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Breast cancer - Hormone Therapy

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of breast cancer.

Alternative Names

Mammograms; Mastectomy

Hormone Therapy:

The goal of hormone therapy is to prevent estrogen from stimulating breast cancer cells. It is recommended for women whose breast cancers are hormone-receptor positive (either estrogen or progesterone), regardless of the size of the tumor and whether or not it has spread to the lymph nodes. Like chemotherapy, hormone therapy works systemically.

Hormone therapy works by blocking estrogen that causes cell proliferation. It is used only for patients with hormone receptor-positive tumors. Different types of hormone therapy work in different ways by:

  • Blocking estrogen receptors in cancer cells (Tamoxifen)
  • Suppressing estrogen production in the body (Aromatase inhibitors)
  • Destroying ovaries, which produce estrogen (Ovarian ablation)

Tamoxifen was the first widely used hormonal therapy drug, but it has been replaced by aromatase inhibitors for some women. Aromatase inhibitors are used only to treat postmenopausal women. Tamoxifen is mainly used as adjuvant therapy for premenopausal women with hormone-sensitive breast cancer.

Tamoxifen and Selective Estrogen Receptor Modulators (SERMs)

Tamoxifen (Nolvadex) has been the standard hormonal drug used for breast cancer. It belongs to a class of compounds called selective estrogen receptor modulators (SERMs). SERMs chemically resemble estrogen and trick the breast cancer cells into accepting it in place of estrogen. Unlike estrogen, however, they do not stimulate breast cancer cell growth. Because SERMs block estrogenâ ' s effects on cancer cells, they are sometimes referred to as "anti-estrogen" drugs.

Tamoxifen is used for all cancer stages in women of all ages with hormone receptor-positive cancers. In addition, it is used to prevent breast cancer in high-risk women. Another SERM drug, toremifene (Fareston), is an option for women with advanced cancer, but this drug is rarely used in the United States. A third drug, fulvestrant (Faslodex), works in a similar anti-estrogen way to tamoxifen but belongs to a different drug class. Fulvestrant is approved only for postmenopausal women with hormone-sensitive advanced breast cancer in which tamoxifen or aromatase inhibitors no longer work.

To prevent cancer recurrence, women should take tamoxifen for 5 years following surgery and radiation. Tamoxifen is an effective cancer treatment, but it can cause unpleasant side effects and has small (less than 1%) but serious risks for blood clots and uterine (endometrial) cancer. Immediately report any signs of vaginal bleeding to the doctor, as this may be a symptom of uterine cancer.

Less serious, but discomforting, side effects include hot flashes and mood swings. According to one study, nearly 25% of women stop taking tamoxifen within 1 year because of these symptoms. By 3.5 years, over 33% stop treatment. Taking tamoxifen for fewer than 5 years, however, increases the risk for cancer recurrence and death. Talk with your doctor about antidepressants or other therapies that may help you cope with tamoxifenâ ' s side effects.

Many doctors now recommend that postmenopausal women switch to an aromatase inhibitor after 2 - 3 years of tamoxifen therapy. Several recent studies have indicated that switching from tamoxifen to an aromatase inhibitor significantly improves survival rates and reduces the risk of death from breast cancer as well as other causes.

Endometrial cancer is a cancerous growth of the endometrium (lining of the uterus). It is the most common uterine cancer.
Endometrial cancer

Aromatase Inhibitors

Aromatase inhibitors block aromatase, an enzyme that is a major source of estrogen in many major body tissues, including the breast, muscle, liver, and fat. Aromatase inhibitors work differently than tamoxifen. Tamoxifen interferes with tumorsâ ' ability to use estrogen by blocking their estrogen receptors. Aromatase inhibitors reduce the overall amount of estrogen in the body.

Because these drugs cannot stop the ovaries of premenopausal women from producing estrogen, they are recommended only for postmenopausal women.

There are currently three aromatase inhibitors approved for treating early-stage, hormone receptor-positive breast cancer in postmenopausal women:

  • Anastrazole (Armidex) for treatment after surgery
  • Exemestane (Aromasin) for women who have taken tamoxifen for 2 - 3 years
  • Letrozole (Femara) for treatment after surgery or for women who have completed 5 years of tamoxifen therapy

All of these drugs are also approved for women with advanced (metastatic) hormone-sensitive breast cancer. Studies indicate that the introduction of aromatase inhibitors has helped greatly in prolonging survival for women with advanced cancer.

Compared to tamoxifen, aromatase inhibitors are less likely to cause blood clots and uterine cancer. However, these drugs are more likely to cause osteoporosis, which can lead to bone loss and fractures. In general, recent studies indicate that aromatase inhibitors are better than tamoxifen in improving survival and reducing the risk of cancer recurrence. Unfortunately, like tamoxifen, they can cause hot flashes, as well as joint pain.

Ovarian Ablation

Ovarian ablation literally shuts down estrogen production from the ovaries. Medications can accomplish ovarian ablation. Destroying the ovaries with surgery or radiation can also shut down estrogen production. (Osteoporosis is one serious side effect of this approach, but several therapies are available to help prevent bone loss.)

Chemical Ovarian Ablation. Drug treatment (non-chemotherapy drugs) to block ovarian production of estrogen is called chemical ovarian ablation. It is often reversible. The primary drugs used are luteinizing hormone-releasing hormone (LHRH) agonists, such as goserelin (Zoladex). (They are also sometimes called GnRH agonists). These drugs block the release of the reproductive hormones LH-RH, therefore stopping ovulation and estrogen production.

Bilateral Oophorectomy. Bilateral oophorectomy, the surgical removal of both ovaries, may modestly improve breast cancer survival rates in some premenopausal women whose tumors are hormone receptor-positive. In these women, combining this procedure with tamoxifen may improve results beyond those of standard chemotherapies. Oophorectomy does not benefit women after menopause, and its advantages can be blunted in women who have received adjuvant chemotherapy. The procedure causes sterility and can have a major negative emotional impact on younger patients.

Resources

References

Berg WA, Blume JD, Cormack JB, Mendelson EB, Lehrer D, Böhm-Vélez M, et al. Combined screening with ultrasound and mammography vs mammography alone in women at elevated risk of breast cancer. JAMA. 2008 May 14;299(18):2151-63.

Boyd NF, Guo H, Martin LJ, Sun L, Stone J, Fishell E, et al. Mammographic density and the risk and detection of breast cancer. N Engl J Med. 2007 Jan 18;356(3):227-36.

Casey PM, Cerhan JR and Pruthi S. Oral contraceptive use and risk of breast cancer. Mayo Clin Proc. 2008;83(1): 86-90.

Chia SK, Speers CH, D'Yachkova Y, Kang A, Malfair-Taylor S, Barnett J, et al. The impact of new chemotherapeutic and hormone agents on survival in a population-based cohort of women with metastatic breast cancer. Cancer. 2007 Jul 23;110(5):973-979 [Epub ahead of print]

Coombes RC, Kilburn LS, Snowdon CF, Paridaens R, Coleman RE, Jones SE, et al. Survival and safety of exemestane versus tamoxifen after 2-3 years' tamoxifen treatment (Intergroup Exemestane Study): a randomised controlled trial. Lancet. 2007 Feb 17;369(9561):559-70.

Ferguson T, Wilcken N, Vagg R, Ghersi D and Nowak AK. Taxanes for adjuvant treatment of early breast cancer. Cochrane Database Syst Rev. 2007;(4): CD004421.

Geiger AM, Thwin SS, Lash TL, Buist DS, Prout MN, Wei F, et al. Recurrences and second primary breast cancers in older women with initial early-stage disease. Cancer. 2007 Mar 1;109(5):966-74.

Harris L, Fritsche H, Mennel R, Norton L, Ravdin P, Taube S, et al. American Society of Clinical Oncology 2007 update of recommendations for the use of tumor markers in breast cancer. J Clin Oncol. 2007 Nov 20;25(33):5287-312.

Hayes DF. Clinical practice. Follow-up of patients with early breast cancer. N Engl J Med. 2007;356(24): 2505-13.

Hudis CA. Trastuzumab--mechanism of action and use in clinical practice. N Engl J Med. 2007; 357(1): 39-51.

Ives A, Saunders C, Bulsara M, Semmens J. Pregnancy after breast cancer: population based study. BMJ. 2007 Jan 27;334(7586):194. Epub 2006 Dec 8.

Jatoi I, Chen BE, Anderson WF, Rosenberg PS. Breast cancer mortality trends in the United States according to estrogen receptor status and age at diagnosis. J Clin Oncol. 2007 May 1;25(13):1683-90. Epub 2007 Apr 2.

Kerlikowske K, Miglioretti DL, Buist DS, Walker R, Carney PA; National Cancer Institute-Sponsored Breast Cancer Surveillance Consortium. Declines in invasive breast cancer and use of postmenopausal hormone therapy in a screening mammography population. J Natl Cancer Inst. 2007 Sep 5;99(17):1335-9. Epub 2007 Aug 14.

Khatcheressian JL, Wolff AC, Smith TJ, Grunfeld E, Muss HB, Vogel VG, et al.American Society of Clinical Oncology 2006 update of the breast cancer follow-up and management guidelines in the adjuvant setting. J Clin Oncol. 2006 Nov 1;24(31):5091-7. Epub 2006 Oct 10.

Lehman CD, Gatsonis C, Kuhl CK, Hendrick RE, Pisano ED, Hanna L, et al. MRI evaluation of the contralateral breast in women with recently diagnosed breast cancer. N Engl J Med. 2007 Mar 29;356(13):1295-303. Epub 2007 Mar 28.

Lohrisch C, Paltiel C, Gelmon K, Speers C, Taylor S, Barnett J, et al. Impact on survival of time from definitive surgery to initiation of adjuvant chemotherapy for early-stage breast cancer. J Clin Oncol. 2006 Oct 20;24(30):4888-94. Epub 2006 Oct 2.

Marchionni L, Wilson RF, Wolff AC, Marinopoulos S, Parmigiani G, Bass EB, et al.. Systematic review: gene expression profiling assays in early-stage breast cancer. Ann Intern Med. 2008;148(5): 358-69.

Michels KB, Xue F, Colditz GA, Willett WC. Induced and spontaneous abortion and incidence of breast cancer among young women: a prospective cohort study. Arch Intern Med. 2007 Apr 23;167(8):814-20.

Moss SM, Cuckle H, Evans A, Johns L, Waller M, Bobrow L. Effect of mammographic screening from age 40 years on breast cancer mortality at 10 years' follow-up: a randomised controlled trial. Lancet. 2006 Dec 9;368(9552):2053-60.

National Comprehensive Cancer Network. Practice Guidelines in Oncology. Breast Cancer. v.2.2008.

North American Menopause Society. Estrogen and progestogen use in peri- and postmenopausal women: March 2007 position statement of The North American Menopause Society. Menopause. 2007 Mar-Apr;14(2):168-82.

Pierce JP, Natarajan L, Caan BJ, Parker BA, Greenberg ER, Flatt SW, et al. Influence of a diet very high in vegetables, fruit, and fiber and low in fat on prognosis following treatment for breast cancer: the Women's Healthy Eating and Living (WHEL) randomized trial. JAMA. 2007 Jul 18;298(3):289-98.

Punglia RS, Morrow M, Winer EP and Harris JR. Local therapy and survival in breast cancer. N Engl J Med. 2007;356(23): 2399-405.

Qaseem A, Snow V, Sherif K, Aronson M, Weiss KB, Owens DK; Clinical Efficacy Assessment Subcommittee of the American College of Physicians. Screening mammography for women 40 to 49 years of age: a clinical practice guideline from the American College of Physicians. Ann Intern Med. 2007 Apr 3;146(7):511-5.

Ravdin PM, Cronin KA, Howlader N, Berg CD, Chlebowski RT, Feuer EJ, et al. The decrease in breast-cancer incidence in 2003 in the United States. N Engl J Med. 2007 Apr 19;356(16):1670-4.

Reeves GK, Pirie K, Beral V, Green J, Spencer E, Bull D; Million Women StudyCollaboration. Cancer incidence and mortality in relation to body mass index in the Million Women Study: cohort study. BMJ. 2007 Dec 1;335(7630):1134. Epub 2007 Nov 6.

Robson M and Offit K. Clinical practice. Management of an inherited predisposition to breast cancer. N Engl J Med. 2007;357(2): 154-62.

Saslow D, Boetes C, Burke W, Harms S, Leach MO, Lehman CD, et al. American Cancer Society guidelines for breast screening with MRI as an adjunct to mammography. CA Cancer J Clin. 2007 Mar-Apr;57(2):75-89.

Terry KL, Willett WC, Rich-Edwards JW, Michels KB. A prospective study of infertility due to ovulatory disorders, ovulation induction, and incidence of breast cancer. Arch Intern Med. 2006 Dec 11-25;166(22):2484-9.

Turner NC and Jones AL (2008). Management of breast cancer--part I. BMJ. 2008;337: a421.

Turner NC and Jones AL. Management of breast cancer--Part II. BMJ. 2008;337: a540.

Wolff AC, Hammond ME, Schwartz JN, Hagerty KL, Allred DC, Cote RJ, et al. American Society of Clinical Oncology/College of American Pathologists guideline recommendations for human epidermal growth factor receptor 2 testing in breast cancer. J Clin Oncol. 2007 Jan 1;25(1):118-45. Epub 2006 Dec 11.

  • Reviewed last on: 11/10/2008
  • Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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