Marchbanks PA, McDonald JA, Wilson HG, et al.
Oral contraceptives and the risk of breast cancer. N Engl J Med 2002;346:2025-2032.
Neither current nor former use of combined
estrogen plus progestin oral contraceptives (OCs) is associated with increased risk for breast cancer in women, according
to the results of this population-based, case-control study. Investigators interviewed 4,575 women with breast cancer and
4,682 women without breast cancer. Women were aged 35 to 64; 77% of the case subjects and 79% of the controls had used some
type of OC. Compared with never users, the relative risk of breast cancer was 1.0 (95% CI, 0.8-1.3) for current OC users and
0.9 (95% CI,0.8-1.0) for former users. The relative risk did not increase consistently with longer periods of OC use, higher
doses of estrogen, type of progestin used, or age at first use. Also, women with a family history of breast cancer did not
have an increased risk from OC use.
Level II-2 evidence Comment. Oral contraceptives are the most widely used reversible method of contraception used by
US women (approximately 78% of participants in this large study were ever users). They provide consistent users with convenient,
effective, and reversible birth control. Furthermore, use of OCs is associated with important noncontraceptive health benefits,
ranging from lighter less painful more regular menses to prevention of endometrial and ovarian cancers. Perhaps the biggest
concern that women, and their clinicians, have regarding OCs is that their use might increase breast cancer risk. This large,
NIH-sponsored, CDC-conducted, study provides a high level of reassurance that OC users, regardless of age, formulation type,
duration of use, or family history, will not increase their breast cancer risk.