RT Journal Article SR Electronic T1 Monitoring the introduction of new drugs – Herceptin to cardiotoxicity JF Clinical Medicine JO Clin Med FD Royal College of Physicians SP 478 OP 481 DO 10.7861/clinmedicine.6-5-478 VO 6 IS 5 A1 HC Routledge A1 DW Rea A1 RP Steeds YR 2006 UL http://www.rcpjournals.org/content/6/5/478.abstract AB Trastuzumab (Herceptin), currently prescribed for metastatic breast cancer, has recently been shown to be effective as adjuvant therapy in early receptor 2 (HER2)-positive breast cancer. Cardiotoxicity is a serious adverse effect. A decrease in left ventricular ejection fraction (LVEF) occurs in as many as 27% of women treated with trastuzumab when combined with standard chemotherapy. The pathophysiology of this effect, which differs from the cardiotoxicity of anthracyclines, remains poorly understood. While overt heart failure is reversed with standard therapy, the longer-term consequences of asymptomatic declines in LVEF remain unknown. Monitoring 3-monthly for 5–10% changes in LVEF, the criteria for cessation of trastuzumab therapy in the clinical trials, is not possible for the population of women who might benefit from trastuzumab for early breast cancer. Extension of this therapy to an older and less fit population than those enrolled in the trials, with less rigorous cardiac screening, may result in significantly more cardiotoxicity.