (odds ratio = 0.32; 95% CI, 0.22-0.47), and women at moderate risk were about half as likely (odds ratio = 0.54; 95% CI, 0.35-0.84). Nondefinitive local therapy was associated with higher rates of recurrence among women at moderate (hazard ratio = 5.1; 95% CI, 1.9-13.5) and low risk (hazard ratio = 3.2; 95% CI, 1.1-8.9). The association among women at high risk was weak (hazard ratio = 1.3; 95% CI, 0.75-2.1).

CONCLUSIONS

Among these older women with early-stage breast cancer, decisions about therapy partially balanced breast cancer severity against age and comorbidity. However, even among women at low risk, omitting definitive local therapy was associated with increased recurrence.

Long-term safety of radiotherapy and breast cancer laterality in older survivors

BACKGROUND

Although adjuvant radiotherapy (RT) following surgery for breast cancer improves overall survival, controversy exists about its long-term adverse impact on cardiovascular health in older survivors.

AIM

To determine whether incident cardiovascular disease (CVD) is associated with RT and whether tumor laterality modifies this association.

METHODS

Women aged 65+ years diagnosed with stage I and II breast cancer between 1990 and 1994 were identified from three health plans. Women were followed through CVD outcomes, health plan disenrollment, death, or study end (December 31, 2004). The main independent variable was RT use. Adjusted HRs and 95% CIs were estimated using Cox proportional hazards models with time-dependent tamoxifen and RT use status. We adjusted for age, race, stage, estrogen receptor/progesterone receptor, hypertension, and diabetes.

RESULTS

In the full cohort (N = 806), RT was not associated with greater risk of CVD (maximum follow-up was 14 years). However, within the RT-exposed group (N = 340), women treated for left-side breast cancer had a significant increased risk of CVD outcomes (HR = 1.53, 95% CI: 1.06-2.21) compared with women with right-sided tumors.

CONCLUSION

Laterality is critical to understanding the effect of RT on CVD. Studies of more contemporary cohorts of women treated with RT should incorporate this variable to determine whether the risk persists with refinements in the dosing and delivery of RT.

IMPACT

As some irradiation to the heart is unavoidable even with refined modern RT techniques, continued effort is required to minimize such exposures, especially in older women with left-sided tumors.

Tangential beam IMRT versus tangential beam 3D-CRT of the chest wall in postmastectomy breast cancer patients: a dosimetric comparison

Background

This study evaluates the dose distribution of reversed planned tangential beam intensity modulated radiotherapy (IMRT) compared to standard wedged tangential beam three-dimensionally planned conformal radiotherapy (3D-CRT) of the chest wall in unselected postmastectomy breast cancer patients

Methods

For 20 unselected subsequent postmastectomy breast cancer patients tangential beam IMRT and tangential beam 3D-CRT plans were generated for the radiotherapy of the chest wall. The prescribed dose was 50 Gy in 25 fractions. Dose-volume histograms were evaluated for the PTV and organs at risk. Parameters of the dose distribution were compared using the Wilcoxon matched pairs test.

Results

Tangential beam IMRT statistically significantly reduced the ipsilateral mean lung dose by an average of 21% (1129 cGy versus 1437 cGy). In all patients treated on the left side, the heart volume encompassed by the 70% isodose line (V70%; 35 Gy) was reduced by an average of 43% (5.7% versus 10.6%), and the mean heart dose by an average of 20% (704 cGy versus 877 cGy). The PTV showed a significantly better conformity index with IMRT; the homogeneity index was not significantly different.

Conclusions

Tangential beam IMRT significantly reduced the dose-volume of the ipsilateral lung and heart in unselected postmastectomy breast cancer patients.

Cost-effectiveness of zoledronic acid plus endocrine therapy in premenopausal women with hormone-responsive early breast cancer

PURPOSE

The aim of this study was to estimate the cost-effectiveness of adding zoledronic acid 4 mg intravenously every 6 months to endocrine therapy in premenopausal women with hormone receptor-positive early breast cancer from a US health care system perspective.

MATERIALS AND METHODS

A Markov model was developed to predict disease progression, mortality, and costs of breast cancer care for premenopausal women with hormone receptor-positive early breast cancer receiving up to 3 years of (1) endocrine therapy (goserelin plus tamoxifen or anastrozole); or (2) endocrine therapy plus zoledronic acid. Model parameters were obtained from ABCSG-12 (Austrian Breast and Colorectal Cancer Study Group Trial-12) and the literature. The incremental cost per quality-adjusted life year (QALY) gained with zoledronic acid was calculated under 2 scenarios: (1) benefits of zoledronic acid persist to maximum (7 years) follow-up in ABCSG-12 ("trial benefits") or (2) benefits persist until death ("lifetime benefits").

RESULTS

Adding zoledronic acid to endocrine therapy was projected to yield a gain of 0.41 life years (LYs) and 0.43 QALYs assuming trial benefits and 1.34 LYs and 1.41 QALYs assuming lifetime benefits. Assuming trial benefits, the incremental cost per QALY gained with zoledronic acid was $9300. Assuming lifetime benefits, zoledronic acid was estimated to increase QALYs and reduce costs. Cost per QALY gained was <or= $56,000 in all deterministic sensitivity analyses and was <or= $50,000 in 94% and 97% of probabilistic sensitivity analyses for trial and lifetime benefits scenarios, respectively.

CONCLUSION

Adding zoledronic acid to endocrine therapy in premenopausal women with hormone receptor-positive early breast cancer is cost-effective from a US health care system perspective.