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.

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.

High glucose induces trafficking of prorenin receptor and stimulates profibrotic factors in the collecting duct.

Growing evidence indicates that prorenin receptor (PRR) is upregulated in collecting duct (CD) of diabetic kidney. Prorenin is secreted by the principal CD cells, and is the natural ligand of the PRR. PRR activation stimulates fibrotic factors, including fibronectin, collagen, and transforming growth factor-ß (TGF-ß) contributing to tubular fibrosis. However, whether high glucose (HG) contributes to this effect is unknown. We tested the hypothesis that HG increases the abundance of PRR at the plasma membrane of the CD cells, thus contributing to the stimulation of downstream fibrotic factors, including TGF-ß, collagen I, and fibronectin. We used streptozotocin (STZ) male Sprague-Dawley rats to induce hyperglycemia for 7 days. At the end of the study, STZ-induced rats showed increased prorenin, renin, and angiotensin (Ang) II in the renal inner medulla and urine, along with augmented downstream fibrotic factors TGF-ß, collagen I, and fibronectin. STZ rats showed upregulation of PRR in the renal medulla and preferential distribution of PRR on the apical aspect of the CD cells. Cultured CD M-1 cells treated with HG (25 mM for 1 h) showed increased PRR in plasma membrane fractions compared to cells treated with normal glucose (5 mM). Increased apical PRR was accompanied by upregulation of TGF-ß, collagen I, and fibronectin, while PRR knockdown prevented these effects. Fluorescence resonance energy transfer experiments in M-1 cells demonstrated augmented prorenin activity during HG conditions. The data indicate HG stimulates profibrotic factors by inducing PRR translocation to the plasma membrane in CD cells, which in perspective, might be a novel mechanism underlying the development of tubulointerstitial fibrosis in diabetes mellitus.