The Ananlysis Of Risk Factors Of Developping Desmoid Tumours In Patients With Familial Adenomatous Polyposis And The Treatment Evaluation Of Demoid Tumours

Introduction and aims：Desmoid tumor（sDT）represent one major complication of the disease in patients withfamilial adenomatous polyposis (FAP). Our aim was to study factors associated with thedevelopment of desmoid tumors in a large cohort of FAP patients and review the differenttreatment proposed with corresponding results.Methods and Patients：We reviewed retrospectively190cases of patients with FAP, with complete medicalrecords, followed at Edouard Herriot Hospital in Lyon, France between1965and2013.There were10patients with biallelic MUTYH mutation (mean age56,5years) and180patients with either identified APC gene mutation, either a personal and family historysuggesting APC-related polyposis (mean age44,1years,22-85). Treatment of desmoidtumor was proposed in those patients with progressive disease at radiological evaluationon a4to6month observational period. The response was evaluated retrospectively fromthe reports, according to RECIST criteria.Results：The median follow-up since the diagnosis of FAP was of25years. No patients (0/10)with MUTYH mutation ever developed desmoid tumor. In contrast,31/180(17,2%)patients with a mutation/phenotype of APC related polyposis (11M,20F) developed58DTs(some patients have more than one DT in different locations), at a mean age of44,1 years (range22:85). The location of all the58DTs were: mesenteric25, abdominal wall30, extra-abdominal3(breast2, buttocks1).Of these180patients, one patient was diagnosed with desmoid tumor before receivingthe prophylactic surgery. From the rest179FAP patients, a colectomy with ileo-rectalanastomosis had been performed in103(11with DT,10.7%) and proctocolectomy in76(19DT,25%, p=0.015). There was no other factor associated with the development ofDT, including the modality of surgery (laparotomy versus laparoscopy).As regards the treatment of DT: no treatment was proposed in3patients (mean56years, range51:73);12patients (with28DT) had31medical therapeutic sessions with amean duration of12,8months (range3-24months). Following RECIST criteria, aresponse was observed in3tumors (9,7%), a stabilisation in18cases (58,1%) and aprogressive disease in10cases (32,2%). Medical treatment was: celecoxib (6sessions),sulindac (8), tamoxifen (3), imatinib (8), sorafenib (1), bevacizumab (2), adriblastin (1),imatinib+celecoxib (1), tamoxifen+sulindac (1). Surgical treatment of the DT wasattempted in33cases in24patients:12mesenteric (recurrence5,41,6%) et21extramesenteric (6recurrences,28,5%).Conclusion：This study suggests only one risk factor for the development of desmoid tumor in APCrelated FAP patients, that is the type of surgery (colectomy versus proctocolectomy). Ifconfirmed, this may impact profoundly our surgical choices in these patients. On the otherhand, we confirm the low efficacy of available medical treatments in desmoid tumors ofFAP patients, and the high prevalence of recurrent disease after surgery.