Cardiology Involvement in Patients With Breast Cancer Treated With Trastuzumab

BACKGROUND: There is limited evidence regarding the impact of cardiology involvement in the care of cancer patients. OBJECTIVES: This study evaluated the impact of cardiology involvement on guideline-adherent cardiovascular monitoring and risk factor management in patients with breast cancer treated with trastuzumab. METHODS: In a single-center retrospective cohort study, electronic health records from 1,047 patients with breast cancer receiving trastuzumab between January 2009 and July 2018 were evaluated. A visit to a cardiology provider beginning from the 3 months before cancer therapy initiation until the last contact date defined cardiology involvement. Guideline-adherent monitoring, defined by echocardiography assessment within the 4 months before trastuzumab initiation and follow-up echocardiography at least every 4 months during therapy, was compared in patients with and without cardiology involvement before treatment initiation. Multivariable associations between cardiology involvement and the time-varying risk factors blood pressure and body mass index (BMI) were assessed by using generalized estimating equations. RESULTS: Cardiology involvement occurred in 293 (28%) patients. A higher proportion of patients with cardiology involvement before trastuzumab initiation had guideline-adherent monitoring (76.4% vs. 60.1%; p = 0.007). Cardiology involvement was associated with an average 1.5 mm Hg (95% CI: –2.9 to –0.1; p = 0.035) lower systolic blood pressure, which was more pronounced in those with hypertension (–2.7 mm Hg; 95% CI: –4.6 to –0.7; p = 0.007). Cardiology involvement was associated with a lower BMI in patients with baseline BMI ≥25 kg/m(2) (mean difference: –0.5 kg/m(2); 95% CI: –1.0 to –0.1; p = 0.027). CONCLUSIONS: Cardiology involvement in patients with breast cancer treated with trastuzumab is associated with greater adherence to cardiovascular monitoring and modest improvements in risk factor control.