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Breast Cancer

Breast Cancer - What it is

Breast cancer arises from a malignant tumour. It occurs when breast cells become abnormal and divide without control or order. Normal cells divide and produce in an orderly manner. Sometimes this orderly process is disrupted and cells grow and divide out of control, producing extra tissue to form a mass or lump called a tumour. A tumour can be benign (non-cancerous) or malignant (cancerous). The breasts are made up mainly of fat cells and gland cells. Milk-producing glands in the breast are made up of individual cells which normally reproduce under the control of hormones. Sometimes this process of reproduction goes out of control and an abnormal glandular structure develops. This is the beginning of cancer. The majority of breast cancers starts in the milk ducts. A small number start in the milk sacs or lobules.

How Common is Breast Cancer?

More than 25% of all cancers diagnosed in women are breast cancers. Between 2011 and 2015, about 1,927 women were diagnosed to have breast cancer in Singapore each year.

Nine out of 10 women who go to their doctors with breast lumps have a benign disorder, not cancer. Normal changes associated with the menstrual cycle can make breasts feel lumpy.

Age of onset

The risk of breast cancer increases with age. Most women who are diagnosed to have breast cancer are older than 40 years old, but younger women may also be affected.

Breast Cancer - Symptoms

The risk of breast cancer increases with age. Most women who are diagnosed to have breast cancer are older than 40 years old, but younger women may also be affected.

About 80% of women with breast cancer first consult their doctor with a symptom they notice themselves. The most common feature is a breast lump. The lump may or may not be painful. Sometimes the nipple may be puckered (indrawn) or bleeding, or there is swelling of the skin of the breast. There may be a discharge from the nipple. Lymph glands of the armpit may also be enlarged. In advanced cases, breast cancer can spread to the liver, lung, bone, or brain.

Breast Cancer - How to prevent?

Breast Cancer - Causes and Risk Factors

Breast cancer is often triggered by the repeated monthly cycle of normal female hormones. The length of the fertile period, i.e. from the first period to menopause, is a risk factor. A woman whose menopause occurs at 55 years of age has a significantly greater risk than a woman who menopauses at 45 years of age. Age at first completed pregnancy is also important: having the first completed pregnancy after the age of 30 years increases the risk compared to those who complete the first pregnancy before age 30. Likewise, women who have never been pregnant also have a higher risk of getting breast cancer. Breast feeding protects against breast cancer. Hormone replacement therapy increases the risk of breast cancer and this should be discussed before embarking on the treatment.

Between 5 to 10% of all breast cancers are associated with genetic factors. The genes BRCA1 and BRCA2 have been identified and may be associated with breast cancer occurring in approximately half of all families with a very strong history of breast and/or ovarian cancer.

Breast Cancer - Diagnosis

​An x-ray examination called a mammogram and a needle biopsy are necessary when there is a suspicious breast lump. Even if the mammogram returns negative, a biopsy may be needed.

A mammogram is an x-ray examination which helps to define the extent of the lump. It is sometimes combined with an ultrasound of the breast to determine if the lump is mainly solid or cystic, i.e. filled with liquid only. The mammogram examination is slightly uncomfortable as the breast is compressed against a metal surface to obtain a good x-ray image. Mammograms are much more useful for screening than for evaluation of symptomatic masses. Even if the mammogram is completely normal, a symptomatic breast mass may still need to be biopsied.

A biopsy involves removal of tissue from the breast lump using either a core or skinny needle and syringe. This may be done in the clinic. The tissue is processed and sent to the pathologist, a doctor who will look at the tissue under a microscope. The pathologist will be able to tell if the tissue is cancerous.

Mammotome Breast biopsy is a new technology that uses a vacuum-assisted device to obtain a biopsy from non-palpable lesions. This device can either be guided by ultrasound or by X-ray. Small samples of tissue are removed from the breast using a hollow needle which is guided precisely to the suspicious lesion via mammogram. This procedure is minimally invasive as compared to an open surgical biopsy, and it is performed as an outpatient procedure. It can sample tiny x-ray abnormalities, call microcalcifications, making early diagnosis of breast cancer possible. It is done under local anaesthesia and takes about 45 minutes to complete.

Once cancer is diagnosed, other tests such as chest x-ray, ultrasound of the liver and bone scan may be required to determine if the cancer has spread to other parts of the body.

Breast Cancer - Treatments

​Surgery is the usual initial treatment of breast cancer. A desirable aim of surgical treatment is to conserve the breast if possible, and this involves removing the cancer with the safest minimal amount of surrounding tissue (i.e. wide local excision).

For some patients, this is not possible, and total removal of the affected breast and underlying muscles, (i.e. mastectomy), is required. The lymph glands under the armpit may be entirely removed at the time of surgery. (i.e. axillary clearance) or, alternatively, a dye may be injected into the region of the primary tumour to determine the most informative single gland to remove (sentinel mode sampling). This is important to predict the likeliness of recurrence of the cancer.

Radiotherapy after surgery may be recommended to treat cancer cells left in the remaining breast tissue which may cause the cancer to recur in the breast (i.e. local recurrence). Radiotherapy to the chest usually takes place over 5 weeks. Radiotherapy is almost always recommended if only a wide excision of the cancer is performed.

Chemotherapy aims to prevent cancer recurrence in tissues that are distant from the breast. Chemotherapy is usually administered to younger women and it is given over 3 to 6 months. There may be mild nausea or vomiting, hair loss, lethargy or tiredness, and loss of appetite. Most women can continue working during this period. The choice of recommended drugs will depend on the person's general health and other medical problems, stage of cancer, and other risk factors.

Some breast cancers have special protein receptors on the cancer cells, such as oestrogen and progesterone receptors, and HER2/neu receptor. Patients whose breast cancers have oestrogen or progesterone receptors are more likely to benefit from additional hormonal treatment. For patients with advanced breast cancer where the cancer has HER2/neu receptors, an antibody to the HER2/neu has been developed for therapeutic use. Studies with the HER2/neu antibody are still being carried out. Due to possible damage to the heart, it cannot be considered standard therapy in the adjuvant (prophylactic) setting yet.

Sometimes, chemotherapy is given before surgery to shrink the breast cancer before the surgery. This is usually the case if the breast cancer is especially large.

In older women who have reached menopause, chemotherapy may not always be necessary; only hormones such as tamoxifen may be given. This is so if the cancer was oestrogen or progesterone receptor positive.

Advanced Breast Cancer

Breast cancer may spread to the lungs, liver, bones or brain, either at the time of diagnosis or years after the original breast cancer has been removed. Treatment options include hormone treatment, chemotherapy, or radiotherapy.

Prognosis of Breast Cancer

Prognosis means the probable future outcome of an illness based on the relevant facts of the case. All findings from clinical examinations and investigations and pathology reports are important and must be considered together to decide the prognosis of an individual case of breast cancer.

The doctor looks for the following features:
• What is the size of the breast cancer? In general, the larger the cancer, the more likely the cancer will recur. The size of the breast cancer also influences whether breast conservation is an option.
• How many of the lymph glands in the armpit were involved? The likeliness of the cancer recurring is increased if more lymph glands are affected.
• Did the pathologist see high risk features such as involvement of the blood vessels or lymph channels in the resected specimen? Were the cancerous cells mature or immature?

Breast Cancer - Preparing for surgery

Breast Cancer - Post-surgery care

Breast Cancer - Other Information

​1. Can an injury to the breast cause cancer?

An injury to the breast cannot cause cancer. When the body tries to heal the bruise, it can develop scar tissue. This scar tissue can be mistaken as cancer on mammogram. However, symptoms of injury should subside within a month. If you are worried, seek confirmation from your doctor.

2. Are most breast lumps caused by cancer?

No. Only one lump out of every 10 will be cancerous. This means that 90% of all breast lumps are not cancer. However, the chance of a lump being cancerous increases as you get older. Some women do not have a definite lump, but can feel areas of general ‘lumpiness’ in their breasts. Often, your doctor will be able to reassure you that this is normal but it is important that you ask your doctor to check thoroughly for any change.

3. Can a benign (non-cancerous) lump turn into cancer?

The chances of cancer developing in a benign lump may be no different than in any other part of the breast. However, it is very important for you to make sure that the lump is non-cancerous in the first place.

4. If I have a benign breast problem, am I more likely to get breast cancer?

Occasionally, the risk is slightly higher in some women with particular benign breast problems. However, you will need to talk this over with your doctor.

5. Do benign problems come back?

Generally, no. However, a small number of women will develop new benign lumps in the future.

6. I felt a lump in my breast, but it didn’t show up in the mammogram. Does that mean I don’t have cancer?

A lot of women who find lumps in their breasts get frightened and they go for a mammogram. When nothing shows up, they’re very happy because they assume it’s not cancer. No test is perfect. Ask your doctor to conduct more tests and find out the cause of the lumps. Even though many breast lumps are not cancerous, you should still bring it to your doctor’s attention.

7. What if the lump turns out to be cancer?

If breast cancer is detected early, it has a better chance of being cured. You will need to discuss the diagnosis and the best treatment options with your treating doctor.

8. What should I do if my doctor says my breast problem is nothing to worry about but I still feel concerned?

If your doctor has suggested your problem is hormonal, you may wish to wait until after your next period to see if the problem is still there. If it persists or if you are still concerned, you may wish to go back to your doctor or seek a second opinion.

9. What if there is a history of breast cancer in my family?

Women who have a strong family history of breast cancer, such as a mother and/or sister who developed breast cancer before menopause, may be at increased risk of getting breast cancer. If you are concerned about a family history of breast cancer, talk with your doctor. You may also wish to consult a breast specialist.

10. Will I still have my menstrual periods after breast cancer treatment?

Treatment with chemotherapy and hormonal therapy may cause changes in your menstrual cycle, resulting in irregular menstruation or early menopause. If you are already reaching menopause, your menstrual periods may not return.

11. Can I become pregnant when I have breast cancer?

The belief is that changing levels of female hormones during pregnancy could encourage the recurrence of breast cancer. However, there is no data to show that this is so. Some doctors will advise you to wait one or two years after completion of treatment before attempting to conceive. Nevertheless, do discuss with your doctor before planning to conceive.

12. When is a mastectomy recommended?

Some women do better cosmetically with a mastectomy than with the removal of just the lump, since breast reconstruction is now available using tissue expanders or skin flaps. Your surgeon will be able to advise if you are suitable for breast reconstruction.

The Singapore Cancer Society has a Reach to Recovery Programme that provides physical, cosmetic, post-operative and psychological support. The volunteer is usually a female who has undergone a mastectomy.

Early Detection & Prevention

1. If I go for mammogram screening regularly, will I be exposed to dangerous levels of radiation?

Radiation exposure from modern mammogram equipment is believed to be safe.

2. I have a lump in my breast. I am frightened to see the doctor in case it is cancer.

Although your worry is understandable, you should see your family doctor as soon as possible. The great majority of breast lumps are not cancerous.

3. My mother / aunt died of breast cancer. Am I likely to get breast cancer too?

A small proportion of breast cancer is linked to factors that can be inherited from one generation to the next. Depending upon the number of close relatives affected, you may have a greater chance than a woman who does not have a family history of breast cancer. Most family doctors or hospitals will provide information on breast self-examination and mammogram screenings.


1. I have been diagnosed to have breast cancer. Will I get better?

Many women who have had breast cancer live a normal lifespan. Feel free to discuss your own prognosis with your doctor.

2. Will I need to undergo mastectomy?

This depends on the size, position and type of your breast cancer as well as the size of your breast.

3. Does radiotherapy or chemotherapy cause disfigurement and long-term damage?

It is uncommon for women to experience lasting damage from modern radiotherapy techniques. Most chemotherapy side-effects are short-term. Nausea and vomiting are controlled in most patients. Hair loss is still common, and you may require a temporary wig. Your periods may disappear during chemotherapy but may return when you complete chemotherapy. However, for women in their late 30s and 40s, menopause may occur early, perhaps increasing the risk of osteoporosis and heart disease. If a fever occurs while you are on chemotherapy, see your doctor immediately in case antibiotics are needed.

Hormone therapy for Breast Cancer

1. Why do I need hormone therapy?

Normal female hormones like oestrogen may promote growth of normal healthy breast tissue, but may also accelerate the growth and recurrence of certain breast cancers. Drugs that slow breast cancer growth by interfering with normal female hormone action are generically called hormone therapy. Some breast cancers need the hormone, oestrogen, to grow. Hormone therapy can prevent your body’s natural hormones from activating growth or spread of cancer cells.

2. What drug will I be given? What does it do?

The most common drug used for hormone therapy for breast cancer is the oral tablet, tamoxifen, which stops the action of oestrogen.

3. Will I have any side effects? What can I do about them?

You may experience any of the following common side effects:

Hot flushes/sweats. Wear a thin layer of clothing to keep cool when hot flushes occur.
Vaginal irritation. Some women experience vaginal dryness or discharge. Notify your doctor who can recommend a non-oestrogen cream or lubricant.
Irregular menstrual periods
Some pre-menopausal women experience irregular periods. Some women may find that once they stop taking tamoxifen, their menstrual cycle becomes regular again.

Other less common side-effects are depression, mood swings and a slightly increased chance of developing cancer of the uterus and deep vein thrombosis. Regular gynaecological checkups are recommended.

4. How long will I be on hormonal treatment?

When used to treat early breast cancer, tamoxifen is most often prescribed for 5 years. Patients with advanced disease may take it for varying lengths of time depending on their response to treatment.

5. Why do some women need hormonal treatment while others do not?

Many breast cancers have ‘receptors’ for oestrogen and progesterone. Receptors are proteins on the surface of the cancer cells to which specific hormones (e.g. oestrogen or progesterone) attach themselves. If the cancer has oestrogen or progesterone receptors, it is likely that hormonal treatment would benefit this group of women.


1. What choice of prosthesis (breast forms) do I have?

There is a wide range available. The type of breast form you require will depend on your needs. It should closely simulate the weight and shape of a natural breast and your other breast. If you need advice, speak with your Breast Care Nurse.

2. Can the prosthesis be washed? How do I take care of it?

Yes, the prosthesis can be washed. Instructions on the care of the prosthesis can be found in the box when you purchase one. You should also place the prosthesis in the box when you are not using it.

Breast Reconstruction

1. What is a Breast Reconstruction?

Breast reconstruction is an operation to create a new breast to replace the breast which has been removed. Breast reconstruction does not affect breast cancer survival or treatment. The procedure can be performed at the same time as the mastectomy or at a later date. The breast can be reconstructed using an implant such as silicone, normal saline or tissue from your own body. This procedure requires further discussion with your surgeon.

2. When can breast reconstruction be done?

There are differing opinions on this. It can be done at the time of mastectomy, some months afterwards or even years later. The timing may depend on the type of breast cancer you have, whether you need further treatment (e.g. chemotherapy), how you feel about the loss of your breast or breasts, your general health, and other concerns such as costs. Talk over these issues with your breast surgeon and plastic surgeon. You may wish to ask for a second opinion if you would like one.

3. Can I exercise after breast reconstruction?

It will be helpful to stay active and to exercise regularly if you can. Light exercise, such as walking after surgery, can assist in the recovery process. The amount and type of exercise will depend on what you are used to and how well you feel. It is best to discuss your concerns with your doctor.

4. Do I need to go for regular breast screening after a reconstruction?

It is important to have regular scheduled mammograms on the opposite breast. Breast self examination should continue. Check both the remaining and the reconstructed breast at the same time each month. You will learn what is normal for you since the breast reconstruction. The reconstructed breast will feel different and the other breast may have changed too.


1. After being diagnosed with breast cancer, can I still breastfeed my baby?

You can still breastfeed your baby from the unaffected breast. It is not advisable to breastfeed your baby on the breast that is affected by cancer, as it will not be able to produce adequate milk.

2. Can I breastfeed after lumpectomy and radiation therapy?

Yes, you can. Lumpectomy is not so extensive that it will affect your breastfeeding capacity, but radiation therapy will. The breast treated with radiation may go through the same changes as the normal one during pregnancy, but it will produce little or no milk. You can, however, breastfeed your baby with the other breast.

3. Can I breastfeed after mastectomy?

Yes, you can still breastfeed your baby with the other breast. Frequent nursing will be necessary at first so as to build up a good supply of milk.

4. Will I be able to breastfeed after a biopsy?

Yes. A biopsy will not interfere with your ability to breastfeed. Even if you need a biopsy while you are breastfeeding, you can still continue to breast-feed. However, you will need to discuss this with your doctor.

Arm Exercises

1. Why do I need to exercise?

You are encouraged to exercise your affected arm soon after your operation to prevent stiffness of the shoulder joint.

2. When can I start doing arm exercises?

It is normal to feel tired for a few days after an operation. You can start the exercises as soon as you feel strong enough. This can be as early as the first day after your operation. The sooner you start, the faster you regain your shoulder movements.

For more information on Breast Cancer FAQs, please click here.

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