Abstract 2690
Background
GIST in older adults and in children are well-known entities, but this is not the case for AYA patients with GIST. Typically, GIST in children (70% female) rarely show mutations in KIT or platelet-derived growth factor receptor (PDGFR) (<15%), are often Succinate Dehydrogenase (SDH) deficient, are almost always located in the stomach (90%) and have a relatively indolent course of disease. The typical adult GIST (about 50% female) has mutations in KIT (75%) or PDGFR (15%), stomach as main location and an overall 5-years survival of 65% (SEER data). As data on AYA with GIST are very limited, we aimed to study the clinical and genetic characteristics and outcome of this specific group.
Methods
AYA GIST patients (18-40 years at diagnosis) diagnosed between 2009-2019 and registered in the Dutch GIST Registry (DGR) were included. Patients without mutations in KIT/PDGFR/BRAF and SDH deficiency (by immunohistochemistry) were considered quadruple wildtype (WT). Overall survival (OS) was estimated using Kaplan-Meier method. Furthermore, two subgroups were compared: 18-29 years vs. 30-40 years (Chi-square, Fisher’s exact, Mann-Whitney U test).
Results
From 1011 patients in the DGR, 52 AYA patients (5%) were identified: 54% male, median age 35 years. Main primary tumor locations were stomach (46%) and small intestine (46%). Four AYA patients had a known genetic predisposition: 2 Neurofibromatosis 1 (NF1), 1 Carney Triad, 1 KIT exon 11 germline mutation. GIST genetic profiles were reported as KIT mutation 64%, PDGFR mutation 6%, KIT/PDGFR WT 6%, quadruple WT 8%, SDH deficient 6% and NF1 associated 4%. At diagnosis, 42% had high-risk GIST and 13% metastatic disease.
With a median follow-up of 43 months (0-113), median OS for all patients was 8.9 years with a 5-year survival of 85%. No significant differences were found between the two subgroups with regard to gender, location, size, morphology, risk classification and mutation status.
Conclusions
GIST presenting at AYA age is rare. AYA GIST differ from the well-known paediatric GIST, but are also not fully similar to the typical adult GIST. In our series a remarkable high percentage of small intestine GIST and high-risk tumours were observed, 30% non-KIT/PDGFR mutations and a relatively good survival.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The Netherlands Cancer Institute.
Funding
An unrestricted research grant for the Dutch GIST Registry was received from Novartis, Bayer and Pfizer.
Disclosure
I.M.E. Desar: Research grant / Funding (institution): Novartis; Advisory / Consultancy, advisory board: Eisai; Advisory / Consultancy, advisory board: Lilly. R.H.J. Mathijssen: Research grant / Funding (institution), Travel / Accommodation / Expenses: Astellas; Research grant / Funding (institution): Bayer; Research grant / Funding (institution): Boehringer; Research grant / Funding (institution): Cristal Therapeutics; Honoraria (institution), Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Pamgene; Research grant / Funding (institution), Travel / Accommodation / Expenses: Pfizer; Research grant / Funding (institution): Roche; Research grant / Funding (institution): Sanofi; Honoraria (institution): Servier. N. Steeghs: Research grant / Funding (institution): AstraZeneca/MedImmune; Research grant / Funding (institution): Bayer; Research grant / Funding (institution): Bristol-Myers Squibb; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): GlaxoSmithKline; Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): Roche; Research grant / Funding (institution): Genentech/Roche; Research grant / Funding (institution): Boehringer Ingelheim; Research grant / Funding (institution): Blueprint Medicines; Research grant / Funding (institution): AB science; Research grant / Funding (institution): Deciphera; Research grant / Funding (institution): Genentech; Research grant / Funding (institution): Merck Sharp & Dohme; Research grant / Funding (institution): Amgen; Research grant / Funding (institution): Lilly; Research grant / Funding (institution): Incyte; Research grant / Funding (institution): Merus. W.T.A. van der Graaf: Research grant / Funding (institution): Novartis; Advisory / Consultancy: Bayer. All other authors have declared no conflicts of interest.
Resources from the same session
5239 - Treatment patterns and outcomes for patients (pts) with anaplastic lymphoma kinase-positive (ALK+) advanced non-small-cell lung cancer (NSCLC) in US clinical practice
Presenter: Matthew Krebs
Session: Poster Display session 1
Resources:
Abstract
5595 - Is there any prognostic significance in pleural involvement and/or effusion (Ple-I/E) in patients with ALK-positive NSCLC?
Presenter: Saadettin Kilickap
Session: Poster Display session 1
Resources:
Abstract
5840 - Crizotinib in patients with advanced or metastatic ROS1-rearranged lung cancer (EUCROSS): A European phase 2 clinical trial – Updated progression-free survival, overall survival and mechanisms of resistance
Presenter: Sebastian Michels
Session: Poster Display session 1
Resources:
Abstract
1905 - NTRK1-3 Genomic Fusions in Non-Small Cell Lung Cancer (NSCLC) Determined by Comprehensive Genomic Profiling
Presenter: Sai-Hong Ou
Session: Poster Display session 1
Resources:
Abstract
3016 - Preferential expression of the affected MET allele in lung carcinomas with heterozygous MET exon 14 skipping mutations: implications for clinical testing
Presenter: Evgeny Imyanitov
Session: Poster Display session 1
Resources:
Abstract
4120 - Brain metastases, treatment patterns and outcomes in ROS1-positive NSCLC patients from US oncology community centers
Presenter: Matthew G Krebs
Session: Poster Display session 1
Resources:
Abstract
3764 - Patients with metastatic non-small cell lung cancer and targetable molecular alterations in Germany. Treatment and first outcome data from the prospective German Registry Platform CRISP (AIO-TRK-0315)
Presenter: Frank Griesinger
Session: Poster Display session 1
Resources:
Abstract
4070 - Crizotinib vs Platinum-based Chemotherapy as First-line Treatment for Advanced Non-small Cell Lung Cancer with Different ROS1 Fusion Variants
Presenter: Haiyan Xu
Session: Poster Display session 1
Resources:
Abstract
5528 - Genomic and clinical characterization of Non-small cell lung cancer (NSCLC) patients harboring mutations in FGFR2 and FGFR3
Presenter: Matthias Scheffler
Session: Poster Display session 1
Resources:
Abstract
3779 - The expression of HER2-gene polymorphisms -1985G>T and P1170A C>G and their association with the risk of development of lung adenocarcinoma
Presenter: Ivan Aleric
Session: Poster Display session 1
Resources:
Abstract