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Breast Cancer Risk and HT: Focus on Progestogens. Andrew M. Kaunitz, MD Professor and Associate Chairman Department of Obstetrics and Gynecology University of Florida College of Medicine Jacksonville, Florida. Daniel R. Mishell Jr, MD Lyle G. McNeile Professor
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Breast Cancer Risk and HT:Focus on Progestogens Andrew M. Kaunitz, MD Professor and Associate Chairman Department of Obstetrics and Gynecology University of Florida College of Medicine Jacksonville, Florida Daniel R. Mishell Jr, MD Lyle G. McNeile Professor Department of Obstetrics and Gynecology Keck School of Medicine University of Southern California Los Angeles, California An online offering from
Estrogen-Only Regimens:Minimal or no increase in breast cancer risk
Breast Cancer in the WHI • E+P: HR 1.24 (weighted P<.001) • E-alone: HR 0.77 (P=.09) E, estrogen; HR, hazard ratio; P, progestin; WHI, Women’s Health Initiative. Stefanick ML, et al. JAMA. 2006;295:1647-1657. Chlebowski RT, et al. JAMA. 2003;289:3243-3253.
Observational Data • Nurses’ Health Study: Breast cancer risk with E-alone • <5 years: RR 0.96 (95% CI, 0.75-1.22) • 5-9.9 years: RR 0.90 (95% CI, 0.73-1.12) • 10-14.9 years: RR 1.06 (95% CI, 0.87-1.30) • 15-19.9 years: RR 1.18 (95% CI, 0.95-1.48) • 20+ years: RR 1.42 (95% CI, 1.13-1.77) • Finnish experience with systemic estrogen-only for less than 5 years’ duration: • Incidence ratio: 0.93 (95% CI, 0.80-1.04) CI, confidence interval; RR, relative risk. Chen WY, et al. Arch Intern Med. 2006;166:1027-1032.Lyytinen H, et al. Obstet Gynecol. 2006;108:1354-1360.
2005 Meta-analysis • 4 randomized trials • E-alone: 0.79 (95% CI, 0.61-1.02) • E+P: 1.24 (95% CI, 1.03-1.50) • Observational studies with current use • E-alone: 1.18 (95% CI, 1.01-1.38) • E+P: 1.70 (95% CI, 1.36-2.13) Collins JA, et al. Hum Reprod Update. 2005;11:545-560.
Cytoplasmic Vacuoles Gland Mitosis 1 7 14 21 28 Menses Proliferative Phase Secretory Phase Gland Mitoses in Human Breast and Endometrium According to Cycle Day Breast Endometrium Longacre TA, Bartow SA. Am J Surg Pathol. 1986;10:382-393.
Estrogen+Progestin Regimens: Elevated risk for breast cancer after 5+ years of use
Risk/Benefit Ratio:Cancer risks in the Million Women Study Standardized incidence rate per 1000 women over 5-year period Endometrial Breast Cancer Cancer Baseline 3.0 13.6 E-alone 4.9 18.0 E+P 2.0 29.3 Beral V, et al. Lancet. 2005;365:1543-1551.
Breast Cancer Risk with E+P by Duration of Use • <5 years: 1.34 (95% CI, 1.13-1.59) • ≥5 years: 1.89 (95% CI, 1.54-2.31) Meta-analysis of the epidemiologic data, 2005 Collins JA, et al. Hum Reprod Update. 2005;11:545-560.
Differences Among Progestins: Do they affect breast cancer risk?
Progestogens Used in US Postmenopausal HT Regimens • Medroxyprogesterone acetate • Norethindrone acetate • Levonorgestrel • Micronized progesterone
French Cohort Study • E-alone vs never use:RR 1.29 (95% CI, 1.02-1.65) • Oral estrogen-MPA:RR 1.48 (95% CI, 1.02-2.16) • Oral estrogen-norethindrone acetate:RR 2.11 (95% CI, 1.56-2.86) • Transdermal estrogen-progesterone:RR 1.08 (95% CI, 0.89-1.31) MPA, medroxyprogesterone acetate. Fournier A, et al. Breast Cancer Res Treat. 2007;Feb 27 [Epub ahead of print].
Micronized Progesterone • Approved by the FDA for prevention of endometrial hyperplasia in menopausal women using estrogen who have a uterus. • Biochemically identical to the progesterone produced by the ovaries during a woman’s reproductive years.
Transdermal Estrogen • All non-oral estrogen formulations are estradiol, which is biochemically identical to the estrogen produced by reproductive aged women. • Unlike oral estrogen, transdermal estrogen does not appear to increase the risk of venous thromboembolism because it avoids the first pass through the liver.1 1Canonico M, et al. Circulation. 2007;115:840-845.
Reassuring Messages • Estrogen alone does not alter breast cancer risk. • E+P increases risk, but only with use for 5 years or more. • Recent data show that transdermal estrogen with micronized progesterone may be particularly safe.
Use of Oral Micronized Progesterone • 100 mg and 200 mg doses • Formulations contain peanut oil • May cause sleepiness • Use in women with a uterus who are taking estrogen • MP, 200 mg, for cyclic use (days 1-10 or 1-14 of each month) • MP, 100 mg, for daily use at bedtime* *This regimen is not FDA approved.