Aromatase Inhibitors Now Recommended as Adjuvant Therapy for Postmenopausal Women With Early Breast Cancer Today, the American Society of Clinical Oncology (ASCO) Technology Assessment Panel announced a fundamental change to its internationally recognised guidance on the use of aromatase inhibitors (AIs) in the treatment of postmenopausal women with early breast cancer(1). For the first time, the ASCO Panel has agreed that 5 years' tamoxifen is no longer the optimal treatment choice in this setting and recommends that adjuvant therapy should include an AI, such as anastrozole ('Arimidex'), as initial therapy or after treatment with tamoxifen, in order to reduce risk of recurrence. The ASCO Panel states that it is not known whether the AIs are interchangeable in clinical practice and therefore favours using the agent with the most data relevant to each individual clinical setting. Anastrozole is the most studied of all the AIs and the only one with data to support its use as initial adjuvant therapy; therefore, evidence-based medicine suggests that anastrozole should be the preferred choice if an AI is to replace tamoxifen in this setting. This endorsement for anastrozole in the ASCO Technology Assessment, Use of Aromatase Inhibitors in the Adjuvant Setting, is based on the compelling evidence provided by the ATAC ('Arimidex', Tamoxifen, Alone or in Combination) trial(2). The first five years following initial surgery is the period during which women are most at risk of their disease returning and current data demonstrate that anastrozole is significantly more effective than tamoxifen in reducing this risk. Furthermore, the incidence of three life-threatening side effects associated with tamoxifen - endometrial cancer, thromboembolic events and stroke are also significantly reduced with anastrozole. Commenting on this new recommendation, Professor Anthony Howell of Christie Hospital, Manchester, UK said: "Although doctors have been aware of the benefits that anastrozole offers over tamoxifen for some time, many have been awaiting reassurance from guidelines committees such as ASCO before changing their prescribing habits. This is a real milestone in the treatment of early breast cancer. More women will now be able to benefit from the greater protection that anastrozole provides against the cancer coming back, along with a better tolerability profile." In addition to replacing tamoxifen as an alternative initial adjuvant therapy, the ASCO Panel also recognises that women who have already commenced a course of adjuvant tamoxifen are more likely to remain free of the disease if they have their therapy changed to an AI. Therefore the Panel recommends that women on tamoxifen consider switching to an AI such as anastrozole. Professor Howell continued: "I am pleased to see that ASCO have also recognised the value in offering women the opportunity to change their therapy from tamoxifen to an AI, to help improve their chances of remaining disease-free. However, because the risk of recurrence is highest in the first five years, it's important to remember that women gain the greatest benefit when the most effective therapy is used as early as possible, preferably from the outset." There is now little doubt that the AIs play an important role in the adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer. The evidence shows that there is a clear and consistent improvement in disease-free survival over tamoxifen for women who receive an AI and differences in disease-free survival frequently lead to improvements in overall survival with prolonged follow-up. Anastrozole remains the only AI to have demonstrated superiority over tamoxifen as a primary adjuvant therapy in postmenopausal women with early breast cancer and is the only AI approved for use in this setting. With over 1 million patient-years experience, anastrozole has the most mature efficacy and tolerability data available for any AI. The ASCO Panel state that they are still awaiting further data, particularly with respect to long-term toxicity before making their final recommendations on the use of adjuvant AIs. The forthcoming data from the ATAC 5 year Completed Treatment Analysis, due for presentation at the San Antonio Breast Cancer Symposium in 3 week's time, will provide the first long-term data for any AI in the early breast cancer setting. 'Arimidex' (anastrozole) is a trademark, property of the AstraZeneca Group of Companies. References: 1. Winer EP, Hudis C, Burstein HJ et al. American Society of Clinical Oncology Technology Assessment on the Use of Aromatase Inhibitors As Adjuvant Therapy for Postmenopausal Women With Hormone Receptor-Positive Breast Cancer: Status Report 2004. Available on line @ www.JCO.org. To be published in the J Clin Oncol, January 20, 2005. 2. The ATAC ('Arimidex', Tamoxifen, Alone or in Combination) Trialists' Group. Anastrozole alone or in combination with tamoxifen versus tamoxifen alone for adjuvant treatment of postmenopausal women with early breast cancer: results of the ATAC trial efficacy and safety update analyses. Cancer 2003; 98 (9): 1802-1810. SOURCE: AstraZeneca 11/04 www.docguide.com Musa Mayer, author, advocate 12/11/04 With permission Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.