(HealthDay News) — Progestogen-only contraceptive use is associated with a slight increase in breast cancer risk, according to a study published online March 21 in PLOS Medicine.
Danielle Fitzpatrick, M.B.B.S., M.P.H., from the University of Oxford in the United Kingdom, and colleagues compared hormonal contraceptive prescriptions recorded prospectively in a U.K. primary care database in a nested case-control study involving 9,498 women aged younger than 50 years with incident invasive breast cancer (diagnosed in 1996 to 2017) and 18,171 controls.
The researchers found that 44 and 39 percent of women with breast cancer and matched controls, respectively, had a hormonal contraceptive prescription an average of 3.1 years before breast cancer diagnosis. Of the prescriptions, approximately half were for progestogen-only preparation. The odds ratios for breast cancer were increased significantly if the last hormonal contraceptive prescription was for oral combined, oral progestogen-only, injected progestogen, or progestogen-releasing intrauterine devices (IUDs; odds ratios, 1.23, 1.26, 1.25, and 1.32, respectively). Significantly increased relative risks were seen for current or recent use of progestogen-only contraceptives: 1.29, 1.18, 1.28, and 1.21 for oral, injected, implanted, and IUDs, respectively. On combination of these results with those from previously published studies, the 15-year absolute excess risk associated with five years of oral combined or progestogen-only contraceptives in high-income countries was estimated at eight and 265 per 100,000 users from age 16 to 20 and 35 to 39 years, respectively.
“Current or recent use of all types of progestogen-only contraceptives is associated with a slight increase in breast cancer risk, similar to that associated with use of combined oral contraceptives,” a coauthor said in a statement.
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