A recent study of 40,000 UK menopausal women has found using hormone replacement therapy (HRT) triples their risk of developing breast cancer, with the risk increasing the longer they use it. Once HRT use ends, the risk returns to normal levels.
HRT (also referred to as menopausal hormone replacement) is used to treat uncomfortable symptoms of menopause – such as hot flushes, migraines, disrupted sleep, mood changes and depression – by topping up the decreased levels of hormones in the body during menopause and beyond.
According to Cancer Council NSW, in Australia, there are currently around 500,000 women taking HRT to alleviate menopausal symptoms, 12 per cent of women aged 40-65, and the majority of these women have been taking HRT for longer than five years.
The hormones progesterone and estrogen are critical in normal breast development. However, HRT is linked to breast cancer because some types of breast cancer are receptive to female hormones, such as estrogen and progesterone. Boosting the levels of these hormones with HRT can drive tumour growth, and women taking hormone replacement therapy (HRT) that contains synthetic progesterone analogues, called progestins, have an increased breast cancer risk.
NBCF-funded Dr Heidi Hilton is investigating the influence female hormones have at the origin of cancer formation which could not only lead to earlier diagnosis for breast cancer, but also help women are faced with the difficult decision of deciding between using HRT or dealing with the uncomfortable and often debilitating symptoms of menopause.
HRT is an effective treatment that can significantly affect a woman’s quality of life. In conjunction with advice from her doctor, it’s up to each woman to make the decision about risks verses benefits in relation to her own circumstances.
The use of HRT is just one among many other factors that can increase the likelihood of developing breast cancer, and although it can sound dire it’s important to understand that a woman’s actual lifetime risk is fairly low.
Assuming she lives to age 85, a woman’s likelihood of getting breast cancer is 1 in 50 (2018 figure), or about 2.5 per cent, and there are modifiable and non-modfiable factors that can affect this risk.
The level of risk can increase or reduce depending on lifestyle choices, such as exercising, drinking alcohol, having children later in life; but there are some risks, like being a woman and getting older, that women have no control over. In a small percentage of cases, family history is also a risk factor.
While most of us can do little to change the unmodifiable risk factors for developing breast cancer, researchers estimate that close to 30 per cent of all breast cancers could be prevented if women make choices to live healthier lives.