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Sub-category:
Gastrointestinal Stromal Tumors
Category:
Sarcoma
Meeting:
2009 ASCO Annual Meeting
Session Type and Session Title:
Poster Discussion, Sarcoma
Abstract No:
10535
Citation:
J Clin Oncol 27:15s, 2009 (suppl; abstr 10535)
Author(s):
J. Emile Francois, S. Brahimi, J. Coindre, G. Monges, J. Y. Scoazec, J. Blay, O. Bouché, P. Aegerter, Groupe d'Etude des GIST; EA4340, Ambroise Paré Hospital, APHP, UVSQ, Boulogne, France; Institut Bergonié, Bordeaux, France; Institut Paoli-Calmettes, Marseille, France; Edouard Herriot Hospital, Lyon, France; INSERM U590, Centre Léon Bérard, Lyon, France; CHU, Reims, France; Ambroise Paré Hospital, AP-HP, Boulogne, France
Abstract:
Background: KIT exon 11, KIT exon 9, and PDGFRA exon 18 mutations are present in 67%, 10% and 5% of gastrointestinal stromal tumors (GIST). However most of these data are based on analyses of patients with overtly metastatic tumors. The MolecGIST study was design to evaluated prospectively the histological, molecular and clinical characteristics of all GISTs diagnosed at all stages. Methods: All patients leaving in France, whose diagnosis of GIST was achieved between June 1, 2006 and May 31, 2008 were includable in the study. MolecGIST was approved by French ethical comities. Samples were collected in 11 reference centers for histology review, immunohistochemistry and detection of mutations within exon 9, 11, 13, and 17 of KIT and 12, 14, and 18 of PDGFRA. Results: In December 2008, 738 patients were referred to MolecGIST, corresponding to 5.95/million/year incidence of GIST en France (62 millions inhabitants). The median age at diagnosis 63.1 years (range [15-96]), and female/male ratio 0.98. GIST originated in the stomach in 56.3% and small bowel in 29.3% of the cases. Tumors were KIT+ in 90,4% of cases. CD34 was expressed by more than 20% of tumor cells in 83.8% of gastric GIST and 39.7% of small bowel GIST respectively (P<0.0001). The risk of metastatic relapse was moderate or high in 62.7% of the patients, according to Fletcher classification, while only in 44% according to Miettinen's. Mutation analyses were achieved in 438 cases (to be updated), and mutations of either KIT or PDGFRA were detected in 66.2% and 12.6% of the patients, and absent in 21.2%. The most frequent mutations were KIT exon 11 (59.1%), PDGFRA exon 18 (9.8%) and KIT exon 9 (4.3%). The incidence of PDGFRA exon 18 and KIT exon 9 were significantly different than the published data (P=0.0008 and P<0.0001 respectively). Among GIST of the small bowel, the mutations were KIT exon 11 (69.1%) and KIT exon 9 (13.1%). Conclusions: The PDGFRAexon18/KITexon9 mutation ratio is 4.5 times higher in our population based study than in patients included in phase III trials. The incidence of GIST with PDGFRA mutations and intestinal GIST exon KIT exon 11 mutations is underestimated in published series as compared to ours, probably because of the better prognosis.
Abstract Disclosures
Faculty and Discussant Disclosures
Annual Meeting Planning Committee Disclosures
2009 Annual Meeting Proceedings Part I Errata
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy
and are designated with a caret symbol (^) here and in the print version.
 Associated Presentation(s):
Other Abstracts in this Sub-Category:
Abstracts by J. Emile Francois:
Presentations by J. Emile Francois:
Educational Book Manuscripts by J. Emile Francois:
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