The genomic landscape of advanced gastrointestinal (GI) neuroendocrine tumors (NET) and carcinomas (NEC).

Authors

null

Nicole Farha

Cleveland Clinic, Cleveland, OH;

Nicole Farha , Prabhjot Singh Mundi , Wei Wei , Suneel Deepak Kamath , Alok A. Khorana , Antonio Tito Fojo , Bahar Laderian

Organizations

Cleveland Clinic, Cleveland, OH; , Columbia University Medical Center, New York, NY; , Cleveland Clinic Foundation, Cleveland, OH; , Columbia University, New York, NY; , Cleveland Clinic Lerner College of Medicine, Cleveland, OH;

Research Funding

No funding received
None.

Background: The impact of specific genomic alterations in advanced GI neuroendocrine malignancies on prognosis and treatment decisions has not been fully characterized. In this study, we seek to evaluate next-generation sequencing (NGS) panels and corresponding clinical outcomes in patients with metastatic GI NET/NEC. Methods: Patients with GI-NET/NEC were identified from a database of NGS reports performed at the Cleveland Clinic, and clinical variables were extracted by chart review through an IRB-approved protocol. We provide an analysis of this cohort. Results: Of a total n=45 patients, 53% were male. Median age at diagnosis was 60 (range: 35-90 years) and 82% were non-Hispanic white, while 9% were black. There were n=25 GI-NETs, mostly intermediate or high grade (11 G3, 7 G2), and n=20 GI-NECs. There was a balanced distribution of primary sites, including colorectal (27%), pancreas (24%), small intestine (18%), unknown primary (24%) and a single case of biliary primary. High grade GI-NETs and GI-NECs were over-represented in the colorectal primary group vs other sites. (n=10 of 12; p=0.021). The majority of patients (73%) had at least one somatic variant, including 12 patients (27%) with one or more mutations deemed actionable, but only one patient (with MSH2 mutation) has received a mutation-matched drug (pembrolizumab). Some recurrent alterations appeared to co-segregate with aggressive histology (NEC vs NET), including 12 of 13 TP53 mutations (p<0.05 by Fisher Exact Test), 7 of 8 RB1 (p<0.05), and 5 of 6 APC (p=0.074). The most common mutations per person based on primary site is shown. Microsatellite instability high was rare (n=1) and median tumor mutational burden (TMB) was 3/mb, with TMB lower in NETs vs NECs. A number of patients (35%) underwent germline testing, with 6 of 16 having a pathogenic germline variant. Conclusions: As 42% of the 12 patients with actionable mutations were alive at time of analysis, it is possible that additional patients could be treated with mutation-matched therapies. More input will be needed from providers as to the role played by alternative effective treatments and barriers such as insurance coverage and prior authorization to implementing mutation-matched therapies. Given the overall low TMB of GI-NETs, with several tumors having zero or 1 reported mutation on targeted NGS, whole genome sequencing may prove useful. Finally, certain mutations such as RB1 and TP53 were associated with more aggressive histology (i.e. NEC). Lastly, only 9% of our cohort with NGS were black, a significant under-representation based on epidemiological data, which raises concerns about disparate accessibility and barriers to NGS testing. Further studies are needed to address any possible racial disparity.

No. of patients with gene variations in primary sites.

ColorectalPancreasBiliarySmall intestineUnknownTotal
TP535202413
RB1220048
MEN1
150017
DAXX030014

Disclaimer

This material on this page is ©2024 American Society of Clinical Oncology, all rights reserved. Licensing available upon request. For more information, please contact licensing@asco.org

Abstract Details

Meeting

2023 ASCO Gastrointestinal Cancers Symposium

Session Type

Poster Session

Session Title

Poster Session B: Cancers of the Pancreas, Small Bowel, and Hepatobiliary Tract

Track

Pancreatic Cancer,Hepatobiliary Cancer,Neuroendocrine/Carcinoid,Small Bowel Cancer

Sub Track

Tumor Biology, Biomarkers, and Pathology

Citation

J Clin Oncol 41, 2023 (suppl 4; abstr 656)

DOI

10.1200/JCO.2023.41.4_suppl.656

Abstract #

656

Poster Bd #

H6

Abstract Disclosures

Similar Abstracts

First Author: Dustin A. Deming

First Author: Nilesh Verma

First Author: Philippe E. Spiess

Abstract

2024 ASCO Gastrointestinal Cancers Symposium

Prognostic effects of co-occurring TP53 and KRAS aberrations in patients with advanced biliary tract cancer.

First Author: Taro Shibuki