Breast cancer is one of the most common cancers among women worldwide, including in Malaysia. In 2020, there were 2.3 million women diagnosed with breast cancer and 685,000 deaths globally. As of the end of 2020, there were 7.8 million women alive who were diagnosed with breast cancer in the past 5 years, making it the world’s most prevalent cancer. Regardless of gender, breast cancer contributed to 19.0% of all new cancer cases diagnosed in 2012 - 2016, an increment compared with 17.7% in 2007 - 2011 in Malaysia.
Photo by Angiola Harry on Unsplash
It goes without saying that breast cancer is becoming an important cancer among humankind. Therefore, we hope this article can increase awareness about the risks factors of breast cancer.
Risk factors are what increase the odds of developing a particular disease. Scientists conducted many studies carefully to identify risk factors of a disease. While they are not the same as causes, reducing some of the risk factors can give you a higher chance of steering away from breast cancer. Not every risk factor can be changed, but fortunately, some can.
Risks Factors You Cannot Change (Non-Modifiable Risk Factors)
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Age — For starters, the older you get, the higher the chance of developing breast cancer. According to the current SEER report, the risk that a woman will be diagnosed with breast cancer during the next 10 years, starting at the following ages, is as follows:
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Age 30 . . . . . . 0.49% (or 1 in 204)
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Age 40 . . . . . . 1.55% (or 1 in 65)
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Age 50 . . . . . . 2.40% (or 1 in 42)
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Age 60 . . . . . . 3.54% (or 1 in 28)
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Age 70 . . . . . . 4.09% (or 1 in 24)
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Based on the latest National Cancer Registry Report of Malaysia, the incidence started to increase at the age of 25 and peaked at the age of 60 to 64 years old.
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Female sex — Even though breast cancer occurs 100 times more frequently in women than in men, it is not a cancer that is exclusive to female only.
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Family history/Genetic — Similar to many cancers, risk of breast cancer increases with a family history of breast cancer at a young age. This is known as hereditary or familial breast cancer. The risk comes from mutated, hereditary genes known as the BRCA genes. According to the US National Breast Cancer Foundation, 55%-65% of women with a mutated BRCA1 gene will develop breast cancer before the age of 70. Similarly, 45% of women with a mutated BRCA2 gene will develop breast cancer before the age of 70.
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Early menarche (onset of period) or late menopause — Study has found that women who experienced their onset of period before the age of 13 years old are at higher risk of developing hormone receptor-positive breast cancer than those who experienced period at a later age. Similarly, for every year older at menopause, the risk of developing breast cancer is smaller.
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Having dense breasts — Dense breasts have more connective tissue than fatty tissue, which can sometimes make it hard to see tumors on a mammogram. Women with dense breasts are more likely to get breast cancer.
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Personal history of breast cancer or certain non-cancerous breast diseases — The risk of breast cancer is higher for women who developed non-cancerous breast diseases previously, such as atypical ductal hyperplasia and lobular hyperplasia.
It’s difficult or nearly impossible for one to alter any risk factor mentioned above, at least not with our current medical technology. Fortunately, here are risk factors that you can change to reduce the risk of developing breast cancer.
Risk Factors You Can Change
Giving birth and breastfeeding
Nulliparous women, a.k.a women who have never given birth to a child, have a higher risk of developing breast cancer. Giving birth to children confers protection against breast cancer for women who give birth, especially those who do so under the age of 30. In addition to that, breastfeeding also appears to reduce risk of breast cancer.
With that being said, breast cancer is very real for all women, and this doesn’t need to be a cause of panic for nulliparous women only.
Taking oral contraceptive pills
Oral contraceptives contribute a small risk to breast cancer. Study shows that combined oral contraceptive (COC), which contains both oestrogen and progestin, increases the risk of oestrogen-receptor (ER) negative and progesterone-receptor (PR) negative breast cancers, whereas progestin-only contraceptive pill (POC) raises the risk of ER-positive and PR-positive breast cancers (known as hormone receptor-positive breast cancer).
If you’re taking oral contraceptive pills for the long-term, and are worried about your breast cancer risk, consult your doctor to switch to non-hormonal contraception methods.
Being overweight or obese
Being overweight or obese, especially at older age, has a higher risk of developing post-menopausal breast cancer. A meta-analysis of 50 studies has shown that for every 5kg weight gain, the relative risk of post-menopausal breast cancer was increased by 11%. If you’re overweight or obese, or is living a physically inactive lifestyle, we hope this could encourage you to exercise more; and also because study also showed that the more physical activity you have, the lower the breast cancer risk. Staying physically active doesn’t mean that you must hit the gym— about 150 minutes/week of brisk walking or 75 minutes/week of running is a good habit to cultivate.
Alcohol drinking and smoking
Regular alcohol consumption is established as a significant risk factor for breast cancer. The more alcohol one drinks on a regular basis, the higher the risk of developing breast cancer. Smoking cigarettes also raises the chance of getting breast cancer, and evidence on secondhand smoke increases breast cancer risk is also emerging. So, if you want to stay away from breast cancer, stay away from alcohol and cigarette smoking (including secondhand smoke)!
More information
To learn more about breast self-examination, screening and treatment, we encourage you to read our previous series of Breast Cancer Awareness Month articles!
If you would love to learn more about breast cancer genetic testing, you may consult your doctor or a clinical geneticist. Because our genes are really complicated, the genetic testing results should be interpreted by the professionals. You may read more here.
A word from DOC2US
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Cover image credit: Photo by Angiola Harry on Unsplash
