Adjuvant Chemotherapy May not Improve Survival in Postmenopausal
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.
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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