Familial adenomatous polyposis (FAP) is a hereditary disorder that, in the absence of appropriate therapeutic management, invariably progresses to colorectal adenocarcinoma. It represents the most common form of colorectal polyposis and the second leading cause of hereditary colorectal cancer. after lynch syndrom The aim of this study was to identify prognostic factors associated with malignant degeneration.

We conducted a retrospective, descriptive study in the Departments of Gastroenterology and General Surgery at Mohamed Tahar Maamouri University Hospital. A total of 33 patients managed for FAP over a 16-year period (January 2005 to December 2024) were included.

During the study period, 33 patients were included: 16 women and 17 men, with a sex ratio of 1.06. The mean age was 48.2 years [18–78]. FAP was diagnosed after the age of 40 in 21 patients. Fifteen patients were smokers and four were chronic alcohol consumers. A family history of FAP or colorectal cancer in first-degree relatives was documented in 15 patients (45.5%).At diagnosis, the number of polyps exceeded 100 in 4 patients (12%).Colorectal cancer occurred in 15 patients. The mean age at cancer diagnosis was 59 years. Thirteen patients (86%) underwent elective surgery, while two required emergency surgery for bowel obstruction.Seven patients underwent total proctocolectomy with ileal pouch–anal anastomosis. Two underwent subtotal colectomy with ileocolic anastomosis, and six had total colectomy with ileorectal anastomosis.

In univariate analysis, the risk of degeneration was associated with age > 40 years at the time of FAP diagnosis (p = 0.02). A polyp count > 100 at diagnosis—observed in 12% of patients—was correlated with the subsequent development of colorectal adenocarcinoma (p = 0.042).Polyps measuring > 5 mm, with or without high-grade dysplasia on histology and present in 26 patients (78%), also constituted a poor prognostic factor predictive of malignant transformation (p = 0.036).Among the 33 included patients, 23 were diagnosed through colonoscopy performed for gastrointestinal symptoms; this group showed a higher risk of developing colorectal cancer (p = 0.015).Finally, the presence of at least one extracolonic manifestation—documented in 16 patients—was associated with an increased risk of colorectal cancer (p = 0.025).

Our study demonstrated a positive correlation between age at FAP diagnosis, polyp size and number, and the risk of colorectal cancer. It also highlighted the increased risk of colorectal cancer in the presence of extracolonic manifestations and emphasized the importance of diagnosing FAP at the presymptomatic stage to reduce the likelihood of malignant degeneration.