Study Sheds Light on Oral Contraceptives, Breast Cancer
Small increase in breast cancer risk, particularly in parous women who use for years before first pregnancy
THURSDAY, Oct. 19 (HealthDay News) -- Oral contraceptive use is associated with a small increase in premenopausal breast cancer risk, especially in parous women who use them for four or more years before a first full-term pregnancy, according to a meta-analysis published in the October issue of Mayo Clinic Proceedings.
Chris Kahlenborn, M.D., of Altoona Hospital in Altoona, Pa., and colleagues conducted a meta-analysis of 34 studies conducted since 1980.
The researchers found that oral contraceptive use was associated with an increased risk of breast cancer in general (odds ratio, 1.19). In studies that provided separate data for parous and nulliparous women who used oral contraceptives, they found odds ratios of 1.29 and 1.24, respectively. The risk was highest in parous women who used oral contraceptive for at least four years before a first full-term pregnancy (OR, 1.52).
"Although oral contraceptives appear to be carcinogenic, the relative risk is small and the absolute risk (excess breast cancers due to OC exposure) is very small," stated the author of an accompanying editorial. "From the perspective of epidemiology and public health, we must continue to closely follow the epidemiology of OC use and health outcomes, given the widespread use of these agents and their high potential to impact women's health in both a beneficial and deleterious manner. The current study highlights the need for a close evaluation of OC use before first full-term pregnancy..."