Does Hormonal Therapy Cause Breast Cancer?

How would you react if someone suggested hormonal treatment to you? Commonly the question foremost in people’s minds is “Does Hormonal Therapy cause breast cancer?”

The Media Storm around MHT

The media frenzy around hormonal therapy in the early 2000’s struck right to the heart of women’s darkest fears, causing millions to abandon treatments that improved their quality of life and long- term health. We’ve spent more than two decades excavating the truth about HRT (Hormonal Replacement Therapy, now known as Menopausal Hormone Therapy, or MHT) yet negative misconceptions prevail. Why do so many women and doctors still need to ask “Does Hormonal Therapy cause breast cancer?”

The Facts About MHT and Breast Cancer Risk

Headlines in the noughties focused mainly on the fact that HRT use increases breast cancer risk, which we’ve actually known for a very long time. For years I’ve counselled my patients about the very small increase in breast cancer risk associated with certain types of hormonal therapy after 5 years of use.

Unlike those one-sided news headlines however, I also explain that there are certain types of hormonal treatment which do not seem as likely to increase risk. For women who’ve had a hysterectomy for example, the type of treatment used is much lower risk.

Individual Risk Should be Assessed For Every Woman

A woman’s individual risk assessment must take into account ALL her risk factors. For example obesity is a much greater risk factor for breast cancer than hormonal treatment (about 6 times the risk, as shown in this great graphic representation from the British Menopause Society).

This chart also shows that two standard alcoholic drinks per day is equivalent in risk to hormonal treatment use for 5 years, whereas exercise significantly reduces risk.

Every Woman Has a High Baseline Risk of Breast Cancer

A complete risk assessment must also take into account your “background” risk level. Every Australian woman has at least a 1 in 8 lifetime risk of developing breast cancer, even higher if she has a strong family history or other risk factors. Regardless of what medication choices she makes this background risk persists.

I always warn women that one-eighth of MHT users will get breast cancer… because one-eighth of non-MHT users will too! It’s important to understand that if you develop breast cancer whilst using hormones, it doesn’t mean the hormones caused the breast cancer.

How do you prevent Breast Cancer whilst using MHT?

You can’t prevent breast cancer whether you use MHT or not, unless you’re prepared to have mastectomies. My secret to life (literally) is early detection, ie. screening.

Most of the hormonal treatments we prescribe do not significantly increase breast cancer risk. However if you are that one in seven or eight women who develops breast cancer (like me) it’s critical to detect the cancer early and stop the hormonal treatment. Most breast cancers have hormone receptors, so to keep taking them would feed the cancer.

What Breast Cancer Screening Should You Do When Using MHT?

The same as other women. Mammograms every two years from age 50 to 70 plus monthly breast self-examinations are my baseline. Women at increased risk for some reason can start breast screening mammograms earlier, and those with particularly dense breasts may need ultrasound or MRI.

It’s important to understand that “screening” only refers to the population who don’t have any symptoms or signs of disease. If you actually have a lump, pain or other breast changes you should immediately see your GP for an examination and referral for a diagnostic scan, and perhaps a biopsy… do NOT wait for your next screening scan!

Can I use MHT with a Family History of Breast Cancer?

Generally speaking, having one or two relatives who’ve had breast cancer doesn’t usually mean you can’t use MHT. A couple of affected members on one side of the family usually doesn’t indicate a genetic predisposition. Several females in recent generations may be more compelling however.

iPrevent is a free online tool developed by the Peter MacCallum Cancer Centre in Melbourne to help assess your current individual level of breast cancer risk.

If you have a strong family history or a known genetic mutation in the family that puts you at higher risk, the best option is to get a referral from your GP for genetic counselling. The counsellor can work out whether you are at a high level of individual risk, which may also have implications for you kids and grandkids. They can also provide advice and referral for genetic testing if needed.

There Are Important Reasons To Use HRT

Let’s take a step back here. We wouldn’t be having this discussion unless there were good reasons to use MHT: it’s incredibly effective at treating hot flushes and night sweats. For women whose quality of life is eroded by debilitating symptoms, perhaps causing lack of sleep and mood disturbance, MHT can make life worth living again.

As a bonus, women who use estrogen for these symptoms will have reduced bone loss and heart disease risk. They may also experience improvements in mood, vaginal dryness, musculoskeletal pain, brain function and sleep.

The Bottom Line? Personal Choice!

Each woman must work with her doctor to determine the best treatment options based on symptom severity, a personalised risk assessment and personal choice.

If a woman believes that improved quality of life outweighs the potential risks, then her decision should be supported by a health professional who will help to mitigate the risk with regular treatment reviews and a screening plan. The key (as always) is in finding a compassionate doctor with expertise in managing menopausal symptoms to guide you.