Content provided by Parkway Cancer Centre

Breast cancer: Understanding the most common cancer for women in Singapore

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According to the most recent report from the Singapore Cancer Registry, between 2008 and 2012, breast cancer constituted 29.4 per cent of all cancers among women.

During the same period, deaths from breast cancer made up 17.9 per cent of all female deaths by cancer, making it the biggest killer of women.

Causes and risk factors

Cancer is not something that strikes at random. There are a few risk factors that make it more likely that you will get breast cancer: gender, age and genetic factors.

Women are more likely to get breast cancer than men, for example.

Age is another risk factor. The incidence of breast cancer is greater among older women.

According to the Cancer Registry’s report, more than 80 per cent of cases of breast cancer in Singapore are in women aged 45 and over.

Then there are also genetic factors. If you have a harmful mutation of the BRCA1 or BRCA2 gene, you have a higher risk of breast cancer.

A family history of breast or ovarian cancer also puts you at a greater risk, and the same goes if you started menstruating early or if you enter menopause late.

Early detection saves lives

You can detect breast cancer by screening. We do screening to test women who do not have symptoms, to identify people with an increased chance of getting cancer.

With breast cancer, we rely on mammograms, which are X-rays of the breast, to detect small lumps in the breast.

The average size of the lump detected with routine mammogram is 1 cm. In comparison, the average size of the lump found by regularly practising breast self-examination is 2 cm.

Mammograms are thus able to find, on average, smaller lumps than self-examination alone. The bigger the tumour, the greater the risk for it to spread to the lymph nodes, so we want to catch the tumours as early as possible.

Mammograms find slower growing cancer while breast self-examination detects faster growing cancer.

If detected very early, you might need only surgery and radiation, and you might not need chemotherapy.

Also, the smaller the tumour, the better the chances of cure. This is why it is important to catch the tumours early.

If you are over 50, you should go for screenings every two years. If you are over 40, you should screen every year, though you should check with your doctor first so you can weigh the pros and cons of screening at an early age.

Apart from mammograms, breast ultrasounds are sometimes used, especially for younger women whose breast tissues are denser.

Breast MRIs are used only in very specific instances, with younger women or very high risk women.

Treatment

The treatment depends on the stage of the cancer and more than one treatment may be used.

The options are surgery, radiation therapy, chemotherapy, hormone therapy and targeted therapy.

Surgery has progressed considerably over the last few decades. It used to be very radical, now it is very conservative.

Today, we try not to remove the whole breast in a mastectomy. Instead, we try to remove as little as possible in a lumpectomy, without compromising long-term survival.

In the past, surgery also removed all lymph nodes. However, now there is a test called sentinel lymph node (SLN) biopsy. If the results of the SLN biopsy are negative, then no further surgery is needed.

More than 50 per cent of patients who undergo SLN biopsy do not require further removal of lymph nodes from the axilla. This reduces the risk of lymphedema, reduces pain and numbness and gives better shoulder function.

Surgery is not the only solution though. With Stage 3B cancer for example, there is a 70 to 90 per cent recurrence in 10 years. With such a high probability of recurrence, surgery is not the only treatment for people with cancer at this stage.

In addition, some early breast cancers with micro metastasis may recur after surgery. As a result, we add on adjuvant therapy to reduce risk of recurrence.

Adjuvant therapy is treatment given in addition to surgery to reduce the risk of recurrence to achieve a cure. It reduces recurrence and increases survival.

The tumour’s size, grade and the presence of certain biomarkers will give us an idea of the risk of recurrence.

The expression of estrogen receptors, progesterone receptors and the HER2 status in a patient’s breast cancer tell us about how likely the cancer will recur and what treatments work best with that particular type of cancer.

The adjuvant therapy thus consists of chemotherapy, hormonal therapy or the use of Herceptin (Trastuzumab), depending on the type of cancer.

Sometimes, neoadjuvant (primary) therapy is done before surgery, especially if the tumour is too big.

Chemotherapy is given before surgery, to downstage the tumour so that the surgery can be more effective.

Another benefit is that seeing how the tumour reacts to chemotherapy tells us more about the kind of tumour we are dealing with.

Metastatic breast cancer has seen improved survival rates over time. Between 1974 and 1979, the cumulative survival rate after five years was 10 per cent.

However, by the period 1995-2000, the five-year survival rate had increased to just under 50 per cent. This is good news for women with breast cancer today.

What you can do

While better surgery and better drugs have improved survival rates for breast cancer, there are a few things that you can do to reduce your chances of getting breast cancer: stop smoking, drink less alcohol, exercise more, avoid hormone replacement therapy, have children early, eat your fruits and vegetables and eat less red meat and other animal fats and finally, maintain a healthy weight.

These will not stop you from getting breast cancer but it will reduce the risk. Remember that prevention is always better than cure.


Find out more about cancer and how to fight it on ST's Fighting Cancer microsite.