From the Guidelines
The false statement about Gardner's syndrome variant of familial adenomatous polyposis coli is "The vast majority of the polyps are benign and thus the risk of colorectal cancer is small." This is because Gardner's syndrome carries a very high risk of colorectal cancer, approaching 100% if left untreated, as the polyps initially develop as benign adenomas but have a strong tendency to undergo malignant transformation over time 1. Gardner's syndrome is indeed an autosomal dominant condition characterized by a mutation in the APC gene, and patients with this condition develop numerous colorectal polyps beginning in adolescence, and are also at risk for extracolonic manifestations including:
- Retroperitoneal desmoid tumors
- Osteomas
- Epidermoid cysts
- An increased risk of thyroid cancer Due to the extremely high risk of colorectal cancer development, patients typically require prophylactic colectomy rather than just surveillance, as supported by the most recent evidence from 2017 1. Key points to consider in the management of Gardner's syndrome include:
- The condition is caused by a mutation in the APC gene
- Patients are at high risk of developing colorectal cancer, with an average age of diagnosis of 39 years
- Extracolonic manifestations are common, including desmoid tumors and thyroid cancer
- Prophylactic colectomy is often necessary to prevent colorectal cancer, as the risk approaches 100% if left untreated 1.
From the Research
Statements Relating to Gardner's Syndrome
- It is an autosomal dominant condition: This statement is true, as evidenced by studies 2, 3, 4, 5.
- Patients may develop retroperitoneal desmoid tumours: This statement is true, with desmoid tumors being a common extracolonic manifestation of Gardner's syndrome 2, 5.
- The vast majority of the polyps are benign and thus the risk of colorectal cancer is small: This statement is false, as the risk of colorectal cancer in patients with Gardner's syndrome is nearly 100% if left untreated 3, 4.
- Patients are at increased risk of thyroid cancer: This statement is true, with thyroid cancer being one of the extracolonic malignancies associated with Gardner's syndrome 2, 3.
- It is characterised by a mutation in the APC gene: This statement is true, with mutations in the APC gene being the underlying cause of Gardner's syndrome 2, 3, 4, 5, 6.