Mechanisms of Exercise Intolerance Across the Breast Cancer Continuum: A Pooled Analysis of Individual Patient Data

PURPOSE

The purpose of this study is to evaluate the prevalence of abnormal cardiopulmonary responses to exercise and pathophysiological mechanism(s) underpinning exercise intolerance across the continuum of breast cancer (BC) care from diagnosis to metastatic disease.

METHODS

Individual participant data from four randomized trials spanning the BC continuum ([1] prechemotherapy [n = 146], [2] immediately postchemotherapy [n = 48], [3] survivorship [n = 138], and [4] metastatic [n = 47]) were pooled and compared with women at high-risk of BC (BC risk; n = 64). Identical treadmill-based peak cardiopulmonary exercise testing protocols evaluated exercise intolerance (peak oxygen consumption; V̇O2peak) and other resting, submaximal, and peak cardiopulmonary responses. The prevalence of 12 abnormal exercise responses was evaluated. Graphical plots of exercise responses were used to identify oxygen delivery and/or uptake mechanisms contributing to exercise intolerance. Unsupervised, hierarchical cluster analysis was conducted to explore exercise response phenogroups.

RESULTS

Mean V̇O2peak was 2.78 ml O2.kg-1·min-1 (95% confidence interval [CI], -3.94, -1.62 mL O2.kg-1·min-1; P < 0.001) lower in the pooled BC cohort (52 ± 11 yr) than BC risk (55 ± 10 yr). Compared with BC risk, the pooled BC cohort had a 2.5-fold increased risk of any abnormal cardiopulmonary response (odds ratio, 2.5; 95% confidence interval, 1.2, 5.3; P = 0.014). Distinct exercise responses in BC reflected impaired oxygen delivery and uptake relative to control, although considerable inter-individual heterogeneity within cohorts was observed. In unsupervised, hierarchical cluster analysis, six phenogroups were identified with marked differences in cardiopulmonary response patterns and unique clinical characteristics.

CONCLUSIONS

Abnormal cardiopulmonary response to exercise is common in BC and is related to impairments in oxygen delivery and uptake. The identification of exercise response phenogroups could help improve cardiovascular risk stratification and guide investigation of targeted exercise interventions.

Timing of exercise therapy when initiating adjuvant chemotherapy for breast cancer: a randomized trial

AIMS

The most appropriate timing of exercise therapy to improve cardiorespiratory fitness (CRF) among patients initiating chemotherapy is not known. The effects of exercise therapy administered during, following, or during and following chemotherapy were examined in patients with breast cancer.

METHODS AND RESULTS

Using a parallel-group randomized trial design, 158 inactive women with breast cancer initiating (neo)adjuvant chemotherapy were allocated to receive (1:1 ratio): usual care or one of three exercise regimens-concurrent (during chemotherapy only), sequential (after chemotherapy only), or concurrent and sequential (continuous) (n = 39/40 per group). Exercise consisted of treadmill walking three sessions/week, 20-50 min at 55%-100% of peak oxygen consumption (VO2peak) for ≈16 (concurrent, sequential) or ≈32 (continuous) consecutive weeks. VO2peak was evaluated at baseline (pre-treatment), immediately post-chemotherapy, and ≈16 weeks after chemotherapy. In intention-to-treat analysis, there was no difference in the primary endpoint of VO2peak change between concurrent exercise and usual care during chemotherapy vs. VO2peak change between sequential exercise and usual care after chemotherapy [overall difference, -0.88 mL O2·kg-1·min-1; 95% confidence interval (CI): -3.36, 1.59, P = 0.48]. In secondary analysis, continuous exercise, approximately equal to twice the length of the other regimens, was well-tolerated and the only strategy associated with significant improvements in VO2peak from baseline to post-intervention (1.74 mL O2·kg-1·min-1, P < 0.001).

CONCLUSION

There was no statistical difference in CRF improvement between concurrent vs. sequential exercise therapy relative to usual care in women with primary breast cancer. The promising tolerability and CRF benefit of ≈32 weeks of continuous exercise therapy warrant further evaluation in larger trials.

Nomogram for Predicting Risk of Cancer Therapy-Related Cardiac Dysfunction in Patients With Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer

BACKGROUND

Cancer therapy-related cardiac dysfunction (CTRCD) is an important treatment-limiting toxicity for patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer that adversely affects cancer and cardiovascular outcomes. Easy-to-use tools that incorporate readily accessible clinical variables for individual estimation of CTRCD risk are needed.

METHODS AND RESULTS

From 2004 to 2013, 1440 patients with stage I to III HER2-positive breast cancer treated with trastuzumab-based therapy were identified. A multivariable Cox proportional hazards model was constructed to identify risk factors for CTRCD and included the 1377 patients in whom data were complete. Nine clinical variables, including age, race, body mass index, left ventricular ejection fraction, systolic blood pressure, coronary artery disease, diabetes, arrhythmia, and anthracycline exposure were built into a nomogram estimating risk of CTRCD at 1 year. The nomogram was validated for calibration and discrimination using bootstrap resampling. A total of 177 CTRCD events occurred within 1 year of HER2-targeted treatment. The nomogram for prediction of 1-year CTRCD probability demonstrated good discrimination, with a concordance index of 0.687. The predicted and observed probabilities of CTRCD were similar, demonstrating good model calibration.

CONCLUSIONS

A nomogram composed of 9 readily accessible clinical variables provides an individualized 1-year risk estimate of CTRCD among women with HER2-positive breast cancer receiving HER2-targeted therapy. This nomogram represents a simple-to-use tool for clinicians and patients that can inform clinical decision-making on breast cancer treatment options, optimal frequency of cardiac surveillance, and role of cardioprotective strategies.

Association of Circulating Cardiomyocyte Cell-Free DNA With Cancer Therapy-Related Cardiac Dysfunction in Patients Undergoing Treatment for ERBB2-Positive Breast Cancer

Importance

Cancer therapy-related cardiac dysfunction (CTRCD) is a potentially serious cardiotoxicity of treatments for ERBB2-positive breast cancer (formerly HER2). Identifying early biomarkers of cardiotoxicity could facilitate an individualized approach to cardiac surveillance and early pharmacologic intervention. Circulating cell-free DNA (cfDNA) of cardiomyocyte origin is present during acute cardiac injury but has not been established as a biomarker of CTRCD.

Objective

To determine whether circulating cardiomyocyte cfDNA is associated with CTRCD in patients with ERBB2-positive breast cancer treated with anthracyclines and ERBB2-targeted therapy.

Design, Setting, and Participants

A prospective cohort of 80 patients with ERBB2-positive breast cancer enrolled at an academic cancer center between July 2014 and April 2016 underwent echocardiography and blood collection at baseline, after receiving anthracyclines, and at 3 months and 6 months of ERBB2-targeted therapy. Participants were treated with doxorubicin-based chemotherapy followed by trastuzumab (+/- pertuzumab). The current biomarker study includes participants with sufficient biospecimen available for analysis after anthracycline therapy. Circulating cardiomyocyte-specific cfDNA was quantified by a methylation-specific droplet digital polymerase chain reaction assay. Data for this biomarker study were collected and analyzed from June 2021 through April 2022.

Main Outcomes and Measures

The outcome of interest was 1-year CTRCD, defined by symptomatic heart failure or an asymptomatic decline in left ventricular ejection fraction (≥10% from baseline to less than lower limit of normal or ≥16%). Values for cardiomyocyte cfDNA and high-sensitivity cardiac troponin I (hs-cTnI) measured after patients completed treatment with anthracyclines were compared between patients who later developed CTRCD vs patients who did not using the Wilcoxon rank sum test, and the association of post-anthracycline cardiomyocyte cfDNA level with CTRCD was estimated using logistic regression.

Results

Of 71 patients included in this study, median (IQR) age was 50 (44-58) years, all were treated with dose-dense doxorubicin, and 48 patients underwent breast radiotherapy. Ten of 71 patients (14%) in this analysis developed CTRCD. The level of cardiomyocyte cfDNA at the post-anthracycline time point was higher in patients who subsequently developed CTRCD (median, 30.5 copies/mL; IQR, 24-46) than those who did not (median, 7 copies/mL; IQR, 2-22; P = .004). Higher cardiomyocyte cfDNA level after completion of anthracycline chemotherapy was associated with risk of CTRCD (hazard ratio, 1.02 per 1-copy/mL increase; 95% CI, 1.00-1.03; P = .046).

Conclusions and Relevance

This study found that higher cardiomyocyte cfDNA level after completion of anthracycline chemotherapy was associated with risk of CTRCD. Cardiomyocyte cfDNA quantification shows promise as a predictive biomarker to refine risk stratification for CTRCD among patients with breast cancer receiving cardiotoxic cancer therapy, and its use warrants further validation.

Trial Registration

ClinicalTrials.gov Identifier: NCT02177175.

Rationale and design of a cardiac safety study for reduced cardiotoxicity surveillance during HER2-targeted therapy

BACKGROUND

Echocardiograms are recommended every 3 months in patients receiving human epidermal growth factor 2 (HER2)-targeted therapy for surveillance of left ventricular ejection fraction (LVEF). Efforts to tailor treatment for HER2-positive breast cancer have led to greater use of non-anthracycline regimens that are associated with lower cardiotoxicity risk, raising into question the need for frequent cardiotoxicity surveillance for these patients. This study seeks to evaluate whether less frequent cardiotoxicity surveillance (every 6 months) is safe for patients receiving a non-anthracycline HER2-targeted treatment regimen.

METHODS/DESIGN

We will enroll 190 women with histologically confirmed HER2-positive breast cancer scheduled to receive a non-anthracycline HER2-targeted treatment regimen for a minimum of 12 months. All participants will undergo echocardiograms before and 6-, 12-, and 18-months after initiation of HER2-targeted treatment. The primary composite outcome is symptomatic heart failure (New York Heart Association class III or IV) or death from cardiovascular causes. Secondary outcomes include: 1) echocardiographic indices of left ventricular systolic function; 2) incidence of cardiotoxicity, defined by a ≥ 10% absolute reduction in left ventricular ejection fraction (LVEF) from baseline to < 53%; and 3) incidence of early interruption of HER2-targeted therapy.

CONCLUSIONS

To our knowledge, this will be the first prospective study of a risk-based approach to cardiotoxicity surveillance. We expect findings from this study will inform the development of updated clinical practice guidelines to improve cardiotoxicity surveillance practices during HER2-positive breast cancer treatment.

TRIAL REGISTRATION

The trial was registered in the ClinicalTrials.gov registry (identifier NCT03983382) on June 12, 2019.

Innate immune signaling drives late cardiac toxicity following DNA-damaging cancer therapies

Late cardiac toxicity is a potentially lethal complication of cancer therapy, yet the pathogenic mechanism remains largely unknown, and few treatment options exist. Here we report DNA-damaging agents such as radiation and anthracycline chemotherapies inducing delayed cardiac inflammation following therapy due to activation of cGAS- and STING-dependent type I interferon signaling. Genetic ablation of cGAS-STING signaling in mice inhibits DNA damage-induced cardiac inflammation, rescues late cardiac functional decline, and prevents death from cardiac events. Treatment with a STING antagonist suppresses cardiac interferon signaling following DNA-damaging therapies and effectively mitigates cardiac toxicity. These results identify a therapeutically targetable, pathogenic mechanism for one of the most vexing treatment-related toxicities in cancer survivors.

Association of cardiac calcium burden with overall survival after radiotherapy for non-small cell lung cancer

Background and purpose

Coronary calcifications are associated with coronary artery disease in patients undergoing radiotherapy (RT) for non-small cell lung cancer (NSCLC). We quantified calcifications in the coronary arteries and aorta and investigated their relationship with overall survival (OS) in patients treated with definitive RT (Def-RT) or post-operative RT (PORT).

Materials and methods

We analyzed 263 NSCLC patients treated from 2004 to 2017. Calcium burden was ascertained with a Hounsfield unit (HU) cutoff of > 130 in addition to a deep learning (DL) plaque estimator. The HU cutoff volumes were defined for coronary arteries (Plaque_Coro) and coronary arteries and aorta combined (Plaque_Coro+Ao), while the DL estimator ranged from 0 (no plaque) to 3 (high plaque). Patient and treatment characteristics were explored for association with OS.

Results

The median Plaque_Coro and Plaque_Coro+Ao was 0.75 cm³ and 0.87 cm³ in the Def-RT group and 0.03 cm³ and 0.52 cm³ in the PORT group. The median DL estimator was 2 in both cohorts. In Def-RT, large Plaque_Coro (HR:1.11 (95%CI:1.04-1.19); p = 0.008), and Plaque_Coro+Ao (HR:1.06 (95%CI:1.02-1.11); p = 0.03), and poor Karnofsky Performance Status (HR: 0.97 (95%CI: 0.94-0.99); p = 0.03) were associated with worse OS. No relationship was identified between the plaque volumes and OS in PORT, or between the DL plaque estimator and OS in either Def-RT or PORT.

Conclusions

Coronary artery calcification assessed from RT planning CT scans was significantly associated with OS in patients who underwent Def-RT for NSCLC. This HU thresholding method can be straightforwardly implemented such that the role of calcifications can be further explored.

Effects and tolerability of exercise therapy modality on cardiorespiratory fitness in lung cancer: a randomized controlled trial

BACKGROUND

Poor cardiorespiratory fitness (CRF) is a cardinal feature of post-treatment primary lung cancer. The most effective exercise therapy regimen to improve CRF has not been determined.

METHODS

In this parallel-group factorial randomized controlled trial, lung cancer survivors with poor CRF (below age-sex sedentary values) were randomly allocated to receive 48 consecutive supervised sessions thrice weekly of (i) aerobic training (AT)-cycle ergometry at 55% to >95% of peak oxygen consumption (VO₂ peak); (ii) resistance training (RT)-lower and upper extremity exercises at 50-85% of maximal strength; (iii) combination training (CT)-AT plus RT; or (iv) stretching attention control (AC) for 16 weeks. The primary endpoint was change in CRF (VO₂ peak, mL O₂ ·kg^-1 ·min^-1 ). Secondary endpoints were body composition, muscle strength, patient-reported outcomes, tolerability (relative dose intensity of exercise), and safety. Analysis of covariance determined change in primary and secondary endpoints from baseline to post-intervention (Week 17) with adjustment for baseline values of the endpoint and other relevant clinical covariates.

RESULTS

Ninety patients (65 ± 9 years; 66% female) were randomized (AT, n = 24; RT, n = 23; CT, n = 20; and AC, n = 23) of the planned n = 160. No serious adverse events were observed. For the overall cohort, the lost-to-follow-up rate was 10%. Mean attendance was ≥75% in all groups. In intention-to-treat analysis, VO₂ peak increased 1.1 mL O₂ ·kg^-1 ·min^-1 [95% confidence interval (CI): 0.0, 2.2, P = 0.04] and 1.4 mL O₂ ·kg^-1 ·min^-1 (95% CI: 0.2, 2.5, P = 0.02) in AT and CT, respectively, compared with AC. There was no difference in VO₂ peak change between RT and AC (-0.1 mL O₂ ·kg^-1 ·min^-1 , 95% CI: -1.2, 1.0, P = 0.88). Favourable improvements in maximal strength and body composition were observed in RT and CT groups compared with AT and AC groups (Ps < 0.05). No between-group changes were observed for any patient-reported outcomes. Relative dose intensity of exercise was lower in RT and CT compared with AT (Ps < 0.05).

CONCLUSIONS

In the context of a smaller than planned sample size, AT and CT significantly improved VO₂ peak in lung cancer survivors; however, the tolerability-to-benefit ratio was superior for AT and hence may be the preferred modality to target impaired CRF in post-treatment lung cancer survivors.

Coronary Artery Disease in Young Women After Radiation Therapy for Breast Cancer: The WECARE Study

Background

Radiation therapy (RT) for breast cancer increases risk of coronary artery disease (CAD). Women treated for left- vs right-sided breast cancer receive greater heart radiation exposure, which may further increase this risk. The risk of radiation-associated CAD specifically among younger breast cancer survivors is not well defined.

Objectives

The purpose of this study was to report CAD risk among participants in the Women's Environmental Cancer and Radiation Epidemiology Study.

Methods

A total of 1,583 women who were <55 years of age when diagnosed with breast cancer between 1985 and 2008 completed a cardiovascular health questionnaire. Risk of radiation-associated CAD was evaluated by comparing women treated with left-sided RT with women treated with right-sided RT using multivariable Cox proportional hazards models. Effect modification by treatment and cardiovascular risk factors was examined.

Results

In total, 517 women who did not receive RT and 94 women who had a pre-existing cardiovascular disease diagnosis were excluded, leaving 972 women eligible for analysis. Their median follow-up time was 14 years (range 1-29 years). The 27.5-year cumulative incidences of CAD for women receiving left- vs right-sided RT were 10.5% and 5.8%, respectively (P = 0.010). The corresponding HR of CAD for left- vs right-sided RT in the multivariable Cox model was 2.5 (95% CI: 1.3-4.7). There was no statistically significant effect modification by any factor evaluated.

Conclusions

Young women treated with RT for left-sided breast cancer had over twice the risk of CAD compared with women treated with RT for right-sided breast cancer. Laterality of RT is independently associated with an increased risk of CAD and should be considered in survivorship care of younger breast cancer patients.

Increasing Heart Dose Reduces Overall Survival in Patients Undergoing Postoperative Radiation Therapy for NSCLC

Introduction

Given the concern for cardiopulmonary toxicity in patients with NSCLC undergoing postoperative radiation therapy (PORT), the purpose of this study was to evaluate the association between heart dose and overall survival (OS) in patients undergoing PORT with modern techniques.

Methods

This is a retrospective study of consecutive patients with NSCLC treated with PORT between May 2004 and January 2017. Clinical records were reviewed and radiation dose distributions were analyzed for association with OS.

Results

A total of 284 patients were analyzed. At the time of surgery, most patients had pathologic American Joint Committee on Cancer seventh edition stage III disease (91.2 %) and received either preoperative or adjuvant chemotherapy (92.3 %). Most patients underwent a lobectomy (81.3 %) and had R0 (80.6 %) or R1 (19.4 %) resection. PORT was delivered with a median radiation dose of 54 Gy, and 70.4 % of patients were treated with intensity-modulated radiation therapy. Dosimetric variables across a large range of doses to the heart were highly significant (p < 0.05) for OS. The volume of the heart receiving 8 Gy (HV8) was the most significant dosimetric variable (p < 0.001), and the median HV8 was 35.5 %. The median OS was 33.2 versus 53.6 months (p < 0.005) for patients with HV8 above or below 35.5 %, respectively. On multivariable analysis accounting for other potential prognostic confounders, HV8 remained highly significant (p < 0.001).

Conclusions

The data reveal a strong correlation between increasing heart dose and OS in patients with NSCLC undergoing PORT. Taken together with the recently presented LungART trial, lowering heart dose in PORT patients may help to decrease the risk of morbidity and mortality and improve the therapeutic ratio of PORT.

Racial and Socioeconomic Disparities in Cardiotoxicity Among Women With HER2-Positive Breast Cancer

Breast cancer and cardiovascular-specific mortality are higher among blacks compared with whites, but disparities in cancer therapy-related adverse cardiovascular outcomes have not been well studied. We assessed for the contribution of race and socioeconomic status on cardiotoxicity among women with HER2-positive breast cancer. This retrospective cohort analysis studied women diagnosed with stage I-III HER2-positive breast cancer from 2004-2013. All underwent left ventricular ejection fraction assessment at baseline and at least one follow-up after beginning trastuzumab. Multivariable logistic regression was used to assess the association between race and socioeconomic status (SES) on cardiotoxicity, defined by clinical heart failure (New York Heart Association class III or IV) or asymptomatic left ventricular ejection fraction decline (absolute decrease ≥ 10% to < 53%, or ≥ 16%). Blacks had the highest prevalence of hypertension, diabetes, and increased BMI. Neighborhood-level SES measures including household income and educational attainment were lower for blacks compared with whites and others. The unadjusted cardiotoxicity risk was significantly higher in black compared with white women (OR, 2.10; 95% CI, 1.42 to 3.10). In a multivariable analysis, this disparity persisted after controlling for relevant cardiovascular risk factors (adjusted OR, 1.88; 95% CI, 1.25 to 2.84). Additional models adjusting for SES factors of income, educational attainment, and insurance status did not significantly alter the association between race and cardiotoxicity. In conclusion, black women are at increased risk of cardiotoxicity during HER2-targeted breast cancer therapy. Future etiologic analyses, particularly studies exploring biologic or genetic mechanisms, are needed to further elucidate and reduce racial disparities in cardiotoxicity.

Long-term follow-up assessment of cardiac safety in SAFE-HEaRt, a clinical trial evaluating the use of HER2-targeted therapies in patients with breast cancer and compromised heart function

PURPOSE

HER2-targeted therapies are associated with cardiotoxicity which is usually asymptomatic and reversible. We report the updated cardiac safety assessment of patients with compromised heart function receiving HER2-targeted therapy for breast cancer, enrolled in the SAFE-HEaRt trial, at a median follow-up of 3.5 years.

METHODS

Thirty patients with stage I-IV HER2-positive breast cancer receiving trastuzumab with or without pertuzumab, or ado-trastuzumab emtansine (T-DM1), with asymptomatic LVEF (left ventricular ejection fraction) 40-49%, were started on cardioprotective medications, with the primary endpoint being completion of HER2-targeted therapy without cardiac events (CE) or protocol-defined asymptomatic worsening of LVEF. IRB-approved follow-up assessment included 23 patients.

RESULTS

Median follow-up as of June 2020 is 42 months. The study met its primary endpoint with 27 patients (90%) completing their HER2-targeted therapies without cardiac issues. Of the 23 evaluable patients at long-term f/u, 14 had early stage breast cancer, and 9 had metastatic disease, 8 of whom remained on HER2-targeted therapies. One patient developed symptomatic heart failure with no change in LVEF. There were no cardiac deaths. The mean LVEF improved to 52.1% from 44.9% at study baseline, including patients who remained on HER2-targeted therapy, and those who received prior anthracyclines.

CONCLUSIONS

Long-term follow-up of the SAFE-HEaRt study continues to provide safety data of HER2-targeted therapy use in patients with compromised heart function. The late development of cardiac dysfunction is uncommon and continued multi-disciplinary oncologic and cardiac care of patients is vital for improved patient outcomes.

Long-term Cardiopulmonary Consequences of Treatment-Induced Cardiotoxicity in Survivors of ERBB2-Positive Breast Cancer

Importance

Trastuzumab improves outcomes in patients with ERBB2-positive (formerly HER2) breast cancer but is associated with treatment-induced cardiotoxicity, most commonly manifest by an asymptomatic decline in left ventricular ejection fraction (LVEF). Little is known to date regarding the long-term effects of treatment-induced cardiotoxicity on cardiopulmonary function in patients who survive trastuzumab-treated breast cancer.

Objective

To determine whether treatment-induced cardiotoxicity recovers or is associated with long-term cardiopulmonary dysfunction in survivors of ERBB2-positive breast cancer.

Design, Setting, and Participants

This cross-sectional case-control study enrolled patients with nonmetastatic ERBB2-positive breast cancer after completion of trastuzumab-based therapy (median, 7.0 [interquartile range (IQR), 6.2-8.7] years after therapy) who met 1 of 2 criteria: (1) cardiotoxicity (TOX group) developed during trastuzumab treatment (ie, asymptomatic decrease of LVEF≥10% from baseline to <55% [n = 22]) or (2) no evidence of cardiotoxicity during trastuzumab treatment (NOTOX group [n = 20]). Patients were treated at the Memorial Sloan Kettering Cancer Center. Fifteen healthy control participants (HC group) were also enrolled for comparison purposes. All groups were frequency matched by age strata (<55, 55-64, and ≥65 years). Data were collected from September 9, 2016, to August 10, 2018, and analyzed from November 20, 2018, to August 12, 2019.

Main Outcomes and Measures

Speckle-tracking echocardiography and maximal cardiopulmonary exercise testing were performed to measure indices of left ventricular function (including LVEF and global longitudinal strain [GLS]) and peak oxygen consumption (peak VO2).

Results

A total of 57 participants (median age, 60.8 [IQR, 52.7-65.7] years) were included in the analysis. Overall, 38 of 42 patients with breast cancer (90%) were treated with anthracyclines before trastuzumab. Resting mean (SD) LVEF was significantly lower in the TOX group (56.9% [5.2%]) compared with the NOTOX (62.4% [4.0%]) and HC (65.3% [2.9%]) groups; similar results were found for GLS (TOX group, -17.8% [2.2%]; NOTOX group, -19.8% [2.2%]; HC group, -21.3% [1.8%]) (P < .001). Mean peak VO2 in the TOX group (22.9 [4.4] mL/kg/min) was 15% lower compared with the NOTOX group (27.0 [5.3] mL/kg/min; P = .03) and 25% lower compared with the HC group (30.5 [3.4] mL/ kg/min; P < .001). In patients with breast cancer, GLS was significantly associated with peak VO2 (β coefficient, -0.75; 95% CI, -1.32 to -0.18).

Conclusions and Relevance

Treatment-induced cardiotoxicity appears to be associated with long-term marked impairment of cardiopulmonary function and may contribute to increased risk of late-occurring cardiovascular disease in survivors of ERBB2-positive breast cancer.

Cardiotoxicity Surveillance and Risk of Heart Failure During HER2 Targeted Therapy

BACKGROUND

Guidelines recommend left ventricular ejection fraction (LVEF) assessments every 3 months for cardiotoxicity monitoring during human epidermal growth factor receptor 2 (HER2) targeted therapy. Evidence in support of this practice is lacking.

OBJECTIVES

This study examines the association between adherence to cardiotoxicity surveillance guidelines and heart failure (HF) in HER2-positive breast cancer patients.

METHODS

A case-control study was performed in 53 patients who developed cardiotoxicity during HER2 targeted therapy, and 159 controls matched by age, anthracycline exposure, and year of treatment. Cardiotoxicity was defined as HF (New York Heart Association functional class III or IV) or cardiac death. Adherence to cardiotoxicity surveillance guidelines was ascertained from the beginning of HER2 targeted therapy to the diagnosis date of HF for cases or the corresponding timepoint for matched controls. Conditional logistic regression was used for case-control comparisons.

RESULTS

Eighty-one percent of cases and controls were previously treated with an anthracycline. Adherence to cardiotoxicity surveillance guidelines during the entire observation period or during the first 6 months of treatment was not associated with lower risk of HF. An LVEF <55% at any surveillance timepoint was identified in 49% of cases and 3% of controls, and an LVEF <55% during the final surveillance timepoint before developing HF was identified in 54% of cases and 4% of controls. In multivariable-adjusted analyses, LVEF <55% at any timepoint or during the final surveillance timepoint (odds ratio: 27.0; 95% confidence interval: 9.3 to 78.8 and odds ratio: 25.6; 95% confidence interval: 7.3 to 90.3, respectively) was associated with HF.

CONCLUSIONS

Patients with LVEF <55% on routine surveillance during HER2 targeted therapy are at increased risk for HF. Additional studies to define their optimal management are warranted.

Effects of Exercise Therapy Dosing Schedule on Impaired Cardiorespiratory Fitness in Patients With Primary Breast Cancer: A Randomized Controlled Trial

BACKGROUND

Current exercise guidelines for clinical populations recommend an exercise therapy (ET) prescription of fixed intensity (moderate), duration (40-50 minutes per session), and volume (120-160 min/wk). A critical overarching element of exercise programming that has received minimal attention is dose scheduling. We investigated the tolerability and efficacy of 2 exercise training dose regimens on cardiorespiratory fitness and patient-reported outcomes in patients with posttreatment primary breast cancer.

METHODS

Using a parallel-group randomized trial, we randomly allocated 174 postmenopausal patients (2.8 years after adjuvant therapy) with impaired peak oxygen consumption (VO₂peak) to 1 of 2 supervised exercise training interventions delivered with a standard linear (LET) (fixed dose intensity per session for 160 min/wk) or nonlinear (NLET) (variable dose intensity per session for ≈120 min/wk) schedule compared with a stretching attention control group for 16 consecutive weeks. Stretching was matched to exercise dosing arms on the basis of location, frequency, duration, and treatment length. The primary end point was change in VO₂peak (mL O₂·kg^-1·min^-1) from baseline to after intervention. Secondary end points were patient-reported outcomes, tolerability, and safety.

RESULTS

No serious adverse events were observed. Mean attendance was 64%, 75%, and 80% for attention control, LET, and NLET, respectively. In intention-to-treat analysis, VO₂peak increased 0.6±1.7 mL O₂·kg^-1·min^-1 (P=0.05) and 0.8±1.8 mL O₂·kg^-1·min^-1 (P=0.07) in LET and NLET, respectively, compared with attention control. Change in VO₂peak ranged from -2.7 to 4.1 mL O₂·kg^-1·min^-1 and from -3.6 to 5.1 mL O₂·kg^-1·min^-1 in LET and NLET, respectively. Approximately 40% of patients in both exercise dosing regimens were classified as VO₂peak responders (ie, Δ ≥1.32 mL O₂·kg^-1·min^-1). NLET improved all patient-reported outcomes compared with attention control.

CONCLUSIONS

Short-term exercise training, independently of dosing schedule, is associated with modest improvements in cardiorespiratory fitness in patients previously treated for early-stage breast cancer.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01186367.

Cardiotoxicity of Contemporary Breast Cancer Treatments

OPINION STATEMENT

Treatment-related cardiotoxicity remains a significant concern for breast cancer patients undergoing cancer treatment and extends into the survivorship period, with adverse cardiovascular (CV) outcomes further compounded by the presence of pre-existing CV disease or traditional CV risk factors. Awareness of the cardiotoxicity profiles of contemporary breast cancer treatments and optimization of CV risk factors are crucial in mitigating cardiotoxicity risk. Assessment of patient- and treatment-specific risk with appropriate CV surveillance is another key component of care. Mismatch between baseline cardiotoxicity risk and intensity of cardiotoxicity surveillance can lead to unnecessary downstream testing, increased healthcare expenditure, and interruption or discontinuation of potentially life-saving treatment. Efforts to identify early imaging and/or circulating biomarkers of cardiotoxicity and develop effective management strategies are needed to optimize the CV and cancer outcomes of breast cancer survivors.

Prospective evaluation of the cardiac safety of HER2-targeted therapies in patients with HER2-positive breast cancer and compromised heart function: the SAFE-HEaRt study

Purpose

HER2-targeted therapies have substantially improved the outcome of patients with breast cancer, however, they can be associated with cardiac toxicity. Guidelines recommend holding HER2-targeted therapies until resolution of cardiac dysfunction. SAFE-HEaRt is the first trial that prospectively tests whether these therapies can be safely administered without interruptions in patients with cardiac dysfunction.

Methods

Patients with stage I–IV HER2-positive breast cancer candidates for trastuzumab, pertuzumab or ado-trastuzumab emtansine (TDM-1), with left ventricular ejection fraction (LVEF) 40–49% and no symptoms of heart failure (HF) were enrolled. All patients underwent cardiology visits, serial echocardiograms and received beta blockers and ACE inhibitors unless contraindicated. The primary endpoint was completion of the planned HER2-targeted therapies without developing either a cardiac event (CE) defined as HF, myocardial infarction, arrhythmia or cardiac death or significant asymptomatic worsening of LVEF. The study was considered successful if planned oncology therapy completion rate was at least 30%.

Results

Of 31 enrolled patients, 30 were evaluable. Fifteen patients were treated with trastuzumab, 14 with trastuzumab and pertuzumab, and 2 with TDM-1. Mean LVEF was 45% at baseline and 46% at the end of treatment. Twenty-seven patients (90%) completed the planned HER2-targeted therapies. Two patients experienced a CE and 1 had an asymptomatic worsening of LVEF to ≤ 35%.

Conclusion

This study provides safety data of HER2-targeted therapies in patients with breast cancer and reduced LVEF while receiving cardioprotective medications and close cardiac monitoring. Our results demonstrate the importance of collaboration between cardiology and oncology providers to allow for delivery of optimal oncologic care to this unique population.

Electronic supplementary material

The online version of this article (10.1007/s10549-019-05191-2) contains supplementary material, which is available to authorized users.

Assessment of Early Radiation-Induced Changes in Left Ventricular Function by Myocardial Strain Imaging After Breast Radiation Therapy

BACKGROUND

Radiation therapy (RT)-induced cardiotoxicity is among the concerning sequelae of breast cancer (BCA) treatment, particularly in HER2-positive BCA patients who receive anthracyclines and trastuzumab-based therapy. The aim of this study was to assess for early RT-induced changes in echocardiographic and circulating biomarkers of left ventricular (LV) function and evaluate their association with radiation dose to the heart among patients with HER2-positive BCA treated with contemporary RT.

METHODS

A total of 47 women with HER2-positive BCA who were treated with an anthracycline, trastuzumab, and RT to the breast and/or chest wall ± regional lymph nodes were included in this study. Two-dimensional echocardiography with speckle-tracking imaging was performed at baseline (prechemotherapy), prior to and after RT (pre-RT and post-RT), and 6 months post-RT. High-sensitivity troponin I (hsTnI) was measured pre-RT and post-RT. Associations between mean heart dose (MHD) and changes in LV function after RT were examined in multivariable linear regression models.

RESULTS

The MHD was 1.8 ± 1.5 Gy for patients receiving left-sided RT (n = 26) and 1.1 ± 1.3 Gy for patients receiving right-sided RT (n = 21). Pre-RT, post-RT, and 6-month post-RT echocardiograms were performed at median (interquartile range) of 49 days (27, 77) before and 54 days (25, 78) and 195 days (175, 226) after RT, respectively. Compared with pre-RT, a minimal decrease in LV ejection fraction was observed post-RT (61% ± 7% vs 59% ± 8%; P = .003) without any significant change in global longitudinal, circumferential, or radial strain or diastolic indices at the post-RT timepoint. Median (interquartile range) concentrations of hsTnI decreased from 5.7 pg/mL (3.0, 8.7) pre-RT to 3.7 pg/mL (2.0, 5.9) post-RT. There was no significant change in systolic or diastolic indices of LV function at 6 months post-RT compared with pre-RT. MHD was not associated with changes in echocardiographic parameters of LV function after RT.

CONCLUSIONS

Breast RT using contemporary techniques can be delivered without evidence of early subclinical LV dysfunction or injury as measured by echocardiography and hsTnI in patients treated with anthracyclines and trastuzumab. Future studies should focus on identifying alternative biomarkers to elucidate early RT-induced cardiovascular effects and further characterizing long-term cardiovascular outcomes associated with contemporary breast RT.

Management and outcomes of patients with atrial fibrillation and a history of cancer: the ORBIT-AF registry

Aims

The presence of cancer can complicate treatment choices for patients with atrial fibrillation (AF) increasing both the risk of thrombotic and bleeding events.

Methods and results

Using data from Outcomes Registry for Better Informed Treatment of Atrial Fibrillation, we aimed to characterize AF patients with cancer, to describe their management and to assess the association between cancer and cardiovascular (CV) outcomes. Among 9749 patients, 23.8% had history of cancer (57% solid malignancy, 1.3% leukaemia, 3.3% lymphoma, 40% other type, and 2.2% metastatic cancer). Patients with history of cancer were older, more likely to have CV disease, CV risk factors, and prior gastrointestinal bleeding. No difference in antiarrhythmic and antithrombotic therapy was observed between those with and without cancer. Patients with history of cancer had a significantly higher risk of death (7.8 vs. 4.9 deaths per 100 patient-years follow-up, P = 0.0003) mainly driven by non-CV death (4.2 vs. 2.4 per 100 patient-years follow-up; P = 0.0004) and higher risk of major bleeding (5.1 vs. 3.5 per 100 patient-years follow-up; P = 0.02) compared with non-cancer patients; no differences were observed in risks of strokes/non-central nervous system embolism (1.96 vs. 1.48, P = 0.74) and CV death (2.89 vs. 2.07, P = 0.35) between the two groups.

Conclusion

A history of cancer is common among AF patients with up to one in four patients having both. Antithrombotic therapy, rates of cerebrovascular accident, other thrombotic events and cardiac death were similar in AF patients with or without a history of cancer. Patients with cancer, however, were at higher risk of major bleeding and non-CV death.

Prognostic and Added Value of Two-Dimensional Global Longitudinal Strain for Prediction of Survival in Patients with Light Chain Amyloidosis Undergoing Autologous Hematopoietic Cell Transplantation

BACKGROUND

Autologous hematopoietic cell transplantation (HCT) is a first-line therapy for prolonging survival in patients with light-chain (AL) amyloidosis. Cardiac involvement is the most important determinant of survival. However, patients with advanced cardiac involvement have often been excluded from HCT because of high risk for transplantation-related mortality and poor overall survival. Whether baseline left ventricular global longitudinal strain (GLS) can provide additional risk stratification and predict survival after HCT in this high-risk population remains unclear. The aim of this study was to evaluate the prognostic implication of baseline GLS and the added value of GLS beyond circulating cardiac biomarkers for risk stratification in patients with AL amyloidosis undergoing HCT.

METHODS

Eighty-two patients with newly diagnosed AL amyloidosis who underwent upfront HCT between January 2007 and April 2014 were included in the study. Clinical, echocardiographic, and serum cardiac biomarker data were collected at baseline and 12 months following HCT. GLS measurements were performed using a vendor-independent offline system. The median follow-up time for survivors was 58 months.

RESULTS

Sixty-four percent of patients were in biomarker-based Mayo stage II or III. GLS, brain natriuretic peptide, troponin, and mitral E/A ratio were identified as the strongest predictors of survival (P < .0001). Other predictors included sex, creatinine, free AL, wall thickness, and ejection fraction. Mayo stage was significantly associated with outcome, with 5-year survival of 93%, 72% and 31% in stage I, II, and III patients, respectively. GLS of 17% was identified as the value that best discriminated survivors from nonsurvivors, and the application of this cutoff value provided further mortality risk stratification within each Mayo stage.

CONCLUSIONS

GLS is a strong predictor of survival in patients with AL amyloidosis undergoing HCT, potentially providing incremental value over serum cardiac biomarkers for risk stratification. GLS should be considered as a standard parameter along with serum cardiac biomarkers when evaluating eligibility for HCT or other investigational therapies.

Cardiac safety of non-anthracycline trastuzumab-based therapy for HER2-positive breast cancer

PURPOSE

Trastuzumab improves overall survival for women with HER2-positive breast cancer but is associated with cardiotoxicity, especially when administered after anthracyclines. Use of non-anthracycline trastuzumab-based regimens is rising, particularly for patients with low-risk disease or with multiple cardiovascular risk factors. We performed a single-center retrospective cohort study to assess the cardiac safety of trastuzumab without anthracyclines outside of a clinical trial setting.

METHODS

A retrospective chart review was conducted of patients with HER2-positive early-stage breast cancer receiving non-anthracycline trastuzumab-based therapy between January 2010 and June 2014. Cardiovascular risk factors, left ventricular ejection fraction (LVEF), and treatment interruption data were collected. The primary outcome was a cardiac event (CE), defined by New York Heart Association class III or IV heart failure or cardiac death. The secondary outcome was a significant asymptomatic decline of LVEF (>10% to <55% or >16% from baseline).

RESULTS

A total of 165 patients were identified with a median age of 59 years (range 32-85 years). Seventy (42%) had hypertension, 52 (32%) had hyperlipidemia, 29 (18%) had diabetes, and 5 (3%) had coronary artery disease. All patients had a LVEF >50% (median 67%; range 50-80%) at baseline. Two (1.2%) patients with multiple cardiovascular risk factors developed a CE. After discontinuation of trastuzumab, both patients had recovery of LVEF to >50% and resolution of heart failure symptoms. Ten (6.1%) patients developed significant asymptomatic LVEF decline during trastuzumab therapy.

CONCLUSIONS

The overall incidence of symptomatic heart failure and asymptomatic LVEF decline among patients receiving trastuzumab without anthracyclines remains low. These findings suggest that less intensive cardiac monitoring may be appropriate during trastuzumab therapy without anthracyclines.

Management of ischemic coronary disease in patients receiving chemotherapy: an uncharted clinical challenge

Acute coronary syndrome (ACS) coinciding with active malignancy presents a unique clinical challenge given intersecting pathophysiology and treatment-related effects. There is little established clinical guidance on management strategies, rendering most treatment approaches anecdotal. We present a case highlighting the complexity of managing a patient being treated for malignancy who concurrently suffers from ACS. We then review the literature on co-management of ACS and malignancy, including reports of specific cancer therapies associated with ACS, unique features of clinical presentation and optimal use of dual antiplatelet therapy to minimize risks of bleeding and thrombosis. We also describe gaps in current literature, challenges in systematically studying the clinical intersection of these disease processes and propose alternative methodologies for further research.

Cardiac Safety of Dual Anti-HER2 Therapy in the Neoadjuvant Setting for Treatment of HER2-Positive Breast Cancer

BACKGROUND

Trastuzumab and pertuzumab are approved for the neoadjuvant treatment of human epidermal growth receptor 2 (HER2)-positive breast cancer, but cardiac safety data is limited. We report the cardiac safety of dose-dense doxorubicin and cyclophosphamide (AC) followed by paclitaxel, trastuzumab, and pertuzumab (THP) in the neoadjuvant setting followed by adjuvant trastuzumab-based therapy.

METHODS

Fifty-seven patients treated with neoadjuvant dose-dense AC-THP followed by adjuvant trastuzumab-based therapy between September 1, 2013, and March 1, 2015, were identified. The primary outcome was cardiac event rate, defined by heart failure (New York Heart Association [NYHA] class III/IV) or cardiac death. Patients underwent left ventricular ejection fraction (LVEF) monitoring at baseline, after AC, and serially during 1 year of anti-HER2 therapy.

RESULTS

The median age was 46 years (range 26-68). Two (3.5%) patients developed NYHA class III/IV heart failure 5 and 9 months after initiation of trastuzumab-based therapy, leading to permanent discontinuation of anti-HER2 treatment. Seven (12.3%) patients developed a significant LVEF decline (without NYHA class III/IV symptoms). The median LVEF was 65% (range 55%-75%) at baseline and 64% (range 53%-72%) after AC, and decreased to 60% (range 35%-70%), 60% (range 23%-73%), 61% (range 25%-73%), and 58% (range 28%-66%) after 3, 6, 9, and 12 months (± 6 weeks) of trastuzumab-based therapy.

CONCLUSION

The incidence of NYHA class III/IV heart failure after neoadjuvant AC-THP (followed by adjuvant trastuzumab-based therapy) is comparable to rates reported in trials of sequential doxorubicin and trastuzumab. Our findings do not suggest an increased risk of cardiotoxicity from trastuzumab plus pertuzumab following a doxorubicin-based regimen.

IMPLICATIONS FOR PRACTICE

Dual anti-human epidermal growth receptor 2 (HER2) therapy with trastuzumab and pertuzumab combined with standard chemotherapy has received accelerated approval for the neoadjuvant treatment of stage II-III HER2-positive breast cancer. Cardiac safety data for trastuzumab and pertuzumab in this setting are limited to clinical trials that utilized epirubicin-based chemotherapy. Formalized investigations into the cardiac safety of trastuzumab and pertuzumab with doxorubicin- (rather than epirubicin) based regimens are important because these regimens are widely used for the adjuvant and neoadjuvant treatment of breast cancer. The known role of HER2 signaling in the physiological adaptive responses of the heart provides further rationale for study on the potential cardiotoxicity of dual anti-HER2 blockade. Findings from this retrospective study provide favorable preliminary data on the cardiac safety of trastuzumab and pertuzumab in combination with a regimen of neoadjuvant doxorubicin and cyclophosphamide followed by paclitaxel, one of the preferred breast cancer treatment regimens, according to the National Comprehensive Cancer Network.

Pathologic Complete Response with Neoadjuvant Doxorubicin and Cyclophosphamide Followed by Paclitaxel with Trastuzumab and Pertuzumab in Patients with HER2-Positive Early Stage Breast Cancer: A Single Center Experience

OBJECTIVES

Trastuzumab (H) and pertuzumab (P) with standard chemotherapy is approved for use in the neoadjuvant setting for human epidermal growth receptor 2 -positive patients. A retrospective analysis was performed of patients treated with dose-dense (dd) doxorubicin and cyclophosphamide (AC) followed by paclitaxel (T), trastuzumab, and pertuzumab (THP) in the neoadjuvant setting. Here, the pathologic complete response (pCR) rates are reported.

METHODS

An electronic medical record review was conducted of patients treated with HP-based therapy in the neoadjuvant setting from September 1, 2013, to March 1, 2015. Data on patient demographics, stage of breast cancer, pathology reports, surgical data, and information on systemic therapy were collected. The pCR was defined as total (tpCR, ypT0/is ypN0), German Breast Group (GBG) pCR (ypT0 ypN0), breast pCR (bpCR) with in situ disease (ypT0/is) and without in situ disease (ypT0), and explored axillary pCR (ypN0).

RESULTS

Charts from 66 patients were reviewed, and 57 patients were evaluable for pCR. Median age was 46 years (range 26-68 years). Median tumor size was 4 cm. Of 57 patients, 53 (93%) had operable breast cancer (T1-3, N0-1, M0). Three patients (5.3%) had locally advanced disease (T2-3, N2-3, M0 or T4a-c, any N, M0), and 1 (1.7%) had inflammatory breast cancer (T4d, any N, M0). Overall, 44 (77%) and 13 (23%) had hormone receptor (HR)-positive and negative diseases, respectively. Median numbers of cycles of neoadjuvant treatment were as follows: AC (4, range 1-4), T (4, range 1-4), trastuzumab (6, range 3-8), and pertuzumab (6, range 2-8). In these 57 patients, the rates of tpCR and bpCR with in situ disease were demonstrated in 41/57 (72%) patients, and the rates of GBG pCR and bpCR without in situ disease were found in 30/57 (53%) patients. Of 26 patients with biopsy-proven lymph nodal involvement, axillary pCR occurred in 22 (85%) patients.

CONCLUSION

At a single center, the tpCR and GBG pCR rates of dd AC followed by THP are high at 72% and 53%, respectively. The Oncologist 2017;22:139-143Implications for Practice: This is the first study describing the role of doxorubicin and cyclophosphamide followed by paclitaxel and dual anti-HER2 therapy with trastuzumab and pertuzumab (ACTHP) in patients with early stage HER2-positive breast cancer. Total (breast + lymph node) pathological complete remission (pCR) remission (ypT0/is ypN0) and German Breast Group pCR rates (ypT0/ ypN0) were high at 72% and 53%, respectively, with the ACTHP regimen. Rate of axillary clearance in patients with known axillary involvement was high at 85%, which may translate into less extensive axillary surgeries in this subset in the future.

Obesity As a Risk Factor for Anthracyclines and Trastuzumab Cardiotoxicity in Breast Cancer: A Systematic Review and Meta-Analysis

PURPOSE

Patients with metabolic syndrome have a greater risk of cardiovascular disease, although their susceptibility to chemotherapy-induced cardiac disease is not well documented. The aim of this meta-analysis was to assess associations between obesity or being overweight and cardiotoxicity from anthracyclines and sequential anthracyclines and trastuzumab in patients with breast cancer.

METHODS

We performed a random-effects analysis and a network meta-analysis and assessed publication bias. We included 15 studies and 8,745 patients with breast cancers who were treated with anthracyclines and sequential anthracyclines and trastuzumab.

RESULTS

Combination of obesity and being overweight was significantly associated with a greater risk of developing cardiotoxicity after anthracyclines and a sequential anthracyclines and trastuzumab regimen in patients with breast cancer. Pooled odds ratio for cardiotoxicity was 1.38 (95% CI, 1.06 to 1.80; I(2) = 43%; N = 8,745) for overweight or obesity (body mass index > 25 kg/m(2)), 1.47 (95% CI, 0.95 to 2.28; I(2) = 47%; n = 2,615) for obesity, and 1.15 (95% CI, 0.83 to 1.58; I(2) = 27%; n = 2,708) for overweight. Associations were independent of study design, year of publication, drug regimen (anthracyclines alone v sequential anthracyclines and trastuzumab), or definitions of cardiotoxicity and of overweight or obesity. There was no evidence of publication bias; however, we could not separate the contributions of obesity-related cardiovascular risk factors, such as diabetes and hypertension, from that of obesity itself in this largely unadjusted analysis.

CONCLUSION

Our findings in a largely unadjusted analysis suggest that overweight and obesity are risk factors for cardiotoxicity from anthracyclines and sequential anthracyclines and trastuzumab.

Cardiac Safety of Paclitaxel Plus Trastuzumab and Pertuzumab in Patients With HER2-Positive Metastatic Breast Cancer

The results of a preplanned cardiac safety analysis of global longitudinal strain (GLS), and troponin-I (TnI) and brain natriuretic peptide (BNP) levels in the phase II study of paclitaxel, trastuzumab, and pertuzumab (THP) for metastatic HER2-positive breast cancer are reported. There were no statistically significant changes in GLS, and TnI and BNP levels. The finding supports the cardiac safety of THP in this group of patients.

Introduction.

Myocardial strain imaging and blood biomarkers have been proposed as adjuncts to left ventricular ejection fraction (LVEF) monitoring for the early detection of cardiotoxicity during cancer therapy. We report the results of a preplanned cardiac safety analysis of global longitudinal strain (GLS), and troponin-I (TnI) and brain natriuretic peptide (BNP) levels in the phase II study of paclitaxel, trastuzumab, and pertuzumab (THP) for metastatic HER2-positive breast cancer.

Patients and Methods.

Patients with 0–1 lines of prior therapy were treated with weekly paclitaxel (80 mg/m²) plus trastuzumab (8 mg/kg loading dose followed by 6 mg/kg) and pertuzumab (840 mg loading dose followed by 420 mg) every 3 weeks. Exploratory endpoints were GLS measured with speckle-tracking echocardiography every 3 months and TnI and BNP levels measured every 6 weeks (immediately pre- and postchemotherapy infusion) at 6 time points.

Results.

Sixty-seven of 69 enrolled patients were treated with THP: 19 (28%) had hypertension, 8 (12%) had diabetes, 11 (16%) had hyperlipidemia, and 26 (38%) had smoking history. After a median follow-up of 21 months (range: 3–38 months), no patients developed symptomatic heart failure. Two patients (3.0%) experienced asymptomatic LVEF decline (grade 2). The mean GLS (±SD) was 19% ± 2% (baseline), 19% ± 2% (month 6), and 19% ± 3% (month 12). Detectable TnI (>0.06 ng/mL) and elevated BNP (>100 pg/mL) levels were observed in 3 (4.3%) and 2 (3.0%) patients, respectively, but were not associated with LVEF decline.

Conclusion.

The absence of any significant changes in GLS and cardiac biomarkers (TnI and BNP) further support the cardiac safety of THP in patients with metastatic HER2-positive breast cancer.

Implications for Practice:

Dual anti-HER2 therapy with trastuzumab and pertuzumab in combination with taxane-based chemotherapy improves overall survival in patients with metastatic HER2-positive breast cancer. There is a critical need to investigate the potential cardiotoxicity of dual anti-HER2 blockade, given the importance of HER2 signaling in cardiac homeostasis and stress response. Global longitudinal strain and cardiac biomarkers have been proposed as adjuncts to left ventricular ejection fraction for the early detection of cardiotoxicity. In this phase II study of combination trastuzumab and pertuzumab with paclitaxel, no clinically significant change was observed in global longitudinal strain or cardiac biomarkers. These results further support the cardiac safety of dual anti-HER2 blockade previously reported in the CLEOPATRA study. The findings in the current study also call into question the role of intensive cardiac monitoring among patients treated with anti-HER2 therapy in the absence of anthracyclines. Less frequent cardiac assessments could lead to a reduction in unnecessary treatment interruption and is an important consideration given the rise in medical expenditures, but this requires further investigation.

Breast cancer treatment-associated cardiovascular toxicity and effects of exercise countermeasures

Advances in breast cancer treatment have improved disease-free survival and overall survival in women with early-stage breast cancer. However, these improvements may be attenuated by the adverse cardiovascular effects associated with breast cancer adjuvant therapy. Exercise may be a potential strategy to counteract these toxicities. The purpose of this paper is to provide an overview on the adverse cardiovascular effects of breast cancer therapy as well as the evidence supporting the potential cardioprotective effects of exercise training in breast cancer patients during and after treatment. We will also discuss research gaps and avenues for future research.

Abstract P4-14-09: Cardiac safety of trastuzumab without an anthracycline in patients with HER2-positive early stage breast cancer: A single center experience

Background: Trastuzumab (H) improves disease-free survival and overall survival in HER2+ early breast cancer (EBC) but is associated with risk of treatment-induced cardiotoxicity especially when administered after an anthracycline. We performed a single center retrospective study to assess the cardiac safety of adjuvant trastuzumab therapy without anthracyclines in a real-world clinical setting.

Methods: Patients (pts) with HER2+ early breast cancer (EBC) who received H without anthracycline-based chemotherapy between January 2010 and June 2014 were studied. Patients enrolled in a clinical trial were excluded. Tumor characteristics, chemotherapy regimen, cardiovascular risk factors, left ventricular ejection fraction (LVEF), and treatment interruption data were collected. A cardiac event (C.E.) was defined as New York Heart Association class III or IV heart failure with LVEF decline of &gt; 10% to &lt; 55% or possible/probable cardiac death, as previously defined by the NSABP B-31 trial.

Results: In total, 174 pts with HER2+ EBC treated with H-based therapy without anthracyclines were identified. Median age was 59 years (range, 32 to 85 years), 72 (41%) had hypertension, 55 (32%) had hyperlipidemia, 29 (16%) had diabetes, and 5 (3%) had coronary artery disease. At baseline, all pts had a LVEF &gt; 50% (median, 66%; range, 50% to 81%). Two (1.1%) pts developed a C.E. Both pts had risks factors for C.E. (1 - age &gt; 60 years, hypertension, and prior history of anthracycline exposure; 1- age &gt; 60 years, hypertension, hyperlipidemia, and baseline LVEF of 50-55%). After discontinuation of H, both patients had recovery of LVEF to &gt; 50% and resolution of heart failure symptoms. Twelve (6.9%) pts developed asymptomatic LVEF decline of &gt; 10% points to &lt; 55% during H therapy. Of the 14 patients who developed cardiotoxicity, H was prematurely interrupted or discontinued in 8 patients.

Conclusion: In our single center experience of patients being treated off study, the incidence of C.E.s and asymptomatic LVEF decline during H therapy without an anthracycline was 1.1% and 6.9%, respectively. These appeared higher than events reported in clinical trials possibly due to the inclusion of an older group of women with a higher prevalence of cardiovascular risk factors. Overall, the incidence of symptomatic heart failure is low for H without an anthracycline even in this older group.

Citation Format: Mukku RB, Verma S, Liu J, Steingart R, Hudis C, Yu AF, Dang C. Cardiac safety of trastuzumab without an anthracycline in patients with HER2-positive early stage breast cancer: A single center experience. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-09.

Roadmap for biomarkers of cancer therapy cardiotoxicity

Contemporary cancer treatment uses multiple modalities such as chemotherapy, targeted therapy and radiotherapy. These therapies, often used in combination, are associated with an increased risk of cardiotoxicity, specifically cardiomyopathy and heart failure. Cardiologists and oncologists are faced with the challenge of maximising the clinical benefit from cancer therapy while minimising the risk of early and late-onset cardiotoxicity. The current paradigm for cardiotoxicity detection and management relies primarily upon the assessment of left ventricular ejection fraction (LVEF). However, LVEF alone is limited in both diagnostic and prognostic ability. There is growing enthusiasm over the identification of newer biomarkers of cardiotoxicity that can detect cardiac injury at earlier stages of disease and could be used as an adjunctive prognostic measure to routine LVEF assessment. Thus, imaging and circulating biomarkers are currently under active investigation for use throughout the continuum of cancer care-for risk stratification of cardiotoxicity prior to treatment, detection of early cardiotoxicity during treatment and diagnosis of late cardiotoxicity in survivorship. Myocardial strain, cardiac troponin and brain natriuretic peptide are the most prominent biomarkers currently being studied, although data on novel circulating biomarkers are emerging.

Modulation of cardiovascular toxicity in Hodgkin lymphoma: potential role and mechanisms of aerobic training

Hodgkin lymphoma (HL) outcomes have improved due to advances in cancer treatment. However, HL survivors remain at increased risk for cardiovascular (CV) morbidity and mortality related to the long-term cardiotoxicity of HL treatment, particularly anthracycline chemotherapy and mediastinal radiotherapy. The role of aerobic training for the prevention of CV disease in the general population has been well established. However the safety and efficacy of aerobic training on CV outcomes has not been well studied in HL survivors. The purpose of this paper is to provide an up-to-date summary of the treatment-related adverse CV effects in HL survivors, review the CV benefits of exercise and review the limited evidence on the potential CV benefit of aerobic training in HL survivors.

Continuous Trastuzumab Therapy in Breast Cancer Patients With Asymptomatic Left Ventricular Dysfunction

BACKGROUND

Adjuvant trastuzumab is a highly effective targeted treatment that improves survival for patients with HER2-positive breast cancer. However, trastuzumab interruption is recommended for patients who develop treatment-induced cardiotoxicity (i.e., decline in left ventricular ejection fraction [LVEF], with or without symptoms) and can lead to an incomplete course of treatment. We studied the cardiac safety of continuous trastuzumab therapy among patients with asymptomatic declines in LVEF.

METHODS

We retrospectively evaluated patients with HER2-positive breast cancer treated with adjuvant trastuzumab at our institution between 2005 and 2010. Treatment-induced cardiotoxicity was defined by an absolute decrease in LVEF of ≥10% to below 55% or an absolute decrease of ≥16%. Logistic regression was used to determine the association between candidate risk factors and treatment-induced cardiotoxicity.

RESULTS

Among 573 patients, 92 (16%) developed treatment-induced cardiotoxicity. Trastuzumab was continued without interruption in 31 of 92 patients with treatment-induced cardiotoxicity—all were asymptomatic with LVEF of ≥50% at cardiotoxicity diagnosis with median LVEF of 53% (range, 50%-63%), and none developed heart failure during follow-up. Risk factors associated with treatment-induced cardiotoxicity included age (p = .011), anthracycline chemotherapy (p = .002), and lower pretrastuzumab LVEF (p < .001).

CONCLUSION

Among patients who develop asymptomatic treatment-induced cardiotoxicity with LVEF of ≥50%, continuous trastuzumab therapy appears to be safe.

Abstract P5-18-02: Trastuzumab interruption for treatment-induced cardiotoxicity in HER2 positive early breast cancer

Background

Trastuzumab (H) improves outcomes among patients with HER2-positive breast cancer but is associated with a risk of treatment-induced cardiotoxicity (TIC), especially when administered after an anthracycline (A). H interruption is recommended for significant asymptomatic or symptomatic declines in left ventricular ejection fraction (LVEF). It is unclear how frequently TIC leads to H interruption, and the subsequent management is variable in clinical practice.

Methods

Patients (pts) with HER2-postive early breast cancer receiving adjuvant H with chemotherapy between January 2005 and October 2010 were studied (n=608). Tumor characteristics, chemotherapy regimen, cardiac risk factors, LVEF (at baseline and during treatment), and treatment interruption were obtained from the medical record. We evaluated the incidence, time of occurrence, management, and associated risk factors of H interruption due to TIC.

Results

Median age was 51 years (range 26-81); 488 (80%) pts had A prior to H administration. H was interrupted in 108 (18%) pts. Cumulative dose of H was lower among pts in the interrupted group (median 86 vs. 108 mg/kg, p &lt; 0.0001). The most common reason for interruption was TIC (66 of 108 pts): 20 (30%) had symptomatic congestive heart failure and 46 (70%) had asymptomatic decline in LVEF. Of the 66 pts, 55 (83%) were referred to a cardiologist and 36 (55%) were prescribed a new cardiac medication. The mean LVEF at baseline, at time of cardiotoxicity diagnosis, and at follow-up after interruption of H was 63%, 45%, and 55%, respectively. Pts with H interruption for TIC were older (54 vs. 50 years, p=0.014) with lower LVEF before A (63 vs. 67%, p&lt;0.0001) and before H therapy (62% vs. 67%, p&lt;0.0001), compared to those with continuous H treatment. Thirty-three of 66 pts were re-treated with H, and 5 pts had a significant recurrent decline in LVEF.

Conclusion

At our institution, interruption of H therapy is common and most often due to TIC, from both A and H, with the majority of pts receiving A prior to H. Risk factors associated with H interruption were older age and lower LVEF prior to A and H administration. Cardiac dysfunction improved after interruption of treatment but did not fully recover to baseline. Strategies to prevent cardiotoxicity and minimize H treatment interruption should be investigated to prevent persistent LV dysfunction in affected pts.

Citation Format: Anthony F Yu, Nandini U Yadav, Betty Y Lung, Anne A Eaton, Howard T Thaler, Clifford A Hudis, Chau T Dang, Richard M Steingart. Trastuzumab interruption for treatment-induced cardiotoxicity in HER2 positive early breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-18-02.