Familial Adenomatous Polyposis (FAP): Symptoms, Causes, Diagnosis & Treatment

Familial adenomatous polyposis (FAP) is a rare inherited disorder that causes hundreds to thousands of polyps—small growths—in the lining of the colon and rectum. These polyps are initially benign but have a high chance of turning into colorectal cancer if not detected and managed early. Because of this, FAP is considered a serious condition that requires lifelong surveillance and often preventive treatment.

What Causes Familial Adenomatous Polyposis?

FAP is caused by mutations in the APC gene, which is responsible for controlling cell growth and death in the colon lining. This mutation is inherited in an autosomal dominant manner, meaning only one copy of the defective gene from a parent is sufficient to develop the condition (Genetics Home Reference, NIH).

The mutated APC gene disrupts normal cell regulation, leading to rapid polyp formation starting often in teenage years or early adulthood. Without intervention, the likelihood of one or more polyps turning cancerous approaches 100%, typically by the age of 40-50.

Recognizing the Symptoms of FAP

Many people with FAP may initially have no symptoms. However, as polyps grow in size and number, common symptoms include:

• Rectal bleeding or blood in stool
• Abdominal pain or cramping
• Changes in bowel habits such as diarrhea or constipation
• Unexplained weight loss and fatigue (in advanced cases)

Because symptoms may be subtle or absent in early stages, people with a family history of FAP are advised to undergo regular screening even without symptoms.

How Is FAP Diagnosed?

Diagnosis relies on a combination of factors including family history, physical examination, and diagnostic testing:

• Colonoscopy: The gold standard test, which visually inspects the colon and rectum to detect and remove polyps.
• Genetic testing: Identifies mutations in the APC gene to confirm diagnosis and help screen family members.
• Upper endoscopy: Since polyps can also develop in the upper digestive tract, this test may be recommended.

Early diagnosis allows for timely intervention, reducing the risk of progression to colorectal cancer significantly (American Cancer Society).

Treatment Approaches for FAP

Because of the high cancer risk, treatment focuses on removing polyps and preventing cancer development:

• Regular polyp surveillance: Frequent colonoscopies to detect and remove polyps early.
• Colectomy (surgical removal of the colon): Often recommended when polyps become numerous or show signs of dysplasia (precancerous changes). Types of colectomy include:
• Total proctocolectomy with ileal pouch-anal anastomosis (IPAA): Removal of colon and rectum, with creation of an internal pouch to maintain bowel function.
• Subtotal colectomy: Removal of most of the colon, preserving the rectum temporarily.
• Surveillance of remaining tissues: Monitoring the rectum and other tissues post-surgery for new polyp growth.

Advances in surgical techniques and ongoing screening have greatly improved outcomes for FAP patients.

Living with FAP: Lifestyle and Support

Managing FAP involves more than medical treatment. Lifestyle changes and emotional support play a key role:

• Maintain a healthy diet: High-fiber, low-fat foods may support digestive health.
• Stay physically active: Exercise helps maintain overall well-being.
• Avoid tobacco and limit alcohol: These substances can increase cancer risk.
• Seek psychological support: Coping with a genetic cancer risk can be stressful; counseling and support groups can help.
• Family screening: Encourage relatives to get genetic testing and surveillance.

Conclusion

Familial adenomatous polyposis (FAP) is a life-altering hereditary condition with a high risk of colorectal cancer. Early diagnosis, regular surveillance, and timely intervention are essential to managing the disease and improving long-term outcomes. If you or a family member are at risk or have symptoms suggestive of FAP, consult a healthcare professional promptly. With proactive care and support, individuals with FAP can lead fulfilling lives.