Necessity of Individualized Approach for Gastric Subepithelial Tumor Considering Pathologic Discrepancy and Surgical Difficulty Depending on the Gastric Location

Background: Depending on the location of gastric subepithelial tumors (SETs), surgical access is difficult with a risk of postoperative complications. This study aimed to evaluate the clinicopathological characteristics of small-sized gastric SETs and their surgical outcomes depending on location and provide considering factors for their treatment plans. Methods: This single-center, retrospective study reviewed patients who underwent surgical resection for gastric SETs (size < 5 cm). SETs were divided into benign SETs and gastrointestinal stromal tumors (GISTs) for comparison. The clinicopathological characteristics of SETs in the cardia were compared to those in the other regions. Results: Overall, 191 patients with gastric SETs (135 GISTs, 70.7%; and 56 benign SETs, 29.3%) were included. In multivariate analysis, age > 65 years (odds ratio (OR), 3.183; 95% confidence interval (CI), 1.310−7.735; p = 0.011), and non-cardiac SETs (OR, 2.472; 95% CI, 1.110−5.507; p = 0.030) were associated with a significant risk of malignancy. Compared to SETs in other locations, cardiac SETs showed more complications (3 versus 0; p = 0.000), and open conversion rates (2 versus 0; p = 0.003). However, the proportion of GISTs of SETs in the cardia is not negligible (52.9%). Conclusions: Considering the malignancy risk of SETs, active surgical resection should be considered in old age and/or location in the non-cardiac area. However, in young patients, SETs located in the gastric cardia have a considerably benign nature and are associated with poor short-term surgical outcomes. An individualized surgical approach for asymptomatic small SETs according to the gastric location is warranted.

Tissue diagnosis necessary for small endoscopic ultrasound-suspected gastric gastrointestinal stromal tumors 2 cm or less in size: A prospective study focusing on the endoscopic incisional biopsy

BACKGROUND AND AIM

The small endoscopic ultrasound (EUS)-suspected gastric gastrointestinal stromal tumors (GISTs), gastric subepithelial tumors at the muscularis propria layer on EUS, are detected frequently. Bite-on-bite forceps biopsy and EUS-guided tissue sampling yield variable results. This study aimed to analyze clinicopathologic features of the small EUS-suspected gastric GISTs 2 cm or less in size and to evaluate the efficacy and safety of the endoscopic incisional biopsy (EIB) for these small tumors.

METHODS

This prospective study investigated 70 patients with small EUS-suspected gastric GISTs 2 cm or less in size in two stages. Firstly, 30 patients were recruited for the efficacy and safety evaluation of the EIB. Secondly, 40 patients were randomly assigned to receive either EIB or the bite-on-bite biopsy for comparison of the diagnostic yield, procedure time, and adverse event rate.

RESULTS

Combining two study stages, leiomyoma (74%) was diagnosed histologically to outnumber GIST (26%) with a diagnostic rate of 94% for patients receiving EIB. KIT exon 11 mutations (50%) and PDGFRA exon 12 mutations (16%) were detected in the small gastric GISTs. In the direct comparison, the diagnostic yield of EIB and the bite-on-bite biopsy was 85% and 50%, respectively (P = 0.018). There was no statistically significant difference of the mean procedure time or adverse event rate between these two groups.

CONCLUSIONS

Leiomyoma is more common than expected among these small tumors. Tissue diagnosis with an effective and safe sampling technique, such as EIB, is necessary for making further clinical decisions.

Laparoscopic resection for imatinib-resistant recurrent tumors of gastric gastrointestinal stromal tumors: A case report

An 82-year-old woman underwent laparoscopic partial gastrectomy for fundal gastrointestinal stromal tumor (GIST) in a previous hospital. She visited our hospital for the treatment of recurrence, because two nodules, one each on the gastric suture line and in the peritoneum of the left diaphragm, were pointed out. Imatinib therapy was immediately initiated, and the size of both nodules decreased. However, the one on the gastric suture line showed regrowth after 4 years, which was eventually diagnosed as imatinib-resistant GIST. Hence, laparoscopic partial gastrectomy with peritoneal imatinib-sensitive nodule resection was subsequently performed. Pathologically, the nodule on the gastric suture line was confirmed as a GIST, whereas the other was diagnosed as a hyaline-degenerated GIST. Surgical intervention for imatinib-resistant GISTs has been reported to improve the outcomes of recurrent GISTs. Laparoscopic resection of localized imatinib-resistant GISTs could safely and less invasively be performed in this case; however, caution should be paid to the indication of the approach.

Tensin2 Is a Novel Diagnostic Marker in GIST, Associated with Gastric Location and Non-Metastatic Tumors

GIST is a rare soft tissue sarcoma, for which KIT and DOG1 are used as highly sensitive diagnostic markers. Other diagnostic markers include CD34, protein kinase C θ, deficiency of succinate dehydrogenase complex subunit B, carbonic anhydrase II, and type I insulin-like growth factor receptor. We investigated the role of TNS2 as a diagnostic biomarker by using immunohistochemistry in 176 GISTs and 521 other sarcomas. All GISTs expressed TNS2, with intermediate or high expression in 71.4% of samples. The majority (89.8%) of other sarcomas were negative for TNS2, and intermediate to strong staining was only seen in 2.9% of samples. Strong TNS2 staining was associated with gastric location (gastric 52.8% vs. non-gastric 7.2%; p < 0.001), absence of metastases (non-metastatic tumors 44.3% vs. metastatic tumors 5.9%; p = 0.004), female sex (female 45.9% vs. male 33.8%; p = 0.029), and tumors of lower risk categories (very low or low 46.9% vs. intermediate 51.7% vs. high 29.0%; p = 0.020). TNS2 expression did not correlate with overall survival or metastasis-free survival. No associations between TNS2 expression and KIT/PDGFRA mutation status, tumor size, mitotic count, or age of the patient were detected. The results provide conclusive evidence for the value of TNS2 as a sensitive and specific diagnostic biomarker for GIST.

Setting the international research agenda for sarcoma together with patients and carers: first results of the Sarcoma Patient EuroNet (SPAEN) priority setting partnership

Background

Research in sarcomas has historically been the domain of scientists and clinicians attempting to understand the disease to develop effective treatments. This traditional approach of placing scientific rigor before the patient’s reality is changing. This evolution is reflected in the growth of patient-centered organizations and patient advocacy groups that seek to meaningfully integrate patients into the research process. The aims of this study are to identify the unanswered questions regarding sarcomas (including gastrointestinal stromal tumors and desmoid fibromatosis) from patient, carer, and clinical perspectives and examine how patients and carers want to be involved in sarcoma research.

Methods

The Patient-Powered Research Network of Sarcoma Patients EuroNet set up a Priority Setting Partnership (PSP) in collaboration with stakeholders from the sarcoma research field. This PSP is largely based on the James Lind Alliance methodology.

Results

In total, 264 sarcoma patients (73%) and carers (27%) from all over the world participated in the online survey and covered the full spectrum of sarcomas. The topics mentioned were labeled in accordance with the Common Scientific Outline of the International Cancer Research Partnership and lists for potential research topics, advocacy topics, and requests for information were constructed. With regard to patient and carer involvement, 64% were very willing to be actively involved and mainly in the following areas: sharing perspectives, discussing patient-clinician interactions, and attending research meetings.

Conclusions

The first results of this sarcoma PSP identified important research questions, but also important topics for patient advocacy groups and further improvement of information materials. Sarcoma patients and carers have a strong wish to be involved in multiple aspects of sarcoma research. The next phase will identify the top 10 research priorities per tumor type. These priorities will provide guidance for research that will achieve greatest value and impact.

•

The results from this international sarcoma Priority Setting Partnership (PSP) identified important research questions.

•

This PSP also identified important topics for patient advocacy and requests for information.

•

Sarcoma patients and carers have a strong wish to be involved in multiple aspects of sarcoma research.

•

The next phase of this PSP will aim to prioritize the research questions per tumor type.

Pimitespib in patients with advanced gastrointestinal stromal tumor (CHAPTER-GIST-301): a randomized, double-blind, placebo-controlled phase 3 trial

BACKGROUND

Prognosis of advanced gastrointestinal stromal tumors (GIST) refractory to tyrosine kinase inhibitors (TKIs) is poor. This randomized, placebo-controlled, phase 3 trial evaluated the efficacy and safety of pimitespib, a novel heat shock protein 90 inhibitor, in advanced GIST refractory to standard TKIs.

PATIENTS AND METHODS

Patients with histologically confirmed GIST refractory to imatinib, sunitinib, and regorafenib were randomized 2:1 to oral pimitespib 160 mg/day or placebo for five consecutive days per week in 21-day cycles. Following disease progression by blinded central radiological review (BCRR), crossover to open-label pimitespib was permitted. The primary endpoint was progression-free survival (PFS) by BCRR in the full analysis set. Secondary endpoints included overall survival (OS) adjusted using the rank preserving structural failure time method to reduce the expected confounding impact of crossover.

RESULTS

From Oct 31, 2018 to Apr 30, 2020, 86 patients were randomized to pimitespib (n=58) or placebo (n=28). Median PFS was 2.8 months (95% CI 1.6-2.9) with pimitespib versus 1.4 months (0.9-1.8) with placebo (hazard ratio [HR] 0.51 [95% CI 0.30-0.87]; one-sided p=0.006). Pimitespib showed an improvement in crossover-adjusted OS compared with placebo (HR 0.42 [0.21-0.85], one-sided p=0.007). Seventeen (60.7%) patients receiving placebo crossed-over to pimitespib; median PFS after crossover was 2.7 (95% CI 0.7-4.1) months. The most common (≥30%) treatment-related adverse events (AEs) with pimitespib were diarrhea (74.1%) and decreased appetite (31.0%); the most common (≥10%) grade ≥3 treatment-related AE was diarrhea (13.8%). Treatment-related AEs leading to pimitespib discontinuation occurred in 3 (5.2%) patients.

CONCLUSION

Pimitespib significantly improved PFS and crossover-adjusted OS compared with placebo and had an acceptable safety profile in patients with advanced GIST refractory to standard TKIs.

Jejunojejunal intussusception with chronic bleeding caused by gastrointestinal stromal tumor: a case report and literature review

Background

Intussusception is a rare clinical condition in adults. The majority of patients present with symptoms of bowel obstruction. Intussusception is often misdiagnosed and the majority of cases are diagnosed intraoperatively. In this paper, we present a rare case of adult jejunojejunal intussusception with chronic bleeding caused by a gastrointestinal stromal tumor (GIST). We emphasize the role of contrast-enhanced computed tomography (CT) and enteroscopy in the presurgical diagnosis and the good prognosis in the high-risk GIST patient after surgery and targeted therapy.

Case Description

Herein, we present the case of a 63-year-old female patient with small bowel intussusception with chronic bleeding caused by a GIST. Her main symptoms were intermittent melena and progressive anemia. She had a 20-year history of hypertension and had never undergone previous abdominal surgery. After failure of an esophagogastroduodenoscopy and colonoscopy to locate the hemorrhagic foci in the gastrointestinal tract, contrast-enhanced CT and enteroscopy were used and a small bowel intussusception and an intraluminal mass with a bleeding ulcer was identified. The patient underwent laparoscopic partial small bowel resection, and postoperative pathological examinations showed a small intestinal GIST with a high risk of recurrence. It was suggested that the patient take imatinib regularly for at least 3 years. At the time of writing, she has remained in good health without relapse for 24 months after discharge. We also review 20 published cases of intussusception caused by small bowel GIST in the PubMed database.

Conclusions

Obscure gastrointestinal hemorrhage needs meticulous examinations to promptly determine the cause and location of bleeding. This case and literature review revealed that comprehensive surgical resection-centered treatment was the standard treatment for primary localized GISTs in patients at significant risk of relapse.

Gastroduodenal intussusception caused by gastric gastrointestinal stromal tumor in adults: a case report and literature review

Intussusception mostly occurs in childhood and is rare in adults. Although intussusception can occur in any part of the gastrointestinal tract, gastroduodenal intussusception caused by a gastric tumor is relatively uncommon in clinical practice. A PubMed search identified 24 published cases of gastroduodenal intussusception caused by gastric gastrointestinal stromal tumor (GIST); however, it is possible that we missed other cases not included in PubMed. Here we report a case of gastroduodenal intussusception caused by gastric GIST in an 85-year-old man. He came to the hospital because of recurrent black stools. Plain computed tomography (CT) scan indicated a mass in the gastric antrum, with slight enhancement in the arterial phase on enhanced CT scan. He was diagnosed with GIST. In addition, images indicated that the mass overlapped into the duodenum, and gastroduodenal intussusception was thus considered. Gastroscopy showed a huge mass in the gastric body. According to the gastroscopy and CT results, gastroduodenal intussusception caused by a gastric tumor was considered. The patient underwent complete surgical removal, which revealed a mass originating from the gastric antrum and overlapping into the duodenum. The postoperative pathological diagnosis was intermediate-risk gastric GIST. The patient was followed up for 4 months without tumor recurrence.

Tropomyosin-Related Kinase Fusions in Gastrointestinal Stromal Tumors

Simple Summary

The canonical mutations in gastrointestinal stromal tumors (GISTs) are typically activating mutations in KIT and platelet-derived growth factor receptor alpha (PDGFRA). Imatinib, the treatment of choice for GISTs, shows a lower response in KIT/PDGFRA wild-type GISTs. Neurotrophic tyrosine receptor kinase (NTRK) fusion, which can be treated with an NTRK target agent, has been reported in KIT/PDGFRA wild-type GISTs, and, therefore, the Yonsei Cancer Center analyzed NTRK fusion incidence in KIT/PDGFRA wild-type GISTs. At the Yonsei Cancer Center, NTRK fusion was confirmed in 16% of cases. Confirmation of NTRK fusion in KIT/PDGFRA wild-type GISTs provides important information for improving therapeutic outcomes. NTRK fusion was confirmed in 16% of KIT/PDGFRA wild-type GIST cases at the Yonsei Cancer Center. Confirmation of NTRK fusion in KIT/PDGFRA wild-type GISTs will improve therapeutic outcomes.

Abstract

The canonical mutations in gastrointestinal stromal tumors (GISTs) are typically activating mutations in KIT and platelet-derived growth factor receptor alpha (PDGFRA). GISTs with non-canonical mutations are a heterogeneous group. Here, we examined tropomyosin-related kinase (TRK) fusion in GIST cases without KIT/PDGFRA mutations (KIT/PDGFRA wild-type (WT) GISTs). We retrospectively analyzed patients who were diagnosed with GISTs at the Yonsei Cancer Center, Severance Hospital, between January 1998 and December 2016. Thirty-one patients with KIT/PDGFRA WT GISTs were included in the analysis. TRK expression in tumor samples was assessed by pan-TRK immunohistochemistry (IHC), and the neurotrophic tyrosine receptor kinase (NTRK: the gene encoding TRK) rearrangement was analyzed by fluorescence in situ hybridization (FISH). IHC analyses revealed that five cases in this cohort exhibited a weak to moderate TRK expression. NTRK1 fusions were detected in three tumor samples, and two samples harbored NTRK3 fusions. The remaining 26 samples did not harbor NTRK fusions. Two types of NTRK fusions were detected, and the overall NTRK fusion frequency in KIT/PDGFRA WT GIST cases was 16% (5/31). Our data provide insights into the molecular alterations underpinning KIT/PDGFRA WT GISTs. More effort should be devoted to improve methods to identify this distinct disease subtype within the KIT/PDGFRA WT GIST group.

CV2/CRMP5-antibody-related Paraneoplastic Neurologic Syndrome Associated with Gastrointestinal Stromal Tumor

Paraneoplastic neurological syndrome (PNS) is a heterogeneous group of neurological disorders caused by immune-mediated inflammatory mechanisms. We herein report a 77-year-old man with CV2/CRMP5-antibody-related PNS associated with a gastrointestinal stromal tumor (GIST). He was admitted for forgetfulness and delusional behavior. His neurological symptoms were subacute, and a whole-body examination revealed a gastric GIST. Serology showed CV2/collapsin response mediator protein (CRMP)-5 antibodies. Partial gastrectomy was performed for the GIST, and the neurological symptoms and serum CV2/CRMP5 antibodies disappeared. No relapse has occurred since the surgery. PNS should be considered in patients with subacute neurological disorders.

Effect of imatinib on oral wound healing after extraction: A rare case report

BACKGROUND

Proper tissue repair and healing after oral surgery are vital to achieve optimal outcomes. Certain medications may interfere with wound healing, but this debilitating adverse drug reaction is often not reported in the literature. It is unknown whether imatinib (Gleevec; Novartis Pharmaceuticals) interferes with gingival healing after oral surgery.

CASE DESCRIPTION

A 58-year-old man with a dislodged crown and core buildup of tooth no. 19 sought treatment at a prosthodontic clinic. After examination, the patient consented to extraction, ridge preservation, and future implant placement. He had previous surgical resection of a gastrointestinal stromal tumor and was taking 400 mg of imatinib daily. After extraction and ridge preservation, delayed soft-tissue healing and loss of the coronal portion of bone graft were observed at 8 weeks after surgery. Delayed wound healing was observed again after revision surgery. After imatinib therapy was paused, the adverse effect subsided and the wound healed properly. On the basis of causality assessment and clinical judgment, the authors determined that imatinib was the probable cause of this adverse drug reaction. To their best knowledge, this is the first report of delayed gingival healing after oral surgery secondary to imatinib.

PRACTICAL IMPLICATIONS

Dental practitioners should consider the possibility of impaired healing among their patients taking imatinib, especially before procedures that damage gingival tissue, although this adverse drug reaction is not reported in the drug's package insert. Consult with the patient's oncologist is advised before dental manipulations; temporary discontinuation (or dose reductions) of imatinib may be warranted until wounded tissue heals properly.

Value of artificial intelligence with novel tumor tracking technology in the diagnosis of gastric submucosal tumors by contrast-enhanced harmonic endoscopic ultrasonography

BACKGROUND AND AIM

Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) is useful for the diagnosis of lesions inside and outside the digestive tract. This study evaluated the value of artificial intelligence (AI) in the diagnosis of gastric submucosal tumors by CH-EUS.

METHODS

This retrospective study included 53 patients with gastrointestinal stromal tumors (GISTs) and leiomyomas, all of whom underwent CH-EUS between June 2015 and February 2020. A novel technology, SiamMask, was used to track and trim the lesions in CH-EUS videos. CH-EUS was evaluated by AI using deep learning involving a residual neural network and leave-one-out cross-validation. The diagnostic accuracy of AI in discriminating between GISTs and leiomyomas was assessed and compared with that of blind reading by two expert endosonographers.

RESULTS

Of the 53 patients, 42 had GISTs and 11 had leiomyomas. Mean tumor size was 26.4 mm. The consistency rate of the segment range of the tumor image extracted by SiamMask and marked by the endosonographer was 96% with a Dice coefficient. The sensitivity, specificity, and accuracy of AI in diagnosing GIST were 90.5%, 90.9%, and 90.6%, respectively, whereas those of blind reading were 90.5%, 81.8%, and 88.7%, respectively (P = 0.683). The κ coefficient between the two reviewers was 0.713.

CONCLUSIONS

The diagnostic ability of CH-EUS results evaluated by AI to distinguish between GISTs and leiomyomas was comparable with that of blind reading by expert endosonographers.

Cost-Effectiveness Analysis of Tyrosine Kinase Inhibitors in Gastrointestinal Stromal Tumor: A Systematic Review

Background: The introduction of tyrosine kinase inhibitor (TKI) therapy has dramatically improved the clinical effectiveness of patients with locally advanced and/or metastatic gastrointestinal stromal tumors (GIST), and this systematic review was conducted aiming at the cost-effectiveness analysis of TKIs in GIST.

Methods: A thorough literature search of online databases was performed, using appropriate terms such as “gastrointestinal stromal tumor or GIST,” “cost-effectiveness,” and “economic evaluation.” Data extraction was conducted independently by two authors, and completeness of reporting and quality of the evaluation were assessed. The systematic review was conducted following the PRISMA statement.

Results: Published between 2005 and 2020, 15 articles were incorporated into the systematic review. For advanced GIST, imatinib followed by sunitinib was considered cost-effective, and regorafenib was cost-effective compared with imatinib re-challenge therapy in the third-line treatment. For resectable GIST, 3-year adjuvant imatinib therapy represented a cost-effective treatment option. The precision medicine-assisted imatinib treatment was cost-effective compared with empirical treatment.

Conclusion: Although identified studies varied in predicted costs and quality-adjusted life years, there was general agreement in study conclusions. More cost-effectiveness analysis should be conducted regarding more TKIs that have been approved for the treatment of GIST.

Systematic Review Registration:https://www.crd.york.ac.uk/, PROSPERO: CRD42021225253.

Comparison of Prognosis Between Microscopically Positive and Negative Surgical Margins for Primary Gastrointestinal Stromal Tumors: A Systematic Review and Meta-Analysis

Background

This meta-analysis aimed to determine the prognostic impact of microscopically positive margins (R1) on primary gastrointestinal stromal tumors.

Methods

A literature search was performed using PubMed, Embase, Web of Science, and Cochrane Library for studies up to 23 November 2020. The pooled disease-free survival (DFS) and overall survival (OS) between R1 and negative margins (R0) were estimated using a random-effects model.

Results

Twenty studies with 6,465 patients were included. Compared with R0 resection, R1 was associated with poor DFS in patients who did not receive adjuvant Imatinib (HR: 1.62, 95% CI: 1.26-2.09; P = 0.48, I² = 0%; reference: R0). This negative impact of R1 disappeared with the use of adjuvant Imatinib (HR: 1.23, 95% CI: 0.95-1.60; P = 0.38, I2 = 6%; reference: R0). R1 was related to poor DFS in gastric GISTs (HR: 2.15, 95% CI: 1.15-5.02, I² = 0%; reference: R0), which was attenuated in the subgroup of adjuvant Imatinib (HR: 2.24, 95% CI: 0.32-15.60; P = 0.84, I² = 0%; reference: R0). Rectal GIST with R1 margin who even received adjuvant Imatinib still had poor DFS (HR: 3.79, 95% CI: 1.27-11.31; P = 0.54, I² = 0%; reference: R0). Patients who underwent R1 resection had similar OS compared with those underwent R0 resection regardless of the use of adjuvant Imatinib.

Conclusion

R1 was associated with poor DFS for primary GISTs, which was attenuated by adjuvant therapy with Imatinib. Similar result was observed in the gastric GISTs subgroup. Rectal GIST patients with R1 resection had poor DFS even when they received adjuvant Imatinib. The R1 margin did not influence the OS of GISTs.

Minimal change disease associated with gastrointestinal stromal tumor accompanied by significantly elevated serum IgE level: a case report

BACKGROUND

Minimal change disease (MCD) is a common cause of the nephrotic syndrome. Several studies have shown an increased incidence of cancer in patients with MCD. However, there are no reports on the association between MCD and gastrointestinal stromal tumor (GIST).

CASE PRESENTATION

We report a case of a 66-year-old female with severe nephrotic syndrome and concomitant duodenal GIST. Immunoglobulin test showed a significant increase of IgE levels. The diagnosis of renal histopathology was MCD with subacute tubulointerstitial injury. The combination of preoperative Imatinib mesylate chemotherapy and tumor excision was accompanied by significant remission of proteinuria, and IgE level decreasing, without immunosuppressivetherapy.

CONCLUSIONS

It is the first case report that MCD was associated with GIST and elevated IgE level. Clinically, in patients with elevated IgE level associated with nephrotic syndrome, the possibility of tumor must be taken into account when allergic factors are excluded.

Gastrointestinal stromal tumors with Kit gene mutation in 4 guinea pigs (Cavia porcellus)

Gastrointestinal stromal tumors (GISTs) have been rarely reported in guinea pigs. We aimed to characterize the clinical and pathological features of GISTs in 4 guinea pigs and investigate the presence of mutations in exon 11 of the KIT proto-oncogene receptor tyrosine kinase (Kit) gene. Two subjects were male and 2 were female; 2 were 6 years old, 1 was 7 years old, and 1 was of an unknown age. Three cases had primary gastric tumors, whereas 1 had a primary small intestinal tumor. All cases had tumors that extended from the submucosa to the serosa with extraluminal growth. A gastric tumor had gastric, pancreatic, and cecal metastases. Histologically, the tumors were sharply demarcated and composed of spindle cells arranged in bundles, intermixed with small amounts of collagenous stroma. The tumor cells had mild atypia with few mitotic figures (0-5/50 high power fields, 7.95 mm²) and were immunolabeled for KIT and Discovered-on-GIST 1 (DOG1). All cases had mutations in exon 11 of the Kit gene. These findings indicate that GISTs in guinea pigs are similar to those in humans and dogs. GISTs in guinea pigs are potentially malignant submucosal tumors with KIT- and DOG1-immunolabeling, exon 11 KIT mutations, and the possibility of metastasis.

Health-Related Quality of Life and Side Effects in Gastrointestinal Stromal Tumor (GIST) Patients Treated with Tyrosine Kinase Inhibitors: A Systematic Review of the Literature

BACKGROUND

The introduction of tyrosine kinase inhibitors (TKIs) has revolutionized the treatment of gastrointestinal stromal tumors (GISTs), resulting in a substantial gain in median overall survival. Subsequently, health-related quality of life (HRQoL) has become more relevant. Here, we systematically review the available literature on HRQoL issues and side effects of different TKIs registered for the treatment of GIST.

METHODS

A search through five databases was performed. Full reports in English describing HRQoL outcomes and/or side effects in GIST patients on TKI therapy were included.

RESULTS

A total of 104 papers were included; 13 studies addressed HRQoL, and 96 studies investigated adverse events. HRQoL in patients treated with imatinib, regorafenib, and ripretinib remained stable, whereas most sunitinib-treated patients reported a decrease in HRQoL. Severe fatigue and fear of recurrence or progression were specifically assessed as HRQoL issues and had a negative impact on overall HRQoL as well as psychological and physical well-being. The majority of studies focused on physician-reported side effects. Nearly all GIST patients treated with a TKI experienced at least one adverse event, mostly mild to moderate.

CONCLUSIONS

Despite the fact that almost all patients treated with a TKI experienced side effects, this did not seem to affect overall HRQoL during TKI therapy. In daily practice, it are the side effects that hamper a patient's HRQoL resulting in treatment adjustments, suggesting that the reported side effects were underestimated by physicians, or the measures used to assess HRQoL do not capture all relevant issues that determine a GIST patient's HRQoL.

Catching the GIST: Massive Gastrointestinal Stromal Tumor Presenting as Acute Dyspnea

We present a case of a 55-year-old woman presenting with worsening shortness of breath and constipation over the course of three days. Initial computed tomography scan showed a large, complex abdominal mass with a vascular pedicle and possible pedunculated origin along the inferior aspect of the greater curvature of the stomach. The mass was further evaluated on magnetic resonance imaging showing an active hemorrhage. The patient became hemodynamically unstable and general surgery was consulted for evaluation. Mass resection was performed, and biopsy revealed KIT/CD117+ and DOG1/ANO1+ gastrointestinal stromal tumor staged as T4. Although definitive diagnosis of a gastrointestinal stromal tumor requires biopsy, prompt clinical and radiological recognition is critical for patients to receive definitive treatment of mass resection.

Laparoscopic resection of a gastrointestinal stromal tumor that recurred more than 15 years after surgery using lighted ureteral catheters: A case report

A 69-year-old woman underwent abdominoperineal resection for a gastrointestinal stromal tumor (GIST) of the rectum 15 years ago. She received adjuvant chemotherapy for 8 years. Seven years later, abdominal computed tomography revealed a soft-tissue shadow in the left lower abdomen, and fluorodeoxyglucose uptake was observed at the same site on positron emission tomography. The recurrence of GIST was suspected, and laparoscopic resection was performed. Laparoscopy showed that the tumor was located at the retroperitoneum near to the descending colon and invaded the left ovarian vessels. It also made contact with the left ureter; however, lighted ureteral catheters enabled us to identify and preserve the left ureter. An immunohistochemical examination revealed the recurrence of GIST. Recurrence may become apparent 15 years or more after GIST surgery, and, thus, a long-term follow-up is required. Lighted ureteral catheters were useful for identifying the ureter and preventing ureteral injury in a recurrent case suspected of invading the ureter.

Characterization of Aberrations in DNA Damage Repair Pathways in Gastrointestinal Stromal Tumors: The Clinicopathologic Relevance of γH2AX and 53BP1 in Correlation with Heterozygous Deletions of CHEK2, BRCA2, and RB1

Genetic aberrations involving DNA damage repair (DDR) remain underexplored in gastrointestinal stromal tumors (GISTs). We characterized DDR abnormalities using targeted next-generation sequencing and multiplex ligation-dependent probe amplification, and performed immunofluorescence (IF) and immunohistochemistry (IHC) analyses of γH2AX and 53BP1. Consistent with IF-validated nuclear co-localization, γH2AX and 53BP1 showed robust correlations in expression levels, as did both biomarkers between IF and IHC. Without recurrent pathogenic single-nucleotide variants, heterozygous deletions (HetDels) frequently targeted DNA damage-sensing genes, with CHEK2-HetDel being the most prevalent. Despite their chromosomal proximity, BRCA2 and RB1 were occasionally hit by HetDels and were seldom co-deleted. HetDels of CHEK2 and BRCA2 showed a preference for older age groups, while RB1-HetDel predominated in the non-gastric, high-risk, and 53BP1-overexpressing GISTs. Higher risk levels were consistently related to γ-H2AX or 53BP1 overexpression (all p < 0.01) in two validation cohorts, while only 53BP1 overexpression was associated with the deletion of KIT exon 11 (KITex11-del) among genotyped GISTs. Low expressers of dual biomarkers were shown by univariate analysis to have longer disease-free survival (p = 0.031). However, higher risk levels, epithelioid histology, and KITex11-del retained prognostic independence. Conclusively, IHC is a useful surrogate of laborious IF in the combined assessment of 53BP1 and γ-H2AX to identify potential DDR-defective GISTs, which were frequently aberrated by HetDels and a harbinger of progression.

The Diagnosis of Small Gastrointestinal Subepithelial Lesions by Endoscopic Ultrasound-Guided Fine Needle Aspiration and Biopsy

Endoscopic ultrasonography (EUS) has been widely accepted in the diagnosis of all types of tumors, especially pancreatic tumors, lymph nodes, and subepithelial lesions (SELs). One reason is that the examination can provide a detailed observation, with tissue samples being immediately obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). Many SELs are detected incidentally during endoscopic examinations without symptoms. Most SELs are mesenchymal tumors originating from the fourth layer, such as gastrointestinal stromal tumors (GISTs), leiomyomas, and schwannomas. GISTs are potentially malignant. Surgical treatment is recommended for localized GISTs of ≥20 mm. However, the indications for the diagnosis and follow-up of GISTs of <20 mm in size are controversial. There are several reports on the rapid progression or metastasis of small GISTs. Therefore, it is important to determine whether a SEL is a GIST or not. The main diagnostic method is EUS-FNA. Recently, endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) using a new biopsy needle has been reported to obtain larger tissue samples. Additionally, various biopsy methods have been reported to have a high diagnostic rate for small GISTs. In local gastric SELs, regardless of the tumor size, EUS can be performed first; then, EUS-FNA/B or various biopsy methods can be used to obtain tissue samples for decision-making in relation to therapy and the follow-up period.

Unusual Gastrointestinal Hemorrhaging Mimicking a Rupture of Solitary Gastric Varices Due to a Gastric Gastrointestinal Stromal Tumor with Exogenous Growth

Gastric gastrointestinal stromal tumors can lead to upper gastrointestinal hemorrhaging, which is usually caused by dimpling or ulceration on the tumor surface. While rare, pedunculated gastric gastrointestinal stromal tumors outside the stomach can present as a huge mass with delayed complaints. We herein report an unusual hemorrhaging mimicking a rupture of solitary gastric varices due to a pedunculated gastric gastrointestinal stromal tumor. In this case, contrast-enhanced computed tomography (CECT) was essential for tumor detection. An endoscopic investigation revealed dilated, aberrant veins and arteries in the submucosa of this tumor, recognized as solitary gastric varices.

Malignant Gastrointestinal Stromal Tumor of Rectum: A Case Report and Review of Literature

Gastrointestinal stromal tumors (GISTs) are rare tumors of the gastrointestinal tract accounting for less than 1% of all gut tumors. GISTs occurring in the rectum are extremely rare and these usually present at an advanced stage compared with other sites.

We report a case of a middle-aged female who presented with features of anemia and subacute obstruction due to a large rectal tumor and underwent abdominoperineal resection. The histopathological examination confirmed the diagnosis of high-grade malignant GIST with multiple lymph nodal metastasis. She was started on adjuvant imatinib therapy and is on follow-up without any evidence of recurrence.

The authors conclude that GIST must be included in the differential diagnosis of a rectal tumor. Diagnosis is established by biopsy and immunohistochemistry studies. Surgical resection with histological negative margins is the standard curative treatment. Adjuvant targeted therapy can reduce long-term recurrence in high-risk cases.

FGFR2::TACC2 fusion as a novel KIT-independent mechanism of targeted therapy failure in a multidrug-resistant gastrointestinal stromal tumor

Genetic alterations in FGF/FGFR pathway are infrequent in gastrointestinal stromal tumors (GIST), with rare cases of quadruple wildtype GISTs harboring FGFR1 gene fusions and mutations. Additionally, FGF/FGFR overexpression was shown to promote drug resistance to kinase inhibitors in GISTs. However, FGFR gene fusions have not been directly implicated as a mechanism of drug resistance in GISTs. Herein, we report a patient presenting with a primary small bowel spindle cell GIST and concurrent peritoneal and liver metastases displaying an imatinib-sensitive KIT exon 11 in-frame deletion. After an initial 9-month benefit to imatinib, the patient experienced intraabdominal peritoneal recurrence owing to secondary KIT exon 13 missense mutation and FGFR4 amplification. Despite several additional rounds of tyrosine kinase inhibitors (TKI), the patient's disease progressed after 2 years and presented with multiple peritoneal and liver metastases, including one pericolonic mass harboring secondary KIT exon 18 missense mutation, and a concurrent transverse colonic mass with a FGFR2::TACC2 fusion and AKT2 amplification. All tumors, including primary and recurrent masses, harbored an MGA c.7272 T > G (p.Y2424*) nonsense mutation and CDKN2A/CDKN2B/MTAP deletions. The transcolonic mass showed elevated mitotic count (18/10 HPF), as well as significant decrease in CD117 and DOG1 expression, in contrast to all the other resistant nodules that displayed diffuse and strong CD117 and DOG1 immunostaining. The FGFR2::TACC2 fusion resulted from a 742 kb intrachromosomal inversion at the chr10q26.3 locus, leading to a fusion between exons 1-17 of FGFR2 and exons 7-17 TACC2, which preserves the extracellular and protein tyrosine kinase domains of FGFR2. We present the first report of a multi-drug resistant GIST patient who developed an FGFR2 gene fusion as a secondary genetic event to the selective pressure of various TKIs. This case also highlights the heterogeneous escape mechanisms to targeted therapy across various tumor nodules, spanning from both KIT-dependent and KIT-independent off-target activation pathways.

CADM1 promotes adhesion to vascular endothelial cells and transendothelial migration in cultured GIST cells

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the human gastrointestinal tract. Small intestinal GISTs appear to be associated with poorer prognosis and higher metastasis rate than gastric GISTs of the same size and mitotic index. Recently, we reported that cell adhesion molecule 1 (CADM1) is expressed specifically in most small intestinal GISTs, but not in most gastric GISTs, suggesting that this difference in CADM1 expression between gastric GISTs and small intestinal GISTs might influence the difference in clinical behavior between them. The aim of the present study was to examine whether high CADM1 expression affected proliferation, migration, invasion, adhesion to endothelial cells and transendothelial migration of cultured GIST cells by comparing original GIST-T1 cells with very low CADM1 expression with GIST-T1 cells with high CADM1 expression induced by CADM1 cDNA transfection (GIST-T1-CAD cells). GIST-T1-CAD cells had reduced ability to proliferate, migrate and invade compared with the original GIST-T1 cells, but showed significantly higher ability to adhere to human umbilical vein endothelial cells and migrate through endothelial cell monolayers. Thus, CADM1 may contribute to higher metastasis rates in small intestinal GISTs facilitating tumor cell adhesion to vascular endothelial cell and transendothelial migration of tumor cells. CADM1 might serve as a potential target for inhibition of metastasis in small intestinal GISTs.

[A CASE OF PRIMARY ADRENAL LYMPHOMA SUSPECTED AS ADRENAL METASTATIC TUMOR FROM GASTROINTESTINAL STROMAL TUMOR]

We present a case of 75 year's old man for whom small bowel resection was performed for a small intestinal tumor diagnosed as a gastrointestinal stromal tumor (GIST) with KIT exon 11 mutation and intermediate Miettinen risk. Computed tomography (CT) 18 months after surgery showed a right adrenal mass measuring 20 mm in size. Imatinib therapy couldn't show the tumor shrinkage, and the adrenal mass increased up to 37 mm in size 3 months later. He was referred to our department for further examination and treatment. We diagnosed this adrenal tumor as imatinib resistant GIST or adrenal primary malignancy and performed retroperitoneal laparoscopic right adrenalectomy. The pathological diagnosis was diffuse large B-cell lymphoma (DLBCL) not GIST and PET-CT revealed systemic metastasis of DLBCL one month later after surgery. Six courses of R-CHOP therapy achieved a complete response.

Postoperative Adjuvant Imatinib Therapy-Associated Nomogram to Predict Overall Survival of Gastrointestinal Stromal Tumor

BACKGROUND

Adjuvant imatinib therapy has been shown to improve overall survival (OS) of gastrointestinal stromal tumor (GIST) significantly. Few nomograms combining the use of adjuvant imatinib and clinicopathological characteristics estimate the outcome of patients. We aimed to establish a more comprehensive nomogram for predicting OS in patients with GIST.

METHODS

In total, 1310 GIST patients undergoing curative resection at four high-volume medical centers between 2001 and 2015 were enrolled. Independent prognostic factors were identified by multivariate Cox analysis. Eligible patients were randomly assigned in a ratio of 7:3 into a training set (916 cases) and a validation set (394 cases). A nomogram was established by R software and its predictive power compared with that of the modified National Institutes of Health (NIH) classification using time-dependent receiver operating characteristic (ROC) curves and calibration plot.

RESULTS

Age, tumor site, tumor size, mitotic index, postoperative imatinib and diagnostic delay were identified as independent prognostic parameters and used to construct a nomogram. Of note, diagnostic delay was for the first time included in a prognostic model for GIST. The calibrated nomogram resulted in predicted survival rates consistent with observed ones. And the decision curve analysis suggested that the nomogram prognostic model was clinically useful. Furthermore, time-dependent ROC curves showed the nomogram exhibited greater discrimination power than the modified NIH classification in 3- and 5-year survival predictions for both training and validation sets (all P < 0.05).

CONCLUSIONS

Postoperative adjuvant imatinib therapy improved the survival of GIST patients. We developed and validated a more comprehensive prognostic nomogram for GIST patients, and it could have important clinical utility in improving individualized predictions of survival risks and treatment decision-making.

Primary Localized Gastrointestinal Stromal Tumors: Medication Adherence and Prognosis According to Gender

OBJECTIVE

Gender is associated with medication adherence for imatinib, but whether it is related to the prognosis of primary localized gastrointestinal stromal tumors (GISTs) is unclear. The goal of this study was to clarify the relationship between gender and prognosis in GIST patients, with differences in medication adherence considered.

METHODS

The data of 320 GIST patients were retrospectively collected from the First Affiliated Hospital of Chongqing Medical University. Survival analysis was performed using the Kaplan-Meier method (Log rank test) and the risk factors of recurrence were determined using Cox multivariate analysis. Medication adherence-stratified analyses were performed to control for confounding factors.

RESULTS

Kaplan-Meier analysis revealed that among patients who received postoperative adjuvant imatinib therapy, men had a higher recurrence rate than women (P<0.01). Pearson's chi-square test revealed better medication adherence in women than in men (P<0.01). Cox regression analysis revealed that gender was not an independent risk factor for recurrence-free survival (RFS; P=0.25), but medication adherence was (P<0.01). Among GIST patients with a medication possession ratio (MPR) of less than 90%, 62.86% of male patients took imatinib irregularly or not at all due to limited understanding of the disease, whereas 55.74% of female patients' took imatinib irregularly because they could not tolerate adverse drug reactions.

CONCLUSION

Adherence was poorer in male than in female patients, which might explain the worse prognoses of the former among patients who received adjuvant treatment with imatinib. The gender difference in the degree of adherence should be considered in postoperative pharmacotherapy for patients with primary localized GISTs.

Cost-Effectiveness Analysis of Fourth- or Further-Line Ripretinib in Advanced Gastrointestinal Stromal Tumors

Background

The INVICTUS trial assessed the efficacy and safety of ripretinib compared with placebo in the management of advanced gastrointestinal stromal tumors.

Method

We used a Markov model with three health states: progression-free disease, progression disease and death. We parameterized the model from time-to-event data (progression-free survival, overall survival) of ripretinib and placebo arms in the INVICTUS trial and extrapolated to a patient’s lifetime horizon. Estimates of health state utilities and costs were based on clinical trial data and the published literature. The outcomes of this model were measured in quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratios (ICERs). Uncertainty was tested via univariate and probabilistic sensitivity analyses.

Results

The base-case model projected improved outcomes (by 0.29 QALYs) and additional costs (by $70,251) and yielded an ICER of $244,010/QALY gained for ripretinib versus placebo. The results were most sensitive to progression rates, the price of ripretinib, and health state utilities. The ICER was most sensitive to overall survival. When overall survival in the placebo group was lower, the ICER dropped to $127,399/QALY. The ICER dropped to $150,000/QALY when the monthly cost of ripretinib decreased to $14,057. Probabilistic sensitivity analyses revealed that ripretinib was the cost-effective therapy in 41.1% of simulations at the willingness-to-pay (WTP) threshold of $150,000.

Conclusion

As the fourth- or further-line therapy in advanced gastrointestinal stromal tumors, ripretinib is not cost-effective in the US. Ripretinib would achieve its cost-effectiveness with a price discount of 56% given the present effectiveness.

Immune Infiltration, Cancer Stemness, and Targeted Therapy in Gastrointestinal Stromal Tumor

Objective

To investigate the characteristics of the tumor immune microenvironment in patients with gastrointestinal stromal tumor (GIST) and identify cancer stem-like properties of GIST to screen potential druggable molecular targets.

Methods

The gene expression data of 60 patients with GIST was retrieved from the Array Express database. CIBERSORT was applied to calculate the level of immune infiltration. ssGSEA and ESTIMATE were used to calculate the cancer stemness index and tissue purity. The Connectivity Map (CMAP) database was implemented to screen targeted drugs based on cancer stem-like properties of GIST.

Result

There was a difference in the level of immune infiltration between the metastasis and non-metastasis GIST groups. The low level of T-cell infiltration was correlated with high tumor purity and tumor stemness index, and the correlation coefficients were -0.87 and -0.61 (p < 0.001), respectively. Furthermore, there was a positive correlation between cancer stemness index and cell purity (p < 0.001). The cancer stemness index in the metastasis group was higher than that in the non-metastasis group (p = 0.0017). After adjusting for tumor purity, there was no significant correlation between T-cell infiltration and cancer stemness index (p = 0.086). Through the pharmacological mechanism of topoisomerase inhibitors, six molecular complexes may be the targets of GIST treatment.

Conclusion

Immune infiltration in GIST patients is related to cancer stem-like properties, and the correlation relies on tumor purity. Cancer stemness index can be used as a new predictive biomarker of tumor metastasis and targets of drug therapy for GIST patients.

Primary extra gastrointestinal stromal tumors of the abdomen

OBJECTIVE:

In the present study, we aimed to evaluate the clinicopathological features and prognostic factors in extra-gastrointestinal stromal tumor (EGIST) cases, which are observed very rare, by examining the data the cases obtained in a single center.

METHODS:

Data of 14 EGIST cases who were operated by a general surgeon between January 2007 and May 2020 were obtained and analyzed.

RESULTS:

The median age was 47.5 (range: 34–87) years. A total of 135 patients were operated for GIST, and 14 (10.4%) of these patients were EGIST. The mean tumor diameter was 16.8±10.5 (range: 2.8–40) cm. The mitotic index was 5/50 high power field and below in seven (50%) cases. Twelve (85.7%) of the patients were in the high-risk group. The overall survival (OS) rate was 80%, and the 5-year survival rate was 88.9%. Mean OS was 78.5±50.7 months, 5-year OS and disease-free survival (DFS) were both 53.3±20.0 months, and overall DFS was 58.0±59.8 months. The mean OS and DFS durations were found to be significantly lower in women than men (p=0.006 for both comparisons). The mean OS was found to be significantly lower in patients over 60 years of age compared to those aged 60 and under (p=0.013).

CONCLUSION:

In the present study, it has been determined that the rare EGISTs are large in size and that the mitotic index is often low. In addition, it has been observed that the prognosis may be similar to other GISTs, however, may be worse in elderly patients and in women.

Gastric glomus tumor diagnosed by fine needle aspiration of the stomach: A report of two cases and review of the literature

Glomus tumors make up 1% of stromal tumors of the stomach. Radiologic diagnosis of glomus tumors can be challenging as they share imaging characteristics with other neuroendocrine tumors and gastrointestinal stromal tumors. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been reported as a useful method for the evaluation of gastrointestinal lesions. We report two cases of gastric glomus tumors in which EUS-FNA diagnosis was challenging. Cytologically, neoplastic cells were round to oval, uniform, bland appearing epithelioid cells with delicate chromatin and inconspicuous to vague nucleoli. Both samples lacked worrisome features such as high nuclear grade, high mitotic rate, and necrosis. Neoplastic cells were negative for Cam5.2 and AE1/AE3 with focal expression of synaptophysin in one of the cases. A definitive diagnosis was not made based on FNA. Familiarity with glomus tumors in the GI system and procurement of adequate material for cell block allowing the use of immunohistochemistry may allow an accurate preoperative diagnosis.

Ripretinib for advanced gastrointestinal stromal tumor: Plain language summary of the INVICTUS study

The purpose of this summary is to help you understand the results of the INVICTUS study originally published in the journal Lancet Oncology. INVICTUS is a clinical study which looked at ripretinib as a potential treatment for advanced gastrointestinal stromal tumor, also known as GIST. GIST is a type of cancer that starts in the digestive tract, also known as the gastrointestinal tract. In the study, all participants had advanced GIST and needed a fourth-line (or greater) treatment following the failures of three previous treatments. The study looked at how well ripretinib worked compared with a nonactive medicine (known as a placebo) and at the side effects. Participants were given ripretinib at a dose of 150 mg once a day or a placebo. The results of the INVICTUS study showed ripretinib increased the length of time participants survived before their cancer got worse. Treatment with ripretinib was associated with side effects that varied in severity. The results of this study led to ripretinib, also known by the brand name Qinlock^®, being approved in the USA by regulators as the only medication for adults with advanced GIST who have previously been treated with 3 or more types of treatment called tyrosine kinase inhibitors. ClinicalTrials.gov NCT number: NCT03353753.

Deep Convolutional Neural Networks Detect Tumor Genotype from Pathological Tissue Images in Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GIST) are common mesenchymal tumors, and their effective treatment depends upon the mutational subtype of the KIT/PDGFRA genes. We established deep convolutional neural network (DCNN) models to rapidly predict drug-sensitive mutation subtypes from images of pathological tissue. A total of 5153 pathological images of 365 different GISTs from three different laboratories were collected and divided into training and validation sets. A transfer learning mechanism based on DCNN was used with four different network architectures, to identify cases with drug-sensitive mutations. The accuracy ranged from 87% to 75%. Cross-institutional inconsistency, however, was observed. Using gray-scale images resulted in a 7% drop in accuracy (accuracy 80%, sensitivity 87%, specificity 73%). Using images containing only nuclei (accuracy 81%, sensitivity 87%, specificity 73%) or cytoplasm (accuracy 79%, sensitivity 88%, specificity 67%) produced 6% and 8% drops in accuracy rate, respectively, suggesting buffering effects across subcellular components in DCNN interpretation. The proposed DCNN model successfully inferred cases with drug-sensitive mutations with high accuracy. The contribution of image color and subcellular components was also revealed. These results will help to generate a cheaper and quicker screening method for tumor gene testing.

Glucose transporter‑1 inhibition overcomes imatinib resistance in gastrointestinal stromal tumor cells

Imatinib mesylate (imatinib) is the primary agent of choice used to treat gastrointestinal stromal tumors (GIST). However, drug resistance to imatinib poses a major obstacle to treatment efficacy. In addition, the relationship between imatinib resistance and glycolysis is poorly understood. Glucose transporter (GLUT)-1 is a key component of glycolysis. The present study aimed to assess the potential relationship between components in the glycolytic pathway and the acquisition of imatinib resistance by GIST cells, with particular focus on GLUT-1. An imatinib-resistant GIST cell line was established through the gradual and continuous imatinib treatment of the parental human GIST cell line GIST-T1. The expression of glycolysis-related molecules (GLUT-1, hexokinase 2, pyruvate kinase M2 and lactate dehydrogenase) was assessed in parental and imatinib-resistant cells by western blotting, reverse transcription-quantitative PCR and glucose and lactate measurement kits. In addition, clinical information and transcriptomic data obtained from the gene expression omnibus database (GSE15966) were used to confirm the in vitro results. The potential effects of GLUT-1 inhibition on the expression of proteins in the glycolysis (GLUT-1, hexokinase 2, pyruvate kinase M2 and lactate dehydrogenase) and apoptosis pathways (Bcl-2, cleaved PARP, caspase-3 and caspase-9) in imatinib-resistant cells were then investigated following gene silencing and treatment using the GLUT-1 inhibitor WZB117 by western blotting. For gene silencing, the mature siRNAs for SLC2A1 were used for cell transfection. Annexin V-FITC/PI double-staining followed by flow cytometry was used to measure apoptosis whereas three-dimensional culture experiments were used to create three-dimensional spheroid cells where cell viability and spheroid diameter were measured. Although imatinib treatment downregulated GLUT-1 expression and other glycolysis pathway components hexokinase 2, pyruvate kinase M2, and lactate dehydrogenase in parental GIST-T1 cells even at low concentrations. By contrast, expression of these glycolysis pathway components in imatinib-resistant cells were increased by imatinib treatment. WZB117 administration significantly downregulated AKT phosphorylation and Bcl-2 expression in imatinib-resistant cells, whereas the combined administration of imatinib and WZB117 conferred synergistic growth inhibition effects in apoptosis assay. WZB117 was found to exert additional inhibitory effects by inducing apoptosis in imatinib-resistant cells. Therefore, the present study suggests that GLUT-1 is involved in the acquisition of imatinib resistance by GIST cells, which can be overcome by combined treatment with WZB117 and imatinib.

Needle rinse cell blocks as an ancillary technique: Diagnostic and clinical utility in gastrointestinal neoplasia

BACKGROUND

Fine-needle aspirate (FNA) cytology is often the first-choice method for diagnosing gastrointestinal nodular lesions. The FNA material can be converted to histopathology specimens by a needle rinse cell block (NRCB) technique, allowing ancillary studies to refine the cytologic diagnosis. Despite use in human pathology, NRCB has never been applied to canine or feline gastrointestinal neoplasia.

OBJECTIVE

This study described NRCB methodology and its diagnostic utility in specific cases of neoplastic gastrointestinal lesions.

METHODS

Needle rinses with saline were performed after ultrasound-guided FNAs of two intestinal lymphomas (canine and feline) and a canine gastrointestinal stromal tumor (GIST). The NRCB was prepared using the cell tube block technique and processed for paraffin embedding. Routine immunohistochemistry protocols (using CD3, PAX-5, and Ki-67 for lymphoma cases and vimentin, desmin, S-100, and KIT markers for GIST) were applied to NRCB sections, and the results were compared with matched tissue biopsies.

RESULTS

NRCBs with adequate cell numbers, preservation, and good separation of blood were obtained. The diagnosis and immunophenotyping were confirmed in both cases of lymphoma in NRCBs. In the GIST, the immunolabeling of the neoplastic cells in NRCB was completely concordant with the tissue biopsy.

CONCLUSIONS

The described methodology is suitable for veterinary settings, having few technical requirements and low invasiveness. The presented cases of gastrointestinal neoplasia highlight the utility of NRCBs as a platform to conduct ancillary studies and refine the cytologic diagnosis.

Not all KIT 557/558 codons mutations have the same prognostic influence on recurrence-free survival: breaking the exon 11 mutations in gastrointestinal stromal tumors (GISTs)

Background:

Although the gastrointestinal stromal tumor (GIST) genotype is not currently included in risk-stratification systems, a growing body of evidence shows that the pathogenic variant (PV) type and codon location hold a strong prognostic influence on recurrence-free survival (RFS). This information has particular relevance in the adjuvant setting, where an accurate prognostication could help to better identify high-risk tumors and guide clinical decision-making.

Materials and Methods:

Between January 2005 and December 2020, 96 patients with completely resected GISTs harboring a KIT proto-oncogene receptor tyrosine kinase (KIT) exon 11 PV were included in the study. We analyzed the type and codon location of the PV according to clinicopathological characteristics and clinical outcome; the metastatic sites in relapsed patients were also investigated.

Results:

Tumors harboring a KIT exon 11 deletion or deletion/insertion involving the 557 and/or 558 codons, showed a more aggressive clinical behavior compared with tumors carrying deletion/deletion/insertion in other codons, or tumors with duplication/insertion/single-nucleotide variant (SNV) (7-year RFS: 50% versus 73.1% versus 88.2%, respectively; p < 0.001). Notably, among 18 relapsed patients with 557 and/or 558 deletion or deletion/insertion, 14 patients (77.8%) harbored deletions simultaneously involving 557 and 558 codons, while only 4 patients (22.2%) harbored deletions involving only 1 of the 557/558 codons. Thus, when 557 or 558 deletions occurred separately, the tumor showed a prognostic behavior similar to the GIST carrying deletions outside the 557/558 position. Remarkably, patients with GISTs stratified as intermediate risk, but carrying the 557/558 deletion, showed a similar outcome to the high-risk patients with tumors harboring deletions in codons other than 557/558, or duplication/insertion/SNV.

Conclusion:

Our data support the inclusion of the PV type and codon location in routine risk prediction models, and suggest that intermediate-risk patients whose GISTs harbor 557/558 deletions may also need to be treated with adjuvant imatinib like the high-risk patients.

Gastrointestinal Stromal Tumor With Chondrosarcomatous Dedifferentiation Following Imatinib Therapy

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the digestive tract, followed by schwannomas, lipomas, leiomyomas, and vascular tumors. They arise more often in the stomach, followed by the small bowel, esophagus, and rectum. Imatinib mesylate, a tyrosine kinase inhibitor with activity against ABL, BCR-ABL, platelet-derived growth factor receptor-alpha (PDGFRA), and c-KIT (CD117), constitutes the cornerstone of treatment for inoperable or metastatic GIST. Cases showing disease progression or resistance to imatinib mesylate may retain their morphology or present unusual morphologic and immunohistochemical characteristics.

We herein describe a case of a 67-year-old patient with a previous history of GIST of the stomach, with local recurrence, who was admitted with a workup of lung nodule on chest computed tomography as part of the routine follow-up. The nodule was resected which showed a malignant tumor composedof epithelioid cells, with an abrupt transition to chondrosarcoma. Epithelioid cells were immunostained for CD117, DOG1, and Vimentin, whereas chondrosarcomatous cells expressed only Vimentin. These findings were consistent with metachronous pulmonary metastasis of the previously diagnosed GIST with chondrosarcomatous dedifferentiation. No KIT or PDGFRA mutation was detected. A review of all accessible pertinent papers disclosed 26 similar cases with unusual morphological and immunohistochemical findings, either post-imatinib treatment or, less commonly, de novo, with heterogeneous differentiation.

Awareness of the histological and immunohistochemical changes in GISTs post imatinib therapy is essential to avoid a severe diagnostic pitfall.

Massive Digestive Hemorrhagia Revealing a Gastro-Intestinal Stromal Tumor of the Jejunum

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that originate from Cajal cells located in different sites of the digestive system. They may occur in the entire gastrointestinal tract. They are diagnosed on the basis of the identification of c-kit-positive cells. We report a case of a stromal tumor of the jejunum revealed by a massive digestive hemorrhagia. Surgical resection is the basis of the treatment of GISTs. Imatinib, a tyrosine kinase inhibitor, is a beneficial treatment after surgical resection of high-risk GISTs.

Endoscopic Resection for Gastric Subepithelial Tumor with Backup Laparoscopic Surgery: Description of a Single-Center Experience

The aim of this study was to analyze patients who underwent endoscopic resection (ER) for gastric subepithelial tumors (SETs) with a high probability of surgical intervention. Between January 2013 and January 2021, 83 patients underwent ER at the operation theater and 27 patients (32.5%) required backup surgery mainly due to incidental perforation or uncontrolled bleeding despite endoscopic repairing. The tumor was predominantly located in the upper-third stomach (81%) with a size ≤ 2 cm (69.9%) and deep to the muscularis propria (MP) layer (92.8%) but there were no significant differences between two groups except tumor exophytic growth as a risk factor in the surgery group (37% vs. 0%, p < 0.0001). Patients in the ER-only group had shorter durations of procedure times (60 min vs. 185 min, p < 0.0001) and lengths of stay (5 days vs. 7 days, p < 0.0001) but with a higher percentage of overall morbidity graded III (0% vs. 7.1%, p = 0.1571). After ER, five patients (6%) had delayed perforation and two (2.4%) required emergent laparoscopic surgery. Neither recurrence nor gastric stenosis was reported during long-term surveillance. Here, we provide a minimally invasive strategy of endoscopic resection with backup laparoscopic surgery for gastric SETs.

Plexiform fibromyxoma: Case report and literature review

Plexiform fibromyxoma (PF) is a rare mesenchymal neoplasm which can be misdiagnosed as the gastrointestinal stromal tumor. This tumor almost formed a lobulated intramural/submucosal mass in the gastric antrum and prepyloric area. It was considered as a benign tumor that exhibited no recurrence, metastasis, or tumor-related mortality. In this study, we reported 2 cases of gastric PF. The first case was a PF patient coexisting with gastric adenocarcinoma. The second case occurred in the gastric upper body close to gastric fundus. They underwent distal gastrectomy and laparoscopic partial gastric resection, respectively. Both of them exhibited a plexiform growth pattern in the submucosa, muscularis propria, and subserosal adipose tissues. The nodules were composed of abundant myxoid or fibromyxoid matrix riching in small thin-walled blood vessels and bland-looking spindle cells. The first case partially showed staggered growth pattern of PF and adenocarcinoma. Immunohistochemically, the spindle cells were diffusely immunoreactive for SMA and vimentin, and focally immunoreactive for CD10. It was important to distinguish the PF from other spindle cell tumors involving the stomach.

Factors predicting technical difficulties during endoscopic submucosal excavation for gastric submucosal tumor

Objective

Endoscopic submucosal excavation (ESE) has been established as an effective method for removal of gastric submucosal tumors (SMTs). The aim of the present study was to explore risk factors for technical difficulties in ESE.

Methods

In this retrospective study, we collected clinical data from patients who underwent ESE for gastric SMTs. Difficult ESE was defined as a procedure time ≥90 minutes, piecemeal resection, and/or occurrence of major adverse events. Univariate and multivariate analyses were performed to explore the risk factors for a difficult ESE.

Results

ESE was successfully performed in 96.5% (195/202) of patients from April 2011 to December 2019. The average tumor size was 17.41 mm, and en bloc resection was achieved in 97.4% of patients (190/195). Five patients (2.56%, 5/195) had complications, including two with delayed bleeding, two with fever, and one with chest pain accompanying ST-T changes in an electrocardiogram. Twenty-four patients (11.88%, 24/202) had a difficult ESE. Logistic analysis showed that outgrowth behavior and an inexperienced surgeon were risk factors for a difficult ESE.

Conclusion

ESE may be safe and effective to treat patients with gastric SMTs. Outgrowth behavior and an inexperienced surgeon were risk factors for a difficult ESE.

RP11-616M22.7 recapitulates imatinib resistance in gastrointestinal stromal tumor

Emerging evidence has shown that long non-coding RNAs (lncRNAs) play crucial roles in human cancers. However, systematic characterization of lncRNAs and their roles in gastrointestinal stromal tumor (GIST) therapy have been lacking. We performed high-throughput RNA sequencing (RNA-seq) of 20 GIST and paired adjacent normal samples. We characterized the transcriptional landscape and dysregulation of lncRNAs in GIST. We identified 866 upregulated and 1,268 downregulated lncRNAs in GIST samples, the majority of which were GIST-specific over other cancer types. Most hallmarks were found to be dysregulated in GIST samples, and lncRNAs were highly associated with cancer-related hallmarks. RP11-616M22.7 was identified to increase in imatinib-resistant samples compared to those in non-resistant samples. Further analysis revealed that RP11-616M22.7 was closely associated with the Hippo signaling pathway. By treating GIST cells with different doses of imatinib, we verified that RP11-616M22.7 knockdown promotes the sensitivity of tumor cells, whereas RP11-616M22.7 overexpression induces resistance to imatinib. We further confirmed reducing of resistance to imatinib by knocking down RP11-616M22.7 in vivo. Additionally, RP11-616M22.7 was observed to interact with RASSF1 protein. Our study revealed that deficiency of RP11-616M22.7 was able to reduce resistance of the GIST cell response to imatinib treatment both in vitro and in vivo.

Demographic and clinicopathological profile of patients of gastrointestinal stromal tumor from a tertiary care center of North India: An observational study

Background

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal system. This study was aimed to analyze the demographic and clinicopathological data of the patient with a primary diagnosis of GIST, who were treated at our center.

Materials and Methodology

Patients of GIST registered at our center from September 1, 2008, to August 31, 2016, were enrolled for this study. Patient's demographic and clinicopathological data were collected from clinical records. The data were represented as absolute number, percentage, and median (range: minimum to maximum), whichever applicable.

Results and Observations

The analysis of 27 patients revealed that pain was the most common clinical feature. The stomach was the most common primary site. Most of the patients underwent upfront radical surgery (92.6%) followed by adjuvant imatinib. Histopathological data revealed that most tumors were >10 cm in size, 51.8% of patients had low mitotic index, and all these patients were either immunohistochemical positive for cluster differentiation 117 or KIT. The median duration of tyrosine kinase inhibitors therapy (imatinib) in our study individual was 2.5 years with a range of 4.8 months-3 years. Response assessment revealed 74.1% complete remission, 11.1% stable disease, and 3.7% progressive disease. Median overall survival in study individuals was 2.63 years (range: 0.1-8.6 years). Patient- and tumor-related factors were analyzed for prognostic significance using univariate survival analysis; however, none was found to have a significant prognostic correlation.

Conclusions

Patients who underwent upfront surgery followed by adjuvant imatinib has shown good response to the treatment. However, the limitation of the small sample size and short follow-up in this study may not be a true data representation of the entire population.

Minimally Invasive Approach to Gastric GISTs: Analysis of a Multicenter Robotic and Laparoscopic Experience with Literature Review

Simple Summary

Gastrointestinal stromal tumors (GISTs) represent about 1–3% of all gastrointestinal malignancies, of which 50–60% are gastric GISTs (GGs). To the date, surgery represents the best therapeutic option, and the robotic gastric surgery could gain an important role, overcoming many laparoscopic drawbacks. The aim of this study is to evaluate safety and effectiveness of minimally invasive surgery (MIS) for GGs, reporting 10-year experience of three different centers. We included a population of 81 patients who underwent MIS approaches (36 laparoscopy vs. 45 robotic surgery). Seventy-two (72) patients were enrolled in a follow-up program to evaluate the long-term oncological outcomes. Furthermore, we discussed some technical notes and also we analyzed the operative and peri-operative outcomes. In conclusion, our results suggest that the robotic approach might be a suitable treatment, especially for GISTs >5 cm, even located in unfavorable places, despite longer operative time and costs than laparoscopic approach.

Abstract

Background: Gastrointestinal stromal tumors (GISTs) are most frequently located in the stomach. In the setting of a multidisciplinary approach, surgery represents the best therapeutic option, consisting mainly in a wedge gastric resection. (1) Materials and methods: Between January 2010 to September 2020, 105 patients with a primary gastrointestinal stromal tumor (GISTs) located in the stomach, underwent surgery at three surgical units. (2) Results: A multi-institutional analysis of minimally invasive series including 81 cases (36 laparoscopic and 45 robotic) from 3 referral centers was performed. Males were 35 (43.2%), the average age was 66.64 years old. ASA score ≥3 was 6 (13.3%) in the RS and 4 (11.1%) in the LS and the average tumor size was 4.4 cm. Most of the procedures were wedge resections (N = 76; 93.8%) and the main operative time was 151 min in the RS and 97 min in the LS. Conversion was necessary in five cases (6.2%). (3) Conclusions: Minimal invasive approaches for gastric GISTs performed in selected patients and experienced centers are safe. A robotic approach represents a useful option, especially for GISTs that are more than 5 cm, even located in unfavorable places.

Prognostic factors for dogs with surgically resected gastrointestinal stromal tumors

Few reports have investigated prognosis of canine gastrointestinal stromal tumor (GIST) cases treated by surgical resection alone. In the present study, we investigated the overall survival (OS) and prognostic factors for dogs with GIST treated by surgical complete resection alone. Fifty-three dogs were included, and the median OS was 18 months. Multivariate analysis showed that primary tumors in small intestine (P=0.04) is significantly associated with shorter OS, and median OS of the cases with cecum lesion and those with small intestine lesion was 22 and 6 months, respectively. The present study suggested primary tumor site was a novel prognostic factor for dogs with GIST treated by surgical complete resection alone.

Combined Inhibition of AKT and KIT Restores Expression of Programmed Cell Death 4 (PDCD4) in Gastrointestinal Stromal Tumor

The majority of gastrointestinal stromal tumor (GIST) patients develop resistance to the first-line KIT inhibitor, imatinib mesylate (IM), through acquisition of secondary mutations in KIT or bypass signaling pathway activation. In addition to KIT, AKT is a relevant target for inhibition, since the PI3K/AKT pathway is crucial for IM-resistant GIST survival. We evaluated the activity of a novel pan-AKT inhibitor, MK-4440 (formerly ARQ 751), as monotherapy and in combination with IM in GIST cell lines and preclinical models with varying IM sensitivities. Dual inhibition of KIT and AKT demonstrated synergistic effects in IM-sensitive and -resistant GIST cell lines. Proteomic analyses revealed upregulation of the tumor suppressor, PDCD4, in combination treated cells. Enhanced PDCD4 expression correlated to increased cell death. In vivo studies revealed superior efficacy of MK-4440/IM combination in an IM-sensitive preclinical model of GIST compared with either single agent. The combination demonstrated limited efficacy in two IM-resistant models, including a GIST patient-derived xenograft model possessing an exon 9 KIT mutation. These studies provide strong rationale for further use of AKT inhibition in combination with IM in primary GIST; however, alternative agents will need to be tested in combination with AKT inhibition in the resistant setting.

Recent Progress and Challenges in the Diagnosis and Treatment of Gastrointestinal Stromal Tumors

Simple Summary

Gastrointestinal stromal tumors (GIST) are potentially malignant tumors and require evidence-based surgical and/or medical treatment. Laparoscopy has similar safety and prognostic outcomes to those of laparotomy and is currently a standard procedure for localized GISTs. However, surgery for gastric GISTs less than 2 cm may be re-evaluated due to the indolent nature of the GIST and other competing risks among GIST patients. A work-up with endoscopy and endoscopic ultrasonography as well as endoscopic or percutaneous biopsy is important for the preoperative diagnosis of GISTs. Medical treatment with tyrosine kinase inhibitors is the mainstay for recurrent/metastatic GISTs. The activity of an individual drug is well correlated with gene alterations, and, in the era of precision medicine, cancer genome profiling should be considered before medical treatment.

Abstract

Gastrointestinal stromal tumors (GISTs) are the most frequent malignant mesenchymal tumors in the gastrointestinal tract. The clinical incidence of GISTs is estimated 10/million/year; however, the true incidence is complicated by frequent findings of tiny GISTs, of which the natural history is unknown. The initial work-up with endoscopy and endoscopic ultrasonography plays important roles in the differential diagnosis of GISTs. Surgery is the only modality for the permanent cure of localized GISTs. In terms of safety and prognostic outcomes, laparoscopy is similar to laparotomy for GIST treatment, including tumors larger than 5 cm. GIST progression is driven by mutations in KIT or PDGFRA or by other rare gene alterations, all of which are mutually exclusive. Tyrosine kinase inhibitors (TKIs) are the standard therapy for metastatic/recurrent GISTs. Molecular alterations are the most reliable biomarkers for TKIs and for other drugs, such as NTRK inhibitors. The pathological and genetic diagnosis prior to treatment has been challenging; however, a newly developed endoscopic device may be useful for diagnosis. In the era of precision medicine, cancer genome profiling by targeted gene panel analysis may enable potential targeted therapy even for GISTs without KIT or PDGFRA mutations.

Laparoscopic Distal Gastrectomy for Synchronous Gastric Cancer and Gastrointestinal Stromal Tumor With Situs Inversus Totalis

BACKGROUND

Situs inversus totalis (SIT) is a rare congenital condition in which the thoracic and abdominal organs are inverted like a mirror image.

CASE REPORT

We present a case of synchronous gastric cancer and gastrointestinal stromal tumor (GIST) associated with SIT in a 74-year-old man who was admitted to our department to treat gastric cancer. Esophagogastroduodenoscopy revealed a depressed lesion and a submucosal tumor (SMT) in the middle-third of the stomach. Abdominal contrast-enhanced computed tomography revealed complete inversion of the internal organs, and the common hepatic artery branched from the superior mesenteric artery. The patient underwent laparoscopic distal gastrectomy with regional lymph node dissection and Billroth I reconstruction. The macroscopic observation of the resected specimen revealed a depressed lesion measuring 2.0×1.5 cm in diameter and an SMT measuring 2.2×1.8 cm.

CONCLUSION

Careful preoperative anatomic evaluation is important in SIT because the situs anomalies may be accompanied by major vascular anomalies.