title: Chemoprevention of breast cancer.
abstract: Trials with tamoxifen have clearly shown that the risk of developing oestrogen receptor positive breast cancer can be reduced at a late stage in the natural history with prophylactic agents. About half of the oestrogen receptor positive cases were prevented, but there was no beneficial effect on ER-negative cancers. The current challenge is to find new agents which achieve this or better efficacy but with fewer side effects. Recent results indicate that the SERM raloxifene has similar efficacy to tamoxifen, but leads to fewer endometrial cancers, gynaecologic symptoms, and thromboembolic events. Results for contralateral tumours in adjuvant trials suggest that aromatase inhibitors may be able to prevent up to 70-80% of ER-positive breast cancers, and this is currently being investigated in two large prevention trials, one using anastrozole (IBIS-II) and the other exemestane (MAP.3). New agents are needed, for receptor negative breast cancer and several possibilities are currently under investigation.
authors.affiliation: Cancer Research UK Centre for Epidemiology, Mathematics and Statistics, Wolfson Institute of Preventive Medicine, Queen Mary's School of Medicine and Dentistry, University of London, London, UK. jack.cuzick@cancer.org.uk
authors.forename: Jack
authors.initials: J
authors.lastname: Cuzick
mesh_terms: D000730:Androstadienes / Q000627:therapeutic use; D016588:Anticarcinogenic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D047072:Aromatase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000517:prevention & control*; D018890:Chemoprevention; D002986:Clinical Trials as Topic; D005260:Female; D006801:Humans; D020849:Raloxifene Hydrochloride / Q000627:therapeutic use; D013629:Tamoxifen / Q000627:therapeutic use
chemical_list: D000730:Androstadienes; D016588:Anticarcinogenic Agents; D047072:Aromatase Inhibitors; D013629:Tamoxifen; D020849:Raloxifene Hydrochloride; C056516:exemestane