Breast cancer risk factors
Women under the age of 40 typically believe they won't get breast cancer and therefore neglect to perform Self-Breast Examinations (BSE). However, studies have shown that Breast Cancer is caused by a combination of risk factors and youth is not a guarantee against breast cancer. Risk factors increase one’s chance of getting a disease such as Breast Cancer, but having a risk factor doesn’t necessarily mean that one will get the disease. Despite this, knowing about them brings this issue to our attention and helps us improve and be mindful of our well-being, especially when it comes to factors that are within our control. So, what exactly are these risk factors?
Lifestyle-related Breast Cancer risk factors (here which also means reducing your risk is possible):
1. Alcohol Intake
Alcohol has been clearly linked to an increased risk of Breast Cancer with the risk increasing depending on the amount of alcohol consumed. Having 1 alcoholic drink per day gives a small (7-10%) increase in risk compared with non-drinkers while having 2-3 drinks per day increases this risk to about 20% higher than non-drinkers for developing Breast Cancer.
2. Being overweight or obese after menopause
Before menopause, a woman’s ovaries produce oestrogen for the body. After menopause fat cells take over this role, therefore women who are overweight after menopause will have more fat cells to produce more oestrogen thus increasing their risk of Breast Cancer.
3. Physical inactivity
There is increasing evidence that proves that physical inactivity can increase Breast Cancer risk, especially after menopause. According to the World Health Organisation (WHO) adults aged 18-64 should have at least 150 minutes of moderate-intense aerobic physical activity or at least 75 minutes of vigorous-intensity aerobic physical activity throughout the week.
4. Reproductive history
Women who have their first pregnancy after the age of 30, or do not breastfeed have a slightly higher breast cancer risk overall. Having multiple pregnancies and becoming pregnant at an early age reduces Breast Cancer risk.
5. Birth control
(i) Oral contraceptive pills: Most studies have linked oral contraceptive users with a higher risk of breast cancer compared to non-users. However, this risk goes back to normal after 10 years.
(ii) Birth control injections: Depo-provera is an injectable form of progesterone that is administered every 3 months for birth control. Some studies have linked this type of birth control with an increased risk of Breast Cancer but some have not.
(iii) Birth control implants, Intrauterine devices (IUDs), skin patches, vaginal rings: As these types of birth control use hormones they could theoretically influence Breast Cancer growth. This link has been studied more in hormone-releasing IUDs but less on implants, patches and rings.
6. Hormone Replacement Therapy (HRT)
There are 2 main types of HRT to control symptoms of menopause in women: Combined HRT which has both oestrogen and progesterone and Estrogen-only therapy. The use of combined HRT after menopause has been linked to increased Breast Cancer risk. This risk is typically seen after 4 years of use with the risk decreasing after 5 years of stopping HRT. Regular monitoring during treatment should also be done.
Unchangeable breast cancer risk factors
1. Getting Older
The risk of Breast Cancer increases with age; the newest diagnosis of Breast Cancer occurs after age 50 but still significantly rises after age 40. Hence, the emphasis on getting a screening mammogram once you hit 40 years old. Our Singapore government has been very active in this area and does allow us to dip into our Medisave accounts or utilise their Screen for Life programmes.
2. Genetic Mutations
About 5% to 10% of Breast Cancers are thought to be linked to hereditary gene changes (mutations) which are passed on from a parent. The most common cause of hereditary Breast Cancer is an inherited mutation in the BRCA1 or BRCA2 gene (think of Angelina Jolie here). Normally these genes are involved in the repair of damaged DNA but mutated versions of these genes lead to abnormal cell growth, which can lead to Cancer.
On average, a woman (or man) with a BRCA1 or BRCA2 gene mutation:
has a 7 in 10 chance of getting Breast Cancer by age 80;
is more likely to be diagnosed with Breast Cancer at a younger age; and
has a higher risk of developing Ovarian Cancer and certain other types of Cancers
3. Having a family history of Breast Cancer
Overall, about 15% of women with breast cancer have a family history of the disease. Having a first-degree relative (mother, sister or daughter) with Breast Cancer almost doubles a woman's risk. Having 2 first-degree relatives increases the risk further by about 3 folds.
4. Age of menarche and menopause
Having early onset menstrual periods before age 12 and menopause after age 55 exposes women to hormones for longer, theoretically raising their risk of breast cancer.
5. Having dense breasts
Breasts that are dense have more connective tissue than fatty tissue which can sometimes make it hard to see tumours on a mammogram. Women with dense breasts on mammograms had a 1 ½ to 2 times increased risk of breast cancer compared to a woman with average breast density.
Non-cancerous lumps can increase your risk too
Meanwhile, you may be comforted and surprised to know that the discovery of a lump in our breasts does not always mean Breast Cancer, there are more often benign (non-cancerous) breast conditions than cancerous ones, for example:
a) Non-proliferative lesions: The most common being breast cysts and the increase in breast cancer risk is very small.
b) Proliferative lesions without atypia (cell abnormalities): These lesions have excessive growth or cells in the ducts or lobules of the breast but do not look very abnormal. They include ductal hyperplasia (without atypia), fibroadenoma and sclerosing adenosis.
c) Proliferative lesions with atypia: In these conditions, the cells in the ducts or lobules of the breast tissue grow excessively, and some of them no longer look normal. These types of lesions include ductal hyperplasia, atypical lobular hyperplasia and intraductal papillomas. Breast cancer risk is about 4 to 5 times higher than normal in women with these changes.
Nevertheless, having them may mean you can eventually and gradually develop Breast Cancer. Thus, you should monitor these conditions regularly, usually between 3 months to one year depending on what your doctor advises.
There is no taboo about it
Without a doubt, breast cancer can be deadly, yet most women don't know what causes it, when to detect it, or how to cure and recover from it. It is frightening to think about breast cancer, but because of this, it should not remain a mystery in our society. Women will be able to take better action when they learn more about this disease. While taking care of ourselves and minimizing lifestyle risks is vital, understanding that breast cancer can be genetically predisposed emphasizes the importance of early detection and screening.