How to diagnose lynch syndrome

Genetic testing is available for Lynch syndrome. However, most colorectal cancer is not caused by inherited mutations, so Lynch syndrome testing will not benefit most people with a family health history of colorectal cancer who have not had cancer themselves. Genetic testing will not identify the cause for some hereditary colorectal cancers, because the genes affected in these cancers are not yet known.

  • Your tumor screening results (IHC or MSI) are abnormal
  • You have had colorectal cancer
  • You had uterine (endometrial cancer) before age 50
  • You have had multiple primary cancer diagnoses
  • Several family members have had cancers related to Lynch syndrome
  • You have a family member with Lynch syndrome

Genetic testing looks for inherited Lynch syndrome mutations. Your doctor may recommend a multi-gene panel, which looks for mutations in several genes at the same time, including the genes associated with Lynch syndrome.

The genetic counselor can help to determine the best testing strategy for you and your family. When possible, testing should start with someone in the family who has had cancer. However, if none of your family members who have had cancer are available for testing, genetic testing can start with an unaffected person.

Genetic Testing Results

Interpretation of genetic testing results may vary, depending on whether you have had colorectal cancer in the past or not.

People with Lynch syndrome carry an increased risk of developing some types of cancers, particularly at a younger age. Knowing about Lynch means patients can take steps including prevention, surveillance, and prophylactic surgery to reduce their risk of developing Lynch-associated cancers.

Lynch syndrome is a genetic, inherited cancer syndrome in females causing mainly bowel and endometrial cancer. Other cancers also include ovarian, stomach, skin, urinary tract cancers, breast, bladder, small intestine, kidney, pancreatic and prostate.

Having Lynch syndrome does not mean it is absolutely certain you will be diagnosed with cancer—just that your likelihood of developing the above cancers is significantly higher.

For example, Cancer Australia reports about 1 in 3 women with Lynch syndrome will develop endometrial cancer before the age of 70 years (compared to about 1 in 100 in the general population).

It is important to know if you have Lynch syndrome because a missed Lynch diagnosis can potentially cause you or a close relative (son, daughter sibling) cancer requiring treatment that could have been prevented or the cancer could have been detected earlier.

First-degree relatives with Lynch syndrome

First-degree relatives (children, siblings) of Lynch patients have a 50% risk to also carry Lynch Syndrome.

Upon confirmation of Lynch syndrome in a patient, their first-degree relatives should also consider genetic testing, even if they have never been diagnosed with cancer before.

This is important, because family members will then have the chance to learn whether they also have a greater risk of developing these cancers. This knowledge means that these family members can reduce that risk by undertaking preventative action and completing surveillance plans aimed at detecting cancer at an early stage.

How to diagnose Lynch syndrome

I routinely request Lynch testing in all patients with endometrial cancer irrespective of age or family history.

This is because if we tested only patients with a positive family history, we would miss 50% of patients with Lynch syndrome who do not carry a family history.

The first step to diagnose Lynch is an immunohistochemical test that can be done from the surgical specimen from the original uterine or bowel cancer specimen. This test is not diagnostically certain, however if the test is positive, confirmatory genetic testing should be instigated and requires a blood or sputum test. Referral to a Family Cancer Clinic or a clinical geneticist is then recommended.

Who should be tested?

Testing for Lynch Syndrome should be offered if you:

  • are newly diagnosed with bowel or endometrial cancer
  • are diagnosed with more than one Lynch-associated cancer
  • diagnosed before 50 years of age with a Lynch-associated cancer
  • have a first-degree relative affected by Lynch Syndrome.

Manage your risk of Lynch-associated cancer

Prevention, surveillance and prophylactic surgery may be possible depending on the type of cancer. For example, an annual screening for bowel cancer via colonoscopy is reliable and recommended from age 25.

For gynaecological cancers, including endometrial or ovarian cancer, unfortunately there are no reliable screening methods. Prophylactic surgery (total hysterectomy, bilateral salpingo-oophorectomy ) is the most effective strategy to prevent gynaecological cancer in women who completed their family.

To manage the risk of developing endometrial cancer, we recommend yearly endometrial sampling (Pipelle) with or without a levonorgestrel intrauterine device.

If surgery is not an option, taking the oral contraceptive pill will decrease the risk of ovarian cancer risk by 50%. For more information on managing your risk of gynaecological cancers associated with Lynch Syndrome, read the Lynch Syndrome treatment page.

As there is no screening for endometrial or ovarian cancer it is important to know the early signs and symptoms. Read more about the signs and symptoms of endometrial or ovarian cancer.

If you have a Lynch syndrome diagnosis and would like to discuss your risk-reducing options for gynaecological cancer, please contact me.


What is Lynch syndrome?

Lynch syndrome is an inherited condition that causes an increased risk for colorectal cancer and cancer in certain other organs.

How common is Lynch syndrome?

Lynch syndrome occurs in approximately 1 in 400 individuals.

Symptoms and Causes

What causes Lynch syndrome?

Lynch syndrome is caused by a mutation (genetic change) in one of five specific genes that are responsible for fixing errors in DNA. To further explain, DNA are the codes that carry genetic information. Every time cells divide, the DNA duplicates. Sometimes errors occur during DNA duplication that damages cells and affects the way cells grow. A buildup of these damaged cells may lead to cancer. Usually, a gene called the DNA mismatch repair (MMR) gene finds and fixes the errors before they damage the cell. People with Lynch syndrome have a mutation in the MMR gene, which means the errors are less likely to be found and fixed, which increases the risk of developing certain cancers.

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

Sometimes Lynch syndrome is also referred to as hereditary non-polyposis colorectal cancer (HNPCC), but the two conditions are subtly different.

Lynch syndrome is classified by a mutation in the MMR gene. HNPCC is defined by family history and individuals must meet specific criteria, which are:

  • At least three relatives have colorectal or other HNPCC-related cancers, with one person being a first-degree relative (parent, child, or sibling) of the other two;
  • At least two generations have been affected;
  • At least one person received a diagnosis of colorectal cancer before age 50;
  • Familial adenomatous polyposis has been excluded.

What are the cancer risks associated with Lynch syndrome?

The specific organs at risk for cancer and the degree of increased risk depends on the gene that mutated and, in some cases, if the patient is male or female. The specific genes associated with Lynch syndrome are MLH1, MSH2, MSH6, PMS2, and EPCAM. The list below shows the organs at risk, lifetime risk of developing cancer and average age that cancer is diagnosed.

Cancer type: Colorectal cancer (general population risk is

  • Lynch syndrome lifetime risk of cancer
    • MLH1/MSH2 Woman, 22 to 53%; Average age at diagnosis: 27 to 46
    • MLH1/MSH2 Man, 27 to 74%
    • MSH6 Woman, 10 to 18%; Average age at diagnosis: 54 to 63
    • MSH6 Man, 18 to 22%
    • PMS2 Woman, 15%; Average age at diagnosis: 47 to 66
    • PMS2 Man, 20%

Cancer type: Endometrial cancer (women only, general population risk is 2.7%

  • Lynch syndrome lifetime risk of cancer
    • MLH1/MSH2 , 14 to 54%; Average age at diagnosis: 48 to 62
    • MSH6, 17 to 71%; Average age at diagnosis: 54 to 57
    • PMS2, 15%; Average age at diagnosis: 49

Cancer type: Stomach cancer (general population risk is Diagnosis and Tests

How is Lynch syndrome diagnosed?

Screening tests and genetic testing are used to diagnose Lynch syndrome. A biopsy of the tumor is used for two screening tests. One test looks for changes that indicate the gene that affects DNA repairs is not working. These changes are called microsatellite instability or MSI. Tumors that have microsatellite instability are called MSI-high (MSI-H). Some 90 to 95 percent of colorectal cancers (and many endometrial cancers) from individuals with Lynch syndrome are MSI-H. This means that the cancer in the family is likely due to Lynch syndrome. However, since about 5 to 10 percent of Lynch syndrome tumors do not show instability, a negative MSI-H test cannot completely rule out the possibility of a Lynch syndrome diagnosis.

There is a second type of screening test for Lynch syndrome that uses a technique called immunohistochemistry (IHC). IHC testing is a screening test done on the tumor that looks for the expression of Lynch syndrome gene products (proteins). If one or more of the proteins are missing in the tumor, it suggests that there is a mutation in that gene, which could then be found through genetic testing. Approximately 88 percent of individuals with Lynch syndrome will have an abnormal IHC result.

Ideally, MSI and/or IHC testing should be done before genetic testing is ordered. However, there are occasions where MSI or IHC cannot be done, in which case genetic testing can be performed. Genetic counseling is recommended before ordering genetic testing. Genetic testing, which involves a blood draw or obtaining a brushing from the inside of the mouth (buccal swab), helps determine if a MLH1, MSH2, MSH6, PMS2, or EPCAM gene mutation is present in the family.

If genetic testing reveals a mutation, a diagnosis of Lynch syndrome is confirmed. Other family members can then be tested. Any other family members who have a mutation would also be at an increased risk for developing cancers associated with Lynch syndrome and should be monitored. If no mutation is found, Lynch syndrome is not necessarily excluded. A genetic counselor can further discuss the meaning of negative genetic test results and cancer risk.

How is Lynch syndrome inherited?

Lynch syndrome is an autosomal dominant disorder. This means that if only one parent carries the mutation for Lynch syndrome, there’s a 50 percent chance a child of the parents will inherit the mutation.

Individuals diagnosed with Lynch syndrome should tell their family members and encourage them to undergo genetic counseling. Counseling includes an evaluation of their personal and family history as well as and genetic testing for the Lynch syndrome gene mutation.

Management and Treatment

How is Lynch syndrome treated?

Currently, there is no cure for Lynch syndrome.

Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is the most common cause of hereditary colorectal (colon) cancer.

People with Lynch syndrome are more likely to get colorectal cancer and other cancers, and at a younger age (before 50), including

  • Uterine (endometrial),
  • Stomach,
  • Liver,
  • Kidney,
  • Brain, and
  • Certain types of skin cancers.

Lynch syndrome causes about 4,000 colorectal cancers and 1,800 uterine (endometrial) cancers per year.

Genetics and Lynch syndrome

Lynch syndrome is due to inherited changes (mutations) in genes that affect DNA mismatch repair, a process that fixes mistakes made when DNA is copied. These genes (MLHL, MSH2, MSH6, PMS2, and EPCAM) normally protect you from getting certain cancers, but some mutations in these genes prevent them from working properly.

Everyone has two copies of each of the genes involved in Lynch Syndrome, one from their mother and one from their father. Even if a person inherits a mutation in a Lynch syndrome gene, they still have the normal copy of the gene from the other parent. Cancer occurs when a second mutation affects the normal working copy of the gene, so that the person no longer has a copy of the gene that works properly. Unlike the inherited Lynch syndrome mutation, the second mutation would not be present throughout the person’s body, but would only be present in the cancer tissue. However, not everyone with Lynch syndrome will get cancer.

Colorectal cancer also can be caused by mutations in genes other than those related to Lynch syndrome. This means that some families with a history of colorectal cancer will not have mutations in a Lynch syndrome gene. These mutations might be picked up through genetic testing using multigene panels, which look for mutations in several different genes at the same time.

You and your family members are more likely to have Lynch syndrome if your family has a strong history of colorectal cancer. Family members who inherit Lynch syndrome usually share the same mutation. If one of your family members has a known Lynch syndrome gene mutation, other family members who get genetic testing should be checked for that mutation.

If you are concerned that you could have Lynch syndrome, or another mutation related to colorectal cancer, the first step is to collect your family health history of colorectal cancer and share this information with your doctor.

ICD 10 – cm stands for the international classification of diseases, clinical modification. 10 stands for the tenth revision in the codes. This method is used by the various healthcare providers to make the classification and coding of all diagnoses, the symptoms of the disease and the treatment procedures. These are all recorded after proper referencing and communication with the hospitals in the united states.

What Is The ICD 10 Code For Lynch Syndrome?

There is an ICD 10 code for lynch syndrome as well. Lynch syndrome is also known as hereditary nonpolyposis colorectal cancer (HNPCC). It is a condition in which a person inherits the risk of getting the colorectal cancer or colon cancer or any other cancers like endometrial cancer, ovarian cancer, kidney cancer etc. this is a genetic condition and is an autosomal dominant condition as well. Hence, the ICD 10-CM classification code for the lynch syndrome is Z15.09. z14-z15 stands for genetic susceptibility to a disease. Z15 stands for genetic susceptibility to a disease. Z15.09 indicates the genetic susceptibility to other malignant neoplasm, thus explaining the code in detail. This edition became effective from 1st October 2018. This is the code in the American version of ICD 10-CM codes. The other international versions may differ in coding for Z15.09. this is a billable code and can be used for the reimbursement purposes.

Z15.0 is a non-billable code. To bill a code, the five child codes of et Z15.0 code should be considered. Herein, the Z15.09 stands for the genetic susceptibility to other malignant neoplasm. Hence, the ICD-10-CM code for the lynch syndrome will be Z15.09

  • ICD 10 codes are applied at various healthcare, public health and information technology sectors.
  • This system offers great chances for fair reimbursements from the health insurance companies.
  • This system helps in implementing quality healthcare worldwide and also helps in the comparison of the health care system globally.
  • This system helps in maintaining and recording the statistics of morbidity and mortality of a particular population.
  • It is a very helpful system in research and development.
  • This system helps in lowering the mistakes in medication.
  • It improves the treatment.
  • It improves the payment systems for claims through reimbursement.
  • Well, this also helps the insurance companies as there is a reduction in claim forms submission.

ICD 10 codes are becoming an important part of clinical practice. Not everyone is keen on its usage tough. However, considering the benefits it’s better for everyone if this system is accepted in practice.

WHO publishes the international classification of the diseases; this code is based upon this classification provided by the WHO. This system uses some typical, unique alpha-numeric codes for the identification of the known diseases and many other health problems. This system also helps many healthcare practitioners, nurses, physicians, coders, and other health information managers to properly store and retrieve the diagnostic information whenever it is needed for future referencing. These codes are also useful in calculating the national mortality and morbidity figures.

ICD 10- CM is a revised system, compared to earlier system ICD-9-CM. many codes and categories are included in the ICD 10- CM additionally, as compared to the previous method. These diagnosis codes contain three to seven digits.

The US department of health and human services has made it mandatory for all the health insurance providers that they should start using this coding system by 1st October 2015.

The ICD 10- CM codes are specifically structured. In these codes, the first character has to be an alpha character. However, there is an exclusion for the letter U. the second and the third characters in the code are numeric characters. The fourth to seventh characters can be a combination of alphanumeric characters. The first three characters denote the illness or the condition and the fourth through sixth characters denote the cause, the location and the severity of the injury in details. The last character denotes the initial, subsequent or later treatment modes.