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breast cancer logoWhat Is Breast Cancer?

A woman's breast is fully developed when she is in her twenties. The female breast is made up of milk glands and ducts and is surrounded by a layer of fat. Each female breast contains about 12 to 15 milk glands. Milk is produced in the milk glands and collects in small ducts. These join together to form larger ducts, which eventually drain via the nipples.

During a woman's reproductive period (approximately between 20 and 40 years old), the breast is affected by female hormones, whose levels vary with the menstrual cycle. This can cause the breast to become tender, hard, or lumpy, especially during the premenstrual phase. When a woman enters her thirties, the milk glands and ducts in her breast become smaller and are replaced by fibrous and fatty tissue. Breast cancer commonly develops within these milk ducts and glands.


Breast cancer usually originates from the cells lining the milk ducts and glands. When breast cancer is detected at this non-invasive or in-situ stage, treatment is easier and patients have a higher chance of recovery.

However, when cancer cells invade the surrounding tissue, known as the stroma, it can gain entry into the circulatory and lymphatic system, and hence, to other organs in the body, through the blood and lymphatic vessels found in the stroma. When these cancer cells reach a new site, they may form a metastatic tumour. The organs most commonly affected by this are the lungs, bones, and liver.




3. Reproductive History

Certain aspects of a woman's reproductive history can increase her risk of breast cancer. These include:

  • Not having children or having the first child after the age of 35
  • Onset of menses before the age of 11
  • Cessation of menses after the age of 55

These risk factors are associated with an early and prolonged exposure to oestrogen. To reduce risk, young girls below the age of 11 should be encouraged to exercise more as physical activity can delay the onset of menses and suppress the secretion of oestrogen.

Breast-feeding, when carried out for more than a year, can also lower exposure to oestrogen and reduce a woman's risk of breast cancer.


4. Diet

Excessive consumption of red meat, animal fat, and alcohol may increase a woman's risk of breast cancer. Women are encouraged to limit the intake of saturated animal fats and increase the intake of fruits and vegetables to reduce the risk of developing cancer. Besides, it is best not to drink alcohol.

Other nutrients that alter a woman's risk of breast cancer include:

  • Soy products in bean curd and soya bean juice could reduce a woman's risk of breast cancer
  • Omega 3 oil from fish could reduce a woman's risk from breast cancer
  • Other nutrients that protect against breast cancer include Vitamin A, Selenium, and Vitamin C and E


5. Body Weight and Physical Activity 

Weight gain, especially in post-menopausal women, is associated with an increased risk of breast cancer. This may be due to the combination of high calories and fat intake as well as a lack of exercise. Physical exercise reduces a woman's risk of breast cancer by lowering her body's level of oestrogen.

Women should engage in regular physical activities as well as moderate calories and fat intake to avoid weight gain.

6. Intake of Hormones

There are 2 groups of women whose intake of oestrogen and/or progesterone supplements may increase the risk of breast cancer.

  • Post-menopausal women who are long term or current users of Hormone Replacement Therapy (HRT) have a 30% increased risk of breast cancer. This risk disappears after three to five years of stopping HRT. Women should engage in close discussion with their doctor(s) before making a decision.
  • Young girls who consume oral contraceptive pills between the ages of 10-15


7. Previous Abnormal Breast Biopsy

A few types of breast biopsy results may be indicative of an increased risk of breast cancer. Women whose biopsies indicate atypical ductal hyperplasia, atypical lobular hyperplasia, or lobular carcinoma in-situ should undergo regular breast screening.

Women with previous instances of breast cancer are also at an increased risk of developing cancer in the same or opposite breast and should seek regular screening.


What can I do if I am at high risk?

Doctors can now provide a fairly good estimate of a woman's risk of breast cancer by tracing a detailed family, social, and medical history.

Women who are at high risk of breast cancer can take action by:

  • starting breast screening at an earlier age
  • altering lifestyle and diet to reduce risk
  • taking Tamoxifen, an important anti-cancer drug, which can significantly reduce the risk of breast cancer
  • undergoing preventive prophylactic mastectomies. Women at high-risk who underwent bilateral mastectomies had a 90% reduction of risk. However, given the extensive nature of the surgery involved, women are advised to carefully consider their options.

Despite the above list of risk factors, the exact cause of breast cancer remains unknown. About 50 per cent of breast cancer patients have no identifiable risk factors.