Background & aims: Desmoid tumors are non-metastasizing fibromatoses that occur in 10%-20% of subjects with familial adenomatous polyposis (FAP). Intra-abdominal desmoid tumors are a major cause of mortality in FAP. FAP-associated desmoid tumors are linked to trauma, particularly abdominal surgery, family history of desmoids, hormonal factors, and the location of the APC mutation. We hypothesized that prophylactic colectomy at an early age might increase the risk of developing desmoids. The aim of this study was to determine whether colectomy earlier in life is a risk factor for the development of desmoid tumors.
Methods: An analysis was made of the association between development of desmoid and age at colectomy, family history of desmoids, gender, and APC mutation in FAP patients in the Registry (1980-2005) at Mount Sinai Hospital, Toronto, Ontario, Canada.
Results: FAP patients (n = 930) from 365 kindreds were identified. Desmoid prevalence was 14% (n = 121). Female patients were more likely to develop desmoids than male patients (17% vs 11%, P = .03). Female patients who had an early colectomy were more than 2 times more likely to develop a desmoid, compared with women who had a colectomy at >18 years (P = .01). Early colectomy did not increase risk of developing a desmoid in male patients (P = .42). Female patients who had an early colectomy (</=18 years) were 2.5 times more likely to develop desmoids, compared with male patients who had a late colectomy (P = .05). The prevalence of desmoids in the 5' and 3' groups was 13% and 38%, respectively (P = .0005). Patients with a mutation after codon 1399 were found to have 4 times greater chance of developing a desmoid.
Conclusions: Female patients with FAP are more likely to develop desmoids than male patients. Female patients who had an early colectomy are at significantly greater risk of developing a desmoid compared with female patients who had a colectomy in adulthood. Patients with APC mutations beyond codon 1399 are more likely to develop desmoids. These results suggest that delayed colectomy might be considered in young female patients with FAP to decrease the chances of developing desmoids.