Neoadjuvant
Arimidex ® Allows more Breast-Conserving Therapy than Tamoxifen
According to results presented at the 2003 San Antonio Breast
Cancer Symposium, neoadjuvant hormone therapy including the
aromatase agent Arimidex ® (anastrozole) appears superior
to Nolvadex ® (tamoxifen) in terms of allowing for breast-conserving
therapy in postmenopausal women with hormone-positive breast
cancer.
A common type of breast cancer, referred to as estrogen-receptor
(ER)-positive breast cancer, is stimulated to grow from the
common female hormone estrogen. One type of therapy offered
to patients with ER-positive breast cancer is referred to
as hormone therapy. Hormone therapy works by reducing the
levels of estrogen produced in the body or through inhibiting
the growth-stimulatory effects of estrogen on a cancer cell.
Tamoxifen (Nolvadex ®), the historically standard agent
used for hormone therapy in breast cancer, is slowly being
replaced by a newer generation of compounds referred to as
aromatase agents. Several clinical trials have recently demonstrated
superiority of aromatase agents to tamoxifen in various clinical
setting as hormone therapy for breast cancer. Many of the
clinical trials involving aromatase agents to date have evaluated
these drugs as treatment in advanced cancers or as treatment
following surgery in breast cancer.
Recently, researchers from the UK conducted a trial comparing
tamoxifen to the aromatase agent Arimidex ® as neoadjuvant
therapy in early breast cancer. Neoadjuvant therapy is treatment
used prior to surgery. It is used to shrink the cancer prior
to surgery in an attempt to provide the option of breast-conserving
surgery (removal of the cancer plus a margin of healthy tissue)
instead of a mastectomy (removal of the complete breast) in
women with early breast cancer. Chemotherapy is often used
as treatment for neoadjuvant therapy; however, researchers
are evaluating hormone therapy as neoadjuvant therapy as it
is associated with fewer side effects than chemotherapy. This
trial, referred to as the IMPACT trial, included 330 postmenopausal
women with ER+ operable breast cancer. Patients were treated
with either neoadjuvant Arimidex ® only (A), tamoxifen
only (T), or both Arimidex ® and tamoxifen (C) for 3 months
prior to surgery and were directly compared. From these patients,
220 had medical records from a surgeon at the time of diagnosis
of their cancer. According to these records, 56% were considered
ineligible for breast-conserving therapy (BCT), and 44% were
considered eligible candidates for BCT. Of the women in the
group that were initially considered ineligible for BCT, 45%
treated with A, 22.2% treated with T, and 26.2% treated with
C had their cancer shrink enough after 3 months of neoadjuvant
therapy that they became eligible for treatment with BCT instead
of a mastectomy.
The researchers concluded that neoadjuvant therapy with Arimidex ®
appears superior to neoadjuvant therapy with tamoxifen or
a combination of the 2 agents in that it approximately doubles
the rate of patients with ER-positive breast cancer who are
initially ineligible for BCT to become eligible candidates
for the procedure. Anti-cancer response rates appeared similar
between all groups of patients. Postmenopausal patients with
ER-positive breast cancer who are considering neoadjuvant
therapy with a hormonal agent may wish to speak with their
physician about the risks and benefits of treatment with an
aromatase agent or the participation in a clinical trial further
evaluating this type of therapeutic approach. Two sources
of information regarding ongoing clinical trials include the
National Cancer Institute ( cancer.gov) and www.cancerconsultants.com.
Personalized clinical trial searches are also performed on
behalf of patients at cancerconsultants.com.
Reference: Smith I, Dowsett M on behalf of the IMPACT Trialists.
Proceedings from the 2003 San Antonio Breast Cancer Symposium.
December 2003. Abstract #1.
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