1673PD - Impact of abstention of diagnostic biopsy in sarcoma

Abstract

BackgroundClinical practice guidelines indicate that tumors<=3cm with a suspected sarcoma diagnosis may be proposed for excision first without prior biopsy. We investigated the impact of preoperative biopsy on the outcome of patients with sarcomas<=3cm (SArcinf3) included in the nationwide NETSARC database from 2010 to 2017. MethodsNETSARC is a network of 26 reference sarcoma centers with specialized multidisciplinary tumor boards (MDTB), funded by the French NCI (INCa). 1720 of 27894 (6.2%) incident patients had a sarcoma with a documented size<=3cm at diagnosis in the database. Statistics were performed with SPSS23.0. Local relapse-free survival (LRFS), metastasis-free survival (MFS), overall survival (OS) were compared with the logrank test. ResultsAs compared to larger sarcoma, Sarcinf3 were less frequently deep seated, from internal trunk, from visceral or bone sites, metastatic at diagnosis and grade 3 (p<0.0001 all). The distribution of gender and age were similar. Different NETSARC centers distributions were observed as compared to larger tumors. The most frequent histotypes were LMS, dermatofibrosarcoma, GIST, UPS, angiosarcoma. Preoperative biopsy was reported in 893 of 1720 (51.9%) of Sarcinf3 vs 68.5% for larger tumors (p<0.0001). Within the entire series of 1720 pts, lack of preoperative biopsy was not found correlated to an increased risk of LRFS, MFS, or death in univariate and multivariate analysis (including gender, age, tumor grade, size, site, depth, histotypes, surgery in NetSARC). Similar results were observed excluding DFSP and within the soft tissue tumor subgroup. Surgery in NETSARC was associated with a lower risk of LRFS in multivariate analysis. However, significantly more patients were re-operated when preoperative biopsy were omitted (21.9% vs 10.0%, p<0.0001). There were significantly more R1 & R2 resections in the non-biopsy group, both after the first (p<0.0001) and after the final surgery (p<0.01). ConclusionsIn this nationwide series of 1720 pts with sarcomas<3cm, those operated without a biopsy and those operated after a diagnostic biopsy had a similar LRFS, MFS and OS. However, both the initial and final quality of surgery was worse, and the rate of reoperation was superior in patients operated first without a biopsy. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.