Sunday, September 18, 2011

Testing options

The good and bad of screening tests.

PREVENTION is better than cure. This is an oft repeated advice from well-meaning friends. Yes, getting ill these days can be an expensive affair.

Some diseases can be prevented if we take the appropriate steps − immunisation, wearing safety helmets and practising a healthy lifestyle are good examples. This kind of prevention is also called “primary prevention”. These methods of preventing the occurrence of disease in the first place are the best form of disease prevention.

What is screening?

For many of diseases, health professionals are still in the dark about the actual causes or the best ways of preventing them. Cancer is a good example. Many causes of cancer have been identified, but the best ways of preventing them from happening is still elusive.

In general, checking for tumour markers is something that is seldom needed in a general medical checkup. – AFP

Since we cannot prevent them from happening, is it possible to detect the cancer at an early stage when treatment is likely to be more effective? It does sound like a good idea if we can do that. In medical parlance, this is also a kind of prevention – we call this “secondary prevention”, or screening.

The good

Screening aims to try and detect the disease at such an early stage before it causes symptoms or ill health. For example, using mammography (a special kind of breast X-ray), it may be possible to pick up a tiny cancerous breast lump that is not even detectable by the human hand. It is believed that treating the early breast cancer at this stage is easier and more effective (ie the cancer may be curable at this stage).

In the case of breast cancer, the screening test mentioned is mammography (an X-ray). In other cases, the screening test may be a clinical examination by a doctor, a blood test, or a clinical procedure.

The Pap smear is a clinical procedure that samples cells from the cervix of women with the aim of detecting cells that may indicate an increased risk of cancer of the cervix. By detecting the abnormal cells in the cervix (she does not have cancer yet), the affected woman can be treated, thus preventing her from getting cancer of the cervix.

Sometimes, screening can be a simple clinical examination by doctors or other healthcare practitioners.

Did you know that getting your blood pressure checked is also considered screening? High blood pressure hardly ever causes symptoms. If your blood pressure is consistently high (after several measurements), modifying your lifestyle or taking blood pressure pills will reduce your chances of getting bad outcomes such as heart attacks and strokes.

Screening can indeed be good for the health of the individual when the screening tests lead to the detection of serious health problems in the early stages and starting specific treatment to prevent the associated complications.

The bad

Since screening is capable of early detection of cancer and other dreadful diseases, is it always a good idea to go for screening? Well, the answer is a guarded yes. It all depends on the type of screening test and the specific diseases that the screening tests are aimed for.

A woman had a blood test called tumour marker CA19.9, which has been touted as a good screening test for cancer of the pancreas. Her CA19.9 level was slightly elevated. Despite extensive investigations such as CT scan of the abdomen and an invasive X-ray called ERCP, no cancer of the pancreas was found. She ended up spending lots of money and had to be subjected to tests that may be harmful to the body.

A smoker requests his doctor to do a chest X-ray to look for lung cancer. If his chest X-ray is normal, does it mean that he does not have lung cancer? Maybe not, as a chest X-ray can only pick up fairly advanced lung cancer, and it is not good enough to detect very early tumour.

The above two case scenarios point to some problems with screening tests: positive results do not always mean the person has the disease (this is called “false positive”), and negative results do not always mean the person does not have the disease (this is called “false negative”).

What it means is that many screening tests that are in common use are actually not good enough. This problem has serious implications for the person requesting for screening because doctors may be forced to initiate a wild goose chase for a non-existing cancer.

And worse still, the person may be wrongly reassured because the screening test is “normal”.

Breast self-examination has been promoted as a good way to detect breast lumps that may be cancerous.

However, studies in various parts of the world have shown that many women are unable to detect small breast lumps despite being taught the technique of breast self-examination.

Women who perform breast self-examination regularly are more likely to have a breast biopsy. Even if breast cancer is detected initially by self-examination, at the end, they did not really fare much better than women with breast cancer who did not do self-examination regularly.

Thus, in developed countries, breast self-examination is now not recommended since it does not do much good and may possible lead to potential harm (such as increasing the chances of needless breast biopsy and the associated anxiety).

What screening should we go for?

Despite the problem with screening tests, there is still a place for screening. The United States Preventive Services Task Force publishes recommendations on screening tests regularly.

In this report, the medical problems, type of screening tests, and the screening frequency are clearly identified. Some examples of useful screening tests are:

·All adults should have blood pressure checks.

·Adults with raised blood pressure should be checked for diabetes.

·Adults 35 years and above should have blood lipids checked regularly.

·Men and women 50 years and above should be checked for colon cancer.

·Sexually active women should have regular Pap smears.

·Women 50 years and above should have mammography once in two years.

·Pregnant women should have a HIV test.

As the frequency of medical problems vary from place to place, and may be altered by personal characteristics, do discuss whether you need screening (and for which disease) with your doctor. You doctor may recommend screening at a younger age for specific conditions if your family has a hereditary type of disease.

If you have certain risk factors (eg obesity, family history of heart attack), you may benefit from earlier checks for diabetes and blood lipids level.

Many of us have friends and relatives who have gone for “screening packages” that include a battery of tests. Not unusually, one or more of these tests may be abnormal and eventually may turn out to be erroneous or harmless. The tumour markers in particular is something that is seldom needed in a general medical checkup.

Screening tests should ideally be done after careful consideration of its benefits and potential harms.

A killer of many women

Contrary to widespread belief, heart disease is the number one killer of women, not breast cancer.

MOST of my patients think that breast cancer is the number one cause of death among women. They worry about it all the time, ask me what they can do to prevent it, and talk about it with their friends.

They are all surprised when I tell them that the biggest killer of women above the age of 50 is actually heart disease, not any type of cancer.

Menopause is one of the main risk factors for developing heart disease in women. This is why women ‘catch up’ (heart disease risk) with men very rapidly from age 50 onwards.

They think that heart attacks and strokes only happen to men. This is partly because many of the stories that we hear related to heart attack cases are about men, whether it’s from family, friends or the news.

But this does not mean that heart disease does not exist in men. Perhaps stories about breast cancer are simply given more prominence compared to stories about heart attacks in women, because of the symbolism of breast cancer and the fearsome role that it occupies in our minds.

As many women are still belabouring under this misconception, I decided to write about heart disease in women to make readers more aware of their heart disease risk and how they can protect themselves.

Blocked arteries

There are many different types of heart disease, but the most common type in women is coronary heart disease (CHD), also called coronary artery disease (CAD).

This form of heart disease affects the coronary arteries, where plaque builds up on the inner walls of the arteries. The build-up of plaque can cause the arteries to become narrow, or can form blood clots. Both these instances reduce or block blood flow to the heart. This is how a heart attack happens.

CHD can also lead to heart failure, irregular heartbeat (arrhythmia) and sudden cardiac arrest.

It’s a woman’s disease, too

The myths and misconceptions that heart disease is “a man’s disease” are exceptionally dangerous. Not only is heart disease also a woman’s disease, but it also kills more women than men.

Women are more likely to die from a heart attack because they usually develop heart disease at an older age (about 10 years later than men) and also tend to have other significant health problems when the heart attack occurs.

There is another reason for the higher number of deaths among women: women are less likely than men to receive appropriate treatment after a heart attack. This may be because their symptoms were not recognised (I will discuss more about symptoms later), or because they respond differently to some cardiovascular medications.

Our symptoms are different

We automatically assume that heart attacks are characterised by chest pain. But women do not always have symptoms related to chest pain or discomfort, and are more likely than men to have other types of symptoms or more subtle symptoms.

Some symptoms that occur in women include pain or discomfort in the neck, shoulder blade or upper back; profound fatigue; difficulty breathing; dizziness; nausea and vomiting; profuse sweating; burning abdominal pain; or even an impending feeling of doom.

As you can see, some of these symptoms could easily be mistaken for exhaustion or some other type of illness or discomfort. Many women may also minimise the significance of their symptoms, telling themselves or those around them that it’s “just indigestion or fatigue”. It is also believed that women have higher tolerance for pain, compared to men (although this does not mean that the disease is less severe in women). All this means is that women may wait too long before seeking help.

Lastly, CHD is often missed or misdiagnosed in women because normal testing procedures, such as the treadmill, stress test and angiography, are not as effective in diagnosing women’s heart disease.

For instance, an angiogram may give false-negative results in women when the plaque lining has not yet entered the blood vessel and shows up as “clear” on the angiogram.

The right treatment

So far, we have seen that the symptoms of heart disease in women are different, and the testing methods are not as effective in women. To add a triple whammy to that, even the treatment of heart disease in women differs from that in men.

Procedures like angioplasty and stenting are designed to treat CHD by flattening bulky, irregular plaques, which are more common in men’s arteries. However, plaque in women’s arteries tend to build up as an even layer along the vessel walls. Therefore, angioplasty and stenting are not as effective in women.

Treatment with medications also tend to vary in efficacy. Certain heart medications, like clot-busting drugs, are known to be more effective in women than in men. Aspirin therapy works better in reducing the risk of stroke in women, as opposed to heart attacks.

These differences in how women and men respond to therapy are important, so that women are not poorly treated, with fatal outcomes.

Reducing your risk

Women of all ages, particularly those with a family history of heart disease, should make a serious effort to reduce their risk of heart disease. We all know about the general risk factors, such as overweight or obesity, high cholesterol and high blood pressure.

However, there are certain risk factors that are more of an issue for women, compared to men. Even though we may not read or hear much about them, we should be equally vigilant about these factors.

First, there’s the deadly quintet of conditions called the metabolic syndrome, which has a greater impact on women than on men. This syndrome is a combination of abdominal fat, high blood pressure, high blood sugar levels, high triglycerides, and low HDL levels, that increases your risk of developing heart disease and diabetes.

Women’s hearts are also more severely affected by psychological stress and depression. We still do not know enough about how mental health affects cardiac health, but we know for sure that stress and depression can impair a woman’s ability to maintain a healthy lifestyle and manage her condition. It is crucial that mental health problems in women are professionally treated.

Smoking is even more detrimental in women than in men, as it causes an even higher risk of heart disease. It is an ugly habit that you should endeavour to stop immediately.

Finally, menopause, and the decrease in the production of oestrogen, is one of the main risk factors for developing heart disease, especially in the smaller blood vessels. This is why women “catch up” with men very rapidly from age 50 onwards, and by the age of 65, have the same risk of having a heart attack, stroke or any other coronary disease as men do.

Reducing the risk factors above will require a lot of effort and a change of lifestyle habits, for most women.

The medical guidelines also recommend that women at high risk of heart disease should take aspirin for prevention. However, this is something that you need to discuss carefully with your doctor or specialist, as there are other side effects involved.

Regardless of your health status now, you should be aware that heart disease is a major killer of women. The risk factors could creep up on you, but it is never too late to make changes in your life to prevent that deadly heart attack or stroke.

http://thestar.com.my/health/story.asp?file=/2011/9/18/health/9508011&sec=health