Breast Cancer: Risk Factors, Symptoms & Screening

27 June 2019

Breast cancer is one of the most common invasive cancers among women and the leading cause of cancer death in Singaporean women. Statistics from the National Cancer Centre show that breast cancer alone accounts for approximately 29.1% of cancer diagnosis among Singaporean women.

How Does Breast Cancer Develop?

Cancer occurs as a result of genetic mutations or other abnormal changes in genes responsible for regulating cell growth. Normally, your body cells replace themselves through an orderly cell growth cycle – healthy new cells develop to replace dead ones. 

However, gene mutations can trigger abnormal and uncontrollable cell growth. This means that some cells gain the ability to multiply without cell death. The excess body cells then form a tumour which can be benign or malignant.

Benign (non-cancerous) tumours grow slowly, are not dangerous to your health, and do not spread to other parts of your body. However, malignant (cancerous) tumours can easily spread beyond the original tumour to other body parts if left unchecked.

The term breast cancer refers to a malignant tumour that has developed from cells in your breast. In most cases, breast cancer starts in the duct or lobules before spreading to other parts of your body.

Absolute Risk and Relative Risk

The risk of developing breast cancer can either be absolute or relative.  

Absolute risk describes the likelihood of an individual developing breast cancer over a certain time period, in view of the average for the whole population. 

For example, if your current age is 40, the probability of developing invasive breast cancer in the next 10 years is 1.45%, or 1 in 69.

Relative risk refers to the likelihood of a group of people developing breast cancer compared to another group with different behaviours, physical conditions, or environment. 

For example, women who have two or more drinks per day have a 50% higher risk of breast cancer, relative to women who do not drink. 

In order to understand your individual breast cancer risk, both absolute and relative risks must be considered. If your current age is 40 (absolute risk of 1.45% of developing breast cancer in the next 10 years), and you have two or more drinks per day (relative risk that is 50% higher than those who do not drink), your individual breast cancer risk will be (1.45% x 1.5 = 2.175%).

Breast Cancer Risk Factors

The exact cause of breast cancer remains unclear, but several risk factors may increase your chances of developing breast cancer. However, having any of these risk factors does not directly equate to you developing cancer.

Age and gender

The risk of developing breast cancer tends to increase with age. Most women who are diagnosed with breast cancer are older than 50 years. But, younger women may also be affected.

Breast cancer can also affect men, but the risk is significantly lower compared to women. When breast cancer is diagnosed in men, it is usually at an advanced stage because of the small size of the male breast.

Family history

If a first-degree relative such as your mother or sister had breast cancer, your risk of getting breast cancer is increased. Having two or more first-degree relatives with breast cancer history increases your risk further.

This is especially true if the relative developed the condition before menopause or if it affected both of her breasts. The risk may also increase if your biological father or brother was diagnosed with breast cancer.

Reproductive history

Certain aspects of your reproductive history may increase your risk of breast cancer. For instance, not having children or having your first child after the age of 35 increases your risk. Same for the onset of periods before the age 11 and cessation of periods after the age of 55. These risk factors are associated with either an early or prolonged exposure to estrogen and progesterone. 

Gene Mutations

Changes to two genes, namely BRCA1 and BRCA2, can lead to breast cancer. In fact, between 5 to 10% of breast cancer cases are associated with genetic factors.

Women with a BRCA1 or BRCA2 gene mutation, have increased chances of developing breast cancer. These genes also raise your risk for ovarian cancer and are linked to male breast cancer as well.

Personal history of breast cancer

Women who have had breast cancer are more likely to develop breast cancer the second time. Some non-cancerous breast diseases such as Lobular Carcinoma In Situ (LCIS) and Atypical Lobular Hyperplasia (ALH) are associated with a higher risk of getting breast cancer.

Hormone therapy

Women who take postmenopausal progesterone or estrogen medications to alleviate their signs of menopause symptoms are at a higher risk of developing breast cancer.

Occupational hazards

Research shows that workplace exposure to certain endocrine disrupting chemicals and carcinogens can cause breast cancer.

Breast Cancer Symptoms

In its early stages, breast cancer does not show any symptoms. However, as the tumour grows, you may notice the following signs:

  • Thickening or swelling of part of your breast
  • New lump forming in your breast or armpit
  • Nipple discharge other than breast milk, possibly blood discharge
  • Sudden and sharp pain or tenderness in your breast
  • Sudden changes to the appearance of the skin on your breasts
  • Scaling, peeling, or flaking of skin on your breast or nipple
  • A flat or indented area on your breast
  • Sudden breast changes: you may notice a difference in contour, size, texture, or temperature of your breast
  • Redness or flaky skin on your breast or nipple area

Keep in mind that these symptoms may appear with other conditions that are not necessarily breast cancer. Nonetheless, if one or both of your breasts develop an abnormal pain or lump that does not go away or feels abnormal, seek a doctor’s advice right away. It could save your life.

Tips on Preventing Breast Cancer and Maintaining a Healthy Lifestyle

The truth is that your chances of developing breast cancer are greatly affected by the various lifestyle choices that you make. Simple lifestyle changes can make a huge difference when it comes to preventing breast cancer. 

Consider these simple breast cancer prevention tips:

  • Stick to a healthy diet: Embrace a diet that is high in fruits and vegetables and low in refined carbohydrates, sugary drinks, and fatty foods. Eat a lot of lean protein such as chicken or fish. 
  • Maintain a healthy weight: Obesity raises the risk of breast cancer, especially after menopause. Avoid gaining too much weight and try as much as possible to maintain a body-mass index under 25.
  • Keep physically active: Increased physical activity reduces the overall risk of breast cancer. Establish and stick to a regular exercise regime to stay healthy. A simple 30-minute walk every day will make the difference.
  • Avoid hormone replacement therapy if possible: Menopausal hormone therapy increases the risk of breast cancer in women. If you must undergo hormone replacement therapy to manage your menopausal symptoms, try to avoid those that contain high amounts of progesterone and ensure that you limit the use of hormone replacement therapy to less than three years. Avoid hormonal creams and gels since they are not safer than prescription hormones.
  • Avoid too much alcohol:  The risk of breast cancer increases with the amount of alcohol that you drink. If you don’t drink alcohol, don’t start. If you are already drinking alcohol, aim to drink moderately or stop in the long run.
  • Get screened for breast cancer regularly: Consult our specialist to determine which type of screening is best for you and how often you need to get screened. If you are at high risk for breast cancer, it may be recommended for you to get screened more regularly.

Breast Cancer Screening In Singapore

Early diagnosis of breast cancer can greatly improve survival rate. If you are diagnosed at Stage 0 or Stage 1 breast cancer, where the cancer cells are localised in breast tissue, you have a 99% 5-year relative survival rate as compared to 27% for advanced stages, where cancer cells have already spread to lymph nodes and other body parts. 

Regular screening is recommended for women of age, or younger if you are at high risk. While you could feel completely healthy with no symptoms, your body could also be harbouring early stages of breast cancer. 

Although screenings may not prevent breast cancer, it ensures that the cancer cells do not go undetected and do not have a chance to proliferate for a long time. 

General screening recommendations for women with average risk:

  • Women 40 – 44 years old: Cancer screening mammograms are optional
  • Women 45 – 54 years old: should get mammograms every year
  • Women 55 and older can switch to a mammogram every other year, or they can choose to continue yearly mammograms. Screening should continue as long as a woman is in good health and is expected to live 10 years more or longer. 

Mammography is the most commonly used breast cancer screening method. This technique involves the use of low-energy x-rays to capture the image of your breast that reveals any underlying abnormalities.

Imaging your breast improves your doctor’s ability to detect small tumours and recommend appropriate action to be taken.  The increased detection of small tumours and abnormal tissues using mammography can significantly reduce the number of deaths from breast cancer.

What Happens If Something Abnormal Is Detected On Your Screening Exam?

Suspicious tissues, lumps, and other abnormalities may be detected during your screening process.  However, it is not always possible to tell from the screening results whether the tumour or lump is cancerous or benign. To determine whether you are at risk of developing breast cancer, your doctor will recommend further imaging test or biopsy to be performed.


Breast cancer is a condition that causes the cells in your breast to grow out of control. It can occur in both men and women, but it is more prevalent among women. If left unchecked, breast cancer can spread outside your breast tissue through the circulatory or lymphatic systems to other parts of your body.

It occurs in four distinct stages and rarely presents symptoms during the early stages. The cause of breast cancer is unknown, but various risk factors may increase your risk of developing breast cancer. Regular checks and screening can help in early detection of breast cancer to increase your chances of survival.


Recommended Specialists