Femara ®
Following Tamoxifen Reduces Recurrences in Breast Cancer
According to results presented at the 2003 annual San Antonio
Breast Cancer Symposium, treatment with Femara ® (letrozole)
following 5 years of tamoxifen (Nolvadex ®) significantly
reduces cancer recurrences in postmenopausal women with early-stage,
hormone-positive breast cancer. 1 Results from this trial
were previously reported in The New England Journal of Medicine2;
however, issues surrounding these results as well as new data
including quality of life were topics of discussion at this
year's symposium.
Early-stage breast cancer refers to cancer that has not spread
from its site of origin. Patients with early-stage breast
cancer may have spread to axillary (under the arm) lymph nodes,
but not to distant sites in the body. Standard treatment for
early-stage breast cancer depends upon several differing factors,
such as the extent of spread of disease (i.e. the size of
the cancer and/or number of involved lymph nodes), age of
the patient, hormone status of the cancer, overall health
of the patient and/or aggressiveness of the cancer. Following
the surgical removal of the cancer, some undetectable cells
may remain in the body that are responsible for cancer recurrences
and ultimately reduced survival. Therefore, standard therapeutic
approaches for early-stage breast cancer often include radiation
therapy, hormone therapy and/or chemotherapy in an attempt
to kill the remaining cancer cells.
Hormone-positive breast cancer refers to a common type of
cancer that is stimulated to grow from the female hormones
estrogen (ER) and/or progesterone (PR). Patients with hormone-positive
breast cancer are often offered hormonal therapy, a type of
therapy that reduces the production or the stimulatory growth
effects of estrogen. Tamoxifen has historically been the standard
agent used for hormonal therapy in women with hormone-positive
breast cancer and is typically used for 5 years. Tamoxifen
works by binding to estrogen receptors in a cell so that estrogen
is unable to bind, ultimately reducing its growth-stimulatory
effects. Recently, however, newer agents referred to as aromatase
inhibitors have entered the clinical arena. These agents work
by inhibiting the enzyme (protein) aromatase, which is involved
in the production of estrogen in the body. Clinical trials
are ongoing in an attempt to answer many questions regarding
the role of aromatase inhibitors in the treatment of breast
cancer, including the timing and sequencing in conjunction
with tamoxifen.
The recent clinical trial was conducted to evaluate the aromatase
inhibitor Femara ® following tamoxifen in women with early-stage
breast cancer. This trial involved over 5,000 postmenopausal
women with hormone-positive breast cancer, who had completed
5 years of treatment with tamoxifen. Approximately half of
the women then received either Femara ® or placebo (inactive
substitute) and were directly compared. At an average of almost
2 years following initiation of the trial, the cancer recurrence
rate was reduced by 43% in the group of patients treated with
Femara ®, compared to those who received placebo. New data
presented at the meeting surrounded quality of life issues
in the group of patients treated with Femara ®. Overall,
patients treated with Femara ® indicated a reduced quality
of life, with decreased physical health, increased bodily
pain and reduced energy and vitality. Hot flashes, pain in
the joints and muscles and osteoporosis (loss of bone density)
were more common in patients treated with Femara ®, compared
to those who received placebo. Bone fractures, however, were
similar between the two groups (3.6% in the group treated
with Femara ®, and 2.9% in the group who received placebo).
The researchers concluded that the addition of Femara ®
after 5 years of treatment with tamoxifen significantly reduces
cancer recurrences in postmenopausal women with early-stage,
hormone-positive breast cancer. Although quality of life was
lower in patients treated with Femara ®, it appears that
a large proportion of women would consider the side effects
to be worth the decreased risk of a recurrence. Postmenopausal
women with early-stage, hormone-positive breast cancer who
have been treated with tamoxifen may wish to speak with their
physician about the risks and benefits of further treatment
with Femara ®.
References:
1. Goss, et al. A randomized trial of letrozole in postmenopausal
women after five years of tamoxifen therapy for early-stage
breast cancer. Proceedings from the 2003 San Antonio Breast
Cancer Symposium. December 2003.
2. Goss P, Ingle J, Martino S, et al. A randomized trial
of letrozole in postmenopausal women after five years of tamoxifen
therapy for early-stage breast cancer. The New England Journal
of Medicine. Early publication available at: www.nejm.org.
October 9, 2003.
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