Cardiac alterations of neoplastic diseases can be due to direct invasion produced by primary cardiac tumors or more frequently secondary to local compression of vascular structures by extracardiac neoplasms, such as superior vena cava syndrome. One of the most important alterations is the cardiotoxicity of anticancer treatments, either chemotherapy drugs or radiotherapy techniques. These treatments cause acute and/or chronic cardiotoxicity that the oncologist and the cardiologist must be aware of. For instance, 4.5% to 7% of patients that have been treated with anthracyclines may suffer cardiac failure in their lifetime. The pathogenesis is still not clear. There is currently a lot of research on cardioprotectors, but nowadays the only one approved by the FDA is dexrazoxane, which is used on breast cancer patients treated with adriamycin.