Risk of breast cancer in relation to the use of injectable progestogen contraceptives and combined estrogen/progestogen contraceptives

Samuel Shapiro, Lynn Rosenberg, Margaret Hoffman, Hanneke Truter, Diane Cooper, Sowmya Rao, David Dent, Anne Gudgeon, Jakobus Van Zyl, Judith Katzenellenbogen, Ross Bailie

Research output: Contribution to journalArticlepeer-review

94 Citations (Scopus)

Abstract

Recent studies have suggested that progestogen-only contraceptives and combined estrogen/progestogen oral contraceptives (COCs) may increase the risk of breast cancer among women less than 35 years of age or among recent users. The authors conducted a case-control study, in which cases of breast cancer (n = 419) and controls (n = 1,625) hospitalized for conditions unrelated to contraceptive use were interviewed from 1994 to 1997 in hospitals in greater Cape Town, South Africa. The women were aged 20-54 years, resided in a defined area around Cape Town, and were Black or of mixed racial descent. The relative risk for exposure to injectable progestogen contraceptives (IPCs), mostly depot medroxyprogesterone acetate, was 0.9 (95% confidence interval (CI) 0.7, 1.2). There were no consistent associations within categories of age or recency or duration of use. For exposure to COCs, the overall relative risk was 1.2 (95% CI 1.0, 1.5). Among women below age 35 years, the relative risk was 1.7 (95% CI 1.0, 3.0), and it was unrelated to the duration or recency of use. The findings suggest that IPCs do not increase the risk of breast cancer, and that COCs may increase the risk among women below age 35 years, although bias cannot be excluded.

Original languageEnglish
Pages (from-to)396-403
Number of pages8
JournalAmerican Journal of Epidemiology
Volume151
Issue number4
DOIs
Publication statusPublished - 15 Feb 2000

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