Lynch Syndrome and HNPCC

Overview

What is Lynch syndrome?

Lynch syndrome is a genetic condition that increases your risk of developing cancer. People diagnosed with Lynch syndrome are more likely to get cancer before 50 years of age.

Who does Lynch syndrome affect?

Lynch syndrome can affect anyone since it’s the result of a genetic mutation. Genetic mutations pass from your parents to you during fetal development. Sometimes, genetic mutations occur randomly, without being present in someone’s family history.

How common is Lynch syndrome?

Lynch syndrome occurs in approximately one in 279 individuals in the United States. An estimated 4,000 cases of colorectal cancer and 1,800 cases of uterine (endometrial) cancer are the result of a Lynch syndrome diagnosis each year.

Symptoms and Causes

What are the symptoms of Lynch syndrome?

Symptoms of Lynch syndrome vary from person to person based on the severity of their diagnosis. People diagnosed with Lynch syndrome have symptoms similar to those of the cancers they cause, the most common being colon and rectal cancer.

Common symptoms of Lynch syndrome that relate to colon or rectal cancer include:

  • Blood in your stool.
  • Constipation.
  • Cramps in your stomach or abdomen.
  • Diarrhea or stool smaller than normal.
  • Fatigue.
  • Feeling full or bloated.
  • Nausea or vomiting.

Not every person will experience symptoms until cancer progresses into an advanced stage. If you experience any symptoms, visit your healthcare provider.

What types of cancers does Lynch syndrome cause?

Lynch syndrome can lead to cancer that affects several organs within your body. Types of cancer Lynch syndrome can cause include:

The specific organs at risk for cancer depend on which gene has a mutation in your body. The genes associated with Lynch syndrome are MLHL, MSH2, MSH6, PMS2 and EPCAM.

Colon cancers caused by Lynch syndrome tend to be more common on the right side of the colon and develop much more quickly than in the general population (one to two years versus 10 years). In addition, people who have colorectal cancer have an increased risk of developing a second colorectal cancer. This risk is approximately 15% within 10 years after the original surgery to remove the first cancer, 40% within 20 years and 60% after 30 years.

What causes Lynch syndrome?

A genetic mutation (genetic change) in one of five genes that are responsible for fixing errors in DNA (mismatch repair gene) causes Lynch syndrome. The five genes are:

  • MLHL.
  • MSH2.
  • MSH6.
  • PMS2.
  • EPCAM.

If you have Lynch syndrome, your DNA mismatch repair gene (MMR) doesn’t have all the instructions to get rid of damaged cells, so they build up in your tissues and cause cancer.

How is Lynch syndrome inherited?

Lynch syndrome is an autosomal dominant condition. This means that only one parent needs to carry and pass the mutated gene to their child for their child to inherit the condition.

Individuals diagnosed with Lynch syndrome should tell their family members and encourage them to undergo genetic counseling. Genetic counseling helps you and your family understand the risks of having a child with a genetic condition. Counseling includes an evaluation of their personal and family history as well as and genetic testing for the Lynch syndrome gene mutation.

Diagnosis and Tests

How is Lynch syndrome diagnosed?

Your healthcare provider will offer prenatal screening tests and genetic testing to diagnose Lynch syndrome before your baby is born. Genetic tests can help diagnose your child after they are born as well.

Genetic testing, which involves a blood draw or obtaining a brushing from the inside of the mouth (buccal swab), helps determine if a MLHL, MSH2, MSH6, PMS2 or EPCAM gene mutation is present in the family. If genetic testing reveals a gene mutation, your healthcare provider will confirm their diagnosis of Lynch syndrome.

What tests diagnose cancers associated with Lynch syndrome?

If you have a Lynch syndrome diagnosis, your healthcare provider will offer regular tests to check for cancer. Tests to detect common cancers associated with Lynch syndrome include:

  • Colonoscopy: A colonoscopy examines the inside of your large intestine, colon and rectum with a camera attached to a scope. Your healthcare provider will recommend scheduling a colonoscopy every one to two years.
  • Transvaginal ultrasound: A transvaginal ultrasound examines your ovaries and uterus via a probe inserted into your vaginal canal. Your healthcare provider will recommend scheduling a transvaginal ultrasound every one to two years.
  • Urinalysis: A sample of your urine helps your healthcare provider screen for renal tumors and other complications associated with Lynch syndrome. Your provider will order a urinalysis annually.
  • Tumor biopsy: If your healthcare provider detects cancer based on a growth of tissue (tumor) on your body, they might perform a biopsy, where they will remove a small sample of the tumor to examine the cells in a laboratory for cancer.
  • Upper endoscopy or capsule endoscopy: Your healthcare provider will use a scope with a camera or a microscopic camera taken as a pill to look for stomach and small bowel cancer. Your provider will schedule an endoscopy every three to five years.

Management and Treatment

How is Lynch syndrome treated?

Treatment for Lynch syndrome focuses on detecting cancer and surgically removing it from your body.

Who treats Lynch syndrome?

It’s highly recommended that you receive expert care for your diagnosis. Because Lynch syndrome can affect many organ systems, the care team will include a variety of clinicians. Team members may include gastroenterologists, surgeons, gynecologic oncologists, urologists, dermatologists, gynecologists, primary care physicians, geneticists, genetic counselors and oncologists.

Will cancer return after treatment if I have Lynch syndrome?

It’s possible that cancer could return, even after it’s surgically removed.

Some people diagnosed with Lynch syndrome choose to have a hysterectomy (surgery to remove the uterus), oophorectomy (surgery to remove both ovaries) or colectomy (bowel resection surgery) since they are at an increased risk of getting cancer in certain parts of their body.

Prevention

How can I prevent Lynch syndrome?

You cannot prevent Lynch syndrome because it’s an inherited condition. However, people with Lynch syndrome should undergo lifelong cancer screenings, beginning in adulthood to detect cancer early.

Outlook / Prognosis

What can I expect if I have Lynch syndrome?

Currently, there is no cure for Lynch syndrome. The best prognosis occurs if your healthcare provider finds and removes cancer early before it has time to spread to other parts of your body. Annual screenings, like a colonoscopy, are highly recommended for people diagnosed with Lynch syndrome.

Will I get tumors in my colon because of a Lynch syndrome diagnosis?

Individuals with Lynch syndrome may develop a few colorectal polyps, called adenomas (non-cancerous tumors), in the colon or rectum. If these polyps aren’t detected and removed, they could turn into cancer. Having regular screening colonoscopies is important for detecting and removing these polyps.

Living With

When should I see my healthcare provider?

If you have Lynch syndrome, it’s important that you visit your healthcare provider for annual checkups and work with your provider to schedule regular screening tests to detect cancer early.

Visit your healthcare provider immediately if you notice any lumps, growths or changes to your skin, which could be a sign of cancer.

What questions should I ask my doctor?

  • How often should I schedule screening tests to detect cancers?
  • Is this lump on my skin cancer?
  • Which gene has a mutation?
  • Can I get a genetic test before I plan on becoming pregnant?

Frequently Asked Questions

Is Lynch syndrome the same as hereditary non-polyposis colorectal cancer (HNPCC)?

Lynch syndrome and hereditary non-polyposis colorectal cancer (HNPCC) can identify the same condition, but the two conditions have a slight difference in their inheritance.

Lynch syndrome is the result of a mutation of the MMR gene. The same genetic mutation also affects people diagnosed with HNPCC, but a person’s family history of HNPCC differentiates the two conditions. Lynch syndrome can be the result of a random genetic mutation with no presence of the condition in their family history. HNPCC is always the result of a family inheritance.

A note from Cleveland Clinic

No one wants to hear the phrase, “you have cancer.” With a Lynch syndrome diagnosis, that phrase might be something that you will hear from your healthcare provider, but it doesn’t have to be a negative experience. After a Lynch syndrome diagnosis, your healthcare provider will work with you to regularly schedule cancer screenings to detect and treat cancer in its earliest stages. Early detection and treatment leads to the best prognosis, so you can live a happy and healthy life.

Last reviewed by a Cleveland Clinic medical professional on 09/12/2022.

References

  • American Gastroenterological Association. Lynch Syndrome: AGA Patient Guideline Summary. (https://doi.org/10.1053/j.gastro.2015.07.020) Gastroenterology. 2015; 149: 814-815. Accessed 9/12/2022.
  • Merck Manual. Lynch Syndrome. (https://www.merckmanuals.com/professional/gastrointestinal-disorders/tumors-of-the-gastrointestinal-tract/lynch-syndrome) Accessed 9/12/2022.
  • StatPearls. Lynch Syndrome. (https://www.statpearls.com/ArticleLibrary/viewarticle/24608) Accessed 9/12/2022.
  • Syngal S, Brand RE, Church JM, et al. Genetic Testing and Management of Hereditary Gastrointestinal Cancer Syndromes. (https://gi.org/guideline/genetic-testing-and-management-of-hereditary-gastrointestinal-cancer-syndromes/) Am J Gastroenterol. 2015; 110: 223–262. Accessed 9/12/2022.
  • U.S. National Library of Medicine. Lynch Syndrome. (https://medlineplus.gov/genetics/condition/lynch-syndrome/#causes) Accessed 9/12/2022.

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