Cardiac toxicity in breast cancer survivors: review of potential cardiac problems

The utility of cardiac biomarkers and echocardiography for the early detection of bevacizumab- and sunitinib-mediated cardiotoxicity

The recent introduction of novel anticancer therapies, including bevacizumab (BVZ) and sunitinib (SNT), is associated with an increased risk of cardiotoxicity. However, early identification of left ventricular (LV) systolic dysfunction may facilitate dose modification and avoid the development of advanced heart failure. Using a murine model of BVZ- and SNT-mediated cardiotoxicity, we investigated whether cardiac biomarkers and/or tissue velocity imaging (TVI) using echocardiography can detect early changes in cardiac function, before a decrease in LV ejection fraction is identified. A total of 75 wild-type C57Bl/6 male mice were treated with either 0.9% saline, BVZ, or SNT. Serial monitoring of blood pressure, high-sensitivity troponin I, and echocardiographic indexes were performed over a 14-day study period, after which the mice were euthanized for histological and biochemical analyses. Mice treated with either BVZ or SNT developed systemic hypertension as early as day 7, which increased by day 14. Cardiac biomarkers, specifically high-sensitivity troponin I, were not predictive of early LV systolic dysfunction. Although conventional LV ejection fraction values decreased at day 13 in mice treated with either BVZ or SNT, TVI confirmed early LV systolic dysfunction at day 8. Histological and biochemical analysis demonstrated loss of cellular integrity, increased oxidative stress, and increased cardiac apoptosis in mice treated with BVZ or SNT therapy at day 14. In a murine model of BVZ- or SNT-mediated cardiomyopathy, noninvasive assessment by TVI detected early LV systolic dysfunction before alterations in conventional echocardiographic indexes.

Internal Mammary and Medial Supraclavicular Irradiation in Breast Cancer

BACKGROUND

The effect of internal mammary and medial supraclavicular lymph-node irradiation (regional nodal irradiation) added to whole-breast or thoracic-wall irradiation after surgery on survival among women with early-stage breast cancer is unknown.

METHODS

We randomly assigned women who had a centrally or medially located primary tumor, irrespective of axillary involvement, or an externally located tumor with axillary involvement to undergo either whole-breast or thoracic-wall irradiation in addition to regional nodal irradiation (nodal-irradiation group) or whole-breast or thoracic-wall irradiation alone (control group). The primary end point was overall survival. Secondary end points were the rates of disease-free survival, survival free from distant disease, and death from breast cancer.

RESULTS

Between 1996 and 2004, a total of 4004 patients underwent randomization. The majority of patients (76.1%) underwent breast-conserving surgery. After mastectomy, 73.4% of the patients in both groups underwent chest-wall irradiation. Nearly all patients with node-positive disease (99.0%) and 66.3% of patients with node-negative disease received adjuvant systemic treatment. At a median follow-up of 10.9 years, 811 patients had died. At 10 years, overall survival was 82.3% in the nodal-irradiation group and 80.7% in the control group (hazard ratio for death with nodal irradiation, 0.87; 95% confidence interval [CI], 0.76 to 1.00; P=0.06). The rate of disease-free survival was 72.1% in the nodal-irradiation group and 69.1% in the control group (hazard ratio for disease progression or death, 0.89; 95% CI, 0.80 to 1.00; P=0.04), the rate of distant disease-free survival was 78.0% versus 75.0% (hazard ratio, 0.86; 95% CI, 0.76 to 0.98; P=0.02), and breast-cancer mortality was 12.5% versus 14.4% (hazard ratio, 0.82; 95% CI, 0.70 to 0.97; P=0.02). Acute side effects of regional nodal irradiation were modest.

CONCLUSIONS

In patients with early-stage breast cancer, irradiation of the regional nodes had a marginal effect on overall survival. Disease-free survival and distant disease-free survival were improved, and breast-cancer mortality was reduced. (Funded by Fonds Cancer; ClinicalTrials.gov number, NCT00002851.).

Dexrazoxane protects breast cancer patients with diabetes from chemotherapy-induced cardiotoxicity

BACKGROUND

To evaluate the cardioprotective effect of dexrazoxane (DEX) on chemotherapy in patients with breast cancer with concurrent type 2 diabetes mellitus (DM2).

METHODS

Eighty female patients with breast cancer with DM2 were randomly assigned to receive chemotherapy only or chemotherapy plus DEX. All patients received 80 mg/m epirubicin and 500 mg/m cyclophosphamide by intravenous infusion every 3 weeks for a total of 6 cycles. The group assigned to receive chemotherapy alone received placebo 30 minutes before epirubicin administration. The group assigned to receive chemotherapy plus DEX received 800 mg/m DEX 30 minutes before epirubicin administration. Cardiac function and hematology before and after 6 cycles of chemotherapy were analyzed.

RESULTS

There was no difference in baseline systole or diastole function between the 2 DM2 groups. Patients receiving chemotherapy alone experienced significantly greater reductions in Ea and significantly greater elevations in E/Ea and Tei index in comparison with patients receiving chemotherapy plus DEX. After chemotherapy, superoxide dismutase was significantly reduced, and serum malondialdehyde (MDA) was significantly increased in patients with DM2. Serum superoxide dismutase levels were comparable between the 2 groups before and after chemotherapy, MDA levels were comparable between the 2 groups before chemotherapy, whereas serum MDA was significantly higher after chemotherapy in the chemotherapy alone group in comparison with the group that received DEX.

CONCULSIONS

DEX protects against cardiotoxicity induced by chemotherapy in patients with breast cancer with concurrent DM2.

Single-isocenter hybrid IMRT plans versus two-isocenter conventional plans and impact of intrafraction motion for the treatment of breast cancer with supraclavicular lymph nodes involvement

The purpose of this study was to compare the single‐isocenter, four‐field hybrid IMRT with the two‐isocenter techniques to treat the whole breast and supraclavicular fields and to investigate the intrafraction motions in both techniques in the superior direction. Fifteen breast cancer patients who underwent lumpectomy and adjuvant radiation to the whole breast and supraclavicular (SCV) fossa at our institution were selected for this study. Two planning techniques were compared for the treatment of the breast and SCV lymph nodes. The patients were divided into three subgroups according to the whole breast volume. For the two‐isocenter technique, conventional wedged or field‐within‐a‐field tangents (FIF) were used to match with the same anterior field for the SCV region. For the single‐isocenter technique, four‐field hybrid IMRT was used for the tangent fields matched with a half blocked anterior field for the SCV region. To simulate the intrafraction uncertainties in the longitudinal direction for both techniques, the treatment isocenters were shifted by 1 mm and 2 mm in the superior direction. The average breast clinical tumor volume (CTV) receiving 100% (V100%) of the prescription dose (50 Gy) was 99.3%±0.5% and 96.4%±1.2% for the for two‐isocenter and single‐isocenter plans (p<0.05), respectively. The breast CTV receiving 95% of the prescription dose (V95%) was close to 100% in both techniques. The average breast CTV receiving 105% (V105%) of the prescription dose was 32.4%±19.3% and 23.8%±13.3% (p=0.08). The percentage volume of the breast CTV receiving 110% of the dose was 0.4%±1.2% in the two‐isocentric technique vs. 0.1%±0.2% in the single‐isocentric technique. The average uniformity index was 0.91±0.02 vs. 0.91±0.01 in both techniques (p=0.04), but had no clinical impact. The percentage volume of the contralateral breast receiving a dose of 1 Gy was less than 2.3% in small breast patients and insignificant for medium and large breast sizes. The percentage of the total lung volume receiving g>20 Gy (V20Gy) and the heart receiving >30 Gy (V30Gy) were 13.6% vs. 14.3% (p=0.03) and 1.25% vs. 1.2% (p=0.62), respectively. Shifting the treatment isocenter by 1 mm and 2 mm superiorly showed that the average maximum dose to 1 cc of the breast volume was 55.5±1.8 Gy and 58.6±4.3 Gy in the two‐isocentric technique vs. 56.4±2.1 Gy and 59.1±5.1 Gy in the single‐isocentric technique (p=0.46, 0.87), respectively. The single‐isocenter technique using four‐field hybrid IMRT approach resulted in comparable plan quality as the two‐isocentric technique. The single‐isocenter technique is more sensitive to intrafraction motion in the superior direction compared to the two‐isocentric technique. The advantages of the single‐isocenter include elimination of isocentric errors due to couch and collimator rotations and reduction in treatment time. This study supports consideration of a single‐isocenter four‐field hybrid IMRT technique for patients undergoing breast and supraclavicular nodal irradiation.

PACS number: 87.55.D, 87.55.de, 87.55.dk,

Design and synthesis of norendoxifen analogues with dual aromatase inhibitory and estrogen receptor modulatory activities

Both selective estrogen receptor modulators and aromatase inhibitors are widely used for the treatment of breast cancer. Compounds with both aromatase inhibitory and estrogen receptor modulatory activities could have special advantages for treatment of breast cancer. Our previous efforts led to the discovery of norendoxifen as the first compound with dual aromatase inhibitory and estrogen receptor binding activities. To optimize its efficacy and aromatase selectivity versus other cytochrome P450 enzymes, a series of structurally related norendoxifen analogues were designed and synthesized. The most potent compound, 4'-hydroxynorendoxifen (10), displayed elevated inhibitory potency against aromatase and enhanced affinity for estrogen receptors when compared to norendoxifen. The selectivity of 10 for aromatase versus other cytochrome P450 enzymes was also superior to norendoxifen. 4'-Hydroxynorendoxifen is therefore an interesting lead for further development to obtain new anticancer agents of potential value for the treatment of breast cancer.

Cardiotoxicity of antineoplastic agents: what is the present and future role for imaging?

As antineoplastic treatment options expand at an increasing rate, both traditional and novel agents continue to be limited by their cardiotoxic effects. While functional decline becomes clinically apparent at late states of toxicity, little is known about early stages during which treatment or prevention may still be an option. Several imaging modalities,including echocardiography, multiple gated acquisition, and cardiac magnetic resonance imaging have the ability to identify cardiac effects before they produce clinical symptoms.Here we discuss the current and future role of cardiac imaging in the assessment of cardiotoxicity of antineoplastic agents. effects on cardiac tissue, resulting in myocardial cellular damage,and ultimately lead to a wide range of effects including electrophysiological abnormalities, symptomatic heart failure(HF), and even death. This represents a limiting factor in the therapy of several otherwise treatable neoplasms [2].The cardiotoxicity of antineoplastic agents raises several important questions regarding the actual prevalence of cardiac toxicity, the ability to effectively treat or prevent such effects with pharmaceutical interventions, and the availability of a means for early diagnosis. Here, we focus on the latter, specifically examining current and potential future imaging strategies to detect the cardiac effects of chemotherapeutic agents.

The utility of cardiac stress testing for detection of cardiovascular disease in breast cancer survivors: a systematic review

Background

Heart function tests performed with myocardial stress, or “cardiac stress tests”, may be beneficial for detection of cardiovascular disease. Women who have been diagnosed with breast cancer are more likely to develop cardiovascular diseases than the general population, in part due to the direct toxic effects of cancer treatment on the cardiovascular system. The aim of this review was to determine the utility of cardiac stress tests for the detection of cardiovascular disease after cardiotoxic breast cancer treatment.

Design

Systematic review.

Methods

Medline and Embase were searched for studies utilizing heart function tests in breast cancer survivors. Studies utilizing a cardiac stress test and a heart function test performed at rest were included to determine whether stress provided added benefit to identifying cardiac abnormalities that were undetected at rest within each study.

Results

Fourteen studies were identified. Overall, there was a benefit to utilizing stress tests over tests at rest in identifying evidence of cardiovascular disease in five studies, a possible benefit in five studies, and no benefit in four studies. The most common type of stress test was myocardial perfusion imaging, where reversible perfusion defects were detected under stress in individuals who had no defects at rest, in five of seven studies of long-term follow-up. Two studies demonstrated the benefit of stress echocardiography over resting echocardiography for detecting left ventricular dysfunction in anthracycline-treated breast cancer survivors. There was no benefit of stress cardiac magnetic resonance imaging in one study. Two studies showed a potential benefit of stress electrocardiography, whereas three others did not.

Conclusion

The use of cardiac stress with myocardial perfusion imaging and echocardiography may provide added benefit to tests performed at rest for detection of cardiovascular disease in breast cancer survivors, and merits further research.

Angiotensin Converting Enzyme Inhibitors (ACEI) and doxorubicin pharmacokinetics in women receiving adjuvant breast cancer treatment

Purpose

Doxorubicin (DOX) chemotherapy can cause cardiac complications. Angiotensin converting enzyme inhibitors (ACEI) may protect against these complications. We performed a pharmacokinetics (PK) study to determine whether DOX levels are altered in the presence of ACEI.

Methods

In this randomized, cross-over, single-blinded drug-drug interaction study, 19 women with breast cancer prescribed DOX and cyclophosphamide every 14 days received one cycle of DOX chemotherapy with ACEI enalapril 10 mg daily and another cycle of DOX with placebo. Blood samples for DOX and doxorubicinol were drawn at baseline, 0.5, 1.0, 2.0, 4.0, 24.0 and 48.0 hours after infusion with and without ACEI enalapril. Correlative laboratories were also obtained. PK data was analyzed using non compartmental methods and DOX and doxorubicinol area under the curve (AUC) 0 to infinity, Cmax and half-life were estimated. Paired t-tests were used to determine whether DOX and its metabolite were altered with the use of enalapril (P < 0.05).

Results

17 women (median age 45 years) received 60 mg/m2 DOX every two weeks for four cycles. Mean (SD) AUC0- ∞ for DOX and doxorubicinol with enalapril exposure was 1185.56 (44.64) hr*ng/ml and 1040 (80.6) hr*ng/ml, respectively. AUC0- ∞ for DOX and doxobubicinol without enalapril was 1167.73 (45.26) hr*ng/ml and 1056.32 (92.03) hr*ng/ml, respectively. There is no interaction between DOX and enalapril. Enalapril was tolerated (33% grade 1 dizziness).

Conclusion

ACEI, enalapril, does not appear to alter the PK of DOX. Ongoing efforts to determine the effectiveness of ACEI as a cardioprotective agent in women receiving DOX chemotherapy should be continued.

Comparison of radiation dose to the left anterior descending artery by whole and partial breast irradiation in breast cancer patients

Purpose

Breast conserving surgery (BCS) followed by whole breast irradiation (WBI) is the standard of care for breast cancer patients. However, there is a risk of coronary events with WBI therapy. In this study, we compared the radiation dose in the left anterior descending artery (LAD) in patients receiving partial breast irradiation (PBI) with WBI.

Material and methods

We evaluated consecutive patients who underwent adjuvant radiotherapy after BCS between October 2008 and July 2014. Whole breast irradiation patients received 50 Gy in fractions of 2 Gy to the entire breast. Partial breast irradiation was performed using multicatheter brachytherapy at a dose of 32 Gy in eight fractions. The mean and maximal cumulative doses to LAD were calculated. The radiotherapeutic biologically effective dose of PBI was adjusted to WBI, and radiation techniques were compared.

Results

Of 379 consecutive patients with 383 lesions receiving radiotherapy (151 WBI and 232 PBI lesions), 82 WBI and 100 PBI patients were analyzed. In WBI patients, the mean and maximal cumulative doses for left-sided breast cancer (2.13 ± 0.11 and 8.19 ± 1.21 Gy, respectively) were significantly higher than those for right-sided (0.37 ± 0.02 and 0.56 ± 0.03 Gy, respectively; p < 0.0001). In PBI patients with left-sided breast cancer, the doses for tumors in inner quadrants or central location (2.54 ± 0.21 and 4.43 ± 0.38 Gy, respectively) were significantly elevated compared to outer quadrants (1.02 ± 0.17 and 2.10 ± 0.29 Gy, respectively; p < 0.0001). After the adjustment, the doses in PBI patients were significantly reduced in patients with tumors only in outer quadrants (1.12 ± 0.20 and 2.43 ± 0.37 Gy, respectively; p = 0.0001).

Conclusions

Tumor control and dose to LAD should be considered during treatment since PBI may reduce the risk of coronary artery disease especially in patients with lateral tumors in the left breast.

Prevention and Treatment of Cardiac Dysfunction in Breast Cancer Survivors

As recurrence free survival following a breast cancer diagnosis continues to improve, cardiovascular morbidity and mortality will assume greater importance in the breast cancer survivorship research agenda particularly for women receiving potentially cardiotoxic therapy. Development of (1) tools to readily identify pre-diagnostic risk factors for cardiac dysfunction, (2) well-tolerated prophylactic treatments to reduce the risk of cardiac injury, and (3) sensitive and affordable monitoring techniques which can identify subclinical toxicity prior to a drop in left ventricular ejection fraction are or should be focus areas of cardio-oncology research. Since weight as well as cardiorespiratory fitness generally decline after a breast cancer diagnosis, behavioral approaches which can improve energy balance and fitness are important to optimize cardiovascular health in all breast cancer survivors not just those undergoing cardiotoxic therapy. These goals are likely best achieved by partnerships between cardiologists, oncologists and internists such as those initiated with the formation of the International CardiOncology Society (ICOS) and the NCI Community Cardiotoxicity Task Force.

Cardiomyopathy associated with cancer therapy

Chemotherapy-associated cardiomyopathy is a well known cardiotoxicity of contemporary cancer treatment and a cause of increasing concern for both cardiologists and oncologists. As cancer outcomes improve, cardiovascular disease has become a leading cause of morbidity and mortality among cancer survivors. Asymptomatic or symptomatic left ventricular systolic dysfunction in the setting of cardiotoxic chemotherapy is an important entity to recognize. Early diagnosis of cardiac injury through the use of novel blood-based biomarkers or noninvasive imaging modalities may allow for the initiation of cardioprotective medications or modification of chemotherapy regimen to minimize or prevent further damage. Several clinical trials are currently underway to determine the efficacy of cardioprotective medications for the prevention of chemotherapy-associated cardiomyopathy. Implementing a strategy that includes both early detection and prevention of cardiotoxicity will likely have a significant impact on the overall prognosis of cancer survivors. Continued coordination of care between cardiologists and oncologists remains critical to maximizing the oncologic benefit of cancer therapy while minimizing any early or late cardiovascular effects.

Codelivery of chemotherapeutics via crosslinked multilamellar liposomal vesicles to overcome multidrug resistance in tumor

Multidrug resistance (MDR) is a significant challenge to effective cancer chemotherapy treatment. However, the development of a drug delivery system that allows for the sustained release of combined drugs with improved vesicle stability could overcome MDR in cancer cells. To achieve this, we have demonstrated codelivery of doxorubicin (Dox) and paclitaxel (PTX) via a crosslinked multilamellar vesicle (cMLV). This combinatorial delivery system achieves enhanced drug accumulation and retention, in turn resulting in improved cytotoxicity against tumor cells, including drug-resistant cells. Moreover, this delivery approach significantly overcomes MDR by reducing the expression of P-glycoprotein (P-gp) in cancer cells, thus improving antitumor activity in vivo. Thus, by enhancing drug delivery to tumors and lowering the apoptotic threshold of individual drugs, this combinatorial delivery system represents a potentially promising multimodal therapeutic strategy to overcome MDR in cancer therapy.

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.

Radiotherapy and anthracyclines - cardiovascular toxicity

The subject of this paper is to analyze the impact of radiotherapy and anthracyclines on the cardiovascular system, based on a survey of contemporary literature. Currently, high efficiency of anticancer therapies has increased the rate of survival in patients treated for cancer. It should be emphasized, however, that these treatments damage not only the affected but also the healthy tissue. Consequently, with the increase of survival rate in these patients, the number of patients with complaints regarding numerous organs and systems also increases as a result of earlier treatment. Thus, during the first decade of the 21^st century, a number of concerns about the relationship between cancer treatment and dysfunction of the cardiovascular system were resolved. Anthracyclines, as well as radiotherapy, are capable of damaging the cardiovascular system, both at the central level, by the deterioration of cardiac function, and at peripheral levels, by increasing the hemodynamic and thrombotic changes.

Cardiac complications of chemotherapy: role of biomarkers

OPINION STATEMENT

Both conventional and novel antineoplastic drugs may cause damage to the heart, ultimately affecting patients' survival and quality of life. In fact, the most frequent and typical clinical manifestation of cardiotoxicity, asymptomatic or symptomatic left ventricular dysfunction, may be induced not only by conventional cancer therapy, like anthracyclines, but also by new antitumoral targeted therapy such as trastuzumab. At present, left ventricular ejection fraction assessment represents the main standard practice for cardiac monitoring during cancer therapy, but it detects myocardial damage only when a functional impairment has already occurred, not allowing for early preventive strategies. In the last decade, a newer approach based on the measurement of cardiospecific biomarkers has been proposed, proving to have higher prognostic value than imaging modalities. In particular, cardiac troponin elevation during chemotherapy allows us to identify patients who are more prone to develop myocardial dysfunction and cardiac events during follow up. In these patients, the use of an angiotensin-converting enzyme inhibitor, such as enalapril, has shown to be effective in improving clinical outcome, giving the chance for a cardioprotective strategy in a selected population.

Apoptosis induction of cardiomyocytes and subsequent fibrosis after irradiation and neoadjuvant chemotherapy

PURPOSE

Breast cancer treatments can induce important cardiovascular complications. The aim of this study was to evaluate cardiac alterations after irradiation and chemotherapy in an animal model.

MATERIAL AND METHODS

Wistar rats were divided into three groups: Control, TC+ IR (received chemotherapy and irradiation) and IR (received only irradiation). After 5 months, echocardiography was performed, the animals were euthanized, and the left ventricle was analyzed using light microscopy techniques and Polymerase Chain Reaction (PCR).

RESULTS

Echocardiography showed decreases in ejection fraction and cardiac output, in TC+ IR group. Both TC+ IR and IR showed reduced intramyocardial vessel-to-cardiomyocyte ratio, increased connective tissue, cardiomyocyte hypertrophy, increased numbers of apoptotic nuclei and increased Bax/Bcl2 expression. We also observed increased Transforming growth factor (TGF) beta 1 mRNA expression in both groups, but type 1 Procollagen expression was increased in TC+ IR group only.

CONCLUSIONS

The study suggests that the induced cardiac remodelling begins with the reduction of intramyocardial vessels in the left ventricle tissue. The main consequence is the loss of cardiomyocytes through apoptosis, leading to the replacement of healthy tissue by fibrous tissue. It was observed that the damage caused by the combination of irradiation and chemotherapy induced functional alterations that did not occur when the animals were only irradiated.

Long-term follow-up for cardiovascular disease after chemotherapy and/or radiotherapy for breast cancer in an unselected population

PURPOSE

Whereas earlier research focused on specific patient groups, this study assessed the risk of cardiovascular disease (CVD) in an unselected population curatively treated for breast cancer (BC), compared with an age-matched random sample of controls.

METHODS

Risks were determined in BC survivors and controls. CVD was divided into three categories: congestive heart failure, vascular cardiac diseases, and "other" cardiac diseases. Hazard ratios (HRs) and 95% confidence intervals (95% CI) adjusted for age, CVD, and CVD risk factors at baseline were determined by Cox regression analyses.

RESULTS

All 561 survivors of BC experienced surgery of whom 229 received (neo)adjuvant radiotherapy, 145 received chemotherapy (with or without radiotherapy), and 187 received no adjuvant therapy. During follow-up (median 9; range 5-57 years), CVD occurred in 176/561 (31%) survivors and in 398/1,635 (24%) controls. After radiotherapy, no increased risks of congestive heart failure (HR 0.5; 95% CI 0.2-1.8), vascular cardiac diseases (HR 1.1; 95% CI 0.7-1.7), or other cardiac diseases (HR 1.3; 95% CI 0.8-2.3) were found compared with controls. Similar results were found after chemotherapy for congestive heart failure (HR 1.8; 95% CI 0.6-5.8), vascular cardiac diseases (HR 1.1; 95% CI 0.5-2.3), and other cardiac diseases (HR 1.2; 95% CI 0.3-5.5).

CONCLUSIONS

In an unselected population of BC survivors, no significant increased risk of CVD after radiotherapy and/or chemotherapy was found compared with controls. However, the HRs after chemotherapy were in-line with previous studies. Future studies should include more detailed information on treatment and more specific outcome measures.

Cardiac complications of chemotherapy: role of imaging

OPINION STATEMENT

New advances in cancer diagnosis and treatment have increased survival rates in patients with cancer. In parallel with this increase in the number of cancer survivors is an increasing prevalence of cardiac complications from cancer treatment. Chemotherapy-induced cardiac dysfunction is a major contributor to adverse morbidity and mortality rates in cancer patients. Evidence suggests that both clinical symptoms and the traditional left ventricular ejection fraction (LVEF) may lack sensitivity as measures of cardiotoxicity. The early identification of subclinical LV dysfunction is becoming increasingly important, as this may allow cancer patients and their physicians to make informed decisions about therapeutic options. The features of echocardiography make it a useful tool in the diagnosis and monitoring of cardiotoxicity. This review will examine the role of cardiac imaging in detecting cardiotoxicity, focusing primarily on the conventional and more recent echocardiographic approaches for assessing subclinical cardiotoxicity.

Aqueous dispersion of polymer coated boron nitride nanotubes and their antibacterial and cytotoxicity studies

The present study focuses on the aqueous dispersion of BNNTs via noncovalent functionalization with four surfactants including pluronic (P123), polyethyleneimine (PEI), pluronic (F127) and ammonium oleate (A.O).

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.

Recombinant lipoproteins reinforce cytotoxicity of doxorubicin to hepatocellular carcinoma

Cancer nanotherapeutics are changing the landscape of tumor treatment and used to circumvent limitations of conventional chemotherapy, such as non-specificity and low bioavailability. Reconstituted high density lipoproteins (rHDL) system is one of the most promising targeting delivery systems of chemotherapeutic drugs toward tumors. Here, we developed recombined high-density lipoprotein which can be functionalized to deliver doxorubicin intracellular with a higher efficiency. The cellular viability assay showed that the rHDL/Dox nanovectors had an enhanced efficiency in inhibiting the cell viability of hepatocellular carcinoma cell lines HepG2 and SMMC-7721. FACS and confocal microscopy was used to observe the doxorubicin delivery into cancer cells. Intracellular drug accumulation analysis confirmed that treatment of rHDL/Dox nanovectors resulted in higher intracellular doxorubicin concentration to the levels exceeding that of free drug. On the premise of efficient drug delivery, rHDL/Dox nanovectors have been preliminarily demonstrated effective inducing of cytotoxic effect and cell apoptosis to both of the cell lines in vitro. Tissue distribution experiment showed that rHDL/Dox nanovectors could also deliver doxorubicin to liver effectively. So, we proposed that this lipoprotein-based strategy holds promise for a safer and more efficient delivery of chemotherapeutic agents in the treatment of hepatocellular carcinoma.

Cardiac toxicity of anticancer agents

Modern cancer therapies are highly effective in the treatment of various malignancies, but their use is limited by the potential for cardiotoxicity. The most frequent and typical clinical manifestation of cardiotoxicity is left ventricular dysfunction, induced not only by cytotoxic conventional cancer therapy like anthracyclines, but also by new antitumor targeted therapy such as trastuzumab. The current standard for monitoring cardiac function, based on periodic assessment of left ventricular ejection fraction detects cardiotoxicity only when a functional impairment has already occurred, precluding any chance of preventing its development. A novel approach, based on the use of cardiac biomarkers has emerged in the last decade, resulting in a cost-effective diagnostic tool for early, real-time identification, assessment and monitoring of cardiotoxicity. In particular, prophylactic treatment with enalapril in patients with an early increase in troponin after chemotherapy has been shown to be very effective in preventing left ventricular dysfunction and associated cardiac events. In patients developing cancer treatment induced-cardiomyopathy, complete left ventricular ejection fraction recovery and a reduction of cardiac events may be achieved only when left ventricular dysfunction is detected early after the end of cancer treatment and treatment with angiotensin-converting enzyme inhibitors, possibly in combination with beta-blockers, is promptly initiated.

Impact of cardiovascular comorbidity on ovarian cancer mortality

BACKGROUND

A retrospective cohort study utilizing prospectively collected data was conducted from August 2003 until March 2008 at M.D. Anderson Cancer Center. It is unknown whether cardiovascular comorbidity and chronic stress impact ovarian cancer outcome, which remains poor despite advances in therapy. The purpose of this study was to determine whether cardiovascular disease and markers that may be associated with stress are also associated with survival in patients with ovarian cancer.

METHODS

Participants with newly diagnosed epithelial ovarian cancer were followed until time of death or truncation of study period (median follow-up = 4.2 years; n = 271). Tumor characteristics (stage, tumor grade, histology, debulking status), demographic variables, and cardiovascular comorbidity were documented and compared to overall survival.

RESULTS

Of the nine cardiovascular events tracked during follow-up, venous thromboembolism [VTE; HR, 3.2; 95% confidence interval (CI), 1.8-5.5] and pulmonary hypertension (HR, 8.5; 95% CI, 3.9-18.7) were associated with shorter survival in multivariate analysis. In addition, high tumor grade, suboptimal cytoreduction, and baseline heart rate (HR, 1.02; 95% CI, 1.01-1.04) were related to decreased survival.

CONCLUSION

Careful management of certain cardiovascular comorbidities may extend survival in patients with ovarian cancer. Our findings suggest that increased baseline heart rate and the development of VTE and pulmonary hypertension after cancer diagnosis may be significant predictors of survival in women with ovarian cancer.

IMPACT

Our study emphasizes the importance of identifying and optimally treating tachycardia, VTE, and pulmonary hypertension in conjunction with cancer therapy.

Cardiac comorbidity is an independent risk factor for radiation-induced lung toxicity in lung cancer patients

PURPOSE

To test the hypothesis that cardiac comorbidity before the start of radiotherapy (RT) is associated with an increased risk of radiation-induced lung toxicity (RILT) in lung cancer patients.

MATERIAL AND METHODS

A retrospective analysis was performed of a prospective cohort of 259 patients with locoregional lung cancer treated with definitive radio(chemo)therapy between 2007 and 2011 (ClinicalTrials.gov Identifiers: NCT00572325 and NCT00573040). We defined RILT as dyspnea CTCv.3.0 grade ≥2 within 6 months after RT, and cardiac comorbidity as a recorded treatment of a cardiac pathology at a cardiology department. Univariate and multivariate analyses, as well as external validation, were performed. The model-performance measure was the area under the receiver operating characteristic curve (AUC).

RESULTS

Prior to RT, 75/259 (28.9%) patients had cardiac comorbidity, 44% of whom (33/75) developed RILT. The odds ratio of developing RILT for patients with cardiac comorbidity was 2.58 (p<0.01). The cross-validated AUC of a model with cardiac comorbidity, tumor location, forced expiratory volume in 1s, sequential chemotherapy and pretreatment dyspnea score was 0.72 (p<0.001) on the training set, and 0.67 (p<0.001) on the validation set.

CONCLUSION

Cardiac comorbidity is an important risk factor for developing RILT after definite radio(chemo)therapy of lung cancer patients.

Breast cancer survivorship issues

Survivors of breast cancer are confronted with a plethora of cancer treatment-related long-term symptoms, the most common being fatigue, hot flashes, sexual dysfunction, arthralgias, neuropathy, and cognitive dysfunction. Survivors of breast cancer also face cancer treatment-related disease states, such as osteoporosis, cardiac dysfunction, obesity, infertility, and secondary cancers. Evidence-based recommendations for screening, prevention, and early intervention should be implemented to improve quality of life and decrease comorbidities in this population.

Managing cardiotoxicity of chemotherapy

OPINION STATEMENT

The increase in survivorship of cancer patients makes the understanding of the available options for prevention and treatment of cardiotoxicity induced by antineoplastic agents a crucial topic both for cardiologists and oncologists. The most frequent and typical clinical manifestation of cardiotoxicity is asymptomatic or symptomatic left ventricular dysfunction, which may progress to overt heart failure. It may be induced not only by conventional cancer therapy, like anthracyclines, but also by new antitumoral targeted therapy such as trastuzumab. The current standard for monitoring cardiac damage during antineoplastic treatment, mainly based on the quantification of left ventricular ejection fraction, detects cardiac toxicity only when a functional impairment has already occurred. Evaluation of cardiac biomarkers such as troponin, however, has shown excellent sensitivity in the early detection of cardiotoxicity by the identification of patients with subclinical cardiac injury that precedes the development of cardiac dysfunction. The use of angiotensin-converting enzyme inhibitors in patients with troponin elevation during chemotherapy may be an effective tool to prevent left ventricular ejection fraction reduction and late cardiac events. There are no well established recommendations for treatment of cancer patients who develop cardiac dysfunction. Angiotensin-converting enzyme inhibitors and beta-blockers have proven to be effective in this setting. However, there are concerns in using these medications in cancer patients, and therefore the tendency is to treat patients only if symptomatic. However, the clinical benefit of these medications may be more evident in asymptomatic patients, and the recovery of cardiac function strongly depends on the amount of time elapsed from the end of chemotherapy to the start of heart failure therapy. This observation suggests that the early detection of cardiac damage is crucial and early use of angiotensin-converting enzyme inhibitors and beta-blockers should be considered in patients with left ventricular dysfunction induced by antineoplastic agents.

Early cardiac function monitoring for detection of subclinical Doxorubicin cardiotoxicity in young adult patients with breast cancer

PURPOSE

As doxorubicin cardiotoxicity is considered irreversible, early detection of cardiotoxicity and prevention of overt heart failure is essential. Although there are monitoring guidelines for cardiotoxicity, optimal timing for early detection of subclinical doxorubicin cardiotoxicity is still obscure. The purpose of this study is to determine optimal timing of cardiac monitoring and risk factors for early detection of doxorubicin cardiotoxicity in young adult patients with breast cancer.

METHODS

Medical records of 1,013 breast cancer patients diagnosed from January 2009 to December 2010 is being reviewed and analyzed. Properly monitored patients are defined as patients who underwent transthoracic echocardiography before and after the chemotherapy. The definition of subclinical cardiotoxicity (SC) either decreases left ventricular ejection fraction (LVEF) more than 10% or the LVEF declines under 55% from baseline without heart failure symptoms.

RESULTS

Twenty-nine out of 174 (16.7%) properly monitored young adult female patients (mean age, 52±10 years old) developed SC. The mean interval of cardiac evaluation of SC group was 5.5±3.0 months. Among the risk factors, the history of coronary artery disease, cumulative dose of doxorubicin ≥300 mg/m(2) and use of trastuzumab after doxorubicin therapy were associated with development of SC. At cumulative dose of doxorubicin 244.5 mg/m(2), SC can be predicted (sensitivity, 71.4%; specificity, 70.9%; area under the curve, 0.741; 95% confidence interval, 0.608-0.874; p=0.001).

CONCLUSION

In young adult patients with breast cancer, SC was common at cumulative dose of doxorubicin <300 mg/m(2) and early performance of cardiac monitoring before reaching the conventional critical dose of doxorubicin might be a proper strategy for early detection of SC.

Using cardiac biomarkers and treating cardiotoxicity in cancer

Cardiotoxicity is a frequent and serious adverse effect of both conventional and novel anticancer treatments, affecting patient survival and quality of life. The current standard for cardiac monitoring during cancer therapy, mainly based on left ventricular ejection fraction assessment, detects myocardial damage only when a functional impairment has already occurred, not allowing for early preventive strategies. Measurement of cardiospecific biomarkers has proven to have higher prognostic value than imaging modalities. In particular, cardiac troponin elevation during chemotherapy allows the identification of patients who are more prone to develop myocardial dysfunction and cardiac events during follow-up. In these patients, the use of an angiotensin-converting enzyme inhibitor such as enalapril has shown to be effective in improving clinical outcome, giving the chance for a cardioprotective strategy in a selected population. Once left ventricular dysfunction occurs, heart failure therapies currently used for other forms of left ventricular dysfunction, particularly angiotensin-converting enzyme inhibitors and β-blockers, seem to be effective. However, their use in cancer patients is still undervalued.

Synthesis of mixed (E,Z)-, (E)-, and (Z)-norendoxifen with dual aromatase inhibitory and estrogen receptor modulatory activities

The first synthesis of the tamoxifen metabolite norendoxifen is reported. This included syntheses of (E)-norendoxifen, (Z)-norendoxifen, and (E,Z)-norendoxifen isomers. (Z)-Norendoxifen displayed affinity for aromatase (Ki 442 nM), estrogen receptor-α (EC50 17 nM), and estrogen receptor-β (EC50 27.5 nM), while the corresponding values for (E)-norendoxifen were aromatase (Ki 48 nM), estrogen receptor-α (EC50 58.7 nM), and estrogen receptor-β (EC50 78.5 nM). Docking and energy minimization studies were performed with (E)-norendoxifen on aromatase, and the results provide a foundation for structure-based drug design. The oral pharmacokinetic parameters for (E,Z)-norendoxifen were determined in mice, and (Z)-norendoxifen was found to result in significantly higher plasma concentrations and exposures (AUC values) than (E)-norendoxifen. The affinities of both isomers for aromatase and the estrogen receptors, as well as the pharmacokinetic results, support the further development of norendoxifen and its analogues for breast cancer treatment.

Association of anthracycline-related cardiac histological lesions with NADPH oxidase functional polymorphisms

OBJECTIVE

Treatment with anthracyclines may cause cardiac dysfunction, but the sequence of anthracycline-induced heart lesions has been incompletely characterized. NADPH oxidase, a key mediator of oxidative cardiac damage and remodeling, modulates anthracycline clinical cardiotoxicity. Our aim was to determine which cardiac histological lesions are specifically induced by anthracycline treatment and to investigate the role of NADPH functional genetic polymorphisms in their development.

PATIENTS AND METHODS

Using a retrospective case-control design, we evaluated cardiac histological lesions and NADPH genotype (polymorphisms rs1883112, rs4673, and rs13058338) in 97 consecutive decedents with a cancer diagnosis (48 treated with anthracyclines).

RESULTS

Myocytolysis (60%), patched myocardial necrosis (19%), and myocardial fibrosis (diffuse and patched; 62% and 23%, respectively) were associated with anthracycline treatment. In patients receiving anthracyclines, NADPH oxidase polymorphism rs4673 protected against focal myocardial necrosis (odds ratio [OR], 0.11; 95% confidence interval [CI], 0.20-0.63) whereas rs1883112 was strongly associated with cardiac fibrosis (OR, 5.11; 95% CI, 1.59-16.43), which was present in all homozygotes.

CONCLUSION

Anthracyclines induce a cardiac remodeling pattern characterized by interstitial or patched fibrosis. The contribution of the functionally relevant NADPH polymorphisms rs1883112 and rs4673 to anthracycline-related heart lesions provides a plausible explanation for their modulation of cardiotoxicity. If confirmed, these findings may lead to better individualized strategies for early detection and prevention of anthracycline cardiotoxicity.

Unintended cardiac irradiation during left-sided breast cancer radiotherapy

OBJECTIVE

Cardiac irradiation during left-sided breast radiotherapy may lead to deleterious cardiac side effects. Using image guided radiotherapy, it is possible to exclude the heart from treatment fields and monitor reproducibility of virtual simulation (VS) fields at treatment delivery using electronic portal imaging (EPI). Retrospectively, we evaluate the incidence of cardiac irradiation at VS and subsequent unintended cardiac irradiation during treatment.

METHODS

Patients receiving left-sided radiotherapy to the breast or chest wall, treated with a glancing photon field technique during a four-month period, were included. VS images and EPIs during radiotherapy delivery were visually assessed. The presence of any portion of the heart within the treatment field at VS or during treatment was recorded. Central lung distance and maximum heart distance were recorded.

RESULTS

Of 128 patients, 45 (35.1%) had any portion of the heart within the planned treatment field. Of these, inclusion of the heart was clinically unavoidable in 25 (55.6%). Of those with no heart included in the treatment fields at VS, 41 (49.4%) had presence of the heart as assessed on EPI during treatment.

CONCLUSION

Unintended cardiac irradiation during left-sided breast radiotherapy treatment occurs in a sizeable proportion of patients.

ADVANCES IN KNOWLEDGE

Despite the use of three-dimensional computed tomography simulation and cardiac shielding, sizeable proportions of patients receiving left-sided breast cancer radiotherapy have unintended cardiac irradiation.

Dose Distribution in the Heart and Cardiac Chambers Following 4-field Radiation Therapy of Breast Cancer: a Retrospective Study

Purpose:

To evaluate cardiac doses in breast cancer patients with stage II/III treated with 4-field radiotherapy based on computed tomography (CT) dose planning.

Methods and Materials:

Based on archived CT images, whole heart and cardiac chamber radiation doses were analyzed in 216 (111 left-sided and 105 right-sided) mastectomized or lumpectomized breast cancer patients treated at a single institution, the Norwegian Radium Hospital, between 2000–2002. Individual dose volume histograms for the whole heart and for the four cardiac chambers were obtained, and mean, median and maximum doses to these structures were calculated. The dose (Gy) delivered to the 5% of the volume of each cardiac structure (D_5%), and the volume percentage of each structure receiving ≥ 25 Gy (V_25Gy) were reported. Normal tissue complication probability (NTCP) calculations were used to estimate the risk for ischemic heart disease (IHD).

Results:

Cohort-based medians of the whole heart mean dose (D_mean) for left- and right-sided tumors were 3.2 Gy and 1.3 Gy, respectively, with similar ventricular but lower atrial values. The atrial doses did not differ according to laterality of the breast tumor. In 13 patients with left-sided cancer, 5% of the heart volume was exposed to >25 Gy. The NTCP estimates were generelly low, with a maximum of 2.8%.

Conclusions:

During adjuvant CT-based locoregional radiotherapy of women with breast cancer, the cardiac radiation doses are, at the group level, below recommended threshold values (D_5% < 25 Gy), though individual patients with left-sided disease may exceed these limits.

Breast cancer subtypes: response to radiotherapy and potential radiosensitisation

Radiotherapy (RT) is of critical importance in the locoregional management of early breast cancer. Over 50% of patients receive RT at some time during the treatment of their disease, equating to over 500 000 patients worldwide receiving RT each year. Unfortunately, not all patients derive therapeutic benefit and some breast cancers are resistant to treatment, as evidenced by distant metastatic spread and local recurrence. Prediction of individual responses to RT may allow a stratified approach to this treatment permitting those patients with radioresistant tumours to receive higher doses of RT (total and/or tumour cavity boost doses) and/or radiosensitising agents to optimise treatment. Also, for those patients unlikely to respond at all, it would prevent harmful side effects occurring for no therapeutic gain. More selective targeting would better direct National Health Service resources, ease the burden on heavily used treatment RT machines and reduce the economic cost of cancer treatment. Unfortunately, there are no robust and validated biomarkers for predicting RT outcome. We review the available literature to determine whether classification of breast cancers according to their molecular profile may be used to predict successful response to, or increased morbidity from, RT. Class-specific biomarkers for targeting by radiosensitising agents are also discussed.

Cardiovascular toxicity induced by chemotherapy, targeted agents and radiotherapy: ESMO Clinical Practice Guidelines

Cardiovascular (CV) toxicity is a potential short- or long-term complication of various anticancer therapies. Some drugs, such as anthracyclines or other biological agents, have been implicated in causing potentially irreversible clinically important cardiac dysfunction. Although targeted therapies are considered less toxic and better tolerated by patients compared with classic chemotherapy agents, rare but serious complications have been described, and longer follow-up is needed to determine the exact profile and outcomes of related cardiac side-effects. Some of these side-effects are irreversible, leading to progressive CV disease, and some others induce reversible dysfunction with no long-term cardiac damage to the patient. Assessment of the prevalence, type and severity of cardiac toxicity caused by various cancer treatments is a breakthrough topic for patient management. Guidelines for preventing, monitoring and treating cardiac side-effects are a major medical need. Efforts are needed to promote strategies for cardiac risk prevention, detection and management, avoiding unintended consequences that can impede development, regulatory approval and patient access to novel therapy. These new ESMO Clinical Practice Guidelines are the result of a multidisciplinary cardio-oncology review of current evidence with the ultimate goal of providing strict criteria-based recommendations on CV risk prevention, assessment, monitoring and management during anticancer treatment.

Late cardiac effects of cancer treatment

Cardiac toxicities from cancer therapy can become evident many years after treatment, and these late cardiac effects can have a profound impact on cancer survivors. There are a myriad of potential cardiovascular complications from cancer therapy, but these can be grouped into three main categories. First, vascular conditions including atherosclerosis, thrombosis, and hypertension predominate. Second, cardiac structural problems, especially valvular degeneration, can have a dramatic impact long term. Lastly, and most importantly, cardiac dysfunction and heart failure are potentially common late cardiac effects and can certainly be prevented or detected early during active cancer therapy to result in optimal outcomes. Future research on late cardiac effects in cancer survivors needs to include advanced cardiac imaging techniques, novel cardiac biomarkers, and genetic determinants of response to cancer treatment.

Comparison of four immunohistochemical tests and FISH for measuring HER2 expression in gastric carcinomas

AIM

: Accurate testing for HER2 is essential to identify patients who are likely to benefit from trastuzumab therapy. Although comparative studies on the performance of commercially available immunohistochemistry (IHC) antibodies for HER2 have been performed in breast cancer, similar studies have not been done in gastric carcinoma (GC) thus far.

METHODS

: Quadruplicate tissue microarrays (TMAs) of 289 advanced GCs were immunostained with HercepTest, A0485, 4B5 and CB11, and the results were compared to those of gene amplification by fluorescence in situ hybridisation (FISH).

RESULTS

: HER2 was amplified by FISH in 38 (13.2%) GCs. HER2 overexpression (2+ or 3+) was observed in 40 (13.8%) cases by HercepTest, 46 (15.9%) by A0485, 40 (13.8%) by 4B5 and 27 (9.3%) by CB11. The sensitivity and specificity of IHC compared to FISH was 78.9%/96% for HercepTest, 86.5%/94.4% for A0485, 76.3%/95.6% for 4B5 and 60.5%/98.4% for CB11. Focal HER2 gene amplification was more common in GCs with no (0 and 1+) or low (2+) HER2 expression. Discordant IHC results were seen in 23 cases (8.0%) with the four antibodies. All HER2 3+ cases (n = 22) by HercepTest were positive with A0485 and 4B5, while one was negative with CB11. CB11 was found to be negative in 10 HercepTest 2+ and FISH+ cases.

CONCLUSION

: Focal HER2 gene amplification is more common in GCs with no or low expression of HER2. Although the specificity and positive predictive value of CB11 for FISH is highest, it lacks sufficient sensitivity to be used as a first line screening test to assess HER2 status in GCs.

Partitioning of excess mortality in population-based cancer patient survival studies using flexible parametric survival models

Background

Relative survival is commonly used for studying survival of cancer patients as it captures both the direct and indirect contribution of a cancer diagnosis on mortality by comparing the observed survival of the patients to the expected survival in a comparable cancer-free population. However, existing methods do not allow estimation of the impact of isolated conditions (e.g., excess cardiovascular mortality) on the total excess mortality. For this purpose we extend flexible parametric survival models for relative survival, which use restricted cubic splines for the baseline cumulative excess hazard and for any time-dependent effects.

Methods

In the extended model we partition the excess mortality associated with a diagnosis of cancer through estimating a separate baseline excess hazard function for the outcomes under investigation. This is done by incorporating mutually exclusive background mortality rates, stratified by the underlying causes of death reported in the Swedish population, and by introducing cause of death as a time-dependent effect in the extended model. This approach thereby enables modeling of temporal trends in e.g., excess cardiovascular mortality and remaining cancer excess mortality simultaneously. Furthermore, we illustrate how the results from the proposed model can be used to derive crude probabilities of death due to the component parts, i.e., probabilities estimated in the presence of competing causes of death.

Results

The method is illustrated with examples where the total excess mortality experienced by patients diagnosed with breast cancer is partitioned into excess cardiovascular mortality and remaining cancer excess mortality.

Conclusions

The proposed method can be used to simultaneously study disease patterns and temporal trends for various causes of cancer-consequent deaths. Such information should be of interest for patients and clinicians as one way of improving prognosis after cancer is through adapting treatment strategies and follow-up of patients towards reducing the excess mortality caused by side effects of the treatment.