Sunday October 5, 2008
Your family history
By DR TEO SOO HWANG and PROF DR THONG MEOW KEONG
This is the final article in a series of four by the Cancer Research Initiatives Foundation (CARIF) that explores how genes are linked to diseases. This week, we explore the importance of an individual’s family history in assessing the need for genetic testing, and the role of experts in providing information and services in the process.
RESEARCHERS and clinicians have known for a long time that most diseases result from the interactions of multiple genes and environmental factors.
Although these interactions are complex, the Human Genome Project and a lot of investment in research have led to the promise of “personalised medicine”. For many observers, “personalised medicine” conjures up hi-tech and space age images of targeted therapy and designer drugs.
It is very seductive to think that these tools have already become the most important tools in healthcare. However, as so often is the case, the new developments do not eclipse tried and tested methods €“ they just give it new meaning. One of the main steps in formulating a diagnosis for a patient’s illness is history-taking. One of the most valuable tools is the family history.
Family history has been shown to help predict risk to such varied health concerns as heart disease, cancer of the breast, ovarian or colon, osteoporosis, asthma, type 2 diabetes, and many more. Yet, most patients in Malaysia are unaware of the medical histories of their relatives, and many doctors are unable to use this information in advising patients about how to maintain good health.
Iza is 28 years old and has been diagnosed and treated for breast cancer. No one in her mother’s side of the family has breast cancer €“ her mother is fit and well at 66, her mother’s four sisters are all well, and her mother’s parents lived to a ripe old age.
Iza naturally assumed that she did not have a family history of breast cancer and that she was just unlucky to have developed breast cancer.
Unfortunately, unbeknownst to Iza, two of her father’s sisters also had breast cancer. This family information makes a huge difference to how the family should have been managed by their doctor.
If it was known earlier, a clinical geneticist and genetic counsellor may have suggested genetic testing for Iza’s aunts. Iza may have had the genetic test before she developed breast cancer and she may have opted for a different screening strategy or preventative surgery to reduce her risk. Because she did not know her true family history, Iza wrongly assumed that she is at low risk to breast cancer and did nothing about breast cancer.
After Iza has consulted a genetics service, a more detailed family tree emerged.
Analysis of the family tree will help to determine whether a person has an average, moderate or high risk of cancer. This in turn will help to personalise medical care whereby a person with high risk of cancer will be referred for genetic counselling and to institute early cancer surveillance programme.
Early detection of cancer saves lives. Based on Iza’s family tree analysis, other individuals with a higher predisposition for breast cancer in her family include Iza’s two other siblings, her father and her father’s two other siblings and parents. This is known as familial cancer, as the same condition runs in the family. A family such as this will benefit from genetic counselling and this will facilitate genetic testing and early follow-up care.
Self-reporting of cancer in Malaysia may be unreliable because Asians are less likely to report a family history of cancer than people who are born in affluent countries and also because there is widespread misunderstanding about genetic inheritance.
A common misconception appears to be that cancer is contagious. Another misconception is that breast cancer is only inherited from the mother’s side and that there is no need to ask about the father’s family history. This gap in understanding poses significant problems in the clinic.
Family history of cancer is one of the main pieces of information that physicians are using in order to decide whether to recommend screening and genetic testing. A clinician’s ignorance of a history of colon cancer in a patient’s family can easily result in a failure to offer potentially lifesaving early colonoscopy.
Similarly, failure to recognise that a family history of breast and ovarian cancer is just as important on the father’s side as it is on the mother’s side can cause a doctor to overlook a woman’s increased risk of breast and ovarian cancer, with potentially tragic consequences.
Researchers at CARIF (Cancer Research Initiatives Foundation) and UM (University Malaya) have found that there is poor understanding and awareness of family history amongst breast cancer patients in Malaysia. The researchers used data from the Malaysian Breast Cancer Genetic Study, which was designed to examine the genetic factors that increase a woman’s risk to breast cancer in Malaysia.
Notably, half of the breast cancer patients were unaware of their full family history at first interview, and the full extent of the family history was only revealed when interviewing the parents or the extended family.
When someone says they have no family history of cancer, is it really “no”, or is it that they don’t know? There is widespread stigma about “the C-word” €“ cancer. Because of that stigma, people may not have shared their diagnoses, even with relatives. Also, distance might make it harder for individuals to communicate with family members, be it in other parts of Malaysia or other parts of the world.
If family history is such a useful tool, why do doctors not use it more effectively? The realities of today’s healthcare are that it is often difficult to find enough time to obtain, organise and analyse family history information. And this is where genetic counselling may help to address this issue.
Genetic counselling is usually provided by medical practitioners trained in medical genetics (clinical geneticists) or by a qualified genetic counsellor. A genetic counsellor may be a nurse, social worker or graduates who have received accredited professional training in genetic counselling.
Genetic counselling is a communication process where an individual or family obtains information regarding an inherited disorder; it helps patients and their families identify and understand the risks of an inherited genetic disease, explain inheritance patterns and outline options, to make an informed decision about the condition and to assist them in coming to terms with issues they face.
The clients may need to make a decision about whether to proceed with genetic testing, their plans for the future and their reproductive options. Genetic counselling is non-directive and clients make their choices after weighing in all the possible options. For example, in genetic testing, they need to understand the limitations of genetic testing.
Arising from ethical concerns, genetic testing is not routinely performed in children unless there are important medical consequences for the child. A “negative” genetic test result does not change the diagnosis or risk assessment. It simply means there may be other unknown genes involved which were not tested for. DNA variants or polymorphism may be mistakenly regarded as disease-causing by professionals not familiar with genetics.
So, how can we increase the effectiveness and use of family history in clinical care? First, we need to increase the awareness of healthcare professionals (doctors, nurses and other allied health professionals) about the value of family history.
Second, we need to get the public to increase their awareness about the value of family history, and that genetic counselling can help them make the right decisions not only for themselves but also for their families.
Malaysia is blessed as a country that values family ties and there is a culture of gathering for celebrations or even for a simple family meal. Perhaps we should use these opportunities as a means of finding out about our families and recording the information for future use.
In fact, despite all the advances made in human genomics, the Centers for Disease Control and Prevention (CDC) and the Surgeon-General in the United States had advocated a public health initiative to develop a family history tool to be used to identify individuals at increased familial risk for common chronic diseases and to offer guidance on disease prevention. The USA Department of Health has a freely available web-based tool to help families record their family history and this may be a useful tool for us all (www.hhs.gov/familyhistory).
The truth is that if we are to beat disease, we must have better awareness about our own families, better awareness about health and better access to screening. No one should die because they lack current information about treatment of the disease, because they are afraid or because they think they can’t afford screening.
Do you know your family history?
> Dr Teo Soo Hwang is the Chief Executive of Cancer Research Initiatives Foundation (CARIF). CARIF is a Malaysian independent cancer research organisation whose mission is to conduct fundamental and pioneering research on cancers prevalent in Malaysia, with potentially far-reaching implications for prevention, diagnosis, treatment and therapy. Prof Dr Thong Meow Keong is a clinical geneticist at the University of Malaya.
RSS
