Adjuvant therapy for rare rectal gastrointestinal stromal tumors: A case report

Key Clinical Message

Anorectal gastrointestinal stromal tumors are extremely rare, constituting less than 0.1% of rectal tumors. Surgical resection using a transanal wide excision followed by adjuvant therapy with tyrosine kinase inhibitors can be a successful treatment combination to remove the mass and prevent recurrence while preserving the integrity of the anal sphincter.

Abstract

Gastrointestinal stromal tumors (GISTs) are a rare subset of neoplasms, accounting for about 1%-2% of primary gastrointestinal malignancies. The stomach is the most common site for GISTs, with anorectal GISTs being exceptionally rare, representing only 0.1% of all rectal tumors. The standard approach for managing localized GIST involves complete surgical excision to achieve negative microscopic margins (R0) while preserving the tumor capsule and maintaining anal sphincter function. Surgical resection with transanal wide excision followed by adjuvant therapy using tyrosine kinase inhibitors can successfully remove the mass, prevent recurrence, and preserve the anal sphincter's integrity. Adjuvant therapy with imatinib is the recommended treatment for all localized GISTs assessed to have an intermediate or high risk of relapse. Here, we report a case of a 63-year-old male with a rectal GIST who underwent transanal wide excision followed by adjuvant therapy with tyrosine kinase inhibitors.

Safety outcomes of low versus high dose imatinib mesylate in patients with advanced, metastatic, or nonresectable gastrointestinal stromal tumors: A systematic review

Background and Objectives

Gastrointestinal stromal tumors (GIST) are a rare cancer where tumors grow along the gastrointestinal tract. While treatment options aim towards surgical resection, some patients present with advanced metastatic and/or nonresectable diseases. The tyrosine kinase inhibitor imatinib mesylate is approved for this indication. However, dose escalation from 400 to 600 mg/d or 800 mg/d is allowed. The present study systematically evaluates the safety outcomes, particularly the incidence of grade ⩾ 3 adverse events (AEs) with low dose compared with high dose imatinib in these patients.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines were utilized to identify relevant studies through the PubMed, Cochrane Library, and Ovid databases and included randomized and non-randomized clinical trials comparing a low dose intervention of imatinib 400 mg/d with a high dose comparator of 600 or 800 mg/d in patients with histologically confirmed advanced metastatic and/or nonresectable GIST. Four studies were reviewed regarding study summaries and patient characteristics, patient demographics, and risk of bias, with a main emphasis on the evaluation of both efficacy outcomes and safety outcomes.

Results

Three of the four studies did not provide significant differences in response outcomes; however, all four studies reported a higher incidence of grade ⩾ 3 AEs in the high dose imatinib groups. Individual study reports of more high dose patients experiencing a grade ⩾ 3 event ranged from 0.6% to 19.8%, while combined low and high dose patient arms revealed a 17.1% difference favoring a high dose patient event. A sub-analysis of the three most frequently occurring categories, blood and lymphatic system disorders, gastrointestinal disorders, and general disorders and administration site conditions each revealed more high dose patients experiencing said category events compared to those low dose counterparts.

Conclusion

Low dose imatinib provides clinically meaningful response and demonstrated better tolerability with less frequently reported reactions. This evidence supports further research into the maintenance of 400 mg/d for this patient population compared to a dose escalation.

Pimitespib for the treatment of advanced gastrointestinal stromal tumors and other tumors

Pimitespib (TAS-116) is the first heat shock protein 90 (HSP90) inhibitor approved in Japan, and it is indicated for the treatment of gastrointestinal stromal tumors (GIST) that have progressed after treatment with imatinib, sunitinib and regorafenib. This review describes the preclinical and clinical research with pimitespib, including its mechanism of action, pharmacokinetics, clinical antitumour activity and safety. In a phase III study, pimitespib significantly prolonged progression-free survival compared with placebo (median 2.8 vs 1.4 months; hazard ratio 0.51; 95% CI 0.30-0.87; p = 0.006). Common treatment-related adverse events were diarrhoea, decreased appetite, increase in serum creatinine, malaise, nausea and eye disorders. The efficacy and safety of pimitespib are being investigated in other tumour types and in combination with other anticancer therapies.

Unexpected reaction of "wild-type" gastrointestinal stromal tumor to imatinib: case report and literature review

Background

Most of gastrointestinal stromal tumors (GISTs) are driven by mutations in the KIT/PDGFRA genes and can benefit from TKIs treatment. However, a small subset of GIST (10%-15%) are called "wild-type" GISTs due to the lack of these mutations. Theoretically, they would not benefit from TKIs treatment and may even develop resistance. Therefore, this unexpected response may challenge inherent perceptions. Herein, we present a case of giant wild-type GIST exhibiting an unexpected response to imatinib(IM), followed by laparoscopic surgical resection. Subsequently, potential underlying mechanisms are discussed.

Case description

This case describes a 57-year-old man who presented with abdominal pain for two weeks. CT revealed a massive lesion near the splenic hilum along the greater curvature of the stomach, concurrently involving the splenic hilar vessels and surrounding lymph nodes. Ultrasound-guided fine needle aspiration biopsy confirmed it is a mesenchymal spindle cell tumor,GIST. Due to the enormous volume and local invasion, neoadjuvant chemotherapy was initially considered. After 6 months of IM 400 mg/d, CT imaging revealed marked changes in tumor heterogeneity and a significant reduction in volume. Subsequently, laparoscopic surgical resection was performed. Postoperative pathological examination, immunohistochemistry, and genetic testing collectively confirmed it is a wild-type GIST.The patient recovered well and was discharged on the 6th day after surgery, with continued oral IM(400 mg/d) after discharge. No recurrence was observed during follow-up until the publication of this report.

Conclusion

This unexpected response suggests that wild-type GISTs may benefit from TKIs treatment, and the potential mechanisms warrant further investigation. Additionally, true wild-type GIST may not be discerned due to current limitations of Next-Generation Sequencing(NGS). Therefore, for advanced/high-risk GIST, additional genetic analysis can be performed after negative NGS results.

A 65-Year-Old Man Presenting to the Emergency Department with Gastric Hemorrhage Caused by a Glomus Tumor

BACKGROUND Glomus tumor is a benign but rapidly growing mesenchymal tumor that is a rare in the gastrointestinal tract, can be locally invasive due to its rapid growth, and can result in perforation of a viscus. We report a 65-year-old man presenting as an emergency with gastric hemorrhage and gastric glomus tumor. CASE REPORT A 65-year-old man came to our hospital for a life-threatening upper digestive hemorrhage. The preoperative examinations (digestive endoscopy without sampling of biopsy fragments and contrast-enhanced computer tomography) led to the presumptive diagnosis of gastrointestinal stromal tumor. Wedge resection of the gastric wall was performed. The histopathological examinations revealed a proliferation of round-oval cells of medium size with a solid disposition and in nests. This proliferation dissected the muscular tunic and caused ulceration of the gastric mucosa. Immunohistochemical tests confirmed the diagnosis of glomus tumor and excluded other diagnoses (neuroendocrine tumor or gastrointestinal stromal tumor). The postoperative evolution was favorable, and at the time of discharge, the biochemical test values normalized. CONCLUSIONS Pathologists are faced with a challenging task due to the deceptive appearance that can be presented by such a rare tumor. Histopathological and immunohistochemical examinations are essential in achieving a precise diagnosis and assessing the biological potential of the glomus tumor. Even if it is a benign tumor, the clinical picture it causes can still be a major risk to the patient's life. Consequently, ensuring effective case management becomes crucial, as it requires a thorough comprehension of all conditions encompassed in the differential diagnosis.

Using machine learning models to predict synchronous genitourinary cancers among gastrointestinal stromal tumor patients

Objectives

Gastrointestinal stromal tumors (GISTs) can occur synchronously with other neoplasms, including the genitourinary (GU) system. Machine learning (ML) may be a valuable tool in predicting synchronous GU tumors in GIST patients, and thus improving prognosis. This study aims to evaluate the use of ML algorithms to predict synchronous GU tumors among GIST patients in a specialist research center in Saudi Arabia.

Materials and Methods

We analyzed data from all patients with histopathologically confirmed GIST at our facility from 2003 to 2020. Patient files were reviewed for the presence of renal cell carcinoma, adrenal tumors, or other GU cancers. Three supervised ML algorithms were used: logistic regression, XGBoost Regressor, and random forests (RFs). A set of variables, including independent attributes, was entered into the models.

Results

A total of 170 patients were included in the study, with 58.8% (n = 100) being male. The median age was 57 (range: 9-91) years. The majority of GISTs were gastric (60%, n = 102) with a spindle cell histology. The most common stage at diagnosis was T2 (27.6%, n = 47) and N0 (20%, n = 34). Six patients (3.5%) had synchronous GU tumors. The RF model achieved the highest accuracy with 97.1%.

Conclusion

Our study suggests that the RF model is an effective tool for predicting synchronous GU tumors in GIST patients. Larger multicenter studies, utilizing more powerful algorithms such as deep learning and other artificial intelligence subsets, are necessary to further refine and improve these predictions.

Metabolic pseudoprogression in a patient with metastatic KIT exon 11 GIST after 1 month of first-line imatinib: a case report

Background

Positron emission tomography (PET) with 18-fluorodeoxyglucose (18FDG) has proven to be highly sensitive in the early assessment of tumor response in gastrointestinal stromal tumors (GIST), especially in cases where there is doubt or when the early prediction of the response could be clinically useful for patient management. As widely known, kinase mutations have an undoubtful predictive value for sensitivity to imatinib, and the inclusion of KIT and PDGFRa mutational analysis in the diagnostic workup of all GIST is now considered standard practice.

Case presentation

Herein, we described in detail a case of an exon 11 KIT mutated-metastatic GIST patient, who presented an unexpected metabolic progression at the early 18FDG-PET evaluation after 1 month of first-line imatinib, unconfirmed at the liver biopsy performed near after, which has conversely shown a complete pathological response.

Conclusions

This report aims to highlight the existence of this metabolic pseudoprogression in GIST at the beginning of imatinib therapy in order to avoid early treatment discontinuation. Therefore, an early metabolic progression during a molecular targeted therapy always deserves to be evaluated in the context of the disease molecular profiling, and in case of a discordant finding between functional imaging and molecular background, a short-term longitudinal control should be suggested.

Epithelioid Subtype Gastrointestinal Stromal Tumors of Stomach in an Endoscopic Biopsy: A Potential Diagnostic Pitfall

Background

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract with a broad morphological spectrum. Although epithelioid GISTs account for 20% of GISTs, their morphological features may pose a diagnostic pitfall for pathologists due to their morphological similarities to poorly differentiated adenocarcinoma and lymphoma.

Case Presentation

Herein, we report a 65-year-old male patient with gastric epithelioid GIST misdiagnosed as adenocarcinoma for four years. During this period, he was treated with chemotherapy combined with PD-L1 immunotherapy. The clinicians thought the treatments were effective. However, there was no significant change in tumor size. The patient's clinical symptoms did not improve significantly as well. Finally, an endoscopic biopsy was performed again and gastric epithelioid GIST was confirmed in our hospital through morphology, immunohistochemistry, and whole-genome sequencing.

Conclusion

A broad morphological spectrum and diverse immunophenotypic changes of GISTs could represent a pitfall for pathologists. However, predisposed anatomical sites, morphology, and corresponding immunohistochemical markers are of great significance for the diagnosis of GISTs and the differential diagnosis from other diseases. On the other hand, clinicians should diagnose and comprehensively evaluate treatment effects based on the patient's clinical symptoms and relevant laboratory examinations, instead of over-reliance on pathological diagnosis.

Diagnosis, Treatment, and Prognosis of Patients with Primary Familial Gastrointestinal Stromal Tumor: A Case Report and Literature Review

Gastrointestinal stromal tumors are the most common mesenchymal tumors of the digestive tract, most of which are sporadic, and familial GISTs with germline mutations are rarely seen. Here, we report a 26-year-old female with a germline p. W557R mutation in exon 11 of the KIT gene. The proband and her father and sister presented with multifocal GIST and pigmented nevi. All 3 patients underwent surgery and imatinib therapy. To date, only 49 kindreds with germline KIT mutations and 6 kindreds with germline PDGFRA mutations have been reported. Summarizing the reported kindreds, the majority of familial GISTs manifest as multiple primary GISTs complicated with special clinical manifestations, including cutaneous hyperpigmentation, dysphagia, mastocytosis, inflammatory fibrous polyps, and large hands. Familial GISTs are generally thought to exhibit TKI sensitivity similar to that of sporadic GISTs with the same mutation.

Lymph node metastases in young patients with gastrointestinal stromal tumor: A nationwide analysis

BACKGROUND

Children, adolescents, and young adults (CAYA) (age ≤39 years) with GIST have high rates of LNM, but their clinical relevance is undefined. This study analyzed the impact of LNM on overall survival (OS) for CAYA with GIST.

METHODS

The National Cancer Database was queried for patients with resected GIST and pathologic nodal staging data from 2004-2019. Factors associated with LNM were identified. Survival was assessed stratified by presence of LNM.

RESULTS

Of 4420 patients with GIST, 238 were CAYA (5.4%). When compared to older adults, CAYA more often had small intestine primaries (51.8% vs. 36.6%, p < 0.0001), T4 tumors (30.7% vs. 24.5%, p = 0.0275) and pN1 disease (11.3% vs. 4.7%, p < 0.0001). Within a multivariable Cox proportional hazards regression model adjusting for age, comorbid disease, mitotic rate, tumor size, and primary site, LNM were associated with increased hazard of death for older adults (hazard ratio [HR]: 1.83; confidence interval [CI]: 1.35-2.42; p < 0.0001), but not CAYA (HR: 3.38; CI: 0.50-14.08; p = 0.13). For CAYA, only high mitotic rate predicted mortality (HR: 4.68; CI: 1.41-18.37: p = 0.02).

CONCLUSIONS

LNM are more commonly identified among CAYA with resected GIST who undergo lymph node evaluations, but do not appear to impact OS as observed in older adults. High mitotic rate remains a predictor of poor outcomes for CAYA with GIST.

Case Report: Multiple gastrointestinal stromal tumors along with numerous cutaneous neurofibromas: a case description and literature analysis

Multiple gastrointestinal stromal tumors (GISTs) combined with cutaneous multiple neurofibromas are clinically rare. This paper presents a case of multiple gastrointestinal stromal tumors in the jejunum of a 68-year-old mother, along with her daughter who also had coexisting cutaneous multiple neurofibromas. The mother had been experiencing repeated melena for over 2 years and had previously been diagnosed with multiple small intestinal masses at other hospitals. Additionally, her 42-year-old daughter was admitted to our department due to recurrent abdominal pain caused by cholecystolithiasis. The mother and daughter both exhibited multiple nodular masses of varying sizes on their skin, including the truncus, limbs, and face, which were diagnosed as neurofibromas. The mother underwent a partial excision of the jejunum and a lateral jejunojejunal anastomosis side-to-side, as well as excision of skin lesions in our department. The final diagnosis of wild-type GISTs associated with neurofibromatosis type 1 (NF1) was confirmed through postoperative pathology, immunohistochemistry, and genetic testing results. During preoperative gastrointestinal endoscopy and intraoperative laparoscopic exploration of the gastrointestinal tract, no obvious tumors were found in her daughter. A combination of patient observations and a review of relevant literature in the field suggests that when patients present with gastrointestinal symptoms and multiple irregular painless swellings in the skin, it is important to consider the possibility of an association with NF1 and GIST. Additionally, obtaining a detailed family history can save time and improve the diagnosis of patients with both NF1 and GIST. We recommend that even if there are no gastrointestinal manifestations of GISTs in the offspring of newly mutated NF1 patients, regular review of gastroenteroscopy, imaging examination, and long-term follow-up after middle age are still crucial for the early diagnosis and treatment of NF1-related GISTs.

Molecular landscape and clinical significance of exon 11 mutations in KIT gene among patients with gastrointestinal stromal tumor: a retrospective exploratory study

Objective

This aim of this study was to investigate the prognostic significance of KIT exon 11 mutation subtypes in patients with GISTs.

Methods

A total of 233 consecutive patients diagnosed with GISTs at the First Affiliated Hospital of Zhengzhou University from January 2013 to August 2018 were included in this study. The prevalence and mutation landscape of exon 11 in KIT was presented. The clinicopathological characteristics and prognosis among the different mutation subtypes were analyzed. All the statistical analyses were performed by SPSS22.0.

Results

Somatic mutational analysis indicated that point mutations were the most frequently detected mutations followed by deletions & compound mutations and insertion and tandem duplication mutations in the stomach. Point mutations showed a low mitotic count and a high risk of recurrence, and deletions and compound mutations have a high mitotic count while insertions and tandem duplication mutations showed a low mitotic count with an intermediate recurrence risk. Point mutations and deletions frequently occurred in sequence region codons 550-560 of exon 11, while compound mutations, insertion, and tandem duplication were mainly detected in codons 557-559, 572-580, and 577-581, respectively. The multi-variation analysis demonstrated that tumor diameter and high recurrence risk groups had worse prognostic values. However, mutation types were not significant predictors of relapse-free survival (RFS) in GISTs. Survival analysis suggested no significant difference in RFS between the 557/558 deletion and the other deletions.

Conclusion

This study suggested that mutations in exon 11 of the KIT gene were common with intermediate/high recurrence risk in GISTs patients. Tumor diameter ≥5 cm, and deletions mutations might predict a worse prognosis.

Clinicopathological and immunohistochemical characterization of gastrointestinal stromal tumour at four tertiary health centers in Nigeria using CD117, DOG1, and human epidermal growth factor receptor-2 biomarkers

Aims

Gastrointestinal stromal tumors (GISTs) are neoplastic lesions that primarily affect the digestive tract and develop from interstitial cells of Cajal. These lesions require histopathological and immunohistochemical characterization due to their malignant potential and personalized treatment. In this investigation, the sex, age, lesional sites of origin, histopathological types, the prevalence of human epidermal growth factor receptors (HER-2) expression, prognostic indices (based on tumor size and mitotic figures), expression of CD117 and DOG1, and characteristics of patients with GIST were all characterized.

Materials and Methods

This was a retrospective cross-sectional analysis of GIST cases seen at four tertiary health-care centers in Nigeria over a 10-year period (2008-2017) and investigated utilizing histopathological and immunohistochemical (CD117, DOG1, and HER-2) methods.

Results

In this investigation, there were twenty GIST cases. Notably, the majority (40%) of the cases had tumors with sizes between 7.0 and 8.0 cm; the stomach was the most frequent site (70%) and the spindle cell type of GIST was the most prevalent (80%) histopathological type. In addition, the stomach was significantly associated with GIST as an origin site (with a P = 0.001), and 100% and 50% of these tumors were immunoreactive with CD117 and DOG1, respectively.

Conclusions

In our study, GISTs most frequently develop in the stomach, and CD117 and DOG1 are essential for correctly diagnosing these tumors. However, HER-2 immunoreactivity is a predictive marker of survival for personalized care.

Ripretinib for the treatment of advanced, imatinib-resistant gastrointestinal stromal tumors

Discovery of constitutive activation of KIT/PDGFRA tyrosine kinases in gastrointestinal stromal tumors (GISTs) leads to the development of the targeted drug imatinib. However, the inevitable development of imatinib resistance remains a major issue. Ripretinib is a novel targeted drug that inhibits the activities of a broad spectrum of drug-resistant KIT/PDGFRA mutants. It was approved in 2020 and is currently recommended by major international guidelines as the fourth-line and beyond therapy for advanced GISTs. Emerging evidence shows that ripretinib is superior to sunitinib as a second-line treatment for KIT exon 11-mutated GISTs due to its activity against highly heterogeneous frequently occurring secondary mutations. This review summarizes current data on the use of ripretinib to treat advanced imatinib-resistant GISTs. We also propose future research directions to improve the targeted GIST treatment.

Local excision and radical excision for rectal gastrointestinal stromal tumors: a meta-analysis protocol

Background

To date, several studies have compared the surgical and oncological outcomes of local excision (LE) and radical excision (RE) for rectal gastrointestinal stromal tumors (GISTs), but some have limited numbers of small series. This protocol outlines the planned scope and methods for a systematic review and meta-analysis that will compare the surgical and oncological outcomes of LE and RE in patients with rectal GISTs.

Methods

This protocol is presented in accordance with the PRISMA-P guideline. PubMed, Embase, Web of Science, Cochrane Library and Wanfang database will be systematically searched. Furthermore, reference lists of all included articles will be screened manually to add other eligible studies. We will include randomized controlled trials (RCTs) and non-randomized studies (NRS) in this study. The primary outcomes evaluated will be R0 resection rate and disease-free survival, while the secondary outcomes will contain overall survival, length of stay, tumor rupture rate and complications. Two reviewers will independently screen and select studies, extract data from the included studies, and assess the risk of bias of the included studies. Preplanned subgroup analyses and sensitivity analyses are detailed within this protocol. The strength of the body of evidence will be assessed using GRADE.

Discussion

This review and meta-analysis will provide a comprehensive evaluation of the current evidence concerning the application of LE and RE in patients with rectal GISTs. The findings from this review will serve as a foundation for future research and emphasize the implications for clinical practice.

Systematic review registration

PROSPERO (CRD42017078338), https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=387409, PROSPERO CRD42017078338.

Endoscopic resection of gastrointestinal stromal tumors

Surgical resection is regarded as the main modality for the treatment of gastrointestinal stromal tumors (GISTs). With the advancement of endoscopic techniques and the introduction of super minimally invasive surgery (SMIS), endoscopic resection has been an alternative option to surgery. Recently, various endoscopic resection techniques have been used for the treatment of GISTs, including endoscopic submucosal dissection (ESD), endoscopic submucosal excavation (ESE), endoscopic full-thickness resection (EFR), submucosal tunneling endoscopic resection (STER), and laparoscopic and endoscopic cooperative surgery (LECS). Studies on the safety and efficacy of the endoscopic treatment of GISTs have emerged in recent years. Endoscopic resection techniques have demonstrated to be effective and safe for the treatment of GISTs. However, there is currently no consensus on the optimal follow-up strategy and the appropriate cut-off value of tumor size for endoscopic resection. In this review we discussed the indications, preoperative preparation, procedures, efficacy, safety, postoperative evaluation, follow-up, and perspectives of endoscopic resection modalities for GISTs.

Gastrointestinal Stromal Tumors: Our Ten-Year Experience of a Single-Center Tertiary Hospital

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are the most frequent mesenchymal neoplasms of the gastrointestinal tract. They have variable clinical presentation, prognosis, and molecular characteristics. Here, we present the results of our retrospective study including patients operated on for GIST during the last decade.

METHODS

All the patients who underwent GIST resection during the decade 2008-2018 were included in the study. The diagnosis was based on the pathology report. All the data were collected and analyzed statistically using the Statistical Package for Social Science v25.0. Finally, after having applied the proper search terms, a comprehensive review of articles published in the Medline database was held.

RESULTS

Thirty-two patients (sixteen women) were included in the study with a mean age of 69.6 years old (SD = 13.9). Twenty-one patients had a GIST in the stomach, eight in the small intestine, and three had an extra GIST. Of the 29 patients contacted, 21 were alive with a mean survival time of 74.3 months (SD = 49.6 months, min: 3.0 months, max: 161.0 months), whereas eight patients passed away. Finally, 13 patients were treated with tyrosine kinase inhibitors (TKIs) of whom only one died, while 9 patients passed away from those treated with surgery alone (p = 0.031).

CONCLUSIONS

Our results were in concordance with the existing data in the literature. GISTs require patient-based therapeutical management depending on the histology of the tumors. Gastric tumors present a better prognosis than those localized in the intestine, while the use of TKIs has led to an improvement in patient survival rate.

Identification of novel c-Kit inhibitors from natural sources using virtual screening and molecular dynamics simulations

The Mast/Stem cell growth factor receptor Kit (c-Kit), a Proto-oncogene c-Kit, is a tyrosine-protein kinase involved in cell differentiation, proliferation, migration, and survival. Its role in developing certain cancers, particularly gastrointestinal stromal tumors (GISTs) and acute myeloid leukemia (AML), makes it an attractive therapeutic target. Several small molecule inhibitors targeting c-Kit have been developed and approved for clinical use. Recent studies have focused on identifying and optimizing natural compounds as c-Kit inhibitors employing virtual screening. Still, drug resistance, off-target side effects, and variability in patient response remain significant challenges. From this perspective, phytochemicals could be an important resource for discovering novel c-Kit inhibitors with less toxicity, improved efficacy, and high specificity. This study aimed to uncover possible c-Kit inhibitors by utilizing a structure-based virtual screening of active phytoconstituents from Indian medicinal plants. Through the screening stages, two promising candidates, Anilinonaphthalene and Licoflavonol, were chosen based on their drug-like features and ability to bind to c-Kit. These chosen candidates were subjected to all-atom molecular dynamics (MD) simulations to evaluate their stability and interaction with c-Kit. The selected compounds Anilinonaphthalene from Daucus carota and Licoflavonol from Glycyrrhiza glabra showed their potential to act as selective binding partners of c-Kit. Our results suggest that the identified phytoconstituents could serve as a starting point to develop novel c-Kit inhibitors for developing new and effective therapies against multiple cancers, including GISTs and AML. The use of virtual screening and MD simulations provides a rational approach to discovering potential drug candidates from natural sources.Communicated by Ramaswamy H. Sarma.

Artificial intelligence in endoscopic ultrasonography: risk stratification of gastric gastrointestinal stromal tumors

Background

Previous studies have identified useful endoscopic ultrasonography (EUS) features to predict the malignant potential of gastrointestinal stromal tumors (GISTs). However, the results of the studies were not consistent. Artificial intelligence (AI) has shown promising results in medicine.

Objectives

We aimed to build a risk stratification EUS-AI model to predict the malignancy potential of GISTs.

Design

This was a retrospective study with external validation.

Methods

We developed two models using EUS images from two hospitals to predict the GIST risk category. Model 1 was the four-category risk EUS-AI model, and Model 2 was the two-category risk EUS-AI model. The diagnostic performance of the models was validated with external cohorts.

Results

A total of 1320 images (880 were very low-risk, 269 were low-risk, 68 were intermediate-risk, and 103 were high-risk) were finally chosen for building the models and test sets, and a total of 656 images (211 were very low-risk, 266 were low-risk, 88 were intermediate-risk, and 91 were high-risk) were chosen for external validation. The overall accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the four-category risk EUS-AI model in the external validation sets by tumor were 74.50%, 55.00%, 79.05%, 53.49%, and 81.63%, respectively. The accuracy, sensitivity, specificity, PPV, and NPV for the two-category risk EUS-AI model for the prediction of very low-risk GISTs in the external validation sets by tumor were 86.25%, 94.44%, 79.55%, 79.07%, and 94.59%, respectively.

Conclusion

We developed a EUS-AI model for the risk stratification of GISTs with promising results, which may complement current clinical practice in the management of GISTs.

Registration

The study has been registered in the Chinese Clinical Trial Registry (No. ChiCTR2100051191).

Gene polymorphisms affect postoperative imatinib plasma levels and edema in adults with gastrointestinal stromal tumor

Aim: To assess the role of genetic polymorphisms in postoperative imatinib concentrations and edema in patients with gastrointestinal stromal tumor. Methods: The relationships between genetic polymorphisms, imatinib concentrations and edema were explored. Results: Carriers of the rs683369 G-allele and rs2231142 T-allele had significantly higher imatinib concentrations. Grade ≥2 periorbital edemas were related to the carriership of two C-alleles in rs2072454 with an adjusted odds ratio of 2.85, two T-alleles in rs1867351 with an adjusted odds ratio of 3.42 and two A-alleles in rs11636419 with an adjusted odds ratio of 3.15. Conclusion: rs683369 and rs2231142 affect the metabolism of imatinib; rs2072454, rs1867351 and rs11636419 are related to grade ≥2 periorbital edemas.

Efficacy and safety of ripretinib in Chinese patients with advanced gastrointestinal stromal tumors: a real-world, multicenter, observational study

Introduction

Mutations in KIT proto-oncogene, receptor tyrosine kinase (KIT) and platelet-derived growth factor receptor-α (PDGFRA) render the available tyrosine kinase inhibitors (TKI) ineffective in treating advanced gastrointestinal stromal tumors (GIST). Ripretinib, a broad-spectrum switch-control kinase inhibitor, has shown increased efficacy and manageable safety, but real-world evidence remains scarce. This study evaluates the efficacy and safety of ripretinib among Chinese patients in a real-world setting.

Methods

Advanced GIST patients (N=23) receiving ripretinib following progression on previous lines of TKI treatment were enrolled to determine the efficacy [progression-free survival (PFS) and overall survival (OS)]. Safety was assessed by the incidence and severity of adverse events (AEs). All statistical analyses were performed using SPSS version 20.0 and a p-value of <0.05 was considered significant.

Results

The median PFS (mPFS) of efficacy analysis set (EAS) (N=21) was 7.1 months. mPFS of patients receiving ripretinib following ≤2 lines of previous TKI treatment and ≥3 prior lines of therapy were 7.1 and 9.2 months, respectively. The median OS (mOS) was 12.0 months and shorter interval between the end of the latest TKI and ripretinib therapy was correlated with longer median PFS and OS (p=0.054 and p=0.046), respectively. Alopecia and asthenia were the most common AEs observed.

Conclusion

Compared to previous lines of TKI in advanced GIST patients, ripretinib showed superior efficacy with clinically manageable AEs. Real-world results are comparable to that of phase III INVICTUS study and its Chinese bridging study. Hence, ripretinib can be used for the clinical management of advanced GIST patients.

A combined radiomic model distinguishing GISTs from leiomyomas and schwannomas in the stomach based on endoscopic ultrasonography images

BACKGROUND

Endoscopic ultrasonography (EUS) is recommended as the best tool for evaluating gastric subepithelial lesions (SELs); nonetheless, it has difficulty distinguishing gastrointestinal stromal tumors (GISTs) from leiomyomas and schwannomas. GISTs have malignant potential, whereas leiomyomas and schwannomas are considered benign.

PURPOSE

This study aimed to establish a combined radiomic model based on EUS images for distinguishing GISTs from leiomyomas and schwannomas in the stomach.

METHODS

EUS images of pathologically confirmed GISTs, leiomyomas, and schwannomas were collected from five centers. Gastric SELs were divided into training and testing datasets based on random split-sample method (7:3). Radiomic features were extracted from the tumor and muscularis propria regions. Principal component analysis, least absolute shrinkage, and selection operator were used for feature selection. Support vector machine was used to construct radiomic models. Two radiomic models were built: the conventional radiomic model included tumor features alone, whereas the combined radiomic model incorporated features from the tumor and muscularis propria regions.

RESULTS

A total of 3933 EUS images from 485 cases were included. For the differential diagnosis of GISTs from leiomyomas and schwannomas, the accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve were 74.5%, 72.2%, 78.7%, and 0.754, respectively, for the EUS experts; 76.8%, 74.4%, 81.0%, and 0.830, respectively, for the conventional radiomic model; and 90.9%, 91.0%, 90.6%, and 0.953, respectively, for the combined radiomic model. For gastric SELs <20 mm, the accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve of the combined radiomic model were 91.4%, 91.6%, 91.1%, and 0.960, respectively.

CONCLUSIONS

We developed and validated a combined radiomic model to distinguish gastric GISTs from leiomyomas and schwannomas. The combined radiomic model showed better diagnostic performance than the conventional radiomic model and could assist EUS experts in non-invasively diagnosing gastric SELs, particularly gastric SELs <20 mm.

Automated machine learning to predict the difficulty for endoscopic resection of gastric gastrointestinal stromal tumor

Background

Accurate preoperative assessment of surgical difficulty is crucial to the success of the surgery and patient safety. This study aimed to evaluate the difficulty for endoscopic resection (ER) of gastric gastrointestinal stromal tumors (gGISTs) using multiple machine learning (ML) algorithms.

Methods

From December 2010 to December 2022, 555 patients with gGISTs in multi-centers were retrospectively studied and assigned to a training, validation, and test cohort. A difficult case was defined as meeting one of the following criteria: an operative time ≥ 90 min, severe intraoperative bleeding, or conversion to laparoscopic resection. Five types of algorithms were employed in building models, including traditional logistic regression (LR) and automated machine learning (AutoML) analysis (gradient boost machine (GBM), deep neural net (DL), generalized linear model (GLM), and default random forest (DRF)). We assessed the performance of the models using the areas under the receiver operating characteristic curves (AUC), the calibration curve, and the decision curve analysis (DCA) based on LR, as well as feature importance, SHapley Additive exPlanation (SHAP) Plots and Local Interpretable Model Agnostic Explanation (LIME) based on AutoML.

Results

The GBM model outperformed other models with an AUC of 0.894 in the validation and 0.791 in the test cohorts. Furthermore, the GBM model achieved the highest accuracy among these AutoML models, with 0.935 and 0.911 in the validation and test cohorts, respectively. In addition, it was found that tumor size and endoscopists' experience were the most prominent features that significantly impacted the AutoML model's performance in predicting the difficulty for ER of gGISTs.

Conclusion

The AutoML model based on the GBM algorithm can accurately predict the difficulty for ER of gGISTs before surgery.

Primary vulvar extragastrointestinal stromal tumor in a 77-year-old woman

Extragastrointestinal stromal tumors (EGISTs) carry the same morphological, immunohistochemical and molecular features as gastrointestinal stromal tumors (GISTs) and involve extragastrointestinal tract soft tissue. The majority of reported EGIST cases arise from intraabdominal, retroperitoneal, or pelvic soft tissue. A significant subset of such tumors originates from the gastrointestinal muscle layer, grows in an exophytic manner, then loses attachment to the gastrointestinal tract. Consequently, true EGISTs are exceedingly rare. Herein, we are reporting a case of a vulvar EGIST. A 77-year-old woman presented with a painless subcutaneous nodule on the right perineum. An excisional biopsy showed a fairly circumscribed bland spindle cell lesion in the dermis. The tumor cells were positive for CD117 and ANO1/DOG-1 and negative for smooth muscle myosin, smooth muscle actin, STAT6, low- and high-molecular-weight cytokeratins, SOX10, MART-1, CD10, S-100 protein, and estrogen and progesterone receptors. A diagnosis of EGIST was made and complete excision was recommended. Superficial/subcutaneous EGISTs are extremely rare, and it is important for dermatopathologists to be aware of this entity as it can be misdiagnosed as more common spindle cell neoplasms, both benign and malignant, including but not limited to smooth muscle neoplasms (leiomyoma/leiomyosarcoma), spindle cell melanoma, and sarcomatoid squamous cell carcinoma.

Emerging Targeted Therapeutic Strategies to Overcome Imatinib Resistance of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common malignant mesenchymal neoplasms of the gastrointestinal tract. The gold standard for the diagnosis of GISTs is morphologic analysis with an immunohistochemical evaluation plus genomic profiling to assess the mutational status of lesions. The majority of GISTs are driven by gain-of-function mutations in the proto-oncogene c-KIT encoding the tyrosine kinase receptor (TKR) known as KIT and in the platelet-derived growth factor-alpha receptor (PDGFRA) genes. Approved therapeutics are orally available as tyrosine kinase inhibitors (TKIs) targeting KIT and/or PDGFRA oncogenic activation. Among these, imatinib has changed the management of patients with unresectable or metastatic GISTs, improving their survival time and delaying disease progression. Nevertheless, the majority of patients with GISTs experience disease progression after 2-3 years of imatinib therapy due to the development of secondary KIT mutations. Today, based on the identification of new driving oncogenic mutations, targeted therapy and precision medicine are regarded as the new frontiers for GISTs. This article reviews the most important mutations in GISTs and highlights their importance in the current understanding and treatment options of GISTs, with an emphasis on the most recent clinical trials.

An evaluation of the use of double-curved endoscopes for gastric gastrointestinal stromal tumors

BACKGROUND

Endoscopic full-thickness resection (EFTR) is a standard treatment method for gastric gastrointestinal stromal tumors (gGISTs). Evidence of the safety and efficacy of a double-curved endoscope (DCE) in EFTR of gGISTs is limited. We aimed to compare the operative outcomes of DCE versus single-curved endoscopes (SCE) in EFTR of gGISTs.

MATERIAL AND METHODS

This retrospective observational study was conducted at four Chinese tertiary institutes. From January 2019 to November 2021, 104 patients who underwent EFTR by SCE (n = 57) or DCE (n = 47) were enrolled. One-to-one propensity score matching (PSM) was performed between the two groups to compare the demographics and operative outcomes.

RESULTS

All gGISTs were resected successfully with no recurrence during follow-up. The median (range) tumor size was 1.2 (0.5, 3.5) cm in DCE and 2.0 (0.6, 4.8) cm in SCE (p < .001), and the procedure time was shorter in the DCE group than in the SCE group (50.0 min vs. 62.0 min, p < .05). After PSM, 41 pairs were selected, and no difference was noted in demographics. The procedure time was also shorter in the DCE group than in the SCE group (50.0 min vs. 55.0 min, p < .05). Subgroup analysis showed that the DCE group had a shorter procedure time in the gastric fundus than the SCE group (47.0 min vs. 55.0 min, p < .05). In multiple linear regression analysis, significant factors related to prolonged procedure time were the type of endoscope of SCE and larger tumor size (p < .05).

CONCLUSIONS

EFTR of gGISTs using DCE is safe and effective. Compared with SCE, DCE had an advantage in terms of operative time, especially in the gastric fundus.

Rectal Gastrointestinal Stromal Tumors

Rectal gastrointestinal stromal tumors (GISTs) are rare types of tumors, but the incidence is increasing, and we now know more about the pathogenesis and management of rectal GIST. The main goal is to resect the tumor with negative microscopic margins. With the development of neoadjuvant Imatinib therapy, preoperative reduction in tumor size has become possible, thus introducing the chance for anus-preserving surgery, with better quality of life. We present a case of a 55-year-old female who presented to the emergency department with complaints of bleeding per rectum, abdominal pain, and pain on defecation. A 6-cm mass was detected during the rectal examination and a biopsy confirmed the diagnosis of GIST. The patient was given neoadjuvant imatinib chemotherapy for four months followed by trans-anal resection of the mass. The procedure was done successfully, and she received further adjuvant imatinib for a course of three years. Follow-up by magnetic resonance imaging and a colonoscopy after two years showed no recurrence. The patient is living healthily and doing well.

A patient's perspective on the side effects of tyrosine kinase inhibitors in the treatment of advanced and metastatic gastrointestinal stromal tumors

Aim: To provide the gastrointestinal stromal tumor patient's perspective on side effects of tyrosine kinase inhibitors and compare this with that of healthcare professionals. Materials & methods: Semi-structured interviews were conducted with 19 patients with an advanced or metastatic gastrointestinal stromal tumor, as well as six healthcare professionals, and five patients participated in a focus group. Thematic analysis was used to interpret the data. Results: Most participants (n = 29) reported gastrointestinal symptoms followed by tiredness (n = 25), edema (n = 22), muscle cramps (n = 21), skin problems (n = 21), eye problems (n = 11) and trouble sleeping (n = 10). Patients, but not healthcare professionals, reported cognitive problems or symptoms of depression. Conclusion: These results underline the importance of including the patient's perspective, as there is a gap in symptom reporting between patients and healthcare professionals.

LAPAROSCOPIC VERSUS OPEN SURGERY IN GASTRIC GASTROINTESTINAL STROMAL TUMORS LARGER THAN 5 CM: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

Surgical resection represents the main treatment for resectable nonmetastatic gastric gastrointestinal stromal tumors. Despite the feasibility and safety of laparoscopic resection, its standard use in gastric tumors larger than 5 cm is yet to be established.

AIMS

This study aimed to compare the current evidence on laparoscopic resection with the classical open surgical approach in terms of perioperative, postoperative, and oncological outcomes.

METHODS

The PubMed, Scopus, and Web of Science databases were consulted. Articles comparing the approach to gastric gastric gastrointestinal stromal tumors larger than 5 cm by open and laparoscopic surgery were eligible. A post hoc subgroup analysis based on the extent of the surgery was performed to evaluate the operative time, blood loss, and length of hospital stay.

RESULTS

A total of nine studies met the eligibility criteria. In the study, 246 patients undergoing laparoscopic surgery and 301 patients undergoing open surgery were included. The laparoscopic approach had statistically significant lower intraoperative blood loss (p=0.01) and time to oral intake (p<0.01), time to first flatus (p<0.01), and length of hospital stay (0.01), compared to the open surgery approach. No significant differences were found when operative time (0.25), postoperative complications (0.08), R0 resection (0.76), and recurrence rate (0.09) were evaluated. The comparative subgroup analysis between studies could not explain the substantial heterogeneity obtained in the respective outcomes.

CONCLUSION

The laparoscopic approach in gastric gastrointestinal stromal tumors larger than 5 cm compared to the open surgical approach is a technically safe and feasible surgical method with similar oncological results.

Changes in imatinib plasma trough level during long-term treatment in patients with intermediate- or high-risk gastrointestinal stromal tumors: Relationship between covariates and imatinib plasma trough level

Background

Imatinib is the first-line adjuvant treatment for gastrointestinal stromal tumors (GISTs). Considering that some studies have suggested that imatinib (IM) plasma trough levels (C_min) change with time, the aim of this study is to assess the changes in IM C_min in patients with GIST in a long-term study and to elucidate the relationships between clinicopathological features and IM C_min.

Methods

In 204 patients with intermediate- or high-risk GIST who were taking IM, IM C_min was analyzed. Patient data were grouped according to the duration of medication (A: 1-3 months, B: 4-6 months, C: 7-9 months, D: 10-12 months, E: ≤12 months, F: 12<-≤36 months, G: >36 months). The correlation between IM C_min at different time stages and clinicopathological characteristics was assessed.

Results

Statistically significant differences were observed between Groups A, C, and D (P = 0.049 and 0.01, respectively). In Group E, IM C_min correlated with sex (P = 0.049) and age (P = 0.029) and negatively correlated with body weight, height, and body surface area (P = 0.007, 0.002, and 0.001, respectively). In Groups F and G, IM C_min was significantly higher in non-gastric operation patients than in patients with gastrectomy (P = 0.002, 0.036) and was significantly higher in patients with the primary sites of others than in the stomach (P < 0.001, = 0.012). In addition, IM C_min was much higher in patients with mutation sites other than KIT exon 11 in Group F (P = 0.011).

Conclusion

This is the first study of IM C_min during the long-term treatment of patients with intermediate- or high-risk GIST. IM C_min was the highest for the first 3 months and then declined, and long-term administration of IM showed a relatively stable plasma trough level. The IM C_min correlated with different clinical characteristics at different durations of medication. This meant that future "trough level-clinicopathological characteristics" analyses should be time-point-specific. We also need to formulate time-specific medication monitoring plans in clinical practice to study disease progression caused by the occurrence of drug resistance.

Boring biopsy with rapid on-site evaluation for gastric gastrointestinal stromal tumor: A pilot study

One of 4 patients (25%) and 2 of 3 patients (67%) were correctly diagnosed by conventional and hot boring biopsies, respectively. The median procedure time of conventional and hot boring biopsies was 21 (range, 13-33) and 17 (range, 16-23) min, respectively. Rapid on-site evaluation was performed totally 12 times in 7 patients. The positive and negative predictive values of rapid on-site evaluation for gastrointestinal stromal tumor were 0.5 (0.12-0.88) and 1.0 (0.42-1.00), respectively.

Construction and validation of a prognostic model for gastrointestinal stromal tumors based on copy number alterations and clinicopathological characteristics

Background

The increasing incidence of gastrointestinal stromal tumors (GISTs) has led to the discovery of more novel prognostic markers. We aim to establish an unsupervised prognostic model for the early prediction of the prognosis of future patients with GISTs and to guide clinical treatment.

Methods

We downloaded the GISTs dataset through the cBioPortal website. We extracted clinical information and pathological information, including the microsatellite instability (MSI) score, fraction genome altered (FGA) score, tumor mutational burden (TMB), and copy number alteration burden (CNAB), of patients with GISTs. For survival analysis, we used univariate Cox regression to analyze the contribution of each factor to prognosis and calculated a hazard ratio (HR) and 95% confidence interval (95% CI). For clustering groupings, we used the t-distributed stochastic neighbor embedding (t-SNE) method for data dimensionality reduction. Subsequently, the k-means method was used for clustering analysis.

Results

A total of 395 individuals were included in the study. After dimensionality reduction with t-SNE, all patients were divided into two subgroups. Cluster 1 had worse OS than cluster 2 (HR=3.45, 95% CI, 2.22-5.56, P<0.001). The median MSI score of cluster 1 was 1.09, and the median MSI score of cluster 2 was 0.24, which were significantly different (P<0.001). The FGA score of cluster 1 was 0.28, which was higher than that of cluster 2 (P<0.001). In addition, both the TMB and CNAB of cluster 1 were higher than those of cluster 2, and the P values were less than 0.001.

Conclusion

Based on the CNA of GISTs, patients can be divided into high-risk and low-risk groups. The high-risk group had a higher MSI score, FGA score, TMB and CNAB than the low-risk group. In addition, we established a prognostic nomogram based on the CNA and clinicopathological characteristics of patients with GISTs.

SH3BP2 Silencing Increases miRNAs Targeting ETV1 and Microphthalmia-Associated Transcription Factor, Decreasing the Proliferation of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Gain of function in receptor tyrosine kinases type III, KIT, or PDGFRA drives the majority of GIST. Previously, our group reported that silencing of the adaptor molecule SH3 Binding Protein 2 (SH3BP2) downregulated KIT and PDGFRA and microphthalmia-associated transcription factor (MITF) levels and reduced tumor growth. This study shows that SH3BP2 silencing also decreases levels of ETV1, a required factor for GIST growth. To dissect the SH3BP2 pathway in GIST cells, we performed a miRNA array in SH3BP2-silenced GIST cell lines. Among the most up-regulated miRNAs, we found miR-1246 and miR-5100 to be predicted to target MITF and ETV1. Overexpression of these miRNAs led to a decrease in MITF and ETV1 levels. In this context, cell viability and cell cycle progression were affected, and a reduction in BCL2 and CDK2 was observed. Interestingly, overexpression of MITF enhanced cell proliferation and significantly rescued the viability of miRNA-transduced cells. Altogether, the KIT-SH3BP2-MITF/ETV1 pathway deserves to be considered in GIST cell survival and proliferation.

Efficacy and Safety of Avapritinib in Treating Unresectable or Metastatic Gastrointestinal Stromal Tumors: A Phase I/II, Open-Label, Multicenter Study

BACKGROUND

Avapritinib is a type 1 kinase inhibitor designed to potently and selectively inhibit oncogenic KIT/PDGFRA mutants by targeting the kinase active conformation. This multicenter, single-arm, open-label, phase I/II bridging study of NAVIGATOR in Chinese patients evaluated the safety and the antineoplastic activity of avapritinib in Chinese patients with unresectable/metastatic gastrointestinal stromal tumors (GIST).

METHODS

Phase I comprised dose escalation for safety and phase II dose determination. Phase II comprised dose expansion for safety/efficacy evaluations in patients with PDGFRA D842V mutations or patients having received at least 3 lines of therapy without PDGFRA D842V mutations. The primary endpoints were recommended phase II dose, safety, and Independent Radiology Review Committee (IRRC)-assessed objective response rate (ORR).

RESULTS

No dose-limiting toxicities occurred (n = 10); the recommended phase II dose was avapritinib 300 mg once daily orally. Fifty-nine patients initially received avapritinib 300 mg. Common grade ≥3 treatment-related adverse events were anemia, decreased white blood cell count, increased blood bilirubin levels, and decreased neutrophil count. In patients with PDGFRA D842V mutations, IRRC- and investigator-assessed ORRs were 75% and 79%, respectively; clinical benefit rates were both 86%. Median duration of response/progression-free survival were not reached. IRCC- and investigator-assessed ORRs in patients in the fourth- or later-line setting were 22% and 35%, respectively. Median progression-free survivals were 5.6 months for both. Overall survival data were immature and not calculated.

CONCLUSION

Avapritinib was generally well tolerated and showed marked anti-tumor activity in Chinese patients with GIST bearing PDGFRA D842V mutations and notable efficacy as fourth- or later-line monotherapy (ClinicalTrials.gov Identifier: NCT04254939).

miRNA Expression May Have Implications for Immunotherapy in PDGFRA Mutant GISTs

Gastrointestinal stromal tumors (GISTs) harboring mutations in the PDGFRA gene occur in only about 5-7% of patients. The most common PDGFRA mutation is exon 18 D842V, which is correlated with specific clinico-pathological features compared to the other PDGFRA mutated GISTs. Herein, we present a miRNA expression profile comparison of PDGFRA D842V mutant GISTs and PDGFRA with mutations other than D842V (non-D842V). miRNA expression profiling was carried out on 10 patients using a TLDA miRNA array. Then, miRNA expression was followed by bioinformatic analysis aimed at evaluating differential expression, pathway enrichment, and miRNA-mRNA networks. We highlighted 24 differentially expressed miRNAs between D842V and non-D842V GIST patients. Pathway enrichment analysis showed that deregulated miRNAs targeted genes that are mainly involved in the immune response pathways. The miRNA-mRNA networks highlighted a signature of miRNAs/mRNA that could explain the indolent behavior of the D842V mutated GIST. The results highlighted a different miRNA fingerprint in PDGFRA D842V GISTs compared to non-D842Vmutated patients, which could explain the different biological behavior of this GIST subset.

Gastrointestinal Stromal Tumors: 10-Year Experience in Cancer Center-The Ottawa Hospital (TOH)

(1) Background: The management of gastrointestinal stromal tumors (GIST) has significantly evolved over the last two decades, with the introduction of tyrosine kinase inhibitors (TKI). We aim to report 10 years of experience of GIST management at a regional cancer center in Canada. (2) Methods: We retrospectively analyzed the records of 248 consecutive patients diagnosed with GIST between 2011 and 2021. We describe the clinical and pathological data, management, and outcome, including survival. (3) Results: The most common GIST sites were the stomach 63% (156), followed by the small bowel 29% (73). At diagnosis, 83% (206) of patients had localized disease (stage I-III). According to the modified National Institutes of Health consensus criteria (NIH) for GIST, around 45% (90) had intermediate or high-risk disease. Most patients, 86% (213), underwent curative surgical resection. Forty-nine patients received adjuvant imatinib, while forty-three patients had advanced disease and received at least one line of TKI. With a median follow-up of 47 months, the 5-year recurrence-free survival (RFS) rates for very low and low risk were 100% and 94%, respectively, while those for intermediate and high risk were 84% and 51%, respectively. The 5-year overall survival (OS) rates for very low and low risk were 100% and 94%, while intermediate, high risk, and advanced were 91%, 88%, and 65%, respectively. Using the Kaplan-Meier method, there were statistically significant differences in RFS and OS between NIH risk groups, p < 0.0005. In univariate analysis, ECOG, site, mitosis, secondary malignancy, and size were predictors for OS. High mitosis and large size (>5 cm) were associated with worse RFS. (4) Conclusions: Curative surgical resection remains the gold standard management of GIST. Our results are comparable to the reported literature. Further research is needed to explore histology's role in risk stratification and initiating adjuvant TKI.

Abdominal tumors in patients with neurofibromatosis type I: Genotype-phenotype relationships

BACKGROUND

Gastrointestinal stromal tumors have been detected in 25% of the necropsies performed on NF1 patients, but have been reported only in 7% of NF1 patients in the largest series. Such data imply an important gap between the true presence of tumors and those diagnosed. Few genotype-phenotype relationships have been described but to date none referring to abdominal tumors.

OBJECTIVES

Evaluate retrospectively the efficacy of a regular and proactive follow-up of NF1 patients to early diagnose abdominal tumors and report their mutations.

METHODS

Cohort study performed between 2010 and 2020, with 43 NF1 adult patients followed at our Dermatology department.

RESULTS

Eight abdominal tumors were diagnosed in six patients, meaning that 14% of the followed patients developed an abdominal tumor. Five patients (83%) were asymptomatic. Five (83.3%) had a family history of NF1 with abdominal tumors (patients 1,2 and 3,4,5 were relatives).

CONCLUSIONS

Although currently gastrointestinal routine screening investigations for asymptomatic patients are not recommended in the guidelines, the family aggregation in our series suggests it should be considered a close follow-up of the relatives of a patient with an NF1-related abdominal tumor. Also, for the first time, two mutations [c.2041C > T (p.Arg681Ter) and c.4537C > T (p.Arg1513*)] have been associated with family aggregation of abdominal tumors in NF1 patients.

Correlation of treatment outcome in sanger/RT‑qPCR KIT/PDGFRA wild‑type metastatic gastrointestinal stromal tumors with next‑generation sequencing results: A single‑center report

In patients with gastrointestinal stromal tumors (GIST), it has become mandatory to determine the driver mutation in order to predict the response to standard treatment with tyrosine kinase inhibitors (TKI). A total of 10–15% of all GIST lack activating mutations in KIT proto-oncogene, receptor tyrosine kinase (KIT)/platelet-derived growth factor receptor alpha (PDGFRA) and have been classified as KIT/PDGFRA wild-type (WT) GIST. They are characterized by poor response to TKI. From a group of 119 metastatic GIST patients, 17 patients with KIT/PDGFRA/BRAF WT GIST as determined by reverse transcription-quantitative (RT-q) PCR and Sanger sequencing were profiled by a targeted next-generation sequencing (NGS) approach and their treatment outcome was assessed. In the present study, 41.2% of patients as KIT/PDGFRA/BRAF WT GIST examined with RT-qPCR and Sanger sequencing were confirmed to be carriers of pathogenic KIT/PDGFRA mutations by NGS and were responsive to TKI. The percentage of genuinely KIT/PDGFRA WT GIST in the present study thereby dropped from the initial 14.3% detected with the RT-qPCR and Sanger sequencing to 7.6% after NGS. Their outcome was universally poor. The reliability of RT-qPCR and direct Sanger sequencing results in this setting is therefore insufficient and it is recommended that NGS becomes a requirement for treatment decision at least in KIT/PDGFRA/BRAF WT GIST as determined by RT-qPCR and Sanger sequencing.

Application of artificial intelligence in the diagnosis of subepithelial lesions using endoscopic ultrasonography: a systematic review and meta-analysis

Endoscopic ultrasonography (EUS) is the most common method for diagnosing gastrointestinal subepithelial lesions (SELs); however, it usually requires histopathological confirmation using invasive methods. Artificial intelligence (AI) algorithms have made significant progress in medical imaging diagnosis. The purpose of our research was to explore the application of AI in the diagnosis of SELs using EUS and to evaluate the diagnostic performance of AI-assisted EUS. Three databases, PubMed, EMBASE, and the Cochrane Library, were comprehensively searched for relevant literature. RevMan 5.4.1 and Stata 17.0, were used to calculate and analyze the combined sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and summary receiver-operating characteristic curve (SROC). Eight studies were selected from 380 potentially relevant studies for the meta-analysis of AI-aided EUS diagnosis of SELs. The combined sensitivity, specificity, and DOR of AI-aided EUS were 0.92 (95% CI, 0.85-0.96), 0.80 (95% CI, 0.70-0.87), and 46.27 (95% CI, 19.36-110.59), respectively). The area under the curve (AUC) was 0.92 (95% CI, 0.90-0.94). The AI model in differentiating GIST from leiomyoma had a pooled AUC of 0.95, sensitivity of 0.93, specificity of 0.88, PLR of 8.04, and NLR of 0.08. The combined sensitivity, specificity, and AUC of the AI-aided EUS diagnosis in the convolutional neural network (CNN) model were 0.93, 0.81, and 0.94, respectively. AI-aided EUS diagnosis using conventional brightness mode (B-mode) EUS images had a combined sensitivity of 0.92, specificity of 0.79, and AUC of 0.92. AI-aided EUS diagnosis based on patients had a combined sensitivity, specificity, and AUC of 0.95, 0.83, and 0.96, respectively. Additionally, AI-aided EUS was superior to EUS by experts in terms of sensitivity (0.93 vs. 0.71), specificity (0.81 vs. 0.69), and AUC (0.94 vs. 0.75). In conclusion, AI-assisted EUS is a promising and reliable method for distinguishing SELs, with excellent diagnostic performance. More multicenter cohort and prospective studies are expected to be conducted to further develop AI-assisted real-time diagnostic systems and validate the superiority of AI systems. Systematic Review Registration: PROSPERO (https://www.crd.york.ac.uk/PROSPERO/), identifier CRD42022303990.

Clinical outcomes of endoscopic treatment for gastric gastrointestinal stromal tumors: a single-center study of 240 cases in China

BACKGROUND AND AIMS

Endoscopic resection (ER) gradually becomes an important treatment method for gastrointestinal stromal tumors (GISTs). The aim of this study is to evaluate the efficacy and safety of ER of gastric GISTs.

METHODS

This retrospective study included 240 patients with gastric GISTs who underwent ER at Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 2010 to December 2019. The clinicopathologic, endoscopic and follow-up data of the patients were collected and analyzed.

RESULTS

The mean maximum tumor diameter was 1.67 ± 1.00 cm (range 0.2-6.5 cm), of which 156 cases (65.00%) were small gastric GISTs (tumor diameter < 2 cm). A total of 43 patients (17.92%) had perioperative bleeding, including 40 cases (16.67%) of minor bleeding and three cases (1.25%) of major bleeding. Perioperative perforation occurred in 101 patients (42.08%), of which 51 patients (21.25%) were active perforation and 50 patients (20.83%) were passive perforation. The en bloc resection rate was 97.08% (233/240), and seven cases (2.92%) had piecemeal resection. There were three cases (1.92%) of small gastric GISTs at intermediate risk and one case (0.64%) at high risk. A total of 193 patients were followed up, and no tumor residual, recurrence or metastasis occurred within a median follow-up time of 30 months (range 1-127 months).

CONCLUSIONS

Endoscopic treatment for gastric GISTs is safe and effective. Piecemeal resection does not seem to be related to the patient's prognosis. Endoscopic resection can be performed if patients are willing to remove small gastric GISTs.

Role of Positron Emission Tomography/Computed Tomography in Gastrointestinal Malignancies: A Brief Review and Pictorial Essay

Positron emission tomography/computed tomography (PET/CT) is increasingly becoming a mainstay in diagnosis and management of many malignant disorders. However, its role in the assessment of gastro-intestinal lesions is still evolving. The aim of this review was to demonstrate the areas, where PET/CT is impactful and where it has limitations. This will allow for us to reduce unnecessary investigations and develop methods to overcome the limitations.

The analysis of prognostic factors of primary small intestinal gastrointestinal stromal tumors with R0 resection: A single-center retrospective study

OBJECTIVE

We aim to assess factors that affect overall survival in patients with primary small intestinal gastrointestinal stromal tumors (GISTs) who had undergone R0 resection.

METHOD

A retrospective analysis reviewed the data of 82 consecutive confirmed GIST patients at a single medical center in China from January 2012 to June 2020. The survival curve was estimated using the Kaplan-Meier method, and independent prognostic factors were confirmed using the Cox regression model.

RESULTS

A total of 82 patients were included in the study: 42 men and 40 women, the mean age was 59 years old (23-83 years old). Tumors were commonly found in the jejunum (46.3%), ileum (20.7%), and duodenum (32.9%). The median tumor size was 6.0 cm (range: 1.0-15.0 cm). The number of mitoses per one 50 high-power field was used to define the mitotic rates. In our present study, 56 patients presented a mitotic rate ≤5 (68.3%) and 26 patients showed a rate >5 (31.7%) at the time of diagnosis. All patients accepted tumor resection without lymph node resection. The positivity rate was 97.6% for CD117, 96.3% for delay of germination 1, 65.9% for CD34, 6.1% for S-100, and 59.8% for smooth muscle actin using immunohistochemistry. Tumor size, tumor rupture, Ki67 index, mitotic index, and postoperative imatinib were independent prognostic factors for small intestinal GISTs.

CONCLUSIONS

In this study, larger tumor size, high Ki67 index, high mitotic index, the occurrence of tumor rupture, and use of imatinib were independent unfavorable prognostic indicators.

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.

A novel fusion between CDC42BPB and ALK in a patient with quadruple wild-type gastrointestinal stromal tumor

Background

Gastrointestinal stromal tumors (GISTs) are the most common type of mesenchymal tumor in gastrointestinal tract, with striking features of morphology and immunohistochemistry. But GISTs in pregnancy could seldom be found. Pathogenic activating mutations of the proto‐oncogene KIT and PDGFRA are detected in majority GISTs, and adjuvant imatinib therapy targeting KIT and PDGFRA mutations is recommended for patients with high‐risk GIST. However, some rare subgroups with distinct molecular features remain uncovered and more therapeutic targets need to be revealed.

Methods

The DNA/RNA samples were detected using the NGS‐based YuanSu450 gene panel. After identifying the CDC42BPB‐ALK fusion by NGS, this novel fusion was further confirmed by Sanger sequencing. Subsequently, FISH analysis was performed using the Vysis ALK Break Apart FISH Probe kit to testify the ALK status. ALK protein expression was confirmed by IHC (D5F3 and 5A4).

Results

Herein, we reported the first case of quadruple wild‐type (WT) GIST with ALK‐CDC42BPB fusion and ALK (D5F3) overexpression. In this study, we described a 33‐year‐old pregnant patient in lactation who had a massive space occupying lesion (with the maximum diameter of 22 cm) in the stomach and was eventually diagnosed as quadruple WT GIST (KIT^WT/PDGFRA^WT/SDH^WT/RAS‐P^WT).

Conclusion

We unexpectedly found that this GIST patient showed ALK (D5F3) overexpression and harbored a novel fusion CDC42BPB exon 24‐ALK in exon 20.

Gastric Schwannoma: A Case Report and Literature Review

Gastric schwannomas (GS) are very rare spindle cell, submucosal mesenchymal tumors that arise from Schwann cells of nerve plexuses in the stomach wall. They are usually benign but can become malignant and metastasize to other organs. Surgical resection with biopsy is the gold standard for diagnosis and management of GS. In this article, we present a 68-year-old female patient who presented with abdominal pain, nausea, vomiting, and belching for a couple of months. Upon further evaluation, she was found to have a 4.2 cm gastric mass, which was consistent with gastric schwannoma through biopsy and immunohistochemistry. The patient underwent complete surgical resection of the tumor without any complications. In this article, we will discuss the literature about GS including its clinical presentation, diagnosis, and management options.

Diagnostic accuracy of endoscopic ultrasound with artificial intelligence for gastrointestinal stromal tumors: A meta-analysis

OBJECTIVES

Gastrointestinal stromal tumors (GISTs) are thought to have a malignant potential. However, utilizing endoscopic ultrasound (EUS) to differentiate GISTs from other types of subepithelial lesions (SELs) remains challenging. Artificial intelligence (AI)-based diagnostic systems for EUS have been reported to have a promising performance, although the results of the previous studies remain controversial. In this meta-analysis, we aimed to assess the diagnostic accuracy of AI-based EUS in distinguishing GISTs from other SELs.

METHODS

A literature search was conducted on MEDLINE and EMBASE databases to identify relevant articles. The sensitivity, specificity, and area under the summary receiver operating characteristic curve (AUROC) of eligible studies were analyzed.

RESULTS

Seven studies were eligible for the final analysis. The combined sensitivity and specificity of AI-based EUS were 0.93 (95% confidence interval [CI] 0.88-0.96) and 0.78 (95% CI 0.67-0.87), respectively. The overall diagnostic odds ratio of AI-based EUS for GISTs was 36.74 (95% CI 17.69-76.30) with an AUROC of 0.94.

CONCLUSIONS

AI-based EUS showed high diagnostic ability and might help better differentiate GISTs from other SELs. More prospective studies on the diagnosis of GISTs using AI-based EUS are warranted in clinical setting.

Effects of Endoscopic Submucosal Excavation With Non-Submucosal Injection on Stromal Tumors in Stomach

Background and Aim

Endoscopic submucosal excavation (ESE) is commonly used to treat gastrointestinal stromal tumors (GISTs), especially for tumor sizes within 2 cm; compared with the conventical ESE, the efficacy and safety of the no-submucosal injection (NSI) ESE remains unclear. The aim of this study was to assess the clinical efficacy and safety of NSI-ESE for gastric stromal tumors.

Methods

ESE was performed in 102 patients at our hospital between January 2018 and January 2020, and the clinical features, surgical outcomes, complications, cost of performance, pathological diagnosis, and risk classification were evaluated.

Results

All tumors were completely resected by endoscopic resection (ER), with a complete resection rate of 100%. It was achieved by ESE/EFTR (endoscopic full-thickness resection) in 49 cases with submucosal injection, and by ESE/EFTR in 53 cases with NSI-ESE. The mean surgical time in cases with submucosal injection was 25.86 ± 4.45 min, compared to the cases without submucosal injection (17.23 ± 3.47 min), and the difference was significant (p < 0.001); the exposure time of tumor, the time of complete excavation of tumor, procedure cost, and hospital stay in the NSI-ESE group were all lower than those cases with submucosal injection (p < 0.05). In the risk classification, 95 (93.1%) cases had a very low risk, 4 (4.0%) cases had a low risk, and 2 (2.0%) cases had a high risk. No recurrence or metastasis was observed during the follow-up period of 18 ± 6 months (range: 13–25 months).

Conclusions

NSI-ESE is a feasible, effective, and safe treatment for gastric GISTs; compared to the conventional ESE, NSI-ESE has the following advantages: it decreases procedure time, it lowers the risk of perforation, and it is cost-effective.

A rare case of cardiac toxicity in a patient with imatinib treatment: Case report

Imatinib, a tyrosine kinase inhibitor, primarily used to treat chronic myeloid leukemia, has shown a survival benefit in gastrointestinal stromal tumors (GISTs). The most common toxicities of imatinib include fluid retention, diarrhea, nausea, fatigue, muscle cramps, abdominal pain, and rash. Imatinib-related cardiotoxicity is a rare condition, and its clinical severity varies between asymptomatic mild ventricular dysfunction and severe congestive heart failure (CHF). We report the case of a 64-year-old woman with a history of GIST who presented to our clinic with rapidly progressive dyspnea. After 8 weeks of imatinib treatment, the patient developed CHF. Echocardiography showed decreased ejection fraction. Imatinib was stopped and diuretic therapy was started. Two weeks later, she died. Cardiac shock was her cause of death.

Development and external validation of a nomogram for individualized adjuvant imatinib duration for high-risk gastrointestinal stromal tumors: A multicenter retrospective cohort study

Introduction

The main emphasis of the research about adjuvant imatinib for high‐risk gastrointestinal stromal tumors (GISTs) is prolonging the treatment duration and ignores the heterogeneous that 10‐year recurrence rates ranged from about 20%–100%. Thus, this study evaluated the effect of different durations of adjuvant imatinib on outcomes in high‐risk GISTs to explore the feasibility of individual treatment.

Methods

We analyzed 855 high‐risk GIST patients from three centers who underwent macroscopically complete resection between December 2007 and September 2020. The patients were divided into training (n =564) and two validation cohorts (n = 238 and53) based on their source. Recurrence‐free survival (RFS) was the primary point. Cox multivariate analysis was used to develop the nomogram. C‐index, time‐dependent area under the curves, and calibration plots were used to assess the performance of the nomogram.

Results

Univariate analysis showed that longer adjuvant imatinib was significantly associated with better 5‐year RFS (p < 0.0001). Further investigation identified that the same high‐risk patients with lower tumor‐associated recurrence risk benefitted little from prolonged treatment and that the recommended adjuvant imatinib duration was insufficient for those with higher recurrence risk. A nomogram for predicting 2‐, 3‐, and 5‐year RFS based on different treatment durations and four major risk factors, namely, tumor site, size, mitotic count, and rupture status, was built and validated, with a C‐index of 0.82, 0.74, and 0.70 in training and two external validation cohorts, respectively. An online dynamic nomogram was further developed for clinical applications (https://ruolinliu666.shinyapps.io/GIST/), offering predictive recurrence rates based on different treatment durations and tumor features.

Conclusions

We developed a nomogram to predict the recurrence risk for high‐risk patients according to tumor features and treatment durations of imatinib to help physicians on decision‐making for individualized treatment duration.

[Performance of the Combined Model Based on Both Clinicopathological and CT Texture Features in Predicting Liver Metastasis of High-risk Gastrointestinal Stromal Tumors]

Objective To investigate the performance of the combined model based on both clinicopathological features and CT texture features in predicting liver metastasis of high-risk gastrointestinal stromal tumors(GISTs). Methods The high-risk GISTs confirmed by pathology from January 2015 to December 2020 were analyzed retrospectively,including 153 cases from the Cancer Hospital of the University of Chinese Academy of Sciences and 51 cases from the Shaoxing Central Hospital.The cases were randomly assigned into a training set(n=142)and a test set(n=62)at a ratio of 7∶3.According to the results of operation or puncture,they were classified into a liver metastasis group(76 cases)and a non-metastasis group(128 cases).ITK-SNAP was employed to delineate the volume of interest of the stromal tumors.Least absolute shrinkage and selection operator(LASSO)was employed to screen out the effective features.Multivariate logistic regression was adopted to construct the models based on clinicopathological features,texture features extracted from CT scans,and the both(combined model),respectively.Receiver operating characteristic(ROC)curve and calibration curve were established to evaluate the predictive performance of the models.The area under the curve(AUC)was compared by Delong test. Results Body mass index(BMI),tumor size,Ki-67,tumor occurrence site,abdominal mass,gastrointestinal bleeding,and CA125 level showed statistical differences between groups(all P<0.05).A total of 107 texture features were extracted from CT images,from which 13 and 7 texture features were selected by LASSO from CT plain scans and CT enhanced scans,respectively.The AUC of the prediction with the training set and the test set respectively was 0.870 and 0.855 for the model based on clinicopathological features,0.918 and 0.836 for the model based on texture features extracted from CT plain scans,0.920 and 0.846 for the model based on texture features extracted from CT enhanced scans,and 0.930 and 0.889 for the combined model based on both clinicopathological features and texture features extracted from CT plain scans.Delong test demonstrated no significant difference in AUC between the models based on the texture features extracted from CT plain scans and CT enhanced scans(P=0.762),whereas the AUC of the combined model was significantly different from that of the clinicopathological feature-based model and texture feature-based model(P=0.001 and P=0.023,respectively). Conclusion Texture features extracted from CT plain scans can predict the liver metastasis of high-risk GISTs,and the model established with clinicopathological features combined with CT texture features has best prediction performance.