New ASCO Recommendation for Postmenopausal Women With Early Breast Cancer
16 November 2004 - 12:00AM
PR Newswire (US)
New ASCO Recommendation for Postmenopausal Women With Early Breast
Cancer LONDON, November 15 /PRNewswire-FirstCall/ -- - Optimal
Adjuvant Therapy Should Now Include an AI Such as 'Arimidex'
(anastrozole) in Order to Reduce the Risk of Tumour Recurrence
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 @ http://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. Notes to Editors: Full
Recommendations of the ASCO Technology Assessment Committee: -
Based on results from multiple large randomised trials, adjuvant
therapy for postmenopausal women with hormone receptor-positive
breast cancer should include an aromatase inhibitor in order to
lower the risk of tumour recurrence. Neither the optimal timing nor
duration of aromatase inhibitor therapy is established. - Aromatase
inhibitors are appropriate as initial treatment for women with
contraindications to tamoxifen. For all other postmenopausal women,
treatment options include 5 years of aromatase inhibitors treatment
or sequential therapy consisting of tamoxifen (for either 2 to 3
years or 5 years) followed by aromatase inhibitors for 2 to 3, to 5
years. - Patients intolerant of aromatase inhibitors should receive
tamoxifen. - There are no data on the use of tamoxifen after an
aromatase inhibitor in the adjuvant setting. - Women with hormone
receptor-negative tumours should not receive adjuvant endocrine
therapy. - The role of other biomarkers such as progesterone
receptor and HER2 status in selecting optimal endocrine therapy
remains controversial. - Aromatase inhibitors are contraindicated
in premenopausal women; there are limited data concerning their
role in women with treatment-related amenorrhoea. - The side effect
profiles of tamoxifen and aromatase inhibitors differ. The late
consequences of aromatase inhibitor therapy, including
osteoporosis, are not well characterised. AstraZeneca continues its
tradition of research excellence and innovation in oncology that
led to the development of its current anti-cancer therapies
including 'ARIMIDEX' (anastrozole), 'CASODEX' (bicalutamide),
'FASLODEX' (fulvestrant), 'NOLVADEX' (tamoxifen), 'ZOLADEX'
(goserelin), 'TOMUDEX' (raltitrexed) and 'IRESSA' (gefitinib) as
well as a range of novel targeted products such as
anti-proliferatives, anti-angiogenics, vascular targeting and
anti-invasive agents. AstraZeneca is also harnessing rational drug
design technologies to develop new compounds that offer advantages
over current cytotoxic and hormonal treatment options. The company
has over 20 different anti-cancer projects in research and
development. AstraZeneca is a major international healthcare
business engaged in the research, development, manufacture and
marketing of prescription pharmaceuticals and the supply of
healthcare services. It is one of the world's leading
pharmaceutical companies with healthcare sales of over $18.8
billion and leading positions in sales of gastrointestinal,
oncology, cardiovascular, neuroscience and respiratory products.
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