Skip to Main Content

Lynch Syndrome


Some families have multiple relatives who have colon cancer or other types of cancer. These cancers may be caused by a rare inherited genetic condition called Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC). Lynch syndrome significantly increases your chance of developing colon cancer, and often earlier than the general population – before the age of 45. Nearly 3 percent of all colon cancers are caused by Lynch syndrome. It may also increase your risk of other cancers, such as endometrial and ovarian cancer in women.

The good news is that genetic screening and testing, available at major medical centers, detects Lynch syndrome in an estimated 95 percent of people.

By determining whether you and your family members have Lynch syndrome, you can take steps to seek appropriate medical care and surveillance, such as regular and consistent colonoscopies and check-ups at earlier ages. This can help to detect and prevent cancer, and ultimately, to save lives.

Our Approach to Lynch Syndrome

UCSF offers comprehensive genetic counseling for families with a history of cancer. Our goal is to help you manage your cancer risk. If you need to be screened for Lynch syndrome, our team can assess your personal and family history, and if appropriate, conduct genetic testing.

If you have the testing, genetic counselors and doctors will design a risk management program for you. It will include individualized recommendations for cancer screening, guidance on prevention and options for treatment. We will also counsel you on how to share this information with other family members who may be at risk.

Awards & recognition

  • usnews-neurology

    Among the top hospitals in the nation

  • Best in Northern California and No. 7 in the nation for cancer care

  • NIH-2x

    Designated comprehensive cancer center

Signs & symptoms

People with Lynch syndrome may have:

Those with Lynch syndrome have a 70 percent chance of developing colon cancer by age 70. Colon cancer patients with Lynch syndrome have an estimated 40 percent risk of developing a second primary colon cancer within seven years of being diagnosed after the first tumor. Women with Lynch syndrome have a 40 percent to 60 percent estimated lifetime risk of developing endometrial cancer.

Lynch syndrome may also increase a person's risk for cancers of the stomach, ovary, urinary tract, hepatobiliary tract, brain, small intestine, skin and pancreas.


If you have a family history of cancer, it is extremely important that you let your doctor know. Your doctor will then take a thorough recording of your family history, paying particular attention to cancer diagnoses. If your doctor suspects that you may have Lynch syndrome, they will refer you to a health care professional who specializes in genetic cancer screening, testing and counseling.

In addition, all newly diagnosed colorectal cancer or endometrial cancer patients also should be screened or tested for Lynch syndrome.

Genetic Testing

Genetic testing involves a simple blood test. Your blood sample is sent to a special laboratory where it is analyzed for certain changes or mutations that indicate Lynch syndrome.

If you test positive for Lynch syndrome, meaning that genetic mutations were found in your blood, this does not necessarily mean that you will get cancer. It means that your lifetime risk of developing colon cancer is between 60 to 80 percent. You also have an increased chance of developing other cancers associated with Lynch syndrome.

A negative test result for Lynch syndrome, meaning that genetic mutations were not found in your blood, depends on additional factors such as whether your family members have Lynch syndrome or colon cancer. If you test negative for Lynch syndrome but have family members with the syndrome, your risk for colon cancer is not increased, but remains the same as the general population. However, in some cases, such as if you have a strong family history of colon cancer, a negative test result may still mean that you are at an increased risk for colon cancer.

Your genetic counselor will explain your test results and help you make decisions regarding cancer prevention, screening and treatment options.

Who Should Be Screened or Tested

Based on established medical criteria, the following people should be screened or tested for Lynch syndrome:

  • Newly diagnosed colorectal or endometrial cancer patients The first step in Lynch syndrome diagnosis is evaluating your tumor for molecular features associated with Lynch syndrome. When a tumor is not available for screening, DNA blood testing can be done if your family history and cancer diagnosis strongly suggest Lynch syndrome. UCSF's Cancer Genetics and Prevention Program, in conjunction with our Gastrointestinal Cancer Prevention Program, offers a unique service to all colorectal cancer and endometrial cancer patients. We automatically screen patients' tumors for Lynch syndrome at the time of their surgery for colorectal or endometrial cancer. Patients who screen positive are then referred for genetic counseling and testing.
  • Patients diagnosed with more than one Lynch syndrome-related cancers If you have been diagnosed with multiple cancers associated with Lynch syndrome including colorectal, endometrial, ovarian, gastric, small bowel, upper urinary tract, hepatobiliary tract, pancreas, brain and sebaceous neoplasia of the skin, you should be screened or tested for Lynch syndrome.
  • Patients with a family history of colorectal or endometrial cancer If you have two or more relatives with colorectal or endometrial cancer, particularly if one was affected before age 50, you should be screened or tested for Lynch syndrome.


Based on your family history, genetic testing results and other cancer risk factors, your counselors and doctors will provide you with an individualized risk management program that includes recommendations for cancer screening, prevention and treatment options.

Cancer Screening for People with Lynch Syndrome

If you tested positive for Lynch syndrome, but do not have a cancer diagnosis, or your doctor suspects that you have Lynch syndrome, the following cancer screening plan may be recommended.

Colorectal Cancer Screening

Colonoscopy every one to two years, starting at the age of 20 to 25 years (age 30 years in families with a certain mutation known as MSH6) or 10 years younger than the youngest age at diagnosis in the family, whichever comes first.

Endometrial Cancer Screening

While there is no established screening for endometrial cancer at this time, given the high risk of developing the disease in women with Lynch syndrome, the following may be recommended:

  • Endometrial biopsy every year beginning at age 30 to 35. An endometrial biopsy is necessary in women with Lynch syndrome who report abnormal symptoms such as irregular vaginal bleeding or post-menopausal bleeding.
  • Transvaginal ultrasound for endometrial and ovarian cancer every year beginning at age 30 to 35.
  • Urinalysis with cytology every one to two years beginning at age 25 to 35.
  • Detailed medical history and examination, education and counseling regarding Lynch syndrome every year beginning at age 21.

Treatment for Cancer Patients with Lynch Syndrome

Surgery may be recommended to patients with colorectal cancer who test positive for Lynch syndrome in order to prevent additional cancer. For instance, if you have colorectal cancer and test positive for Lynch syndrome, it may be recommended to remove the majority of your colon at the time of your surgery for colon cancer, which would reduce your risk of developing another primary colorectal cancer tumor from 40 percent to 1 percent. Likewise, female patients with colorectal cancer may also want to consider having their uterus and ovaries removed to prevent the occurrence of endometrial and ovarian cancer associated with Lynch syndrome.

Your counselors and doctors can help you decide which treatment option is the best for you.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.

Recommended reading

Colorectal Cancer Prevention and Screening

Find out how to prevent colorectal cancer with regular screenings, healthy eating, and lifestyle. Learn the steps for early detection and prevention.

FAQ: Genetic Testing for Hereditary Cancer

Do you have a family history of cancer? Genetic counselors can help you understand your cancer risk and make recommendations for screening tests and preventive treatments.

Skin Cancer Prevention

Skin cancer is largely preventable, and if caught early, it's usually curable. It's important to take precautions when spending time outdoors. Learn more.

Sunscreen for Skin Cancer Prevention

All sunscreens have a sun protection factor (SPF) rating that indicates how long a sunscreen remains effective on the skin. Learn more.

Where to get care (7)

    Related clinics (4)


    Cancer Symptom Management

    Cancer Symptom Management

    San Francisco

    Osher Center for Integrative Health

    Osher Center for Integrative Health

    1545 Divisadero St., Fourth Floor
    San Francisco, CA 94115


    Cancer Survivorship and Wellness Institute

    Cancer Survivorship and Wellness Institute

    See both of our San Francisco locations.




    San Francisco

    Support services

    Support Group

    Art for Recovery

    Creativity can help people with serious illnesses cope, heal and express what they're going through. Find out about our program and how to join.


    Cancer Exercise Counseling

    Our one-on-one exercise training sessions, customized for your needs and abilities, can complement other cancer treatments and speed your recovery.

    Patient Resource

    Cancer Nutrition Counseling

    UCSF Health offers free nutrition counseling to our patients with cancer, as well as nutrition seminars that are open to anyone. Learn more.

    Support Group

    Cancer Support Groups

    These groups offered by the Ida and Joseph Friend Patient and Family Cancer Support Center are free and available to all patients, whether or not you get your health care at UCSF.


    Core & More Class for Cancer Patients

    A strong body helps you fight cancer and enjoy life. Join this class to stabilize your core, strengthen your muscles and improve overall fitness. For cancer patients and caregivers!

    Patient Resource

    Friend to Friend Specialty Shops

    A one-stop boutique for patients with cancer. Get professional help with wigs, prostheses, sun-protective clothing, makeup, skin care and more.


    Meditation & Guided Imagery for Cancer Patients

    Drop in for a free class designed to help you heal, relax and find balance during your treatment. UCSF and non-UCSF patients are welcome.

    Patient Resource

    Oncology Social Work

    Social workers offer support, problem-solving, help accessing UCSF cancer-related resources and more. Find out how to contact the social worker for your clinic.

    Patient Resource

    Patient & Family Cancer Support Center

    The center offers wellness programming, community, support groups, classes, workshops and more at no cost to people facing cancer and their loved ones.

    Support Group

    Peer Support Programs for Cancer

    Patients are matched with peer support volunteers according to criteria such as diagnosis, cancer stage, age or gender. Speak to someone who's "been there."