Should you consider genetic testing?

Some of your relatives have had cancer. And, you’ve heard that people with a family history of the disease may be more likely to get cancer.

So, should you consider genetic testing to find out if cancer runs in your family?

Here’s what you need to know to make a more informed decision.

Most cancer cases aren’t related to family history.

Only about 5 to 10% of cancer cases are due to an inherited cause. Genetic testing is a powerful tool to identify those individuals who are at especially increased risk for developing certain cancers.

You can inherit abnormal genes from a parent. And, if you inherit one of these genes, you’re much more likely to develop cancer — and at a younger age.

Breast, colorectal, ovarian, prostate, pancreatic and endometrial cancers sometimes run in the family.

But most cancers are related to lifestyle choices like smoking, not exercising and eating unhealthy foods.

Map your family’s cancer history

You can begin to gauge your risk for an inherited cancer by mapping your family’s cancer history.

Start by using the Surgeon General’s Office Family Health Portrait or MD Anderson’s family history form. Then, speak with relatives to fill in as much information as possible.

Pay special attention to the cancer histories of first- and second-degree blood relatives. First-degree relatives include siblings, parents and children. Second-degree relatives include grandparents, aunts, uncles, nieces and nephews.

In general, people at risk for an inherited cancer have one or more first- or second-degree members who were diagnosed with:

  • Cancer at a young age (before age 50)
  • The same type of cancer
  • Two or more different cancers in the same person
  • A rare cancer, such as male breast cancer or sarcoma
  • A BRCA1 or BRCA2 mutation

Discuss your family history with your doctor

Does your family history raise some red flags? Use your completed form to talk to your doctor about your cancer risks.

Based on your family history, your doctor may refer you to a genetic counselor, who will review your family medical history, discuss the role of genetics in cancer and perform a hereditary cancer risk assessment. This assessment covers:

  • Your odds of having a genetic mutation
  • An estimate of your cancer risks
  • Personalized genetic testing recommendations
  • Individualized cancer screening and prevention recommendations

Based on your cancer risk assessment, the genetic counselor may recommend genetic testing. This simply involves having blood drawn.

The best person to test is usually the person with cancer. After the mutation that caused the cancer is identified, we can test first-degree relatives — mother, sisters, daughters — to see if they also carry it.

Carefully weigh the pros and cons of testing

One of the benefits of knowing if you have a genetic mutation is that you can work with your doctor to monitor and address your cancer risks. This can help prevent cancer or find it early, when it’s most treatable.

But your decision won’t just affect you. It will also impact your family since your test results may forecast their cancer risks, too.

Some people worry that their results will make it harder for them to get insurance coverage. But group plans are prohibited by law from using genetic information to discriminate against you.

No matter what you decide, remember: finding out that you have a gene mutation doesn’t mean you’ll definitely get cancer. And, learning that you don’t have a gene mutation doesn’t guarantee that you won’t get cancer.

Karen Lu is a professor in the Department of Gynecologic Oncology and co-director for the Clinical Cancer Genetics Program at The University of Texas MD Anderson Cancer Center in Houston, Texas.

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  • Sheri

    In speaking to a genetic counselor regarding my cancer risks, I was told that it wouldn’t be possible to test for all the potential genetic links to cancer in my family.  After being diagnosed with breast cancer and my BRCA tests being negative, I was told this was only one of many expensive tests available at this point and that there are still limitations as to what can be checked for.  Since my diagnosis, I have met so many people who make all the “right” lifestyle choices and are diagnosed with horrendous cancers.  I am always horrified by doctors who blame patients for their cancers.  Sometimes they are responsible but many times are not and you nor they may ever have an answer. Your statement “But most cancers are related to lifestyle choices like smoking, not exercising and eating unhealthy foods” is a little narrow minded and I hope you tell the whole story to the patient before delivering that message to them. What about environmental causes? If we knew how all cancers were caused, we would be much further along with curing this disease.

  • Violetta V

    “But most cancers are related to lifestyle choices like smoking, not exercising and eating unhealthy foods”

    Would you care to recite studies that show this? Yes, we all know that smoking is the big thing that increases one’s risk of lung cancer by 1000%  (raising lifetime risk from 1% to 10%), but this isn’t true for other cancers, is it?  The link between diet and cancer is not nearly as big. Would you care to show studies that quantify by how much diet increases risk of cancer?

    Mathematically, to make a claim that most cancers are related to lifestyle choices you have to prove that lifestyle choices as a whole increase the risk of getting cancer by over 100%. Otherwise, e.g if lifestyle choices increase the risk by say 60%, then out of 16 people who get cancer 6 got it because of lifestyle choice and 10 would’ve gotten it anyway.

    If you make statements like the above, you have to be ready to prove it. WITH STUDIES AND NUMBERS.

    • Anonymous

      What are we to make of data showing that some cancers are 5 to 10X more common in certain populations than others especially when we see people who’ve left those low-risk cultures and reloacted in a high-risk culture and seen their risk of certain cancer increase dramatically versus siblings left behind? Yes population data is not the same as a controlled clinical trial but when was a controlled clinical trial ever done with people asigned randomly to smoke or not smoke? Of course, in America we have plenty of smokers and nonsmokers but what if everyone smoked between one and two packs a day? You would not see a much of a difference between the incidence of lung CA in the one, 1.5, and 2 pack a day smokers and yet we see dietary studies in which many dietary variables vary only modestly.  

      Dietary practices within modern cultures are increasingly homogeneous and people’s diets often change over time sometimes in response news. People who fear breast or colon CA because it runs in their family might be less likely to eat red meat and might work harder to control their weight than people less concerned which tends to make association seem weaker than they really are as the higher risk people are less likely to eat foods associated with a greater CA risk. Sometimes figuring out the connection between an illness like most cancers is not that easy to study within a populaton as homogeneous as most are today. So even if one were to cite studies and numbers for various cancers linked to diet I doubt you’d be convinced. But the reality is there are thousands of studies showing links between various dietary components and various types of cancer. The data are not always consistent perhaps because estimating what people ate over a lifetime is an inexact science. The noise in determining what people ate (and even when they ate it) would likely lead most studies to underestimate the real impact of dietary factors in promoting CA.

      Obviously most cancers result from genetic factors interacting with various environmental insults and/or protective substances in food, air, and water. For now it is clear that most CA are not caused by genes alone. Even though we know smoking accounts for about 30% of all cancer deaths in the USA we still have plenty of people who put themselves at risk. The relationship between diet and cancer is far harder to study but most experts believe a typical modern diet with lots of fatty animal products and not much minimally processed plant foods causes as much or likely more cancer than smoking does. Of course, adopting a healthy diet at 60y and expecting it to prevent CA may be like quitting smoking at 60y and expecting to avoid lung CA. It’ll help but sadly by age 60y a lot of the risk is already baked into the cake.

  • Leigh Fazzina

    Ok, so thanks for sharing this info but I have to tell you – I went through this and I got so far and stopped myself because of the below. Hoping one of you can shed light on this.

    I enrolled in the Generic Testing program Fox Chase Cancer Center – this year in 2011. I did b/c cancer is in my entire family. I’m 38, pretty healthy but scared to death of the big C. So I decided to go through with it because I felt like “knowledge is power.”

    The two clinicians I met with at Fox Chase were very nice and professional I have to say. But I am not so sure I agreed with the protocol. I felt like there was “something else” behind their whole process.

    My mother came with me to the initial appt (she is a breast cancer survivor who is a patient at Fox Chase). Theses clinicians spent lots of time with me explaining everything in terms of genetic testing and how it works. BUT, in order for me to get tested (the actual blood work) I had to make a pedigree of my entire family and map out who had cancer, when, and the cancer type. I had to do this with every relative who I knew who had cancer and passed on, who is a cancer survivor, or who was living with cancer now. My pedigree was rather large.

    I have a family tree that dates back literally to the 1700s of my Italian family. I know many of my 3rd and 4th cousins. Some I know well, others I “know of” and some I don’t at all but know others in my family who do know them.

    In short, what Fox Chase wanted me to do is to go ask my 2nd, 3rd and 4th cousins who had cancer at some point if they would come in to their hospital and get tested for certain genes. They told me that in order for me to get the blood work for the cancer genes, they wanted them to get tested too. Hmmmm I thought.

    I posed many questions to the staff such as:
    1) What if I didn’t know these relatives had cancer, would you test me anyway?
    2) Why do you need to test them? What if they don’t agree? Do you realize how uncomfrtable this is for me to have to ask family memebrs I don’t know very well?
    3) Are you using their tests for patient recruitment info and for additional scientific findings?
    4) What if I told you I was adopted and I didn’t really know my biological family? If I knew my biological mother had breast cancer, would you still test me?
    5) cant you just take my blood work without having all these relatives of mine get tested? That’s a lot to ask of them. What if they say “no?”

    See where I am going with this?

    As soon as Fox Chase heard that all these people in my family had cancer – their eyes popped up (like it was big business) and they requested I ask my relatives to all come in and get tested. They said if my relatives got tested then it would help determine my risk better and they would give me the blood work/test. (To be frank, I felt like they were being awarded $ or something for getting more people to come in the door to get tested. Now I could be wrong, but this is what it felt like b/c here is what happened next:

    As we were sitting in the room (mom, me and two clinical people at Fox Chase), a knock was made on the door. A nurse came by with plastic bucket/carrying case of needles, band aids and various blood work-taking supplies – all ready to take my blood work. The woman asked if I was ready to have the blood work done. trying to be discrete, the two clinicians  said “No, we’re not ready to take her blood today. But thank you.”  They smiled and the nurse left. Hmmmmmmm I thought. 

    I work in healthcare communications. I am not a typical lay-person patient. With my knowledge and my gut feeling – I felt like something was really off here. Why would the nurse be coming by ready to take my blood work? And when why were they seo keen on wanting all these relatives of mine to come in and get tested?

    Couldn’t they have done the blood-work on me and gotten the answer as to whether or not I have these genes?

    Can someone please shed some intelligent light on this for me? How do you interpret this?

    Thanks for taking the time to read my post. And thanks again for writing in this important topic.

    • Robert West


      Clinicians involved in research are funded, usually
      by NIH, to conduct studies with patients that have specific aims that must be
      met to continue the funding cycle. Sure, you’re being a guinea pig if you
      enroll, but you are contributing in a very basic way to knowledge of human
      structure and function, and most often you will be rewarded with specific
      information about your health related to the study. There is no mechanism to
      support genetic testing in the fashion you might wish for (i.e.
      “free”). While it’s possible the Fox Chase group could increase their
      transparency with patients, the fact that they have a web site describing their
      mission suggests they are not behaving totally inappropriately (assuming you
      went here: For me, the key question would be, will the
      results of the study be readily made available to me (agreement in writing
      prior to starting).


      Certainly, they could have gotten the answer
      about what cancer-causing mutations you carry without testing also any of your
      relatives. And if testing of relatives is a prerequisite for their particular
      study, that should have been made clear to begin with (i.e. on their website).
      If not, those you met with should have been more professional about the way
      they handled your family history, requesting information that would be helpful
      to your diagnosis, but without using pressure tactics.


      - Bob

  • Kathy Kaufman

    There are so many clinical studies going on now related to Gene SNPs like for example ACE – rs4646994 - increased gall bladder cancer in women and GSTT1 – increased vulnerability to environmental toxins and increased risk of leukemia.  Genetics is like a loaded gun and environment is the trigger.

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