MHT and breast cancer



Breast cancer mortality rates have fallen 30% in the past 20 years

Middle aged woman looking confident

Certain hormonal factors that may increase the risk of breast cancer include starting your periods early (under 12 years of age), having your first pregnancy over 30 years of age, having no children and having late menopause. Breastfeeding for 12 months or more may reduce the risk of breast cancer.

There could be a slight increase while taking the combined oral contraceptive pill, but the increased risk will disappear within a few years of stopping. The recommended age in Australia to stop taking the combined oral contraceptive pill is 50 or 35 if you are a smoker.

The risk of MHT and breast cancer has been misreported by the media based on the earlier World’s Health Initiative (WHI) study results in 2002. The type of MHT in this study is not generally prescribed today. This media misrepresentation has left some women confused, anxious and refusing to take MHT during perimenopause and menopause. In the 20 years that have passed, new information about MHT has helped doctors better understand the risks and benefits of MHT and, for most women, the benefits of taking MHT outweigh the risks.

Oestrogen-alone menopausal hormone therapy (MHT) does not appear to increase breast cancer risk.

Combined MHT confers a small increase in risk, (approximately one extra case per 1000 women using MHT for one year), but this decreases over time when MHT is stopped. The risk is mostly attributed to the addition of progesterone to oestrogen therapy and is related to the duration of use.

Low-dose topical oestrogen in the vagina does not increase the risk of breast cancer because changes in the vaginal tissues limit the amount of oestrogen that is absorbed.

If you have been diagnosed with breast cancer, you should not take systemic (whole-body) hormone therapy. 

Significant risk factors for breast cancer include regular alcohol consumption (32-46%), obesity (26–152%), and physical inactivity (7–33%).

Research does not support a link between underarm deodorant or underwired bras and breast cancer.

Cancers occurring at older ages are less likely to be inherited. One should suspect a genetic predisposition if they have two or more first-degree relatives with breast cancer.

An inherited tendency can be several close relatives developing breast cancer, or family members with breast cancer, ovarian cancer, prostate cancer, or both breast and ovarian cancer at a young age.

About 5% to 10% of breast cancers result directly from gene changes (mutations) passed on from a parent. BRCA1 and BRCA2 (the most common causes of hereditary breast cancer) are inherited mutations.

Individuals with an inherited breast cancer gene, such as BRCA mutation carriers, without a personal history of breast cancer, may use MHT to improve their quality of life.

There are several online tools to help assess breast cancer risk. These include iPrevent (Peter MacCallum Cancer Centre) and CanRisk.

( and

Should you have an increased risk of breast cancer, you may be offered extra breast screening (MRI) to help pick up cancers as early as possible.

Doctors generally do not recommend MHT if you have previously been treated for breast cancer. Studies show that MHT can increase the risk of cancer recurrence. Symptoms associated with menopause in women who have had breast cancer are the same as they are for any woman going through menopause. At times, menopausal symptoms may be induced by cancer treatment.

Endocrine therapy for breast cancer is used to block hormones from attaching to receptors on cancer cells or to decrease the body’s production of hormones. It can also be used as an adjuvant therapy to shrink a tumour before surgery. Tamoxifen and Aromatase inhibitors are endocrine treatments for breast cancer and can cause menopausal symptoms such as hot flushes. Aromatase inhibitors should only be prescribed for postmenopausal women, whereas Tamoxifen can be prescribed for both premenopausal and postmenopausal women.

Surgery to remove the ovaries or medication to deactivate the ovaries can cause sudden and severe menopause symptoms.

Management for treating menopause after breast cancer requires individualised care and support from your GP or treating specialist. There are several non-hormonal options that assist in symptom management, including cognitive behavioural therapy (CBT) and prescribed medications that are safe and effective.