important menopause information
Gynecologists often prescribe oral contraceptives to manage the perimenopausal symptoms of irregular cycles, heavy and prolonged bleeding, and hormonal variations that can result in mood changes, irritability, headaches and hot flashes. The data regarding the risks of oral contraception increasing breast cancer incidence has been confusing.
An editorial published in the May, 2018, issue of the journal Menopause, addressed this controversy.
The New England Journal of Medicine published a Danish study recently that demonstrated a small but statistically significant increase in breast cancer in women who currently or recently used birth control pills. The relative risk was in the range of 1.2, and was similar to the increased risk of women who used the progesterone containing IUD. Because this was on observational study and looked at women only below the age of 50 (most breast cancers occur in women over the age of 50), the authors noted that the study did not control for other factors that also increase the risk of breast cancer such as age at first menses, alcohol intake, exercise. and a history of lactation. The study also did not take into account the surveillance for breast cancer such as clinical breast exams and mammograms. it is probable that women receiving regular exams and being prescribed medication would have greater surveillance than women not seeing a physician as regularly. Because the elevated risk was modest and this was an observational study, the study does not prove cause-and-effect, and the data should be interpreted within its limitations.
Several studies published prior to this one differed in conclusions. The NIH funded a population-based study looking at women ages 35 to 64, performed by the CDC and published in 2002. The study was felt be rigorously conducted and detailed regarding oral contraceptive use and breast cancer incidence. The results of this study did not demonstrate an increase in breast cancer in uses of birth control pills, progesterone only pills, and progesterone implants or injections. The doses of oral contraceptives were often higher prior to 2002 than they are now.
The follow-up analysis done in 2012 did not demonstrate a difference between the ten most commonly prescribed formulations of oral contraceptives. A different study did show in increase of breast cancer in formulations with higher doses of estrogen and the progestin ethynodial acetate which is rarely used today. Lower dose OC’s did not demonstrate an increased risk of breast cancer.
A study which came from the UK and published in 2017 was the longest-term study published to date. On average, they followed women for 40 years since 1968. Many of the women were in their 70’s, and the results were impressive. There was no increase in breast cancer for women who ever used oral contraceptives vs. never users, but the risks of colon, endometrial, and ovarian cancer were significantly decreased!! The risk of cervical cancer was increased but not statistically significant.
When multiple studies were analyzed, there was not found to be an increased all-cause mortality or breast cancer specific mortality for women who ever took OC’s, despite length of use or time since discontinuation.Women who ever took OC’s demonstrated a reduced mortality of ovarian cancer to RR 0.58.
Women at risk of breast cancer because of family history do not further increase their risk by taking oral contraceptives, when pooled data were evaluated.
What about carriers of the BRCA genes? The data varies, but multiple studies do demonstrate an increased incidence of breast cancer which is moderate, and not always statistically significant, but a very definite decrease in ovarian cancer which is significant.
The use of hormonal contraception to manage peri-menopause must take into account multiple variables. Women in this age group with untreated hypertension are at increased risk of stroke, heart attacks, and peripheral vascular disease. Healthy, normal weight, non-smokers can use oral contraceptives until menopause or the age of 55 to manage the menopausal transition. Available data demonstrated no increase in breast cancer or all-cause mortality of this intervention, while offering protection against endometrial, ovarian and colon cancer.
As will similar medical decisions, consult your gynecologist to choose the best intervention for your particular situation.
Marilyn C. Jerome, MD
Foxhall Ob-Gyn Associates
Editorial: Hormonal contraception and the risk of breast cancer: a closer look, Andrew M. Kunitz, MD, JoAnn V. Pinkerton, MD, JoAnn Manson, MD
Menopause: The Journal of the North American Menopause Society, Volume 25, Number 5, May 2018