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STK11 (Peutz-Jeghers Syndrome): Options for Managing Risk

Learn about the screening and prevention guidelines for people with a mutation in their STK11 gene. Stay up to date by signing up for our community newsletter.

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Risk Management for People with Inherited Mutations

Experts at the National Comprehensive Cancer Network (NCCN) created guidelines for people with an inherited STK11 mutation to manage their cancer risk.

We recommend that you speak with a genetics expert who can look at your personal and family history of cancer and can help you decide on a plan for managing your risk.

NCCN recommends that all people with an STK11 mutation receive education on the signs and symptoms of related cancers. NCCN guidelines for specific cancers are listed below.

People with an STK11 mutation may also qualify for clinical trials looking for more effective screening or prevention for cancer.

Risk management in children

Breast cancer

Gynecologic cancer

Gastrointestinal tract cancers

Participate in Research

Pancreatic Cancer Early Detection for People at High Risk

Risk management for children

An inherited STK11 mutation can increase the risk for cancer beginning during childhood. Risk management for some cancers begins at a young age.

Beginning Age	Recommendation
At age of diagnosis with a mutation	Girls should have an annual exam by a doctor to look for evidence of early-onset puberty.
At age of diagnosis with a mutation	Boys should have an annual physical exam by a doctor and evidence of feminizing changes.
8-10 years continuing into adulthood	Boys and girls should have a colonoscopy, upper endoscopy and small bowel exam using CT, or video capsule endoscopy with followup every 2-3 years depending on if abnormalities are found.
Source: NCCN Guidelines: Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, Gastric, v. 1, 2025.

Breast cancer risk management

Beginning Age	Recommendation	Additional Information
25	Learn to be aware of changes in your breasts.	Self exams may be most informative at the end of the menstrual cycle.
30 (or earlier based on youngest age of breast cancer in the family)	Breast exam by doctor (also known as a clinical breast exam) every 6-12 months.	The guidelines recommend that people who have risk-reducing mastectomy continue to receive clinical breast exams.
30 (or earlier based on youngest age of breast cancer in the family)	Yearly breast MRI with and without contrast.
30 (or earlier based on youngest age of breast cancer in the family)	Yearly .
No set age	Discuss the benefits, risks and costs of double mastectomy with your doctor.	Risk-reducing mastectomy lowers breast cancer risk by 90%, but has not been shown to improve survival. Even after double mastectomy, some breast tissue, and therefore cancer risk remains. The guidelines recommend continuing clinical breast exam after risk-reducing mastectomy.
No set age	Discuss the benefits, risks and costs of medication to lower the risk for breast cancer with your doctor.	Tamoxifen and other estrogen-blocking drugs may reduce breast cancer risk for high-risk women, but more research is needed to prove this in people with an STK11 mutation.
75	Have a discussion with your doctor about whether to continue, stop or change breast screening.
Source: NCCN Guidelines: Genetic/Familial High-Risk Assessment: Breast, Ovarian, Pancreatic, , vs. 1 2026.

Risk management for gynecologic cancer

Beginning Age	Recommendation	Additional Information
18-20	annual pelvic exam annual pelvic annual Pap smear.	Endometrial biopsy is recommended if there is any abnormal bleeding.
After childbearing	Have a discussion with your doctor about the risks, benefits and costs of removing your uterus (hysterectomy).
Source: NCCN Guidelines: Genetic/Familial High-Risk Assessment: Breast, Ovarian, Pancreatic, Prostate, v. 1, 2026; NCCN Guidelines: Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, Gastric v. 1, 2025.

Risk management for gastrointestinal tract cancer

Beginning Age	Recommendation
18	Colonoscopy every 2–3 years or more frequently depending on number, size and type of found.
18	Upper endoscopy every 2–3 years or more frequently depending on number, size and type of polyps found.
18	Small intestine exam using CT, MRI or video capsule endoscopy with followup every 2-3 years or more frequently depending on if abnormalities are found.
Source: NCCN Guidelines: Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, Gastric, v. 1, 2025.

Risk management for pancreatic cancer

There are two tests that are used to look for pancreatic cancer in high-risk people.

MRCP (Contrast-enhanced magnetic resonance cholangiopancreatography) is a special type of MRI imaging that looks closely at the pancreas, liver, gallbladder, bile duct and pancreatic duct to find abnormalities such as cancer.
EUS (Endoscopic ultrasound) involves passing a tiny scope with an attached ultrasound probe down the esophagus to the stomach. This allows doctors to look closely at the pancreas.

Beginning Age	Recommendation
30-35 years (or 10 years younger than the earliest case of pancreatic cancer in the family)	Discuss the benefits, risks, costs and limitations of screening with your doctor. Screening should include annual MRCP or EUS or both. Screening should be performed in a facility with experience in screening high-risk patients for pancreatic cancer.
Source: NCCN Guidelines: Genetic/Familial High-Risk Assessment: Breast, Ovarian, Pancreatic, Prostate, vs. 1 2026.

Risk management for testicular cancer

Beginning Age
18	Yearly testicular exam and observation for feminizing changes (e.g., breast enlargement).

Risk management for lung cancer

Beginning Age
No set age	Learn about the risks and signs of lung cancer and the benefits of quitting smoking.

Other cancers

There has not been enough research to show a benefit from screening and prevention for other cancers in people who have an STK11 mutation. For this reason, experts recommend managing other cancer risks based on family history. Cancer screening and prevention research studies may be available for people with STK11 mutations.