Occurrence of desmoid tumours in familial adenomatous polyposis and results of treatment.

Desmoids are of major concern in patients with familial adenomatous polyposis (FAP) besides the cancer risk. We estimated the risk for desmoid tumours and the results of their treatment in the Finnish Polyposis Registry. The analysis included 202 FAP patients, of whom 169 had undergone colectomy. Desmoids were observed in 29 cases: 15 in the mesentery, 10 in the abdominal wall and 4 in other sites. There were 12 male and 17 female patients with a mean age of 28.2 years (range 7 months to 59 years). The cumulative life-time risk was 21%; 1.5, 3.0, 8.9, 16 and 18% at ages of 10, 20, 30, 40 and 50 years, respectively. The risk of postcolectomy desmoids was 17% after ileorectal anastomosis and 12% after proctocolectomy. There were no deaths due to desmoids. One abdominal scar desmoid disappeared spontaneously and all the other abdominal wall desmoids could be excised without complications, but recurrence occurred in five (45%) cases. Excision was possible in only nine mesenteric desmoids (56%); in these cases recurrence was less common (two cases, 22%) but two others had life-threatening complications (bleeding, short bowel). We conclude that the desmoid problem concerns more than 20% of all FAP patients in long-term. Despite high recurrence rates and surgical hazards surgery remains a useful option for most desmoid tumours in FAP patients considering that other treatments are often ineffective or hazardous as well.