Posted 3 weeks ago
Around 150,000 new cases of colon and rectal cancer are diagnosed each year in the United States. With improved screening practices through routine colonoscopies, the number of new patients diagnosed with these cancers has been going down. It is great news that we are now catching many of these cancers in their very early stages. Despite this, the number of younger patients diagnosed with colorectal cancer is on the rise.
What Causes Lynch Syndrome?
Most cases of colorectal cancer are sporadic, meaning that we can’t identify any genetic predisposing factor that caused them. Somewhere between 10 and 30% of colorectal cancer cases are related to risk factors that run in families, and around 2-5% of all colon cancers are caused by a familial syndrome called Lynch Syndrome, which is also known as Hereditary Nonpolyposis Colorectal Cancer.
In the general population, an individual’s lifetime risk of having colon cancer is around 5-6%. However, in patients who have Lynch Syndrome, the risk of developing colorectal cancer in their lifetime can be as high as 70-80%. These individuals are also at higher risk of developing other cancers, including uterine, ovarian, and stomach cancers. Patients with a Lynch Syndrome-related colorectal cancer are more likely to be diagnosed at a younger age, with the average age at diagnosis being 45 years.
In Lynch Syndrome, there is a mutation in genes encoding mismatch repair enzymes, resulting in something called high microsatellite instability. This makes cells more prone to mutations. Because of this unique feature, patients with Lynch Syndrome actually tend to respond better to certain treatments and have a better prognosis overall for their colorectal cancer compared to patients without Lynch Syndrome.
The Value of Genetic Testing
If you have a strong family history of cancers (particularly colon or uterine cancer) or have family members who were diagnosed with cancer at a young age, you should talk with your doctor about whether you should be tested for Lynch Syndrome. In addition to the Medical Oncology care here at Ironwood, we have excellent genetic counselors that can set up testing for these conditions, and let you know what this means for you and your family.
According to Ironwood genetic counselor, Rachel Mador-House, “Lynch syndrome is caused by specific changes in your DNA. We can look for those changes by doing genetic testing. If we find a change in your DNA that tells us you have Lynch Syndrome, then your doctors will be able to take better care of you. We could then do genetic testing for your family members to see if any of them have Lynch Syndrome, which is another reason that genetic testing is very important.”
If it does turn out that you have Lynch Syndrome, there are important screening recommendations that you should know about. Patients with Lynch Syndrome should start getting screening colonoscopies much earlier than the general population, between ages 20-25. In addition, your doctor will talk to you about other procedures that are recommended to reduce your risk of having uterine, ovarian, and stomach cancers.
Dealing with cancer is always stressful, especially when it can have implications for both you and your family members. Through the Medical Oncology services here at Ironwood, we strive to provide you with the best comprehensive oncologic care, so that both you and your family members understand your diagnosis and the management options you have moving forward.
About the Author
Dr. Chandar joined Ironwood Cancer & Research Centers in September 2019. After receiving her medical degree from Midwestern University, she spent three years in Internal Medicine residency training at the University of Chicago and subsequently completed a fellowship in Hematology & Oncology at Baylor College of Medicine in Houston, TX.
Dr. Chandar specializes in all areas of adult cancers and hematologic disorders. She sees patients at the Ironwood Cancer & Research Centers Mesa Arbor location.