Get notified of page updates

APC: Options for Managing Cancer Risk

Q: Gastric Adenocarcinoma and Proximal Polyposis of the Stomach (GAPPS)

Some people with a mutation in a section of their APC gene called "promoter 1B" have a different condition called Gastric Adenocarcinoma and Proximal Polyposis of the Stomach (GAPPS). People with GAPPS tend to develop many polyps in the upper part of the stomach and have a high risk for gastric cancer. Expert guidelines on risk-management for people with GAPPS are listed below. Ask your doctor to explain the signs of cancers related to GAPPS and report any symptoms to your doctor. It's important to seek care from healthcare providers with expertise in managing risk in people with GAPPS.

People with an APC mutation have options for managing their cancer risk. Learn about the screening and prevention guidelines. Stay up to date by signing up for our community newsletter.

Glossary on

off

Risk Management for People with an Inherited Mutation

FAP and AFAP

GAPPS

APC mutation I1307K

Familial adenomatous polyposis (FAP) and attenuated FAP (AFAP)

Expert guidelines on risk-management for people with FAP and AFAP are listed below. Ask your doctor to explain the signs of cancers related to FAP and report any symptoms to your doctor. It's important to seek care from healthcare providers with expertise in managing risk in people with FAP.

Researchers are looking at new ways to prevent or intercept cancer in people with FAP or AFAP. Speak with your doctor to learn if you are eligible for a clinical trial and to decide if it's the best option for you.

Importantly, people with a specific mutation known as I1307K do not develop FAP. The guidelines in the large table do not apply to people with this mutation. See the bottom section of this page for the specific guidelines for people with an I1307K mutation.

Using the Drug eRapa to Prevent the Growth of Polyps in People with Familial Adenomatous Polyposis (SERENTA)

Clinicaltrials.gov identifier: NCT06950385

Guidelines for people with FAP and AFAP

Beginning Age	Recommendation
Infants	Physical exam to screen for liver tumors; abdominal and AFP (alpha-fetoprotein) blood levels every 3-6 months until age 5.
10-15 (people with AFAP may start screening at age 18)	Annual high-quality colonoscopy.
Late teenage years	Thyroid every 2-5 years, with referral to thyroid expert if findings are abnormal (or more frequently, based on family history of thyroid cancer).
No specified age (depends on personal history of and individual preferences)	Risk-reducing colectomy; speak with health care experts about benefits and risks of each colectomy surgical option. See our section on colectomy for descriptions of the different types of procedures.
After colectomy	Scoping of remaining tissue depending on type of surgery (type of scoping and frequency depends on type of surgery and amount of tissue remaining): sigmoidoscopy pouchoscopy limited scoping of terminal ileum
After colectomy	Have a conversation with your doctor about the potential benefits and limitations of sulindac to decrease polyp formation. Note: sulindac is not FDA-approved for this use.
20-25 (or earlier, based on family history)	Upper endoscopy of the stomach and small intestine (frequency depends on number, size, and type of found), typically with a specialized scope that can evaluate the ampullar of Vater.
No specified age	Consider capsule endoscopy (this involves swallowing a pill-sized camera that takes photos of your intestines as it travels through your digestive tract) or an endoscopic evaluation of the lower small intestine (called an enteroscopy) may be considered on a case by case basis for individuals felt to have a particular risk of in the lower small intestine (the jejunum and the ileum).
No specified age	Routine CT or imaging to evaluate for desmoid tumors is not recommended, but worrisome abdominal symptoms (e.g., unexplained pain) should prompt abdominal imaging. Individuals with known abdominal desmoid tumors may warrant regular surveillance imaging.
No specified age	Learn the signs and symptoms of other FAP-related tumors, including central nervous system cancers and desmoid tumors.
No specified age	Speak with your doctor about the benefits and risks of medications and the availability of clinical trials for managing risk of colorectal cancer.
Source: NCCN Guidelines: Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, and Gastric v.1 2025.

Gastric and Proximal Polyposis of the Stomach (GAPPS)

Some people with a mutation in a section of their gene called "promoter 1B" have a different condition called Gastric and Proximal Polyposis of the Stomach (GAPPS). People with GAPPS tend to develop many in the upper part of the stomach and have a high risk for gastric cancer. Expert guidelines on risk-management for people with GAPPS are listed below. Ask your doctor to explain the signs of cancers related to GAPPS and report any symptoms to your doctor. It's important to seek care from healthcare providers with expertise in managing risk in people with GAPPS.

Gastric cancer screening and prevention options

There are two main options for managing gastric cancer risk in people with GAPPS.

Upper endoscopy

This screening is done under anesthesia. The endoscopist passes a scope with a video camera through the mouth into the stomach in order to get a close look. The endoscopist then passes a tiny instrument through the scope to take tissue samples of . These samples are sent to a pathologist to check them for cancer.

Preventive gastrectomy

Preventive gastrectomy (also known as prophylactic or risk-reducing gastrectomy) involves surgery to remove the entire stomach before cancer can develop. The procedure is effective at lowering risk for stomach cancer, but can have a large impact on lifestyle, (such as eating habits, symptoms that happen with eating, and the ability to maintain your weight). It can also have an impact on overall health, (such as increased risk of vitamin and mineral deficiencies, increased risk of bone disease and other effects).

Guidelines for people with GAPPS

Beginning Age	Recommendation
15	Yearly upper endoscopy screening.
25	Baseline colonoscopy to check for . Follow up screening may be recommended based on prior screening findings and family history.
Age 30 or later	Speak with your doctor about the benefits and risks of risk-reducing surgery to remove the stomach.
After colectomy	Have a conversation with your doctor about the potential benefits and limitations of sulindac to decrease polyp formation. Note: sulindac is not FDA-approved for this use.
Source: NCCN Guidelines: Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, and Gastric v.1 2025.

APC mutation I1307K

People with the I1307K mutation are recommended to begin colorectal cancer screening at age 40 (or younger depending on family history of cancer). Recommendations include a high-quality colonoscopy every 5 years.

Participate in Prevention Research

Testing the Safety And Action of the Investigational Drug REC-4881 in People With Familial Adenomatous Polyposis (FAP)

Clinicaltrials.gov identifier: NCT05552755

This study is looking at how safe and effective the research drug REC-4881 is for treating polyps in people with Familial Adenomatous Polyposis (FAP). Participants will receive the oral drug REC-4881. A participant's dose will...

Learn more

Testing the Drug Obeticholic Acid for Familial Adenomatous Polyposis

Clinicaltrials.gov identifier: NCT05223036

This study is no longer enrolling patients.

Learn more

Registry to Discover New Treatments and Developmental Processes of Colorectal and Endometrial Cancer in Patients with Hereditary Cancer

Clinicaltrials.gov identifier: NCT06096688

This research registry will collect and save data, cancer samples and family health history information to discover new ways cancer develops. It will look to find new genes that could be used for treatments and...

Learn more