Whether it’s genetics or lifestyle choices, there are always certain things that raise your risk of developing certain conditions, such as the development of particular types of cancers. One of the most prevalent and deadliest cancers in the United States today is colon cancer, with a near-estimate of 100,000 cases diagnosed each year, and just over 50,000 deaths. Colon cancer or colorectal cancer isn’t often caught until cancer has already spread, at which point it is often too late to save the patient. Because of this, in May 2018, the American Cancer Society lowered its colonoscopy guidelines from age 50 to age 45 for both men and women in the hopes of catching more cases of colorectal cancer sooner. Many risk factors can contribute to colon cancer risk, including a list of inherited genetic syndromes, the most common of which is Lynch syndrome. Read on to learn more about what Lynch syndrome is, how common it is, how commonly it’s linked to colorectal cancer, and how to be genetically tested to see if you have the syndrome.
What is Lynch Syndrome?
Lynch syndrome is an inherited syndrome, which means it is genetic. Many lifestyle factors can contribute to the development of colon cancer; however, there is nothing you can do about your genetics. It is important to note that knowledge is power, and knowing your family history is paramount. This can help provide your physician with a more detailed background in order to decide if you should be genetically tested.
Lynch syndrome increases not only your risk of colon cancer and colorectal cancer, but also endometrial cancer, uterine cancer, and stomach cancer. Lynch syndrome is often used interchangeably with the term hereditary non-polyposis colorectal cancer (HNPCC), however, this is slightly incorrect. The subtle differences between the two conditions have everything to do with genetics. Lynch syndrome is a distinct, notated mutation of the MMR gene. HNPCC is diagnosed solely on family history alone, and the testing of genetics is not involved. However, a person who qualifies for an HNPCC-related family history should absolutely be genetically tested for the MMR mutation.
What causes Lynch Syndrome?
The causes of Lynch syndrome are purely genetic and are autosomal dominant in nature. This means that if a parent is a known carrier of Lynch syndrome, there is a 50 percent chance that he or she will pass it onto their child. In the case of Lynch syndrome, it does not matter whether the mother or father is the carrier, or the son or daughter is the recipient of the mutation. The chances are 50/50 across the board, regardless of the gender of the parent or child.
HOW COMMON IS LYNCH SYNDROME?
The commonality of Lynch syndrome is a diagnosis of roughly 1 in 400 people. However, there are specific genes associated with Lynch syndrome (beyond the primary MMR mutation) that can increase or decrease colon cancer risk or the risks of other types of cancer. This is where gender can play a role, as well as the specific genes involved. The particular gene mutations involved with Lynch syndrome include the MLH1, MSH2, MSH6, PMS2, and EPCAM genes. When it comes to the general population, roughly the risk of developing colon cancer is five percent. For women with a mutation in the MLH1/MSH2 genes, the risk rises to between 22 to 53 percent. For men with that same MLH1/MSH2 mutation, the risk of colorectal cancer is 27 to 74 percent. MSH6 and PMS2 mutations carry lesser risk than the other mutations, but still a far greater number than the effect on the general population (ranging from 10 to 20 percent, depending on gender).
The risk of endometrial cancer for women who carry Lynch syndrome is astoundingly high as well. The threat to the general population is 2.7 percent, while those who carry the MSH6 mutation have a 17 to 71 percent chance of contracting endometrial cancer. The MLH1/MSH2 mutation carries a 14 to 54 percent risk. Men are not at risk for endometrial cancer.
However, Lynch syndrome also raises cancer percentages for stomach cancer, ovarian cancer, hepatobiliary tract cancer, urinary tract cancer, small bowel cancer, brain cancer, skin cancer, and pancreatic cancer. It is also possible that Lynch syndrome contributes to breast cancer and prostate cancer.
How is it diagnosed?
The only way to be diagnosed with Lynch syndrome is to have genetic testing. To determine if genetic testing is right for you, your physician or healthcare provider will ask you for detailed family history. Do your best to fill in any missing pieces that you can, as knowing this information can help you and your extended family greatly. If you have had a relative who was diagnosed with colon or colorectal cancer under the age of 50, you have had three or more relatives who have had colorectal cancer or cancerous polyps, or colon cancer runs in your family, your physician will likely ask you to have genetic testing. “Runs in your family” doesn’t necessarily refer to first-degree relatives. This can be across several generations, and could be grandparents, aunts, cousins, or other relatives – it’s just important information to know.
Genetic testing is performed in several steps. First, you will meet with a genetic counselor who will discuss with you all of the potential outcomes and what they might mean. This person wants to make sure you understand all of the information that is being presented to you. They are also there to counsel you, should you receive information you do not want to hear. Beyond this, they will also explain privacy rights to you, and may also advise you to implore other members of your family (especially parents and children) to be tested as well. Once the genetic counseling portion is over, you will have a simple blood draw, just like you were at your annual physical. However, unlike a complete blood count (CBC), genetic testing is often sent out to a specific lab for analysis, so results may take several weeks. Your genetic counselor should inform you of this if so.
What are the treatment options?
As Lynch syndrome is a genetic mutation, there is no way to eradicate it or treat it specifically. However, you can be very proactive when it comes to colon cancer prevention and prevention of other cancers. Regular colonoscopies will be a must. However, the good news is, colonoscopies are one of the few tests that can both find and treat polyps. During a colonoscopy, if a polyp is found, the physician can remove it with the colonoscope. Keeping on top of other appointments and checkups is imperative as well. The types of colon cancer associated with Lynch syndrome are extremely aggressive, so schedule any appointments or diagnostics your physician suggests. If you need more information about Lynch syndrome or genetic testing or would like to schedule a colonoscopy or meet with a physician, request an appointment at GI Associates & Endoscopy Center today. We have three separate locations and a caring staff who provides highly trained, individualized care.