Adenomatous Polyposis Coli Gene Mutations, Risk Factors, and Long-term Outcomes Associated With Desmoid Tumors in Patients With Familial Adenomatous Polyposis After Colectomy in Japan.

GOALS

To clarify the characteristics of desmoid tumors in Japanese patients with familial adenomatous polyposis after colectomy.

BACKGROUND

Few comprehensive reports have been published on desmoid tumors in Asian patients with familial adenomatous polyposis.

STUDY

This retrospective study included the data of 81 patients with familial adenomatous polyposis who underwent surgery between 1978 and 2021. The adenomatous polyposis coli gene mutation sites, risk factors, and long-term outcomes associated with desmoid tumors in Japanese patients with familial adenomatous polyposis after colectomy were analyzed.

RESULTS

No association was observed between the gene mutation sites and desmoid tumor development in 40 patients who underwent genetic analyses. The rate of desmoid tumor development was 30.3% in 66 patients. Multivariate analysis revealed that age below 32 years at colectomy (hazard ratio = 5.491, 95% confidence interval 1.820-16.50, P < 0.001) and familial adenomatous polyposis-related malignancies other than colorectal cancer (hazard ratio = 5.574, 95% confidence interval 2.075-14.98, P < 0.001) were independent risk factors for desmoid tumor development following colectomy. The 10-year disease-specific survival and overall survival rates for desmoid tumors were 92.9% and 76.9%, respectively. The median surveillance duration was 90 months.

CONCLUSIONS

Adenomatous polyposis coli gene mutation sites alone were not considered a factor for delaying or avoiding colectomy to prevent desmoid tumors in Japanese patients with familial adenomatous polyposis. The timing of colectomy and careful surveillance should be considered for managing patients at a high risk of developing desmoid tumors. Desmoid tumors in patients with familial adenomatous polyposis did not significantly impact prognosis, and pharmacological treatments are important for disease control.