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.
Risk Factors
Research has uncovered many risk factors associated with breast cancer, which can be reduced to prevent its occurrence. These risk factors are affected by:
1. Age and Sex
The risk of breast cancer increases with age. 70% of all breast cancers are diagnosed in women aged 40 years and above. It is uncommon in women before the age of 40.
Breast cancer can also affect men but the risk is much lower as compared to women. However, when breast cancer is diagnosed in men, it is often at an advanced stage because of the small size of the male breast.
2. Family History
Certain genes are responsible for breast cancer, two of which are BRCA1 and BRCA2. Women who inherit the abnormal forms of these genes will have a 40 to 60 per cent chance of developing breast cancer in their lifetimes.
Women with a first degree relative (i.e. sister, mother or maternal grandmother) who has breast cancer is twice as likely to get breast cancer themselves, as compared to women without a family history of breast cancer. The recommendation for women with such a family history is to start breast screening at the early age of 35.
Women whose family histories display the following characteristics are likely to have inherited the BRCA1 and BRCA2 genes:
Relatives who developed breast cancer at an early age (before the age of 40)
Relatives who developed breast cancer in both breasts simultaneously
More than two generations of relatives with breast cancer
The likelihood of a woman in Singapore developing breast cancer in her lifetime is about 5%. However, those with a family history of breast cancer will have twice the risk compared with women without a family history.
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
Consuming too much red meat and animal fat and too little fibre may increase a woman's risk of breast cancer. Women are encouraged to limit the intake of saturated animal fats (less than 20% daily fat allowance) and increasing the intake of fruits and vegetables (5 servings daily) to reduce the risk of cardiovascular disease and cancer. Drinking 1 to 2 glasses of alcohol daily can increase a woman's risk by 1.5 times.
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. Body weight should not be more than 20% above her ideal weight.
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 starting from their mid-thirties.
Women with previous instances of breast cancer are also at an increased risk of developing cancer in the 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.
Screening
When breast cancer develops, it goes through a non-invasive stage where cancer cells are confined to the breast ducts. Breast cancer detected at this stage is not likely to have spread to other parts of the body. When breast cancer is detected and treated at such an early stage, there is a:
higher change that cancerous lumps are small (less than 1cm in diameter) and suitable for less damaging surgery
higher chance of avoiding chemotherapy after surgery
higher chance of successful treatment and survival
The only effective and proven method of detecting breast cancer early is through a mammogram, which is an X-ray of the breasts. A mammogram detects micro-calcifications, which are early signs of non-invasive duct cancer, as well as breast cancers that are too small to be detected by clinical examination (less than 1 cm diameter).
The most common incidences of breast cancer occur, in decreasing order of frequency, as:
Breast lumps
Bloody nipple discharge
Skin changes
Itchy rash of the nipple
Breast pain
8 out of 10 breast lumps are benign or non-cancerous. There are different classifications of breast lumps that can occur, depending on a woman's age.
Women in Their 20s
The most commonly occurring type of breast lump in this age group is a fibroadenoma. It is also known as a breast ‘mouse' as it can be moved within the breast. It is non-cancerous.
Women in Their 30s
The most common type of breast lump for women in this age group is fibroadenosis or fibrocystic disease. It is often a painful hard area in the outer area of the breast and is associated with the female sex hormone oestrogen. It is non-cancerous.
Women in Their 40s and Beyond
Two types of breast lumps are common in older women. One is a breast cyst which is a lump filled with fluid. Breast cysts can be diagnosed by an ultrasound scan and is treated by a needle puncture to extract the fluid. The other type of breast lumps that commonly occur in older women are due to breast cancer. Cancerous breast lumps are usually hard, irregularly shaped, and occupy a fixed position inside the breast. Changes in the skin over the cancerous lump may be observed, such as skin thickening, redness, soreness, and/or depression.
Diagnosis
Detection of breast cancer is based on:
Clinical examination
Mammography
Ultrasound scan of the breast
To confirm the diagnosis, a breast biopsy is performed to remove a piece of tissue for examination under a microscope.
Common biopsy techniques include:
Fine Needle Aspiration (FNA)
Core Needle Biopsy
Excision Biopsy
Sentinel Lymph Node Biopsy (SLNB)
Treatment
Treatment broadly consists of two parts:
Locoregional treatment, which pairs surgery with radiotherapy to treat cancer cells in the breast and armpit lymph nodes
Mastectomy and Lumpectomy
The two surgical techniques used to treat breast cancer are mastectomy and lumpectomy:
A mastectomy entails the removal of the whole breast, including the nipple.
A lumpectomy entails the removal of a tumour along with a margin of normal breast tissue. This leaves the rest of the breast untouched.
After a lumpectomy, radiotherapy is given to the breast for 6 weeks. This treatment is safe and has a low recurrence rate. Breast cancer patients who are suitable for lumpectomy and radiotherapy have:
Tumours situated away from the nipple
Tumours less than 2-3 cm in diameter
Breasts of a suitable size
Breast cancer patients are not suitable for a lumpectomy if they:
Are under the age of 30 due to a high recurrence rate
Are pregnant
Have connective tissue disease
Have 2 or more tumours within the same breast
Armpit Surgery
Armpit surgery is required to remove the axillary lymph nodes for diagnostic and therapeutic purposes. Knowing whether cancer has entered the axillary lymph nodes is important in determining the stage of breast cancer. Removal of the axillary lymph nodes also prevents the recurrence of cancer in this area. Some breast cancer patients may experience temporary shoulder stiffness and arm swelling after this procedure.
Sentinel Lymph Node Biopsy (SLN Biopsy)
1 or 2 lymph nodes act as a gateway to the axilla and will be the first to be affected should cancer enter this area of the body. By identifying and biopsying these sentinel lymph nodes, it can be determined whether the rest of the axillary lymph nodes are affected by cancer.
SLN biopsy is a viable treatment option for patients with:
Small tumours
Non-palpable nodes in the axilla
SLN biopsy is not recommended for:
Patients with large tumours and palpable nodes, who should undergo an axillary dissection
Patients with non-invasive tumours, for whom no axillary surgery is required
Post-Mastectomy Breast Reconstruction
Following a mastectomy, breast reconstruction can be carried out using a variety of techniques.
The following considerations may be important to note:
Timing of Reconstruction
Cost and Complications The breast can be reconstructed using an artificial implant (usually made of silicon) or a skin-muscle flap from the patient's own body. An artificial implant is quicker and cheaper to undertake but some women may be averse to the presence of a foreign object in their body.
Extracting a skin-muscle flap from the patient is a natural method for breast reconstruction but is longer and costlier to undertake. This method may also lead to complications surrounding the area where the skin-muscle is taken.
Cancer Recurrence An artificial implant or a reconstructed breast has not been found to interfere with the detection of cancer recurrence or to increase the risk of cancer recurrence.
Radiotherapy
Radiotherapy utilises radiation to treat breast cancer. Radiotherapy is recommended for the local treatment of breasts following a lumpectomy. It is given over 6 weeks during daily outpatient treatment sessions. Side effects are usually tolerable and mainly confined to the treatment area. Radiotherapy is also recommended for women after mastectomy whose risk of local recurrence is high and whose lymph nodes and tumours are more than 4cm wide.
Systemic treatment utilises chemotherapy or hormonal drugs such as Tamoxifen to eliminate clumps of cancer cells that may be circulating in a woman's body. The type of treatment varies depending on need and appropriate treatment to be adopted.
Risk Assessment
Based on microscopic analysis of biopsies or breast cancer cells, women may be divided into low or high risk groups. Women in the low-risk group may be treated with Tamoxifen while women in the high-risk group are offered systemic treatment. There are 3 main forms of systemic treatment:
A. Cytotoxic Chemotherapy This involves the administration of toxic drugs which are harmful to both cancer cells and healthy cells. Given their toxicity, the drugs are administered at controlled dosages over a period of time to limit their toxicity while eliminating cancer cells.
There are 3 main regimes, each consisting of a combination of cytotoxic drugs. Depending on the condition and needs of the patient, the most suitable regime is selected and administered at 3 weekly intervals over 4 to 6 months.
The following list of short-term side effects resulting from chemotherapy may be severe but are usually tolerable and temporary.
Low total white cell count (Less than 2000/mm3)
Fever
Infection
Nausea
Diarrhoea
Hair loss
Low platelet count (Less than 50,000/mm3)
Blood clots in veins
Cystitis
Weight gain (More than 10%)
Although these are significant side effects associated with cytotoxic chemotherapy, the mortality rate resulting from chemotherapy is low. Nevertheless, in very sick patients, death may result from overwhelming infection or the formation of blood clots in veins.
3 major long-term side effects associated with chemotherapy have been identified:
Premature menopause – A woman in her forties has a 50 per cent chance of experiencing premature menopause if she undergoes chemotherapy. The effects of menopause are more severe in younger women, varying from hot flushes, palpitations, and dry skin to more debilitating conditions such as osteoporosis and increased risk of cardiovascular disease.
Cardiac toxicity – Adriamycin (or Doxorubicin) is a common drug component of chemotherapy that can cause heart failure. However, the probability of experiencing this side effect is low and can be decreased by: 1. Assessing cardiac function 2. Limiting the dose administered 3. Calibrating the method of drug administration
Risk of a second cancer – Rare instances of chemotherapy-induced leukaemia have been recorded.
B. Hormonal Manipulation This entails altering or stopping the secretion of oestrogen in the patient's body as a means of treating breast cancer through the use of Tamoxifen. It is taken orally once a day and causes few side effects.
It is effective for:
Women at high risk of breast cancer and is taken as a preventive drug.
Women whose breast cancer is oestrogen receptor positive (ER+) and is at low risk of recurrence. Tamoxifen is given as the sole systemic drug.
Women whose breast cancer is ER+ and is at high risk of recurrence. Tamoxipfen is combined with chemotherapy or other measures of hormonal manipulation.
C. Ovarian Ablation This refers to methods to stop the secretion of oestrogen in a woman's body in order to reduce the stimulation of cancer cells and hence reduce the chance of cancer recurrence. This method applies only to pre-menopausal women and leads to premature menopause.
Ovarian ablation can be achieved by surgical or non-surgical methods:
Surgical Oophorectomy - Surgery is undertaken to permanently remove the ovaries. This method is now seldom used.
Radiation Castration - Radiotherapy is given to patients over a 2 week period to permanently disable the ovaries from secreting oestrogen. This is a quick and relatively painless method.
Ovarian Suppression - The secretion of oestrogen is controlled by the pituitary gland. Drugs can be prescribed to temporarily suppress oestrogen secretion. Ovarian function usually recovers once the drug is stopped. This is a relatively expensive method.
Support Groups
Bishana is a women's support group that was recently formed in May 2014. It was specifically established for all female cancer patients and survivors. Besides participating in educational, social, and recreational activities, Bishana provides a platform for these women to give and receive psychological and emotional support. Membership is free.
Reach to Recovery (RTR) was established in 1973 as a breast cancer support group to help women cope with life challenges brought about by a diagnosis of breast cancer. Members participate in activities ranging from educational talks or workshops, social and recreational events, outings, and enrichment programmes. Membership is free.
The Look Good Feel Better Programme was developed specifically for women undergoing chemotherapy or radiotherapy. The programme aims to help them minimise and manage the physical changes brought about by cancer treatment. Workshops organised are hands-on and held at various private and public hospitals island-wide. Membership is free.
What Is Breast Cancer?
