Preoperative Tru-Cut biopsy (POB) for the diagnosis of retroperitoneal soft tissue sarcomas (RPS) and risk of local recurrence (LR) compared to primary surgery of the tumor.

10583 Background: Regardless optimal surgery LR is still a major challenge in RPS affecting 60% of the patients (pts). To improve these results pre-operative radiotherapy +/- chemotherapy are under investigation. This strategy requires to perform a POB. The surgical removal of the whole needle track is mandatory for limb sarcomas, but it can hardly ever be achieved in RPS. We explored whether POB did increase the risk of LR in terms of tumor cell seeding (along the needle track) or in the tumor mass area. Methods: We scanned our prospectively (01/2000 to 12/2010) collected RPS database including 176 pts. Complete information (records, CT scans, biopsy-track, follow up data) were available and retrospectively examined in 100 pts. Pts were divided into: group A (POB), group B (direct surgery). The 7 year probability of disease free survival (DFS) was estimated for each pt (ASCO 2012 abs 10000). T student test and Fisher's exact test were used to compare the estimated DFS and the incidence of LR in the 2 gro...