Genetic Counseling and Genetic Screening for Cancer

Pictured: Megan Harlan Fleischut & Kenneth Offit

Genetic counselor Megan Harlan Fleischut (left) and Clinical Genetics Service Chief Kenneth Offit

Some people are genetically predisposed to developing certain types of cancer because they have a genetic mutation inherited from one of their parents — or sometimes both parents. These people have a higher risk of developing the disease than those in the general population.

If you have a family history of cancer, physicians and genetic counselors at Memorial Sloan Kettering are available to help you understand your risk of developing cancer.

We spoke with genetic counselor Megan Harlan Fleischut about genetic counseling and testing and about the services offered by experts on our Clinical Genetics Service.

What percentage of cancers are inherited?

While all cancers are caused by genetic changes (mutations) in tumor cells, most cancers are not hereditary. Only about 5 to 10 percent of cancers — including breast, ovarian, colorectal, and prostate — are thought to be inherited, meaning that they are due to gene mutations passed down in one’s family.

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With some cancers, there are known mutations for which we can screen patients. Two of the most well known are mutations in genes called BRCA1 and BRCA2. These mutations have been linked to some, but not all, hereditary cases of breast and ovarian cancer as well as other cancers.

For cancers for which no tests are currently available, family history is the strongest risk factor.

Our laboratory investigators are working to identify previously unknown hereditary mutations that may predispose people to developing these and many other types of cancer. We are also performing genetic epidemiologic studies to explore how such mutations may contribute to disease in families and in populations.

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If someone has a few relatives with cancer, should he or she consider genetic counseling?

Genetic counseling may be useful for you if you answer yes to any of the following questions:

  • Have you or a close relative been diagnosed with cancer at an early age?
  • Do you have more than one blood relative with the same type of cancer? If yes, is the same type of cancer found in more than one generation?
  • Has anyone in your family had more than one type of cancer, not counting basal cell or squamous cell skin cancers?
  • Some organs, such as the breast, kidney, and eye, come in pairs. Has anyone in your family had cancer on both sides of a pair of organs?
  • Are you related to someone who is known to have an inherited mutation that can cause cancer?

Genetic counseling is typically recommended for individuals who are diagnosed with cancer at a very young age and for families with multiple cases of cancer. If you are interested in learning about your hereditary risk for cancer, we encourage you to schedule an appointment with us.

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What happens during genetic counseling?

Your initial genetic counseling session will focus on your or your family’s risk for cancer. We will tell you about the scientific concepts that relate to genetic testing to help you decide which genetic tests, if any, might be useful for you. Our goal is to provide clear and relevant information about genetic risk factors in a supportive and educational environment.

As part of a genetic counseling session, you will have the opportunity to ask questions and discuss many topics including your individual cancer risk assessment, personalized cancer screening recommendations, and options for participating in research taking place at Memorial Sloan Kettering.

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How should a person decide whether to have genetic testing?

Genetic testing is not the right choice for everyone. Your personality, your coping style, and your family’s experience with cancer may influence your decisions about whether to have a genetic test.

For many people, a cancer risk assessment can be provided through genetic counseling alone, without the use of genetic tests. However, in some cases, genetic testing may help you and your physician make important decisions about your medical care.

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What can a person do if they are at higher risk of developing a certain cancer or cancers?

If there is a history of cancer in your family, we recommend you undergo regular cancer screening, regardless of whether you have received genetic testing. The goal of screening is to prevent cancer or to find the disease at an early stage, increasing the chance that it can be treated. Screening may include colonoscopies for colorectal cancer and prostate-specific antigen (PSA) tests for prostate cancer. You may also wish to enroll in our Special Surveillance Breast Program, which provides services for the prevention and early detection of breast cancer

Our doctors and genetic counselors are available to discuss other options that may be available to you, including preventive surgery such as removal of the breasts or ovaries.

In addition, you may be able to participate in a clinical trial focusing on the study of hereditary cancers. Most of our protocols are registries or long-term follow-up studies to learn more about individuals with a family history of cancer. For example, you and your family members may also be able to enroll in a registry that tracks families who are affected by certain kinds of cancer.

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How can someone make an appointment to speak with an expert in the Clinical Genetics Service?

For more information about Memorial Sloan Kettering’s Clinical Genetics Service and to schedule a consultation, please call us at 646-888-4050.

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Commenting is disabled for this blog post.

Very very concerned!!!!1 my mom had breast cancer, my great grandma and my grandmother has it in it's final stages. She currently has hospice at home. Caring hospice in Brooklyn.

Sharon, if you would like to make an appointment to discuss your situation with one of our clinical geneticists, you can call 646-888-4050. Thank you for your comment.

My family has a history of all types of cancer, on both my father and mother's side: Maternal Grandmother - Breast Cancer, my mother's sister - Ovarian Cancer, My Mother- Uterine cancer (and after the radiation kiiled her bone marrow so she ended up pre-leukemic), My Father- Pancreatic cancer, my father's sister leukemia.... Are there even enough genetic tests to detect these traits and at 50 am I too old for testing, or am I just left with early detection?

I am BRCA 1 and 2 positive and am currently in remission for breast cancer. My question is: what is the current suggested genetic testing age for young adults whose parents are BRCA positive?

Bonnie, thank you for your comment. Our genetic counselors indicate that in general, given that the recommended age to begin breast cancer surveillance for female BRCA mutation carriers is 25 through 30, women in families with a known BRCA mutation may consider meeting with a genetic counselor to discuss testing for themselves in their early- to mid-20’s. Because each case is different, however, we encourage you to contact our Clinical Genetics Service at 646-888-4050 to schedule an appointment with one of our specialists, or search the National Society of Genetic Counselors database to find a genetic counselor located in your area.

Not sure if I should be concerned. This is my family history of cancers:
Maternal grandmother: breast and bone cancer, died at age 80
Paternal grandmother: brain cancer, died at age 65
Paternal grandfather: brain cancer, died at age 70
Paternal uncle: leukemia, died at age 29
Paternal uncle: colorectal cancer, died at age 64
Paternal great aunt: breast cancer
Mother: breast cancer (still living)
Self: Basal cell cancers on scalp and back of neck

Randy, if you would like to make an appointment to discuss your situation with one of our clinical geneticists, you can call 646-888-4050. Thank you for your comment.

Nine cases of colon cancer on Maternal side. Youngest at age 28. (All female.) I have had flat sessile polyps removed for the last four colonoscopies. All benign, but thanks to my own judgment and decision, I avoided a disaster. Switched gastroenterologist because I knew he was WRONG to tell me to return in FIVE years after removing " three tiny flat sessile polyps." I ignored him, and the following year THREE 2.0 flat sessile polyps were removed during the colonscopy with the "new" gastroenterologist. Had to wait 48 hours for the path report, which he rushed due to his worry they were malignant. I was lucky, benign! There are multiple cases of melanoma in my huge family as well. I have a freckle on my retina, and have had a single basal feel carcinoma. Despite my vigilance, and every six month visit to my dermatologist, I never received a full term examination over the course of 50 years. Discovered on my own(only five months ago) that the 32 "freckles" in my vulva were NOT "the result of childbirth." They were diagnosed via the confocal scan as "malignant melanoma." Had my surgery six weeks ago with a plastic surgeon who specializes in disorders of the genitalia. Please take note, in addition to the dermatologists NEVER had a gyn or any of the NINE gyn oncologists ever mention "melanoma of the genitalia." ALL 'spots' and two moles were removed during the plastic surgery. I was NOT mutilated in the process. Clearly, there is some sort of sub mucosa mutation at work here . . . it most likely is the BRAF gene. If you are entered in me, I live across the street from MSKCC. I am a tremendous believer in science, research, and studies. i believe in prevention. And, I can assure you, I am more than motivated. I am dedicated. If you are truly interested in saving lives, I hope to see my comment 'POSTED." It may well save someone's life.