Intersection of Cardiology and Oncology Clinical Practices

2. Introduction Globally, cancer is diagnosed in approximately 13 million people each year. Approximately 1.6 million cancer patients are seen by cancer clinics across the United States (US) at this time. Over the next 2 decades, cancer incidence is estimated to increase by approximately 45% to 2.3 million [1]. In the US, the 5-year relative survival rate of patients diagnosed with cancer in 1975-1977 was 50% improving to 68% in the period 1999-2005. Novel targeted chemotherapeutic agents and improved diagnostic techniques are responsible for this increased survival. However, with the improvement in life expectancy, the adverse effects of chemotherapeutic agents, especially cardiotoxicity, is an emerging health problem. Cardiovascular toxicity on its own has a detrimental effect on both the quantity and quality of life independent of the oncological prognosis. Currently, more than 2 million women with breast cancer are at risk of anthracycline cardiotoxicity in the US [2]. Human epidermal growth factor receptor II (HER2) positive disease comprises approximately 25% of all breast cancer patients and is associated with more aggressive disease activity and worse prognosis. Trastuzumab, a humanized monoclonal antibody used for patients with HER2 positive breast cancer in conjugation with chemotherapy, can provide longer survival and 20% reduction in risk of death [3]. Cardiotoxicity becomes an important health issue because up to 27% of women with breast cancer receiving anthracyclines, cyclophosphamide, and trastuzumab showed cardiac dysfunction [3]. Breast cancer mortality is reduced by approximately one-third, but the risk of heart toxicity is 5 times more likely for women receiving trastuzumab than women receiving standard therapy alone [4]. Patients showing signs of cardiotoxicity often require a dose reduction, a change in the schedule dosing or even cessation of treatment with attendant consequences. Many patients with an asymptomatic decrease in left ventricular ejection fraction (LVEF) are receiving neither the American College of Cardiology/American Heart Association Class I-indicated treatments nor cardiovascular specialty consultation [5]. Concern for cardiotoxicity is not restricted to breast cancer survivors. Based on National Cancer Institute (NCI) data, the number of new renal cancer patients in 2013 is expected to be 65,000. In Europe, the incidence of renal cell carcinoma (RCC) has doubled in the last 3 decades [6]. Improved treatment strategies have increased the 5-year survival of patients with RCC from 50% in 1975-1977 to 72% in