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

Figure 1. Nomogram of risk model for predicting 1‐year probabilities of cancer therapy–related cardiac dysfunction (CTRCD) after human epidermal growth factor receptor 2–targeted therapy. To estimate risk of CTRCD, an individual patient's baseline characteristics are plotted on each variable axis, and a vertical line is drawn to the points’ axis to determine the points for that variable. The points for all 9 variables are added, the sum is located on the “Total Points” axis, and a vertical line is drawn to the bottom axis to obtain the 1‐year probability of CTRCD. The total score can be calculated as follows: {1.4×[age−20]}+{19×[body mass index (BMI)≥30 kg/m2]}+{44×I[Black]}+{73×I[current/prior anthracyclines]}+{30×I[baseline systolic blood pressure (SBP) ≥130 mm Hg]}+{44×I[baseline left ventricular ejection fraction (LVEF) <60%]}+{63×I[coronary artery disease (CAD)]}+{80×I[arrhythmia]}+{13×I[diabetes]}, where I[] denotes the indicator function equal to 1 if the condition within the brackets is present, and 0 otherwise.

Figure 2. Calibration plot of 1‐year cancer therapy–related cardiac dysfunction (CTRCD) nomogram. The x axis displays the nomogram‐predicted probability of 1‐year CTRCD‐free survival. Patients were grouped by quartiles of predicted risk (first quartile, <103 points; second quartile, 103–129 points; third quartile, 130–156 points; and fourth quartile, >156 points). The y axis represents the observed 1‐year probability of CTRCD‐free survival, as estimated by Kaplan‐Meier method. Gray line indicates ideal agreement between observed and predicted probabilities of 1‐year CTRCD. Black line denotes actual prediction from the nomogram. Dots denote apparent predictive accuracy, which was calculated by plotting the mean Kaplan‐Meier estimate for each quartile vs the mean nomogram‐predicted probabilities for patients in each quartile. X denotes the bootstrap‐corrected estimates. Vertical bars indicate 95% CI.

Figure 3. Receiver operating characteristic (ROC) curve for 1‐year cancer therapy–related cardiac dysfunction of the nomogram. AUC indicates area under ROC curve.

Figure 4. Decision curve of the nomogram for 1‐year cancer therapy–related cardiac dysfunction (CTRCD). Net benefit curves show the clinical usefulness of intervention guided by the CTRCD risk nomogram (blue line) relative to a strategy of intervention for all patients regardless of risk (red line) or intervention for no patients irrespective of risk (green line). The net benefit (y axis) is plotted as a function of threshold probability (x axis), defined as the probability of disease that would prompt intervention. The 1‐year CTRCD risk nomogram has positive net benefit for threshold probabilities of 5% to 30%.