Desmoid Tumor in Familial Adenomatous Polyposis (FAP)

Abstract

Purpose: This research was conducted to assess the incidence, clinical characteristics, and treatment outcomes for desmoid tumors in patients with familial adenomatous polyposis (FAP). Methods: At Medical Center, we recruited 47 patients who had been diagnosed as having intraabdominal or abdominal wall desmoid tumor between Aug. 1995 and Dec. 2005. We compared FAP- associated desmoid tumors with non-FAP-associated desmoid tumors according to clinical characteristics and treatment outcomes. Results: Desmoid tumors developed 12/46 (26.1%) in FAP, 1/14 (7.1%) in attenuated FAP and 34 in non-FAP associated. Unlike non-FAP- associated desmoid tumors, the occurrence of FAP- associated desmoid tumors in tended to be higher in the earlier age groups (≤40 yrs, 92.3% vs 67.6%, P=0.082) and no sexual predominancy was observed (male：female ratio of 1.2：1 vs a tumor ratio 1：3.9, P=0.033). Intraabdominal-type desmoid tumors associated for the majority of FAP-associated desmoid tumors (92.3% vs 38.2%, P=0.002), and 70% of the desmoid tumors occurred within 3 years after total proctocolectomy. In the treatment of FAP-associated intraabdominal desmoid tumors, surgery was performed in 7 cases (58.3%), and complete resections were done in only 3 cases (25%), with one recurrence. In non-FAP-associated desmoid tumors, complete resection was possible in 10 cases (76.9%), and there was no recurrence (P=0.036). The medical treatment for unresectable or incompletely resectable cases in cases of non-FAP-associated desmoid tumor was good, but for FAP-associated desmoid tumors, the effectiveness was not good, and further investigation was needed. Conclusions: Intraabdominal desmoid tumors in FAP patients occurred frequently in the early (≤3 yrs) postoperative period, and the treatment, outcome including surgery and medication, outcome was not good in patients with FAP-associated desmoid tumors.