Sporadic extra abdominal wall desmoid-type fibromatosis : surgical resection can be safely limited to a minority of patients

Background To analyse the natural history of extra-abdominal wall desmoid-type fibromatosis (DF) and compare outcome in patients who underwent initial surgery with those who did not. Patients and methods All consecutive patients affected by primary sporadic extra-abdominal wall DF observed between January 1992 and December 2012 were included. Patients were divided into surgical (SG) or non-surgical groups (NSG) according to initial treatment. Relapse free survival was calculated for SG, and crude cumulative incidence (CCI) of switching to surgery or other treatments for NSG. Results 216 patients were identified, 94 in SG (43%), 122 in NSG (57%). A shift towards a more systematic use of a conservative approach (78% of all comers) was observed in the latter years (2006-2012), although a small proportion of patients (28%) had been offered the conservative strategy even in the early period (1992-2005). Median follow-up (FU) was 49 mo. (interquartile (IQ), 20-89 mo.), 76 months for SG and 39 months for NSG. 5-year relapse-free survival (RFS) for SG was 80% (95% confidence interval (CI), 72-89%). For the NSG, 5-year CCI of switching to surgery was 5% (95% CI: 1.7%, 14%), and 51% to other treatments (95% CI: 41%, 65%). 27 (20%) NSG patients underwent spontaneous regression. Conclusion A non-surgical approach to extra-abdominal wall DF allowed surgery to be avoided in the majority of patients. This approach can be safely proposed and surgery offered as an option in selected cases.