In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 27, No. 15_suppl ( 2009-05-20), p. 10535-10535
Abstract:
10535 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. [Table: see text]
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2009.27.15_suppl.10535
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2009
detail.hit.zdb_id:
2005181-5
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