Surgical and medical management of small bowel gastrointestinal stromal tumors: A report of the Dutch GIST registry

Historical trends in histological composition and cause specific mortality of small intestine tumors based on SEER database analysis

Small intestine tumors, though rare, have shown a concerning increase in incidence and mortality in recent years. This study aimed to investigate the historical trends in histological composition and causes of death among patients with small intestine tumors using the SEER database. A total of 18,234 patients diagnosed with primary small intestine cancer from 1992 to 2018 were included in this study. Demographic details, tumor characteristics, treatment modalities, and outcomes were collected. Cause-specific mortality was analyzed using Fine and Gray regression, with non-small intestine-specific deaths considered as competing risks. Small intestine-specific deaths were the leading cause of mortality, with adenocarcinoma and carcinoid tumors being the most common histological types. Heart disease emerged as a significant cause of death following diagnosis, surpassing small intestine-specific deaths after 5-6 years. The study revealed variations in mortality causes across histological subtypes and identified risk factors for small intestine-specific mortality, including age, tumor site, grade, and treatment modalities. The findings highlight the substantial impact of heart disease on the long-term survival of patients with small intestine tumors. This underscores the potential benefits of adopting comprehensive management strategies that integrate oncological and cardiological care to improve survival rates and quality of life. A multidisciplinary approach in oncocardiology may help address the complex needs of these patients and optimize clinical outcomes.

Molecular Portrait of GISTs Associated With Clinicopathological Features: A Retrospective Study With Molecular Analysis by a Custom 9-Gene Targeted Next-Generation Sequencing Panel

Objectives: The study aims to investigate genetic characterization of molecular targets and clinicopathological features with gastrointestinal stromal tumors based on targeted next-generation sequencing.

Materials and Methods: We selected 106 patients with GISTs from Sir Run Run Shaw Hospital between July 2019 and March 2021. FFPE samples and paired blood samples were obtained from these patients who underwent excision of the tumor. A customized targeted-NGS panel of nine GIST-associated genes was designed to detect variants in the coding regions and the splicing sites of these genes.

Results: In total, 106 patients with a GIST were included in the study which presented with various molecular driver alterations in this study. KIT mutations occurred most often in GISTs (94/106, 95.92%), followed by point mutations in PDGFRA. KIT or PDGFRA mutations were detected to be mutually exclusive in the GIST. A total of eight patients with wide-type KIT/PDGFRA were characterized as WT-GISTs, according to clinical diagnosis which included six quadruple-WT GISTs, 1 BRAF-mutant, and 1 NF1-mutant GIST. In KIT exon 11, the most common mutation type was the codon Mutation (in-frame deletion or indels), whereas the missense mutation was the dominant type in KIT exon 13 and KIT exon 17. All variations in KIT exon 11 observed in this study were concentrated at a certain position of codon 550 to codon 576. Mutation in KIT exon 9 was mostly located at codon 502–503. Two germline pathogenic mutations were detected: NF1-R681* and KRAS-T58I. NF1-L591P was a germline mutation to be identified for the first time and is not recorded in the database. The frequency of driving mutations differed between the primary anatomical site in the GIST (p = 0.0206). KIT exon 11 mutants had a lower proliferation index of Ki67 (68.66%,≤5%), while 50.00% of KIT exon 9 mutants had the Ki67 status greater than 10%.

Conclusion: The occurrence and development of a GIST is driven by different molecular variations. Resistance to TKIs arises mainly with resistance mutations in KIT or PDGFRA when they are the primary drivers. Targeted NGS can simultaneously and efficiently detect nine GIST-related gene mutations and provide reference for clinicians’ individualized diagnosis and treatment. Our results have important implications for clinical management.

Current Oncologic Standards for Surgery of Small Bowel Cancers

PURPOSE

The last 2 decades has witnessed efforts towards standardization of surgery for small bowel cancers. The proposed recent guidelines/recommendations pertaining to choice of procedure and extent of lymphadenectomy are based on analysis of data from high volume centres of excellence. We evaluated whether these recently proposed oncologic recommendations can be replicated in the setting of single centre/team.

METHODS

This was a retrospective analysis of consecutive adult patients (age ≥ 18 years) who underwent surgery for tumours of small intestine (duodenum, jejunum, and ileum) by the same team of surgeons from 01/01/2010 to 12/31/2019. The procedure performed and lymph nodes harvested during pathologic examination were compared with recent recommendations.

RESULTS

Of the 32 patients (20 males and 12 females), mean age was 52.4 (range 31-77) years. Twenty-nine (90.6%) patients underwent surgery for small bowel cancers. Duodenum was the most common site, while NET was the commonest cancer. Whipple's procedure was performed for tumours of II part of duodenum, while for the rest, segmental resection was performed. The median number of lymph nodes examined for duodenal adenocarcinoma and NET was 14 and 9, respectively. For jejunal/ileal adenocarcinoma, median lymph node number examined was 11.

CONCLUSION

Our study shows that these recently proposed standards for surgery of small bowel cancers are achievable if basic principles of oncologic surgery are followed.

Characteristics and prognosis of jejunoileal gastrointestinal stromal tumours (GISTs) in the era of imatinib: a comparative study with gastric GISTs

BACKGROUND

Gastrointestinal stromal tumours (GISTs) located in the jejunum or ileum (JI-GIST) are considered worse prognosis compared to those of gastric (G-GIST) location. It has been suggested that this dogma should be revised. The aim of this study was to describe the characteristics of jejunoileal GISTs and its prognosis and to compare them with G-GISTs in the era of imatinib.

METHODS

We retrospectively reviewed the clinical histories of all the patients diagnosed with GISTs between January 2000 and November 2016: Clinical and pathological data, as recurrence, metastatic state, disease-free survival (DFS) as well as overall survival (OS) rates of patients were reviewed.

RESULTS

JI-GIST patients comprise 29 cases (37.7%). Compared to G-GIST, JI-GIST patients had undergone emergency surgery more frequently (37.9% vs. 10.4%, p = 0.007). According to the NIH-Fletcher classification, the low or very-low risk group represents 17.2% of JI-GISTs as opposed to 37.6% of G-GISTs (p < 0.005). When the AFIP-Miettinen system was used the low or very-low group represented 17.2% of JI-GISTs vs. 58.4% in the G-GISTs group (p < 0.001). Both local recurrence (24.1% vs. 12.5%, p < 0.05) and metastatic rate (34.5% vs. 22.9%, p < 0.05) were higher in the JI-GIST group than in G-GIST. 5- and 10-year DFS and 10-year OS rate were lower for JI-GIST (54.5% and 39.6% vs. 77.2% and 60.8%, and 57.9% vs. 65%, respectively, p < 0.05).

CONCLUSIONS

The observed differences between both groups in DFS and OS rates at long term could be attributed to the effect of imatinib.

Gastrointestinal Stromal Tumours (GIST) in Young Adult (18-40 Years) Patients: A Report from the Dutch GIST Registry

Gastrointestinal stromal tumour (GIST) is a disease of older adults and is dominated by KIT/PDGFR mutations. In children, GIST is rare, predominantly occurs in girls, has a stomach location and generally lacks KIT/PDGFR mutations. For young adults (YA), aged 18 to 40 years, the typical phenotypic and genotypic patterns are unknown. We therefore aimed to describe the clinical, pathological and molecular characteristics of GIST in in YA. YA GIST patients registered in the Dutch GIST Registry (DGR) were included, and data were compared to those of older adults (OA). From 1010 patients in the DGR, 52 patients were YA (54% male). Main tumour locations were stomach (46%) and small intestine (46%). GIST genetic profiles were mutations in KIT (69%), PDGFRA (6%), SDH deficient (8%), NF1 associated (4%), ETV6-NTRK3 gene fusion (2%) or wildtype (10%). Statistically significant differences were found between the OA and YA patients (localisation, syndromic and mutational status). YA presented more often than OA in an emergency setting (18% vs. 9%). The overall five-year survival rate was 85%. In conclusion, YA GISTs are not similar to typical adult GISTs and also differ from paediatric GISTs, as described in the literature. In this series, we found a relatively high percentage of small intestine GIST, emergency presentation, 25% non-KIT/PDGFRA mutations and a relatively good survival.