Prognosis of Korean patients with familial adenomatous polyposis who did not undergo colectomy: a retrospective study.

BACKGROUND

The International Society for Gastrointestinal Hereditary Tumors polyposis scoring system (IPSS) categorizes familial adenomatous polyposis (FAP) according to the burden of colorectal polyps and histology. However, the prognosis of patients with uncolectomized FAP has not been established.

METHODS

Medical records of patients diagnosed with FAP between 1991 and 2021 were reviewed, and the IPSS stage was determined. The cumulative upstaging rate and risk factors for IPSS upstaging during surveillance were analyzed in patients without colectomies.

RESULTS

Among 237 patients, 35 (28.9%) with IPSS stages 0-2 did not undergo colectomy. The cumulative risk of upstaging was 0%, 31%, 54%, and 73% at 1, 3, 7, and 10 years after FAP diagnosis, respectively. In univariate analysis, age (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.01-1.08; p=0.014) and having an ampulla of Vater adenoma (HR, 3.95; 95% CI, 1.17-13.30; p=0.027) were associated with upstaging. Multivariate analysis revealed that each 1-year increase in age was an independent risk factor of upstaging (adjusted HR, 1.04; 95% CI, 1.01-1.09; p=0.027).

CONCLUSIONS

In our analysis, patients with uncolectomized FAP and IPSS stages 0-2 at diagnosis showed a time-dependent progression in the IPSS stage.