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Exogenous progestins and breast cancer.
Epidemiol Rev 1993; 15(1):98-107ER

Abstract

More research on the effect of exogenous progestins on breast cancer risk is clearly needed. Biologic evidence that progestins may act synergistically with estrogen to enhance proliferation of breast epithelial cells emphasizes the importance of further exploration of this issue, particularly given the increasing prevalence of exposure to contraceptive and noncontraceptive progestins. No specific type or dose of progestin in monophasic combination oral contraceptives has been linked to breast cancer. Based on the few epidemiologic studies of progestin-only oral contraceptives, there also is no evidence that they increase risk of breast cancer. Two studies found that longer-term use of progestin-only pills was associated with a decreased risk of breast cancer. However, given the low prevalence of use of minipills, it is unlikely that this exposure substantially affects the incidence of breast cancer in the population as a whole. Use of the injectable contraceptive DMPA has been positively associated with risk of breast cancer in some subgroups of women, although no significant overall adverse effect has been observed in the two largest studies conducted to date. There is suggestive evidence that use at an early age or prior to a first term birth and recent use may increase risk of breast cancer. It remains unclear, however, whether or not surveillance bias may explain the positive association observed in recent users. Additional research on DMPA and breast cancer incidence is needed, since studies published to date have lacked sufficient power to evaluate risk in relation to long-term use. Future studies of breast cancer in relation to use of other long-acting progestational agents such as Norplant will also be important. There is concern about the relation between breast cancer incidence and use of combined estrogen-progestin replacement therapy, especially extended periods of use. At the present time, only one study (45) has estimated risk according to duration of use, and it remains uncertain whether the reported elevation in risk seen in long-term users of combined therapy is due to enhanced surveillance for breast cancer among exposed women. Further research will be required before any definitive conclusions can be reached about the potential effect of estrogen-progestin replacement regimens on breast cancer incidence. Future studies should attempt to determine the circumstances under which progestins may alter risk of breast cancer and whether such effects vary by duration of use, dosage, type of preparation, concomitant use of estrogens, regimen of exposure, and the timing of progestin use in relation to age and menstrual and reproductive events.(

ABSTRACT

TRUNCATED AT 400 WORDS)

Authors+Show Affiliations

Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98104.No affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.
Review

Language

eng

PubMed ID

8405216

Citation

Stanford, J L., and D B. Thomas. "Exogenous Progestins and Breast Cancer." Epidemiologic Reviews, vol. 15, no. 1, 1993, pp. 98-107.
Stanford JL, Thomas DB. Exogenous progestins and breast cancer. Epidemiol Rev. 1993;15(1):98-107.
Stanford, J. L., & Thomas, D. B. (1993). Exogenous progestins and breast cancer. Epidemiologic Reviews, 15(1), pp. 98-107.
Stanford JL, Thomas DB. Exogenous Progestins and Breast Cancer. Epidemiol Rev. 1993;15(1):98-107. PubMed PMID: 8405216.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Exogenous progestins and breast cancer. AU - Stanford,J L, AU - Thomas,D B, PY - 1993/1/1/pubmed PY - 1993/1/1/medline PY - 1993/1/1/entrez KW - Age Factors KW - Biology KW - Breast Cancer--etiology KW - Cancer KW - Contraception KW - Contraceptive Agents, Female--side effects KW - Contraceptive Agents, Progestin--side effects KW - Contraceptive Agents--side effects KW - Contraceptive Methods--side effects KW - Cytology KW - Demographic Factors KW - Depo-provera--side effects KW - Diseases KW - Endocrine System KW - Epidemiologic Methods KW - Family Planning KW - Hormones KW - Literature Review KW - Maternal Age KW - Medroxyprogesterone Acetate--side effects KW - Neoplasms KW - Oral Contraceptives, Combined--side effects KW - Oral Contraceptives--side effects KW - Parental Age KW - Physiology KW - Population KW - Population Characteristics KW - Progestational Hormones KW - Progesterone KW - Progestins, Low-dose--side effects KW - Research Activities KW - Research Methodology KW - Risk Factors SP - 98 EP - 107 JF - Epidemiologic reviews JO - Epidemiol Rev VL - 15 IS - 1 N2 - More research on the effect of exogenous progestins on breast cancer risk is clearly needed. Biologic evidence that progestins may act synergistically with estrogen to enhance proliferation of breast epithelial cells emphasizes the importance of further exploration of this issue, particularly given the increasing prevalence of exposure to contraceptive and noncontraceptive progestins. No specific type or dose of progestin in monophasic combination oral contraceptives has been linked to breast cancer. Based on the few epidemiologic studies of progestin-only oral contraceptives, there also is no evidence that they increase risk of breast cancer. Two studies found that longer-term use of progestin-only pills was associated with a decreased risk of breast cancer. However, given the low prevalence of use of minipills, it is unlikely that this exposure substantially affects the incidence of breast cancer in the population as a whole. Use of the injectable contraceptive DMPA has been positively associated with risk of breast cancer in some subgroups of women, although no significant overall adverse effect has been observed in the two largest studies conducted to date. There is suggestive evidence that use at an early age or prior to a first term birth and recent use may increase risk of breast cancer. It remains unclear, however, whether or not surveillance bias may explain the positive association observed in recent users. Additional research on DMPA and breast cancer incidence is needed, since studies published to date have lacked sufficient power to evaluate risk in relation to long-term use. Future studies of breast cancer in relation to use of other long-acting progestational agents such as Norplant will also be important. There is concern about the relation between breast cancer incidence and use of combined estrogen-progestin replacement therapy, especially extended periods of use. At the present time, only one study (45) has estimated risk according to duration of use, and it remains uncertain whether the reported elevation in risk seen in long-term users of combined therapy is due to enhanced surveillance for breast cancer among exposed women. Further research will be required before any definitive conclusions can be reached about the potential effect of estrogen-progestin replacement regimens on breast cancer incidence. Future studies should attempt to determine the circumstances under which progestins may alter risk of breast cancer and whether such effects vary by duration of use, dosage, type of preparation, concomitant use of estrogens, regimen of exposure, and the timing of progestin use in relation to age and menstrual and reproductive events.(ABSTRACT TRUNCATED AT 400 WORDS) SN - 0193-936X UR - https://www.unboundmedicine.com/medline/citation/8405216/Exogenous_progestins_and_breast_cancer_ L2 - https://academic.oup.com/epirev/article-lookup/doi/10.1093/oxfordjournals.epirev.a036120 DB - PRIME DP - Unbound Medicine ER -