Lynch syndrome is an inherited condition that increases your risk of colon cancer and other cancers. Lynch syndrome has historically been known as hereditary nonpolyposis colorectal cancer (HNPCC).
A number of inherited syndromes can increase your risk of colon cancer, but Lynch syndrome is the most common. Doctors estimate that about 3 out of every 100 colon cancers are caused by Lynch syndrome.
Families that have Lynch syndrome usually have more cases of colon cancer than would typically be expected. Lynch syndrome also causes colon cancer to occur at an earlier age than it might in the general population.
People with Lynch syndrome may experience:
When to see a doctor
If a family member has been diagnosed with Lynch syndrome, tell your doctor. Ask to be referred to a genetic counselor. Genetic counselors are trained in genetics and counseling. They can help you understand Lynch syndrome, what causes it and what type of care is recommended for people who have Lynch syndrome. A genetic counselor can also help you sort through all the information and help you understand whether genetic testing is appropriate for you.
Lynch syndrome runs in families in an autosomal dominant inheritance pattern. This means that if one parent carries a gene mutation for Lynch syndrome, there's a 50 percent chance that mutation will be passed on to each child. The risk of Lynch syndrome is the same whether the gene mutation carrier is the mother or father or the child is a son or daughter.
The genes inherited in Lynch syndrome are normally responsible for correcting mistakes in the genetic code, which is made of DNA. DNA is the genetic material that contains instructions for every chemical process in your body. As your cells grow and divide, they make copies of their DNA and it's not uncommon for some minor mistakes to occur. Normal cells have mechanisms to recognize mistakes and repair them. But people who inherit one of the abnormal genes associated with Lynch syndrome lack the ability to repair these minor mistakes. An accumulation of these mistakes leads to increasing genetic damage within cells and eventually can lead to the cells becoming cancerous.
Autosomal dominant inheritance pattern
In an autosomal dominant disorder, the mutated gene is a dominant gene located on one of the nonsex chromosomes (autosomes). You need only one mutated gene to be affected by this type of disorder. A ...
Beyond complications for your health, a genetic disorder such as Lynch syndrome may be cause for other concerns. A genetic counselor is trained to help you navigate the areas of your life that may be affected by your diagnosis, such as:
Preparing for your appointment
If your doctor thinks you could have Lynch syndrome, you may be referred to a genetic counselor. A genetic counselor can give you information to help you decide whether laboratory testing would be useful for diagnosing Lynch syndrome or another genetic disorder. If you choose to have the test, a genetic counselor can explain what a positive or negative result may mean for you.
What you can do
Questions to ask
In addition to the questions that you've prepared to ask your counselor, don't hesitate to ask other questions during your appointment.
What to expect from a genetic counselor
Tests and diagnosis
If it's suspected that you have Lynch syndrome, your doctor may ask you questions about your family history of colon cancer and other cancers. This may lead to other tests and procedures to diagnose Lynch syndrome.
Your doctor may refer you for further Lynch syndrome evaluation if you have:
Tumor testing can reveal whether your cancer was caused by the genes related to Lynch syndrome. Tumor tests include:
Positive IHC or MSI test results indicate that you have malfunctions in the genes that are connected to Lynch syndrome. But results can't tell you whether you have Lynch syndrome because some people develop these gene mutations only in their cancer cells. People with Lynch syndrome have these gene mutations in all of their cells. A small portion of all colon cancers have a positive MSI result, but most aren't caused by Lynch syndrome. Newer tests can help determine if a tumor is Lynch syndrome related or not.
Results of genetic testing may show:
Your genetic counselor can discuss the benefits and risks of genetic testing with you. He or she can explain what genetic testing can tell you and what it can't.
Treatments and drugs
Colon cancer associated with Lynch syndrome is treated similarly to other types of colon cancer. However, surgery for Lynch syndrome colon cancer is more likely to involve the removal of more of the colon, since people with Lynch syndrome have a high risk of developing additional colon cancer in the future. Your treatment options will depend on the stage and location of your cancer, as well as your own health and personal preferences. Treatments for colon cancer may include surgery, chemotherapy and radiation therapy.
Cancer screening for people with Lynch syndrome
As part of your cancer-screening plan, your doctor may recommend you undergo:
Your doctor may recommend other cancer-screening tests if your family has a history of other cancers. Ask your doctor about what screening tests are best for you.
Surgery to prevent cancers caused by Lynch syndrome
Surgical options for preventing cancer may include:
During a colonoscopy, the doctor inserts a colonoscope into your rectum to check for abnormalities in your entire colon. ...
Coping and support
Knowing that you or your family members have an increased risk of cancer can be stressful. Helpful ways to cope might include:
Frequent cancer screening and preventive surgery are the only ways to reduce the risk of cancer in people with Lynch syndrome. No other measures have been proved to reduce your risk. Researchers are studying other ways to reduce cancer risk. One study found people with Lynch syndrome who took aspirin for two years reduced their risk of colon cancer and other Lynch-related cancers. Discuss the benefits and risks of taking aspirin with your doctor.
Taking care of yourself through diet, exercise and other lifestyle changes can help improve your overall health.
Take control of your health by trying to:
Last Updated: 2012-03-10
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