Contraception and Breast Cancer
Kris Bhothisuwan MD*
Affiliation : * Department of Surgery,Faculty of Medicine Siriraj Hospital
Oral contraceptive use is weakly associated with breast cancer risk in the general population, but
the association among women with a fam ilial predisposition to breast cancer is less clear. Recent studies
indicating that oral contraception may increase the risk of breast cancer more in subjects who are BRCA 1
or BRCA 2 mutation carriers.
Features of hormonal contraceptive use, such as duration of use, age at first use, and the dose and
type of hormone within the contraceptives, have little effect on breast cancer risk. Women who begin use
before age 20 have higher relative risks of having breast cancer diagnosed while they are using combined
oral contraceptives and in the 5 years after stopping than do women who begin use at older ages.
Given that on influence of oral contraceptives on the breast has been hypothesized to be greatest
before the cellular differentiation that occurs with a first pregnancy. A significant trend of increasing risk
with first use before age 20 years was observed. Among women diagnosed at ages 30 to 34 years the relative
risk associated with recent oral contraceptive use was 1.54 if use began before age 20 years and 1.13 it use
began at older ages.
Keywords : Contraception, Breast, Cancer
