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
5128 - IO-Synthesise NSCLC: A pooled analysis of real-world survival outcomes for non-small cell lung cancer patients treated with nivolumab in France and Germany
Presenter: Adrien Dixmier
Session: Poster Display session 1
Resources:
Abstract
2066 - Second-line (2L) real-world treatment (tx) patterns and outcomes in patients (pts) with advanced/metastatic non-small cell lung cancer (NSCLC) treated with first line (1L) immuno-oncology (IO) monotherapy (mono tx)
Presenter: Denis Talbot
Session: Poster Display session 1
Resources:
Abstract
5919 - Real-world effectiveness of nivolumab monotherapy after prior systemic therapy in advanced non-small cell lung cancer (NSCLC) in the United States
Presenter: David Stenehjem
Session: Poster Display session 1
Resources:
Abstract
3368 - Pembrolizumab as first-line treatment in NSCLC with PD-L1 ≥50%: Real life results from an all-comer population
Presenter: Nikolaj Frost
Session: Poster Display session 1
Resources:
Abstract
3775 - Patients with metastatic non-small cell lung cancer without molecular alterations or PD-L1 expression in Germany. Treatment and first outcome from the prospective German Registry Platform CRISP (AIO-TRK-0315)
Presenter: Frank Griesinger
Session: Poster Display session 1
Resources:
Abstract
3926 - Impact of second-line (2L) immune checkpoint inhibitors (ICIs) on the treatment (Tx) of advanced non-small cell lung cancer (NSCLC) in a UK centre: a REAL-Oncology analysis from the I-O Optimise initiative
Presenter: Michael Snee
Session: Poster Display session 1
Resources:
Abstract
5068 - First line pembrolizumab for NSCLC with PD-L1 TPS > 50% in a first French real life cohort
Presenter: Karim Amrane
Session: Poster Display session 1
Resources:
Abstract
1182 - Interstitial lung disease induced by immune-checkpoint inhibitors correlates with prognosis of advanced non-small-cell lung cancer patients
Presenter: Teppei Sugano
Session: Poster Display session 1
Resources:
Abstract
2297 - Phase II study to evaluate the peripheral blood mononuclear cell biomarker for nivolumab efficacy on previously treated non-small cell lung cancer subjects (NEJ029B: IMMUNITY-ONE)
Presenter: Yosuke Kawashima
Session: Poster Display session 1
Resources:
Abstract
2739 - Efficacy and safety of nintedanib + docetaxel in lung adenocarcinoma patients (pts) following treatment with immune checkpoint inhibitors (ICIs): Updated results of the ongoing non-interventional study (NIS) VARGADO (NCT02392455)
Presenter: Christian Grohe
Session: Poster Display session 1
Resources:
Abstract