Living with cancer: An ST series

Fighting breast cancer with better knowledge

Breast cancer is not just the top cancer for women here, but also the top killer cancer for them, taking the lives of more than one woman in Singapore every day. But thanks to better screening and treatment, survival rates have shot up.

The numbers are telling.

In the 1970s, only half of breast cancer patients in Singapore were still alive five years after diagnosis. Today, four in five women are still alive after five years, with 72 per cent surviving a decade or more.

Fifty years ago, fewer than 250 women a year here were diagnosed with breast cancer, because many cases went undetected. Today, the figure is about 1,900.

This means that more cases are being detected and at an earlier stage, giving patients a better chance of fighting the condition.

Compared with the past, when breast cancer was often discovered only at the late stage, fewer than one in 10 nowadays discover it at stage four, when it has spread to other parts of the body.

  • Three broad types

  • There are three broad types of breast cancer. The way they progress differs, so treatment also has to be different to be effective.

    The most common, accounting for two in three types of breast cancer, is known as hormone receptor positive, which means it grows in response to certain hormones.

    There are subtypes within this group, such as Luminal A, which tends to grow slowly, is found more often in older women, and responds well to hormonal therapy, said Dr See Hui Ti, a medical oncologist in private practice.

    This type of cancer benefits most from breast screening.

    There is also the slightly faster-growing Luminal B, seen more often in younger women.

    Another breast cancer type is the triple-negative, which grows very quickly and can go from a small lump to becoming widespread in the body within months. This type is easily missed by breast mammograms.

    Dr Yap Yoon Sim, a senior breast oncologist at the National Cancer Centre Singapore, said that this is the most difficult type to treat and there is also a higher chance of relapse. Fortunately, it accounts for only 10 per cent of breast cancers.

    The third type is the human epidermal growth factor receptor 2 (HER2) positive cancer, which grows quickly. In the past, doctors had difficulty stopping this type of cancer. With the introduction of a targetted treatment called Herceptin a decade ago, women with this cancer now do well, said Dr Yap. It accounts for one in five cases.

    Salma Khalik

Better treatment also plays a big role in helping patients.

Dr See Hui Ti, a medical oncologist at Mount Elizabeth Medical Centre, said that, increasingly, women are getting cured of breast cancer and go on to live normal lives. Part of this comes from better understanding of the disease.

As researchers have been able to differentiate between several types of breast cancer and discover how they react to treatment, doctors are now able to give patients the treatment that best suits the type of cancer they have.

There are three broad types of breast cancer: hormone receptor- positive, which accounts for 70 per cent of cases; human epidermal growth factor receptor 2 (HER2) positive, which makes up one in five cases and for which there is now targeted treatment resulting in very good outcomes; and triple-negative, which is the most difficult to treat (see sidebar right).

Knowing the type of cancer helps doctors prescribe the best treatment. Such treatment also depends on the stage of the cancer.

About a third of women here today are diagnosed while the cancer tumour is in stage one and very small. For them, surgery alone often will do the trick.

For those in stages two and three, where the cancer is still localised, treatment involves both surgery and radiotherapy to remove the tumour, and chemotherapy to "mop up" any remaining cancerous cells.

 
 
 

Dr Tan Yah Yuen, a surgeon in private practice at Mount Elizabeth Medical Centre specialising in breast surgery, pointed out that in recent years, doctors have found it better to start patients on chemotherapy so that the tumour shrinks, before surgically removing what is left and then continuing the rest of the chemotherapy sessions.

This method is particularly good for certain breast cancer types - the triple-negative and HER2-positive cancers, as well as the big Luminal B tumours - said Dr Tan, because less tissue is removed and the recovery is better.

Dr See said that about one-third of cancer patients today needing both chemotherapy and surgery do it this way, but she expects more to opt for this method as increasing data emerges.

There is also a small group of women who are at high risk of getting breast and ovarian cancers because they carry mutations in the BRCA gene. The BRCA gene repairs damaged DNA. Mutations cause the gene to malfunction, so cells might remain damaged, eventually leading to cancer.

American actress Angelina Jolie, for example, has the BRCA1 gene mutation, which puts her at 87 per cent risk of getting breast cancer and 50 per cent risk of getting ovarian cancer.

She opted to remove both breasts to reduce her cancer risk.

Dr Tan said that the actress' risk of getting breast cancer has now fallen to 8 per cent to 10 per cent. In other words, she has a more than 90 per cent chance of not getting breast cancer at all.

Dr Tan said doctors think fewer than one in 10 Asian women have this gene, which is mostly found in a Jewish subgroup known as the Ashkenazi Jews.

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•For more information, contact:   supportgroup@singaporecancer society.org.sg or call 6499-9147 or 6499-9132; Breast Cancer Foundation on 6356-0123; National University Cancer Institute, Singapore on 6773-7888 or e-mail ncis@nuhs.edu.sg

•Next week: Prostate cancer


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A version of this article appeared in the print edition of The Straits Times on September 28, 2016, with the headline 'Fighting breast cancer with better knowledge'. Print Edition | Subscribe