Adjuvant
Chemotherapy May not Improve Survival in Postmenopausal, Hormone-Positive
Breast Cancer Patients
According to a recent article in the Journal of the National
Cancer Institute, the addition of chemotherapy to Nolvadex ®
(tamoxifen) following surgery does not appear to improve long-term
outcomes in postmenopausal patients with hormone-positive,
localized breast cancer. 1 However, further clinical trials
are necessary in order to determine the most appropriate adjuvant
regimen for postmenopausal patients with this disease.
Breast cancer is diagnosed in over 200,000 women and is responsible
for approximately 40,000 deaths annually in the United States.
Localized breast cancer refers to breast cancer that has not
spread from the site of origin. Surgery is often used as initial
therapy for localized breast cancer and may be followed by
additional therapy (called adjuvant therapy) which may include
chemotherapy, hormonal therapy, radiation therapy and/or biologic
therapy. Adjuvant therapy is utilized to kill any undetectable
cancer cells that may remain in the body following surgery,
since these remaining cancer cells are responsible for cancer
recurrences.
Hormone-positive breast cancer refers to a type of breast
cancer that is stimulated to grow from exposure to two female
hormones, estrogen and/or progesterone. Hormonal therapy is
a type of therapy that blocks or reduces the formation of
estrogen and/or progesterone in the body or blocks the effects
of estrogen and/or progesterone on a cell. Although it has
become relatively common to use a regimen that includes adjuvant
hormone therapy and chemotherapy to treat women with hormone-positive,
localized breast cancer, doubts have remained regarding the
role of adjuvant chemotherapy in postmenopausal women with
localized, hormone-positive breast cancer who are treated
with hormone therapy.
Recently, researchers affiliated with the National Breast
Cancer Study Group conducted a clinical trial to evaluate
adjuvant chemotherapy in postmenopausal women with hormone-positive,
localized breast cancer. This trial involved 1,217 women whose
cancer had not spread to local (axillary) lymph nodes. Women
were treated with either hormone therapy alone, consisting
of Nolvadex ®, or with Nolvadex ® plus chemotherapy.
The chemotherapy regimen consisted of cyclophosphamide (Cytoxan ®),
methotrexate and 5-fluorouracil , commonly known as CMF. This
trial also included a group of over 300 postmenopausal women
with hormone-negative, localized breast cancer who were treated
with either Nolvadex ® alone or CMF plus Nolvadex ®.
The cancer recurrence rate for hormone-positive patients
was 16% for those treated with CMF plus Nolvadex ®, compared
to 15% for those treated with Nolvadex ® alone. The overall
survival for hormone-positive patients was 95% for those treated
with CMF plus Nolvadex ®, compared to 93% for those treated
with Nolvadex ® alone. The cancer recurrence rate for hormone?negative
patients was only 16% for those treated with CMF plus Nolvadex ®,
compared to 31% for those treated with Nolvadex ® alone.
The overall survival for hormone-negative patients was 89%
for those treated with CMF plus Nolvadex ®, compared to
81% for those treated with Nolvadex ® alone. Overall, chemotherapy
was tolerated well in all groups of patients.
These researchers concluded that adjuvant chemotherapy in
addition to hormone therapy for hormone-positive, postmenopausal
breast cancer patients with no spread of cancer to local lymph
nodes does not appear to improve long-term outcome. These
findings are consistent with a previous clinical trial indicating
that women over 65 years with localized, hormone-positive
breast cancer treated with hormone therapy did not benefit
from adjuvant chemotherapy. 2 However, postmenopausal women
with hormone-negative, localized breast cancer have reduced
cancer recurrences and improved survival with the addition
of adjuvant chemotherapy. Postmenopausal patients with localized
breast cancer may wish to discuss the risks and benefits of
adjuvant chemotherapy as part of their treatment regimen with
their physician.
References:
1. International Breast Cancer Study Group (IBCSG). Endocrine
responsiveness and tailoring adjuvant therapy for postmenopausal
lymph node-negative breast cancer: a randomized trial. Journal
of the National Cancer Institute. 2002;94:1054-1065.
2. Crivellari D, Bonetti M, Castiglione-Gertsch M, et al.
Journal of Clinical Oncology. 2000;18:1412-1422.
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