The study reviewed here found that after surgery and other treatments for hormone-receptor-positive early-stage breast cancer in premenopausal women, treatment with the hormonal therapy medicine Zoladex (chemical name: goserelin) can lower the risk of the cancer coming back (recurrence) and improve overall prognosis.
The ovaries of premenopausal women produce estrogen. Estrogen can make breast cancer cells grow and increase the risk of the cancer coming back. Stopping the ovaries from producing estrogen or blocking the effects of estrogen on breast cancer cells can be an effective part of a treatment plan for premenopausal women.
Removing the ovaries (called oophorectomy or surgical ablation) or destroying the ovaries with radiation therapy permanently stop the ovaries from producing estrogen. But some premenopausal women may want to temporarily stop the ovaries from producing estrogen so they have the option of having children after treatment. Medicines called LHRH (luteinizing hormone releasing hormone) agonists can be used to temporarily stop the ovaries from making estrogen. This is called medical ovarian shutdown. LHRH-agonist medicines include Zoladex and Lupron (chemical name: leuprolide).
Tamoxifen, another hormonal therapy medicine, also can lower the risk of early-stage hormone-receptor-positive breast cancer coming back in both pre- and postmenopausal women. Tamoxifen is a SERM (selective estrogen receptor modulator). Tamoxifen has different effects on different types of cells. In breast cells, tamoxifen blocks estrogen receptors. Blocking the estrogen receptors means that estrogen can't attach to the cell and so can't tell the cell to grow.
In the study reviewed here, the researchers reviewed the information from more than 14 other studies involving more than 12,000 premenopausal women. All of the women in these studies were diagnosed with early-stage breast cancer. Almost all of the cancers were hormone-receptor-positive. To reduce the risk of the cancer coming back, the women were divided into three broad groups:
Many of the women also got chemotherapy to lower the risk of the cancer coming back. Doctors use the term adjuvant chemotherapy to describe chemotherapy used to lower the risk of the cancer coming back.
The researchers found:
If you're a premenopausal woman diagnosed with hormone-receptor-positive early-stage breast cancer, you and your doctor will consider a number of treatment options to reduce the risk of the cancer coming back after surgery. Hormonal therapy and medical ovarian shutdown may be options you consider. Based on this study, you might want to ask your doctor if the combination of tamoxifen and Zoladex makes sense for you, whether or not you get adjuvant chemotherapy.
In the Breastcancer.org Hormonal Therapy section you can learn more about hormonal therapy medicines used to lower the risk of the cancer coming back in premenopausal women.
LONDON, Oct. 10 (MedPage Today) -- Premenopausal women with early-stage breast cancer, will "likely" have a reduced risk of recurrence and live longer when treated with an LHRH agonist, either alone or with tamoxifen, results of a Cochrane systematic review suggest.
Direct comparisons of LHRH agonists and tamoxifen showed similar recurrence rates and recurrence-free survival, Rohini Sharma, M.D., of Hammersmith Hospital Trust here, and colleagues reported online in the Cochrane Database of Systematic Reviews.
Studies comparing both tamoxifen and an LHRH agonist (usually goserelin) with either agent alone have generally favored the combination, but the data are incomplete or inconclusive in some instances, the investigators said.
"For premenopausal women with early breast cancer who are not known to be ER negative, the use of an LHRH agonist, with or without tamoxifen as adjuvant therapy is likely to lead to a reduction in the risk of recurrence and a delay in death," the authors concluded.
Accounting for about 60% of all breast cancer, ER-positive tumors can be treated hormonally in many instances. Three possible treatment strategies are use of anti-estrogens or estrogen receptor antagonists (such as tamoxifen), suppression of estrogen synthesis by LHRH agonists, or ovarian ablation by surgery or radiotherapy.
Chemotherapy-induced amenorrhea in premenopausal patients is associated with better disease-free survival, suggesting that at least some of chemotherapy's benefit is mediated by ovarian toxicity, the authors said.
"LHRH agonists provide effective ovarian suppression in premenopausal women and are an acceptable alternative to oophorectomy or pelvic radiotherapy," the authors said. "These agents induce a menopausal status that is reversible on cessation of therapy."
In a previous meta-analysis, Dr. Sharma and colleagues found that ovarian suppression with LHRH agonists (alone or with tamoxifen) are a "reasonable alternative" to chemotherapy for patients with ER-positive breast cancer. However, data were insufficient at the time to compare LHRH agonists and tamoxifen and to examine the benefits of adding an LHRH agonist to chemotherapy.
The updated analysis comprised 14 randomized trials involving 12,000 premenopausal women with operable breast cancer that was ER-positive in most cases.
The primary outcome measures were recurrence-free survival, overall survival, toxicity, and quality of life.
For most comparisons, the trials were too few, included too few patients, or had insufficient follow-up to permit reliable estimates of treatment effects. Meta-analyses were not performed because of variability in the reporting of the trials and the need for more mature data.
After analyzing the data, the authors reached the following conclusions:
"While we cannot yet recommend using ovarian suppression as the standard therapy for these women, it is possible that LHRH agonists may reduce the risk of cancer reoccurring and extend survival times in premenopausal women who have early breast cancer that is not known to be ER negative," said Dr. Sharma.
"Given this potential, we eagerly await the results of current clinical trials that could answer this important issue," the investigators said.
The review was supported by the National Breast Cancer Center of Australia and the National Collaborating Centre for Cancer, U.K.
Primary source: Cochrane Database of Systematic Reviews Source reference: Sharma R, Hamilton A, Beith J. "LHRH agonists for adjuvant therapy of early breast cancer in premenopausal women" Cochrane Database Syst Rev 2008; 4: DOI: 10.1002/14651858.CD004562.pub3.
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