• 21Jun

    Birth control pills and cancer – is there a relation?

    It is known that circulating hormone level influence the growth of breast, estrogen inducing ductal growth and progesterone promoting alveolar growth. Estrogen for a long time has been recognized as a promoter of cancer growth due to its growth stimulating properties. It was believed to promote cancer development by stimulating proliferation of cells with potential cancer causing mutations. Later studies have proved that estrogen metabolites can bind to DNA and cause mutations. Estrogen metabolites may also affect the level of enzymes involved in the removal of 4-hydroxyestradiol that might initiate cancer. These studies suggest that estrogen may play a role as an initiator of cancer.


    Complications of oral birth control pills

    Earlier the oral contraceptives contained higher dose of estrogens and progestins. The studies conducted then raised many concerns related to risk for breast cancer and other complications. The modern oral contraceptives contain lower dosage of estrogens and progestins which has significantly reduced the risks. Even then major concerns remain regarding association of estrogens with breast cancer, deep vein thrombosis (blood clotting in calf veins), pulmonary embolism (choking of blood vessel leading from heart to lungs with blood), hypertension, gall bladder disease, migraine and mood changes.

    The risk of cancer

    The possibility of developing a cancer is probably the major concern for the use of estrogens and oral contraceptives. Early studies showed that estrogens can induce tumors of the breast, uterus, testis, bone, kidney and several other tissues in various animal species. These early studies disseminated a fear of cancer resulting from estrogen use.

    Modern oral contraceptives contain low dosage of estrogens and progestins

    Modern oral contraceptives contain low dosage of estrogens and progestins

    In later reports an increased incidence of vaginal and cervical (part of uterus) cancer was noted in female offspring of mothers who had taken diethylstilbestrol (synthetic estrogen) during the first trimester of pregnancy. These findings established that developmental exposure to estrogens was associated with human cancer. Other studies revealed that the use of only estrogen (without progesterone) for hormone treatment in postmenopausal women increases the risk of cancer of uterus by five- to fifteen times. This increased risk can be prevented if a progestin is given along with the estrogen which is now a standard practice worldwide.

    Studies on estrogen and progestin

    The association between estrogen and/or estrogen-progestin use and breast cancer continues to be of great concern and debate. The results of two very large, randomized, clinical trials of estrogen-progestin and estrogen-only (The Women’s Health Initiative or WHI) use in postmenopausal women have clearly confirmed a small but significant increase in the risk of breast cancer development, apparently due to the medroxyprogesterone. In the WHI study, an estrogen-progestin combination increased the total risk of breast cancer by 24%. The increase in the actual attributable cases of disease was 6 per 1000 women and required 3 or more years of treatment.

    The Million Women Study (MWS) in the United Kingdom surveyed over one million women, about half receiving some type of hormone treatment and half having never used them. Those receiving an estrogen-progestin combination had an increased relative risk of invasive breast cancer by the factor of 2 (two times greater risk), and those receiving estrogen alone had an increased relative risk by the factor of 1.3, but the increase in actual attributable cases of the disease was again small.

    Both the WHI and MWS data are thus consistent with earlier studies indicating that the progestin component (e.g., medroxyprogesterone) in hormone-replacement therapy plays a major role in this increased risk of breast cancer.

    Decision

    Another study reported that the relative risk is increased in the current and recent users by 1.24 and is higher in women with early start of oral intake before the age of 20 years. The relative risk tends to be zero after ten years of cessation of intake.

    If you are thinking about starting hormonal contraception or taking birth control pills, consult it with your doctor. There are several things that should be taken into consideration – general health condition, genetic loads, chronic diseases and other.

    Anna L.

    It’s all about health!
    I have academic background in drugs related Chemical Technology, as well as extensive professional experience in pharma and medical companies. My main area of interest is everyday life medicine. The goal of my articles is to give people informative answers to the questions that bother them, to dispel doubts and some common misbeliefs and also to inspire everyone to keep healthy lifestyle.

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