Breast Cancer: Side Effects of Tamoxifen and Anastrozole

  • John R. Benson
  • Eleanor H. Turner
  • Zoe Winters
Part of the Methods of Cancer Diagnosis, Therapy and Prognosis book series (HAYAT, volume 1)

Breast cancer remains the commonest malignancy amongst women with a lifetime risk of between 10% to 12%. The incidence continues to increase with almost half a million women dying of the disease worldwide. There are now 45,000 and 15,000 deaths per annum in the United States and United Kingdom, respectively, and the inexorable rise in numbers of women suffering from breast disease is particularly notable in those countries that previously had a relatively low incidence of breast cancer but have now adopted Western lifestyles with changes in reproductive behaviour and greater usage of the oral contraceptive pill. Despite the continued rise in incidence of breast cancer, mortality rates have fallen over the past 2 decades, which is attributable to a combination of screening, heightened public awareness of the disease and the introduction of adjuvant systemic therapies. These epidemiological observations emphasize the hormone dependency of breast cancer and the importance of endocrine factors for tumor initiation and promotion. Breast cancer is a predominantly post-menopausal disease in which more than three-quarters of tumors are hormone responsive. This hormone dependency of breast cancer interacts with environmental and genetic factors to determine incidence and progression of the disease. However, it is the clinical response of these tumors to hormonal manipulation, which provides a unique therapeutic opportunity; tamoxifen has served as a prototype for the development of targeted therapies at the laboratory-clinical interface. Molecular technologies have permitted elucidation of mechanisms for tissue specific action and led to newer selective estrogen receptor modulators (SERM’s) with potentially greater anti-tumor efficacy and attenuated uterotrophic profile. Nonetheless, publications over the past 4–5 years have emphasized the risks of thromboembolism and endometrial carcinoma associated with tamoxifen use, which has accelerated application of other hormonal agents for treatment and chemoprevention of breast cancer. Indeed, there has been a resurgence of interest in hormonal therapies with the advent of third-generation aromatase inhibitors (AI) that represent the most significant advance in endocrine management of breast cancer since the introduction of tamoxifen more than 30 years ago. Recent data showing a survival advantage for aromatase inhibitors versus tamoxifen alone in both the advanced and adjuvant settings has heralded a major shift in standard first-line endocrine therapies for both advanced and early stage disease and perhaps ultimately chemoprevention of breast cancer.


Breast Cancer Endometrial Cancer Aromatase Inhibitor Advanced Breast Cancer Contralateral Breast Cancer 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer Science + Business Media B.V. 2008

Authors and Affiliations

  • John R. Benson
    • 1
  • Eleanor H. Turner
    • 1
  • Zoe Winters
    • 2
  1. 1.Cambridge Breast UnitAddenbrooke’s HospitalCambridgeUK
  2. 2.Department of Clinical Sciences at South BristolUniversity of Bristol, Level 7 Bristol Royal InfirmaryBristolUK

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