SerpApi.Org
Breast cancer is the most commonly diagnosed cancer among women worldwide. One in seven women in the UK will develop it in their lifetime. Breast cancer risk is complex and influenced by a combination of factors, including genetics, lifestyle and environment.
Not all breast cancers are preventable, but breast specialist Zoe Winters, a consultant oncoplastic breast cancer surgeon at London Breast Health and honorary associate professor at University College London, says one of the most important ways a woman can protect herself against the disease is to understand her baseline risk, to attend screenings and be aware of lifestyle factors which can influence risk.
Here, she shares the things she wants every woman to know.
Your risk increases with age
Age is the single biggest independent risk factor for developing breast cancer. “From age 50, breast cancer risks increase exponentially – the majority (about 80 per cent) occur from this age – and that continues on a steep curve until about 65, when it plateaus,” Winters explains. “Though older women are still at the very highest risk.”
For context, around one in five cancers occur in women under 50 (which works out to be about 10,000 women per year in the UK). While about four per cent of breast cancers occur in women under 40. “Young onset breast cancer, in women [under] 45 tends to be characteristically more biologically aggressive and is typically diagnosed later,” she says.
Family history is important
“In clinic, after age, my next question is ‘Have you ever had breast cancer before?’ Because this automatically puts you into a ‘high risk’ group,” Winters continues. “Family history is very important, too.” This means how many first-degree relatives (parents, siblings) and second-degree (aunts, uncles or grandparents) have had breast and/or ovarian cancer, as well as pancreatic and prostate cancers, on both the maternal and paternal sides.
“Most women (90 per cent) who get breast cancer have not inherited gene mutations, such as BRCA1 and BRCA2. However, it is thought that around five to 10 per cent of women have a specific gene mutation, and 30 per cent of these have no family history.”
Hormonal factors can influence risk
Hormones, such as oestrogen and progesterone, can influence your risk. There has been long-held confusion around whether or not taking HRT raises your risk. The NHS states that taking combined HRT (oestrogen and progesterone) can slightly increase risk, but the increase is small, and for many the benefits outweigh the risks. Meanwhile, there is little or no increase in risk from taking oestrogen-only HRT.
“Modern forms of HRT can offer health benefits, providing protection against cardiovascular disease and osteoporosis, for example,” Winters says. “Ideally, I’d advise taking bio-identical transdermal oestrogen and using a preferred low dose, and/or cyclical micronised progesterone or intra-uterine progesterone like a Mirena coil. Ultimately, it’s important to take into account your individual risk factors if taking HRT for more than five years.”
Taking oral contraception may also slightly increase your risk of breast cancer but the risk reduces once you stop taking it. Other factors, such as not having children, having your first full-term pregnancy after the age of 30 or not breastfeeding, can also raise your lifetime risk.
This is because pregnancy and breastfeeding pause the menstrual cycle, or the cycling of estrogen and progesterone, which stimulates the breast duct cells, therefore reducing the amount of hormones a woman is exposed to during her lifetime. Starting your periods early, under 12, or having a late menopause may also increase your risk.
Lifestyle factors can influence breast cancer risk
These factors each represent relatively small increases, Winters says, but they nonetheless add up.
Being overweight
Being overweight, particularly having a higher body fat, and gaining visceral fat around the abdomen after menopause, increases your risk, Winters says. “It’s post-menopausal weight gain that’s most risky. Having more fatty tissue increases your risk of breast cancer, because post-menopausal oestrogen comes predominantly from fat, compared to from ovaries pre-menopause. It also increases the production of insulin, so the higher the body fat, the higher the risk of diabetes or insulin resistance. Excess body fat also leads to more pro-inflammatory chemicals and chronic inflammation can predispose to cancer.”
Alcohol consumption matters
The relationship between alcohol and breast cancer risk is dose-dependent, meaning the risks increase the more you drink. Research suggests even low to moderate intake increases a woman’s breast cancer risk.
“Each daily drink (around 10g of ethanol) increases your risk by around seven to 10 per cent. If you drink up to two drinks per day, then these risks rise. In the UK, it’s estimated one in 12 breast cancers have a strong link to alcohol.”
Exercise can have a meaningful impact
Research suggests women who are physically active can reduce their risk of breast cancer by 10 to 20 per cent, compared to those who lead a sedentary lifestyle, Winters points out. “Studies suggest partaking in regular brisk physical activity – such as one hour of brisk walking per day – can reduce risks by 15 to 25 per cent in peri and post-menopausal women.”
Know your breast density
Breast density (which describes the ratio of fibroglandular tissue to fat in your breasts, as assessed using a mammogram) is an important but perhaps lesser-talked-about risk factor, Winters says. “We were all born with different amounts of breast duct tissue. Having denser tissue, or more milk ducts and connective fibrous tissue, than fat tissue, increases your risk because breast cancers originate from the cells that line the walls of the milk ducts, which are surrounded by supporting connective fibrous tissues.”
Radiologists classify breast density on a scale from A to D. Dense breasts are scored as either C or D. Having dense breasts can also reduce the sensitivity of a mammogram for detecting breast cancers, she adds. “During a mammogram, dense breast tissue absorbs the X-rays, making them appear white, whereas fatty tissue appears very dark or black. Cancers and microcalcifications may not be seen against a white background.
“Women are not always told their breast tissue density but I believe all women should know it, as it is an important factor in their baseline risk profile. Women with dense breasts may require supplemental bilateral breast ultrasound, breast MRI or contrast-enhanced mammograms,” Winters says.
Winters says breast screening also needs to become more personalised with risk-adapted screening.
“A population genetic risk score (PGRS), or polygenic risk score as it is known, assesses how our ‘genetic makeup’ shapes our likelihood of developing diseases and conditions. It is currently being used in clinical trials to determine population genetic risks for breast cancer in the US and Europe. In the UK, this kind of testing is only available privately, although we would hope that the NHS will use PGRSs routinely within the next decade.”
Most importantly, check your breasts monthly
Be breast aware and if you notice any changes, make an appointment with your GP, Winters instructs.
“Learn what your breasts look and feel like and get to know what is normal for you. Breasts may look or feel different at different points in your cycle. For example, the milk-producing tissue becomes active in the days before a period starts, and in some women, this can make breasts feel tender and lumpy, especially in the upper-outer part of the breast near the armpits or close to the nipple areolar area.”
Examine your breasts in the shower at least every three months, if not monthly, using the flat of the hand pressing firmly downwards, “as if pressing down on a mattress,” she advises.
Know the main symptoms
It’s crucial to familiarise yourself with both common and less common symptoms and seek professional advice if you have any concerns, Winters stresses.
- A lump. This is the most common symptom of breast cancer. It might feel a bit like a marble, “meaning it has a discrete circumferential border around it, within the breast or armpit area.”
- Nipple changes, such as an inverted or permanent indrawing of the nipple and/or the surrounding areola.
- Nipple discharge, such as constant nipple discharge, a notable bloody nipple discharge or milky nipple discharge in a non-breastfeeding breast.
- Breast skin indentation, which is persistent.
- Changes in breast size or shape, such as swelling or shrinkage.
- Unexplained redness of the breast. A rash or itchiness, a scaly appearance, unusual redness or any other colour changes, especially of the nipple.
