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Tuesday, June 14, 2011

What causes cancer?

My mom died of cancer, thus the word Cancer means a lot to me. I am sensitive towards this word!

Cancer is essentially a disease of the cells, where individual cells become abnormal and multiply out of control. Cancer can occur in any of the cells in the body, as everything in our body, including our organs, bones, muscles, skin and blood, is made up of millions of tiny cells.

If cancer occurs in the cells of the skin, then the person has skin cancer; if it is in the cells of the breast, then it is breast cancer.

Cancer starts from the genes of one abnormal cell. In a normal cell, there are genes that control how the cell divides and multiplies – a cell becomes abnormal if those genes are damaged or mutated. This causes the cell to start multiplying out of control, to form a cancerous (or malignant) tumour. This tumour may form a lump or a patch of cells that can be seen on a scan.

Every person has a risk of developing cancer, simply because we are made up of cells. There is nothing that can completely prevent cancers from developing because nature cannot be controlled.

However, there are certain biological, environmental and lifestyle risk factors that increase the likelihood of cell mutations. These could range from cigarette smoke and asbestos, to certain viruses.

If you reduce these risk factors in your life, you would contribute towards dramatically diminishing the chances of getting cancer. In other words, don’t give your cells a chance to go bad!

Cancer triggers

We all know that smoking leads to lung cancer. This is because cigarettes and cigarette smoke contain cancer-causing substances that are carcinogenic, like benzenes or ammonia. These carcinogens, which turn cells cancerous, are one of the main causes of cancer.

The longer the duration, and the greater the amount of carcinogens that you are exposed to, the greater your risk of developing cancer. The most commonly known carcinogens are tobacco smoke (causes cancer of the lung, mouth, throat, oesophagus, bladder and pancreas), asbestos (causes mesothelioma), and radiation from UV rays or radioactive materials.

Certain viruses and bacteria can also lead to cancer. This doesn’t mean that you can “catch” a cancer the same way you catch a viral influenza. What happens is that the virus or the bacteria causes cell mutations that lead to cancer.

The hepatitis B and C viruses can increase the risk of liver cancer, while the human papillomavirus (HPV) can lead to abnormalities in the cervical and genital cells that may become cancerous after several years.

There are vaccinations for hepatitis B and HPV, so that can protect yourself from these infections. Furthermore, women should have regular Pap smears to pick up any possible HPV infection and treat it early.

One type of bacteria known to play a role in cancer is Helicobacter pylori, which infects the stomach lining and eventually leads to inflammation and increased risk of cancer. H. pylori infection can be treated with antibiotics.

Lifestyle factors

Some risk factors for cancer are beyond our control. For instance, age increases the likelihood of cancer, but we cannot stop the hands of time from advancing. You are more likely to develop cancer the older you get, because the mutations in the cells take a long time to develop and turn into cancerous cells.

When you are older, your body’s immune system is also weaker and less able to resist the development of abnormal cells or repair them. This is the same reason that certain types of cancer are more likely in people with weakened immune systems, like organ transplant patients who take immunosuppressive medications, people living with HIV and AIDS, or those who have disorders that affect their immunity.

There has been a lot of debate in recent years about whether your diet and physical activity has an impact on cancer development. Increasingly, scientists are starting to say “yes”, as research shows that certain foods have cancer-protective properties, while others can increase the risk of cancer.

Fruits and vegetables are rich in vitamins, minerals and antioxidants that strengthen the body’s immune system and protect it from damage caused by age, the food we eat, and environmental factors. All the different-coloured fruits and vegetables, such as green broccoli, orange carrots, red cabbage, blueberries and purple eggplant, contain unique compounds that may protect against cancer.

Eating at least five servings of colourful fruits and vegetables every day is the easiest form of defence against cancer and keeps the body generally healthy.

Eating too much of high-fat foods is thought to contribute to the risk of cancer, because it is most likely to cause obesity. Along with lack of physical activity and overindulgence in alcohol, obesity has a strong link with certain types of cancers, such as colorectal cancer.

Some of my patients have read emails or heard claims that food additives and artificial sweeteners are carcinogenic. These claims can cause a lot of unnecessary fear in people. All ingredients in our food products are regulated by the Health Ministry, and these products would not be approved if they were shown to cause cancer.

If you are wary, you can reduce your intake of artificial sweeteners and processed foods, so that you consume mostly natural ingredients. However, there is no need to be paranoid, as it would take huge amounts of any substance to cause serious harm – and it is rarely possible for a person to consume so much of any product or ingredient.

Born with cancer?

Some of my patients have asked me whether they have “cancer genes”, because many of their close family members, like their mother, sisters, and aunts, have developed cancer.

Some people may be born with a genetic mutation in their cells that makes them “genetically predisposed” to developing cancer. However, it doesn’t mean that they will definitely get cancer, just that they are at higher risk because they already have one of several mutations needed for cancer to develop.

One instance of genetic predisposition is the BRCA1 and BRCA2 breast cancer genes, where women who carry one of these genes may be at higher risk of developing breast cancer than women who do not have the gene. These genes can be identified through genetic testing.

However, all this talk about genetic predisposition can be misleading. Some women think that just because they have the genes, they are doomed to cancer. Other women think that just because they do not have the genes, they will not get cancer, so they do not have to do breast self-examination or go for regular medical checkups.

Let me use BRCA as an example again. Less than 5% of all breast cancer is due to the mutated BRCA1 or BRCA2 gene – which means at least 95% of breast cancer out there is caused by a multitude of other factors, some of which I have described above.

That is the most important take-home message for cancer prevention – there is not one single cause for cancer, but a combination of risk factors and triggers. There are many things that have to happen before cancer can develop – for instance, whether you have the genetic make-up, have been exposed to carcinogens, how you eat and exercise, and the general state of your health, all of which will have to cause several genetic mutations before cancer develops.

The best advice I can give women is to live healthy, think positively, and always be in control by managing your health. By reducing all of the risk factors listed above, you are giving your body a fighting chance to keep cancer at bay.

Datuk Dr Nor Ashikin Mokhtar is a consultant obstetrician & gynaecologist (FRCOG, UK). For further information, visit The information provided is for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.

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