[63] Impact of Molecular Analysis on the Final Diagnosis of Sarcomas: A Study on 369 Cases Collected in the Setting of a European Epidemiological Study. A Report from CONTICANET Network of Excellence

JM Coindre, AP Dei Tos, D Ranchere-Vince, MC Montesco, AV Decouveleare, L Toffolatti, F Chibon, I Hostein, D Pissaloux, L Alberti, PP Bringuier, E Lazzari, S Albert, C Bellera, JY Blay, CR Rossi. Institut Bergonié, Bordeaux, France; Centre Léon Bérard, Lyon, France; General Hospital of Treviso, Treviso, Italy; University of Padua School of Medicine, Padua, Italy

Background: Sarcomas are rare, heterogeneous and often difficult to classify. A significant subset of sarcomas are associated with specific molecular genetic lesions such as translocations, mutations and amplifications which are helpful in the diagnosis of individual cases. However, the accurate impact of molecular genetics on the final diagnosis of sarcomas is unknown.
Design: All soft tissue and visceral sarcomas arising in patients living in 3 European areas (12 millions inhabitants) have been collected during 2 consecutive years. Every case has been reviewed by a pathologist specialised in sarcomas and a molecular analysis has been performed for any suspicion of a sarcoma with a specific genetic lesion (reciprocal translocation, mutations of KIT/PDGFRA in GIST, amplification of MDM2/CDK4 in atypical lipomatous tumor-well differentiated liposarcoma/dedifferentiated liposarcoma or ALT-WDLPS/DDLPS). In order to evaluate the impact of molecular tests, a pre-molecular analysis diagnosis has been proposed with 3 categories of certainty: 1-Certain diagnosis when the proposed diagnosis is the only possible one; 2-Probable diagnosis when the proposed diagnosis is the first diagnosis contemplated, but a differential diagnostic issue is raised by other tumors; 3-Possible diagnosis when the proposed diagnosis is not the first diagnosis considered.
Results: During the first year, molecular analysis has been performed in 369 / 804 tumors corresponding to 166, 106 and 97 suspicion of respectively GIST, sarcomas with a translocation and ALT-WDLPS/DDLPS. Molecular analysis has been helpful (confirmation of a probable diagnosis) in 7 (4%) GIST, 34 (32%) suspicion of translocation and 31 (32%) suspicion of ALT-WDLPS/DDLPS and necessary (confirmation of a possible diagnosis) in 2 (1%) GIST, 8 (8%) suspicion of translocation and 3 (3%) suspicion of ALT-WDLPS/DDLPS.
Conclusions: In this study, the main use of molecular genetics is to confirm a suspicion of sarcoma with a translocation or an ALT-WDLPS/DDLPS in about one third of cases as well as to make possible the diagnosis of almost 10% of sarcomas with a translocation.
Category: Bone & Soft Tissue

Monday, March 22, 2010 9:00 AM

Platform Session: Section F, Monday Morning


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