Risk Factors for the Development of Desmoid Tumor After Colectomy in Patients with Familial Adenomatous Polyposis: Multicenter Retrospective Cohort Study in Japan

Desmoid tumor (DT) is the primary cause of death in patients with familial adenomatous polyposis (FAP) after restorative proctocolectomy. This study aimed to identify risk factors for DT in a Japanese population. Clinical data for 319 patients with FAP undergoing first colectomy from 2000 to 2012 were reviewed retrospectively. Two hundred seventy-seven FAP patients were included in this study. Thirty-nine (14.1 %) patients developed DT. Occurrence sites were the intraperitoneal region in 25 (64.1 %) cases, intraperitoneal region and abdominal wall in three (7.7 %), and abdominal wall in nine (23.1 %). The mean period from surgery to DT development was 26.3 months (range 4-120 months). Gender (female vs. male, p = 0.03), age at surgery (> 30 vs. aecurrency sign30 years, p = 0.02), purpose of surgery (prophylactic vs. cancer excision, p = 0.01), and surgical procedure (proctocolectomy [ileoanal anastomosis (IAA), ileoanal canal anastomosis (IACA), total proctocolectomy (TPC)] vs. total colectomy [ileorectal anastomosis, partial colectomy]; p = 0.03) significantly influenced the estimated cumulative risk of developing DT at 5 years after surgery. Conversely, approach (laparoscopic vs. open, p = 0.17) had no significant effect on the increased risk of DT occurrence. In multivariate analysis, female gender, with a hazard ratio of 2.2 (p = 0.02,) and proctocolectomy (IAA, IACA, TPC), with a hazard ratio of 2.2 (p = 0.03), were independent risk factors for DT incidence after colectomy. Female gender and proctocolectomy (IAA, IACA, TPC) were independent risk factors for developing DT after colectomy in patients with FAP.