1431P - Gastrointestinal stromal tumors (GIST) and second malignancies: a novel "sentinel tumor"?

Date 29 September 2014
Event ESMO 2014
Session Poster Display session
Topics GIST
Presenter Maria Grazia Rodriquenz
Citation Annals of Oncology (2014) 25 (suppl_4): iv494-iv510. 10.1093/annonc/mdu354
Authors M.G. Rodriquenz1, R. Ricci2, M. Iezzi1, M. Martini2, M. Basso1, V. Dadduzio1, L.M. Larocca2, C. Barone1, A. Cassano1
  • 1Oncologia Medica, Policlinico Universitario A. Gemelli Università Cattolica del Sacro Cuore, 00168 - Roma/IT
  • 2Anatomia Patologica, Policlinico Universitario A. Gemelli Università Cattolica del Sacro Cuore, 00168 - Roma/IT



The association between GIST and second cancers, both synchronous or asynchronous, remains uncertain either in frequency or in molecular pathogenesis and histotypes. The aim of this study was to evaluate the incidence of second malignancies in our series, with particular regard to molecular profiling.


Clinical data were retrospectively collected in 96 patients with GIST treated at our institution between July 2002 and April 2014. Since 2010 molecular analysis of KIT (exon 9, 11 and 13) and PDGFRalfa (exon 12, 14 and 18) genes was performed.


Among 96 GIST patients, 33 (34.4%) had a second cancer (19 synchronous [57.6%], 7 methachronous [21.2%] and 7 previous [21.2%]). Most second tumors (19; 57.5%) raised from gastrointestinal (GI) tract (6 gastric, 4 colorectal, 2 esophageal, 2 duodenal, 1 hepatocellular, 1 colangiocarcinoma, 3 pancreatic). Extraintestinal second tumors included lung, breast, endometrial, prostate, urothelial, thyroid, peritoneal mesothelioma. In our series benign neoplasms were also included (1 meningioma; 2 inflammatory fibrous gastrointestinal polips). Molecular analysis was available for 16/33 patients: 3 had a WT GIST, 10 carried a KIT exon 11 mutation, 2 a PDGFR-α exon 14 mutation and 1 a PDGFR-α exon 18 mutation. Interestingly, exon 11 KIT mutations were mainly associated with GI adenocarcinomas (8/10), while WT GISTs were linked with neoplasms other than Gl. The two patients with PDGFR-α exon 14 mutation were both diagnosed to have a germline mutation with inflammatory fibrous gastrointestinal polips. In metachronous cases the mean time interval between GIST and second tumor was 22.8 months. The mean follow up was 48.7 months (range: 6 - 141 months).


This is the largest series on this topic. The relation between exon 11 mutations and GI second tumors suggests to investigate a possible common molecular mechanism. Following the short interval between GIST diagnosis and onset of second neoplasms, the authors suggest to perform strict follow-up particularly in the first years after diagnosis.


All authors have declared no conflicts of interest.