How medications affect breast cancer risk

Have you ever thought about how your prescription drugs might affect your long term health? It would be logical to think that because they’ve been prescribed by a doctor they would be absolutely safe to take. This is not always the case.

The human body is a finely tuned machine, and although it has many built in fail-safes, changing the conditions in one area will invariably cause something else to fall out of balance at some point. Most medically prescribed drugs are there to treat a symptom, rather than the actual cause of the problem.

 PillsDrugs that “control” hormone levels

Unfortunately with breast cancer, drugs that control or provide hormones can also create imbalances and increase the risk of developing cancer. Hormone replacement therapy, mainly given to peri or post menopausal women (otherwise known as HRT), is a well-known example of this. It has resulted in numerous cases of breast cancer due to its proliferative effect on breast tissue.[1] The Pill increases the risk of cervical cancer and breast cancer particularly for cigarette smokers.

Other drugs, like blood pressure medication (in particular calcium channel blockers) are also under the spotlight. A study found that after following a group of women for 10 years, they were 2.5 times more likely to suffer from breast cancer[2].

SSRI’s (selective serotonin reuptake inhibitors), which are a group of widely-used antidepressants, have also been linked to oestrogen receptor-positive breast cancer, due to serotonin’s stimulating action on the release of prolactin. Prolactin is a hormone that stimulates breast growth and lactation. Although the exact mechanism is not completely understood, it’s thought that prolactin (stimulated by serotonin), promotes cell growth and suppresses programmed cell death, allowing tumour growth to occur.[3]

Although you should not stop taking your prescribed medication, it’s very important to be informed of the risks. If you have any questions at all about the medication you’re taking, speak to Ross or your doctor at your next appointment.



[1] Le Marchand, L et al. MTHFR polymorphism, diet, HRT and breast cancer risk: the multiethnic cohort study. Cancer Epidemiological Biomarkers. 2004 Dec;13(12):2071-7

[2] Li, Cl et al. Use of antihypertensive medications and breast cancer risk among women aged 55 to 74 years. JAMA Intern Med. 2013 Sep 23;173(17):1629-37.

[3] Sethi, K.B et al. Prolactin and cancer: Has the orphan finally found a home?. Indian Journal of Endocrinology & Metabolism. 2012, 16 (8), 195-198

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