Breast Cancer: The Role of Hormone Therapy

ABSTRACT

The possible association of estrogen (E) with or without progestin (P) and breast cancer has been addressed in many studies for several decades. The recent reported prospective double-blind Women's Health Initiative (WHI) study suggests that E + P increases the risk of breast cancer if a woman is an average of 63 years old when she begins replacement therapy. One third of the patients in this study were 70 to 79 years of age when E + P was begun-obviously several decades past menopausal. Retrospective and observational studies suggest protection or no increased risk. The WHI-E only study actually notes a 23% reduction in breast cancer compared with the placebo. It would appear from a review of the literature that if there is an increased risk for breast cancer with E or E + P, it is minimal.

KEYWORDS

Breast cancer - estrogen - progestin - exercise - anthropomorphic factors

REFERENCES

• 1 Lippman M E, Bolan G. Estrogen-responsive human breast cancer in long term cultures.  Nature. 1975;  256 592-593
• 2 Colditz G A, Hankinson S E, Hunter D J et al.. The use of estrogens and progestins and the risk of breast cancer in postmenopausal women.  N Engl J Med. 1995;  332 1589-1593
• 3 Bush T L, Whiteman M, Flaws J A. Hormone replacement therapy and breast cancer: a qualitative review.  Obstet Gynecol. 2001;  98 498-508
• 4 Creasman W T. Estrogen and cancer.  Gynecol Oncol. 2002;  86 1-9
• 5 Collaborative Group on Hormonal Factors in Breast Cancer . Breast cancer and hormone replacement therapy: collaborative reanalysis of data from 51 epidemiological studies of 52,705 women with breast cancer and 108,411 women without breast cancer.  Lancet. 1997;  350 1047-1059
• 6 Santen R J, Petroni G R. Relative versus attributable risk of breast cancer from estrogen replacement therapy.  J Clin Endocrinol Metab. 1999;  84 1875-1881
• 7 WHI . Risks and benefits of estrogen and progestin in healthy postmenopausal women.  JAMA. 2002;  288 321-333
• 8 Chelbowski R T, Hendrix S L, Langer R D et al.. Influence of estrogen plus progestin on breast cancer and mammography in healthy postmenopausal women: the Women's Health Initiative randomized trial.  JAMA. 2003;  289 3243-3253
• 9 McTierman A, Kooperberg C, White E et al.. Women's Health Initiative Cohort Study. Recreational physical activity and the risk of breast cancer in postmenopausal women.  JAMA. 2003;  290 1331-1336
• 10 Morimoto L M, White E, Chem Z et al.. Obesity, body size, and risk of postmenopausal breast cancer. The Women's Health Initiative.  Cancer Causes Control. 2002;  13 741-751
• 11 Million Women Study Collaborators . Breast cancer and hormone replacement therapy in the Million Women Study.  Lancet. 2003;  362 419-427
• 12 WHI . Effects of conjugated equine estrogen in postmenopausal women with hysterectomy.  JAMA. 2004;  291 1701-1712
• 13 Mauvias-Jarvis P, Kultenn F, Gompel A. Antiestrogen action of progesterone in breast tissue.  Breast Cancer Res Treat. 1986;  8 179-187
• 14 Weiss L K, Burkman R T, Cushing-Haugen K L et al.. Hormone replacement therapy regimens and breast cancer risk.  Obstet Gynecol. 2002;  100 1148-1158