John D. Groarke

Cardiotoxicity associated with anthracycline-based chemotherapies has limited their use in patients with preexisting cardiomyopathy or heart failure. Dexrazoxane protects against the cardiotoxic effects of anthracyclines, but in the USA and some European countries, its use had been restricted to adults with advanced breast cancer receiving a cumulative doxorubicin (an anthracycline) dose > 300 mg/m2. We evaluated the off-label use of dexrazoxane as a cardioprotectant in adult patients with preexisting cardiomyopathy, undergoing anthracycline chemotherapy. Between July 2015 and June 2017, five consecutive patients, with preexisting, asymptomatic, systolic left ventricular (LV) dysfunction who required anthracycline-based chemotherapy, were concomitantly treated with off-label dexrazoxane, administered 30 min before each anthracycline dose, regardless of cancer type or stage. Demographic, cardiovascular, and cancer-related outcomes were compared to those of three consecutive patients with asymptomatic cardiomyopathy treated earlier at the same hospital without dexrazoxane. Mean age of the five dexrazoxane-treated patients and three patients treated without dexrazoxane was 70.6 and 72.6 years, respectively. All five dexrazoxane-treated patients successfully completed their planned chemotherapy (doxorubicin, 280 to 300 mg/m2). With dexrazoxane therapy, changes in LV systolic function were minimal with mean left ventricular ejection fraction (LVEF) decreasing from 39% at baseline to 34% after chemotherapy. None of the dexrazoxane-treated patients experienced symptomatic heart failure or elevated biomarkers (cardiac troponin I or brain natriuretic peptide). Of the three patients treated without dexrazoxane, two received doxorubicin (mean dose, 210 mg/m2), and one received daunorubicin (540 mg/m2). Anthracycline therapy resulted in a marked reduction in LVEF from 42.5% at baseline to 18%. All three developed symptomatic heart failure requiring hospitalization and intravenous diuretic therapy. Two of them died from cardiogenic shock and multi-organ failure. The concomitant administration of dexrazoxane in patients with preexisting cardiomyopathy permitted successful delivery of anthracycline-based chemotherapy without cardiac decompensation. Larger prospective trials are warranted to examine the use of dexrazoxane as a cardioprotectant in patients with preexisting cardiomyopathy who require anthracyclines.

Purpose of Review Elucidating the mechanisms that contribute to adverse cardiovascular (CV) outcomes and reduce quality of life among patients with cancer is paramount. Cancer, certain cancer drugs, radiation therapy, cancer-associated lifestyle disturbances, and cancer-independent comorbidities combine to predispose oncology patients to autonomic dysfunction (AD). This review will explore the assessment, etiology, and clinical implications of AD in cancer patients and will speculate on therapeutic and research opportunities. Recent Findings AD is particularly prevalent among patients with advanced cancer, but studies suggest increased prevalence across the entire continuum of cancer survivors compared to cancer-free controls. Data on cancer therapy-induced injury to the autonomic nervous system are limited to small studies. AD has been reported after cranial, neck, and mediastinal radiation therapy. Although AD has been shown to confer increased risk of adverse CV outcomes in cancer-free patients, the prognostic relevance of AD in oncology patients is less well investigated. Markers of AD including elevated resting heart rate (HR), reduced HR variability, and abnormal HR recovery have been associated with shorter survival times in various cancer cohorts. Furthermore, AD has been implicated in the etiology of cancer-related fatigue and exercise limitation. Summary Multiple risk factors predispose oncology patients to AD, which is associated with adverse outcomes, including increased mortality, exercise limitation, and fatigue among this cohort. The contribution of AD to overall morbidity and mortality in cancer survivors has largely been overlooked to date. Further investigation is necessary to better understand cancer-treatment specific autonomic injury and to evaluate the role of various pharmacological and non-pharmacological interventions with potential to tackle the sympathovagal imbalance observed in cancer survivors.

Modifiers of the association of childhood cancer therapies and excess CV risk observed in adult survivors, together with promising strategies for risk reduction and inherent barriers to achieving reduction in CV risk. CV, cardiovascular; GLS, global longitudinal strain; RT, radiation therapy. Modifiers of the association of childhood cancer therapies and excess CV risk observed in adult survivors, together with promising strategies for risk reduction and inherent barriers to achieving reduction in CV risk. CV, cardiovascular; GLS, global longitudinal strain; RT, radiation therapy.