Possibility of Using Conventional Computed Tomography Features and Histogram Texture Analysis Parameters as Imaging Biomarkers for Preoperative Prediction of High-Risk Gastrointestinal Stromal Tumors of the Stomach

BACKGROUND

The objective of this study is to determine the morphological computed tomography features of the tumor and texture analysis parameters, which may be a useful diagnostic tool for the preoperative prediction of high-risk gastrointestinal stromal tumors (HR GISTs).

METHODS

This is a prospective cohort study that was carried out in the period from 2019 to 2022. The study included 79 patients who underwent CT examination, texture analysis, surgical resection of a lesion that was suspicious for GIST as well as pathohistological and immunohistochemical analysis.

RESULTS

Textural analysis pointed out min norm (p = 0.032) as a histogram parameter that significantly differed between HR and LR GISTs, while min norm (p = 0.007), skewness (p = 0.035) and kurtosis (p = 0.003) showed significant differences between high-grade and low-grade tumors. Univariate regression analysis identified tumor diameter, margin appearance, growth pattern, lesion shape, structure, mucosal continuity, enlarged peri- and intra-tumoral feeding or draining vessel (EFDV) and max norm as significant predictive factors for HR GISTs. Interrupted mucosa (p < 0.001) and presence of EFDV (p < 0.001) were obtained by multivariate regression analysis as independent predictive factors of high-risk GISTs with an AUC of 0.878 (CI: 0.797-0.959), sensitivity of 94%, specificity of 77% and accuracy of 88%.

CONCLUSION

This result shows that morphological CT features of GIST are of great importance in the prediction of non-invasive preoperative metastatic risk. The incorporation of texture analysis into basic imaging protocols may further improve the preoperative assessment of risk stratification.

Gastrointestinal stromal tumor in North Africa and the middle east: updates in presentation and management from an 11-year retrospective cohort

OBJECTIVES

This study described the epidemiological, clinical, and survival profiles of patients with gastrointestinal stromal tumor (GIST) in North Africa and the Middle East (AfME).

METHODS

This regional, multicenter, observational, retrospective study collected 11-year data on demographics, medical history, disease characteristics, current treatment approaches of GIST, the safety of the most common tyrosine kinase inhibitors (TKIs), second cancers, and survival status.

RESULTS

Data of 201 eligible patients were analyzed: mean age was 56.9 ± 12.6 years; 111 (55.2%) patients were men, 21 (10.4%) patients had previous personal malignancy. The most common clinical presentation of GIST was dysphagia [92 (45.8%) patients]. The stomach was the most common primary site in 120 (60.7%) patients, 171 (85.1%) patients had localized disease at diagnosis. 198 (98.5%) GIST cases were CD117/CD34-positive. Imatinib was used in the neoadjuvant (18/21 patients), adjuvant (85/89 patients), and first-line metastatic treatment (28/33 patients) settings. The most common non-hematological toxicity associated with TKIs was vomiting in 32/85 (37.6%) patients. Overall, 100 (49.8%) patients (95%CI: 42.8-56.7%) were alive and disease-free while 30 (14.9%) patients were alive with active disease.

CONCLUSION

Presentation of GIST in our AfME population is consistent with global reports, being more frequent in patients >50 years old and having the stomach as the most common primary site. Unlike what is usually reported, though, we did have more patients with lymphatic spread of the disease. Despite the global trend and advances in the treatment of GIST according to molecular profile, this is still far to happen in our population given the lack of access to molecular profiles and the high associated cost.

Cinematic Rendering of Gastrointestinal Stromal Tumors: A Review of Current Possibilities and Future Developments

Gastrointestinal stromal tumors (GISTs) are defined as CD117-positive primary, spindled or epithelioid, mesenchymal tumors of the gastrointestinal tract, omentum, or mesentery. While computed tomography (CT) is the recommended imaging modality for GISTs, overlap in imaging features between GISTs and other gastrointestinal tumors often make radiological diagnosis and subsequent selection of the optimal therapeutic approach challenging. Cinematic rendering is a novel CT post-processing technique that generates highly photorealistic anatomic images based on a unique lighting model. The global lighting model produces high degrees of surface detail and shadowing effects that generate depth in the final three-dimensional display. Early studies have shown that cinematic rendering produces high-quality images with enhanced detail by comparison with other three-dimensional visualization techniques. Cinematic rendering shows promise in improving the visualization of enhancement patterns and internal architecture of abdominal lesions, local tumor extension, and global disease burden, which may be helpful for lesion characterization and pretreatment planning. This article discusses and illustrates the application of cinematic rendering in the evaluation of GISTs and the unique benefit of using cinematic rendering in the workup of GIST with a specific emphasis on tumor characterization and preoperative planning.

Impact of Tumor Size and Management on Survival in Small Gastric Gastrointestinal Stromal Tumors

BACKGROUND

Society guidelines remain inconsistent on the role of endoscopic and radiographic surveillance as an alternative to surgical resection of small gastric gastrointestinal stromal tumors (GISTs). Herein, we aimed to assess survival among patients with gastric GISTs undergoing observation versus surgical resection, stratified by tumor size.

METHODS

The National Cancer Database (NCDB) was queried for gastric GISTs < 2 cm diagnosed from 2010-2017. Patients were stratified by management strategy-observation vs surgical resection. The primary outcome, overall survival (OS), was examined with Kaplan-Meier and multivariable Cox proportional hazard methods. Subgroup analyses were conducted on tumors < 1 cm and 1-2 cm in size.

RESULTS

Altogether, 1208 patients were identified: 439 (36.3%) undergoing observation and 769 (63.7%) receiving surgical resection. In the overall cohort, patients undergoing surgical resection demonstrated improved survival (93.6 vs. 88.8% 5-year OS, p=0.02). In multivariable analysis, upfront surgical resection was not associated with a reduction in mortality; however, there was a significant interaction with tumor size. For patients with tumors < 1 cm, there was no difference in survival based on management strategy. However, resection of tumors 1-2 cm was associated with improved survival relative to surveillance.

CONCLUSIONS

While surgical resection and surveillance were associated with similar survival for patients with gastric GISTs < 1 cm, this NCDB analysis suggests that patients with tumor size ≥ 1 cm may benefit from upfront surgical resection. Prospective studies comparing these two approaches and their impact on recurrence-free and disease-specific survival are needed to better align consensus guidelines and recommendations.

Overexpressed transferrin receptor implied poor prognosis and relapse in gastrointestinal stromal tumors

Ferroptosis, as a novel-induced programmed cell death, plays critical roles in the pathogenesis of cancers. However, the promising biomarkers of ferroptosis in gastrointestinal stromal tumor (GIST) remain to be elucidated. Herein, the expression of ferroptosis-related genes was analyzed in GIST. Among the 64 ferroptosis-related genes, transferrin receptor (TFRC) expression presented a remarkable upregulation in high-risk patients through Gene Expression Omnibus (GEO) dataset analysis, as well as its significant change after imatinib was treated. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of TFRC-relevant genes revealed that TFRC expression was closely associated with cell growth pathways and metabolism-related pathways. Furthermore, patients at high risk of recurrence were more likely to exhibit high TFRC expression by immunohistochemistry. Additionally, high TFRC expression indicated an undesirable state of patient relapse, which could serve as a powerful significant independent predictor of recurrence-free survival (RFS). In summary, we systematically summarize the expression characteristics and clinical relevance of TFRC and show that TFRC can be used as a prognostic factor, which can be considered a potential therapeutic target in GIST.

Telemedicine in Care of Sarcoma Patients beyond the COVID-19 Pandemic: Challenges and Opportunities

BACKGROUND

The COVID-19 pandemic has created a challenging environment for sarcoma patients. Most oncology societies published guidelines or recommendations prioritizing sarcoma patients and established telehealth as an efficient method of approaching them. The aim of this review is the assessment of current evidence regarding the utilization of telemedicine in diagnosis, treatment modalities, telerehabilitation and satisfaction among sarcoma patients and healthcare providers (HP).

METHODS

This systematic review was carried out using the databases PubMed and Ovid MEDLINE according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

The application of telemedicine to the management of sarcoma has yielded improved clinical and psychological outcomes. Specifically, significant progress has been demonstrated in the areas of tele-oncology and telerehabilitation during the last decade, and the COVID-19 outbreak has accelerated this transition toward them. Telehealth has been proven efficient in a wide spectrum of applications from consultations on physical therapy and psychological support to virtual care symptom management. Both HP and patients reported satisfaction with telehealth services at levels comparable to in-person visits.

CONCLUSIONS

Telehealth has already unveiled many opportunities in tailoring individualized care, and its role in the management of sarcoma patients has been established in the post-COVID-19 era, as well.

Ripretinib in combination with tyrosine kinase inhibitor as a late-line treatment option for refractory gastrointestinal stromal tumors: two case reports and literature review

Background: This case report presents two clinical cases of metastatic refractory gastrointestinal stromal tumor (GIST) with treatment history of 6-14 years. The follow-up treatment of both cases comprised ripretinib dose escalation and its combination with other tyrosine kinase inhibitors (TKIs). To the best of our knowledge, this is the first report that explored ripretinib combination therapy in the late-line treatment of GISTs. Case description: Case-1 represents a 57-year-old female patient who underwent surgical resection for retroperitoneal GIST in 2008. After tumor recurrence in 2009, imatinib was started with complete response for 8 years. Imatinib was followed by sunitinib and regorafenib treatment. In March 2021, due to progressive disease (PD), the patient started ripretinib (150 mg QD) and achieved partial response (PR). Six months later, the patient showed PD. Subsequently, ripretinib dose was increased (150 mg BID) followed by ripretinib (100 mg QD) and imatinib (200 mg QD) combination. CT performed in February 2022 revealed stable lesions with internal visible necrosis. Combination therapy achieved stable disease (SD) for 7 months. On further follow-up in July 2022, the patient showed PD and died in September 2022. Case-2: represents a 73-year-old female patient diagnosed with unresectable duodenal GIST with liver, lung, and lymph node metastases in 2016. After treatment with imatinib, followed by sunitinib, regorafenib, and imatinib rechallenge, ripretinib (150 mg QD) was administered in May 2021, and SD was achieved. Ripretinib dose was increased (200 mg QD) due to PD in December 2021. The tumor showed heterogeneous manifestations, with overall size increase and regression in right posterior lobe. In February 2022, ripretinib (150 mg) plus sunitinib (25 mg) QD was commenced. On follow-up in April 2022, the patient showed slightly improved symptoms with stable hematologic parameters. Combination therapy achieved SD for 5 months and the patient showed PD in July 2022 and discontinued the treatment later. The patient was in poor general condition and was receiving nutritional therapy until last follow-up in October 2022. Conclusion: This case report provides evidence that combination therapy of ripretinib with other TKIs could be an effective late-line treatment option for refractory GIST patients.

Predictive Value of a Radiomics Nomogram Model Based on Contrast-Enhanced Computed Tomography for KIT Exon 9 Gene Mutation in Gastrointestinal Stromal Tumors

OBJECTIVES

To establish and validate a radiomics nomogram model for preoperative prediction of KIT exon 9 mutation status in patients with gastrointestinal stromal tumors (GISTs).

MATERIALS AND METHODS

Eighty-seven patients with pathologically confirmed GISTs were retrospectively enrolled in this study. Imaging and clinicopathological data were collected and randomly assigned to the training set (n = 60) and test set (n = 27) at a ratio of 7:3. Based on contrast-enhanced CT (CE-CT) arterial and venous phase images, the region of interest (ROI) of the tumors were manually drawn layer by layer, and the radiomics features were extracted. The intra-class correlation coefficient (ICC) was used to test the consistency between observers. Least absolute shrinkage and selection operator regression (LASSO) were used to further screen the features. The nomogram of integrated radiomics score (Rad-Score) and clinical risk factors (extra-gastric location and distant metastasis) was drawn on the basis of multivariate logistic regression. The area under the receiver operating characteristic (AUC) curve and decision curve analysis were used to evaluate the predictive efficiency of the nomogram, and the clinical benefits that the decision curve evaluation model may bring to patients.

RESULTS

The selected radiomics features (arterial phase and venous phase features) were significantly correlated with the KIT exon 9 mutation status of GISTs. The AUC, sensitivity, specificity, and accuracy in the radiomics model were 0.863, 85.7%, 80.4%, and 85.0% for the training group (95% confidence interval [CI]: 0.750-0.938), and 0.883, 88.9%, 83.3%, and 81.5% for the test group (95% CI: 0.701-0.974), respectively. The AUC, sensitivity, specificity, and accuracy in the nomogram model were 0.902 (95% confidence interval [CI]: 0.798-0.964), 85.7%, 86.9%, and 91.7% for the training group, and 0.907 (95% CI: 0.732-0.984), 77.8%, 94.4%, and 88.9% for the test group, respectively. The decision curve showed the clinical application value of the radiomic nomogram.

CONCLUSION

The radiomics nomogram model based on CE-CT can effectively predict the KIT exon 9 mutation status of GISTs and may be used for selective gene analysis in the future, which is of great significance for the accurate treatment of GISTs.

Self-reported cognitive impairments and quality of life in patients with gastrointestinal stromal tumor: Results of a multinational survey

BACKGROUND

Cancer-related cognitive impairment (CRCI) has long-term effects on survivor quality of life, but CRCI research on patients with gastrointestinal stromal tumor (GIST) is lacking. The aims of this study were to investigate CRCI and concomitant quality of life among patients with GIST.

METHODS

An online survey was used to assess CRCI in adult patients with GIST using the validated Functional Assessment of Cancer Therapy-Cognitive-v.3. Age, education, demographically indexed IQ, general health, and quality of life factors (e.g., fatigue, emotional distress) were also assessed. The online survey was administered through five international GIST and sarcoma support organizations.

RESULTS

Over the 3-month recruitment period, the survey was completed by 485 participants: mean age, 57.80 (SD, 11.51), median 5 years after diagnosis. A majority (63.91%) reported experiencing cognitive symptoms with a significant negative quality of life impact. Controlling for age, patients with GIST ≥5 years after diagnosis reported worse cognitive function than those <5 years after diagnosis (p < .05) but did not differ in educational level or IQ. Whereas longer term survivors were more likely to have been treated with tyrosine kinase inhibitor (TKI) therapies, there was no observed association of TKI therapy with self-reported cognitive impairments.

CONCLUSIONS

A majority of GIST patients report cognitive symptoms that have a negative impact on quality of life, with longer term survivors (≥5 years) tending to report more cognitive impairments. Given the success of TKI therapy to substantially increase overall survival of patients with GIST, addressing CRCI in clinical practice may improve long-term GIST survivor function and quality of life.

An exploration in pitfalls in interpreting SDHB immunohistochemistry

AIMS

Mutations and epimutations in genes encoding the succinate dehydrogenase complex (SDHx) are associated with multiple tumor types in which identification of SDH-deficiency has significant management implications. Immunohistochemistry (IHC) for the SDHB subunit can help detect SDH-deficiency, which manifests as complete loss of staining in tumor cells. However, a subset of SDH-deficient tumors can show aberrant cytoplasmic SDHB-IHC staining patterns and be misinterpreted as "retained," a diagnostic pitfall complicating interpretation. Herein, we characterize in detail aberrant SDHB-IHC staining patterns in SDH-deficient tumors.

METHODS AND RESULTS

We identified 23 tumors from patients with known germline SDHx and/or molecularly confirmed SDHx pathogenic/likely-pathogenic variants in their tumor. Of these, 8 (35%) showed significant SDHB-IHC staining: 1 SDHA-, 1 SDHB-, 3 SDHC- and 3 SDHD-mutated cases. In all 8 cases, closer inspection revealed differences in intensity and intracellular distribution of SDHB-IHC staining in tumor cells compared to adjacent nonneoplastic cells: nonneoplastic cells showed intense cytoplasmic coarse granular staining; tumor cells in 7/8 cases showed weak to focally strong, cytoplasmic blush to fine granular staining, in >80% of cells. The remaining case on initial block showed variably strong nongranular cytoplasmic staining with globular perinuclear accentuation throughout, only subtly distinct from staining pattern of nonneoplastic cells. SDHB-IHC performed on two additional blocks in this latter case revealed significant intratumoral heterogeneity including convincing areas of complete loss.

CONCLUSIONS

When evaluating SDHB-IHC, care should be taken to distinguish true retained expression from aberrant cytoplasmic expression, which may be difficult to appreciate. Sometimes this may require additional molecular testing.

Locoregional Treatments for Metastatic Gastrointestinal Stromal Tumor in British Columbia: A Retrospective Cohort Study from January 2008 to December 2017

Simple Summary

It is not known if surgery, radiation treatment (RT) or other types of locolregional treatment (LRT) may be beneficial for patients with metastatic gastrointestinal stromal tumor (mGIST) in addition to systemic treatment. Our study aims to address this question by analyzing a cohort of 127 mGIST patients in British Columbia over a decade (from January 2008 to December 2017). We showed that mGIST patients who underwent surgery and LRT seemed to have better survival when compared to patients who did not undergo surgery and LRT. However, this treatment strategy should only be considered in patients with limited volume metastatic disease or oligoprogression while the rest of the disease is well controlled with systemic treatment. In addition, RT can offer palliative benefits such as pain relief and bleeding control. Our study, consistent with other retrospective studies, supports LRT consideration in selected mGIST patients within a multidisciplinary setting. This approach is not considered as a “standard of care” due to lack of prospective clinical trials but may improve clinical outcome for some mGIST patients.

Abstract

Introduction: The role of surgery and non-surgical locoregional treatments (LRT) such as radiation therapy (RT) and local ablation techniques in patients with metastatic gastrointestinal stromal tumor (GIST) is unclear. This study examines LRT practice patterns in metastatic GIST and their clinical outcomes in British Columbia (BC). Methods: Patients diagnosed with either recurrent or de novo metastatic GIST from January 2008 to December 2017 were identified. Clinical characteristics and outcomes were analyzed in patients who underwent LRT, including surgical resection of the primary tumor or metastectomy, RT, or other local ablative procedures. Results: 127 patients were identified: 52 (41%) had de novo metastasis and 75 (59%) had recurrent metastasis. Median age was 67 (23–90 years), 58.2% were male, primary site was 33.1% stomach, 40.2% small intestine, 11% rectum/pelvis, and 15.7% others. 37 (29.1%) of patients received palliative surgery, the majority of which had either primary tumor removal only (43.3%) or both primary tumor removal and metastectomy (35.1%). A minority of patients underwent metastectomy only (21.6%). A total of 12 (9.5%) patients received palliative RT to metastatic sites only (58.3%) or primary tumors only (41.7%), mostly for symptomatic control (n = 9). A few patients (n = 3) received local ablation for liver metastatic deposits with 1 patient receiving microwave ablation (MWA) and 2 receiving radiofrequency ablation (RFA). Most patients (n = 120, 94.5%) received some type of systemic treatment. It is notable that prolonged progression free survival (PFS) was observed for the majority of patients who underwent surgery in the metastatic setting with a median PFS of 20.5 (95% confidence interval (CI): 14.29–40.74) months. In addition, significantly higher median overall survival (mOS) was observed in patients who underwent surgery (97.15 months; 95% CI: 77.7-not reached) and LRT (78.98 months; 95% CI: 65.58-not reached) versus no surgery (45.37 months; 95% CI: 38.7–64.69) and no LRT (45.27 months; 95% CI: 33.25–58.66). Almost all patients (8 out of 9) achieved symptomatic improvement after palliative RT. All 3 patients achieved partial response and 2 out of 3 patients had relatively durable responses of 1 year or more after local ablation. Discussion: This study is among the first to systematically examine the use of various LRT in metastatic GIST management. Integration of LRT with systemic treatments may potentially provide promising durable response and prolonged survival for highly selected metastatic GIST patients with low volume disease, limited progression and otherwise well controlled on systemic treatments. These observations, consistent with others, add to the growing evidence that supports the judicious use of LRT in combination with systemic treatments to further optimize the care of metastatic GIST patients.

Hybrid approach with laparoscopic wall-inversion surgery and single-incision intragastric surgery for intraluminal gastrointestinal stromal tumor: A case report

Laparoscopic wedge resection (LWR) for intraluminal gastrointestinal stromal tumor (GIST) leads to excessive resection of normal gastric wall. We report a case of GIST around the cardia successfully treated with full-thickness partial resection using a hybrid approach of laparoscopic surgery and single-incision intragastric surgery (SIIGS). A 69-year-old woman had a 5 cm intraluminal GIST at the posterior wall around the cardia. Submucosal injection of glycerin and indigo carmine was performed with transoral endoscopy. Circumferential seromuscular incision followed by placement of seromuscular sutures to invert the lesion into the stomach was performed under laparoscopy. By SIIGS, resection of the inverted mucosa and retrieval of the tumor were completed. A hybrid approach consisting of laparoscopic wall-inversion surgery and SIIGS was useful for intraluminal GIST and may expand the indications for laparoscopic wall-inversion surgery by removing size limitations.

Imatinib Regulates miR-483-3p and Mitochondrial Respiratory Complexes in Gastrointestinal Stromal Tumors

Metabolic adaptation to increased oxidative phosphorylation (OXPHOS) has been found in gastrointestinal stromal tumor (GIST) upon imatinib treatment. However, the underlying mechanism of imatinib-induced OXPHOS is unknown. Discovering molecules that mediate imatinib-induced OXPHOS may lead to the development of therapeutic strategies synergizing the efficacy of imatinib. In this study, we explored the role of microRNAs in regulating OXPHOS in GIST upon imatinib treatment. Using a microarray approach, we found that miR-483-3p was one of the most downregulated miRNAs in imatinib-treated tumors compared to untreated tumors. Using an extended series of GIST samples, we further validated the downregulation of miR-483-3p in imatinib-treated GIST samples by RT-qPCR. Using both gain- and loss-of-function experiments, we showed that miR-483-3p could regulate mitochondrial respiratory Complex II expression, suggesting its role in OXPHOS regulation. Functionally, miR-483-3p overexpression could rescue imatinib-induced cell death. These findings provide the molecular link for imatinib-induced OXPHOS expression and the biological role of miR-483-3p in regulating cell viability upon imatinib treatment.

Early and Next-Generation KIT/PDGFRA Kinase Inhibitors and the Future of Treatment for Advanced Gastrointestinal Stromal Tumor

The majority of gastrointestinal stromal tumors (GIST) harbor an activating mutation in either the KIT or PDGFRA receptor tyrosine kinases. Approval of imatinib, a KIT/PDGFRA tyrosine kinase inhibitor (TKI), meaningfully improved the treatment of advanced GIST. Other TKIs subsequently gained approval: sunitinib as a second-line therapy and regorafenib as a third-line therapy. However, resistance to each agent occurs in almost all patients over time, typically due to secondary kinase mutations. A major limitation of these 3 approved therapies is that they target the inactive conformation of KIT/PDGFRA; thus, their efficacy is blunted against secondary mutations in the kinase activation loop. Neither sunitinib nor regorafenib inhibit the full spectrum of KIT resistance mutations, and resistance is further complicated by extensive clonal heterogeneity, even within single patients. To combat these limitations, next-generation TKIs were developed and clinically tested, leading to 2 new USA FDA drug approvals in 2020. Ripretinib, a broad-spectrum KIT/PDGFRA inhibitor, was recently approved for the treatment of adult patients with advanced GIST who have received prior treatment with 3 or more kinase inhibitors, including imatinib. Avapritinib, a type I kinase inhibitor that targets active conformation, was approved for the treatment of adults with unresectable or metastatic GIST harboring a PDGFRA exon 18 mutation, including PDGFRA D842V mutations. In this review, we will discuss how resistance mutations have driven the need for newer treatment options for GIST and compare the original GIST TKIs with the next-generation KIT/PDGFRA kinase inhibitors, ripretinib and avapritinib, with a focus on their mechanisms of action.

Utility of noncontrast MRI in the detection and risk grading of gastrointestinal stromal tumor: a comparison with contrast-enhanced CT

Background

Recently developed adjuvant therapies for gastrointestinal stromal tumor (GIST) have been shown to improve patient survival. Guidelines currently recommend contrast-enhanced computed tomography (CECT) for GIST detection and surveillance. Patients with moderate-to-high risk GISTs require more frequent surveillance due to a higher 5-year recurrence rate. Our study aimed to compare noncontrast magnetic resonance imaging (MRI) with CECT for GIST detection, and evaluate volumetric apparent diffusion coefficients (ADCs) for risk stratification of GIST.

Methods

We retrospectively enrolled 83 patients with histopathologically confirmed GISTs for lesion detection efficiency analysis between noncontrast MRI and matched CECT studies. A 5-point scale was used by two independent reviewers to determine if the lesion was present or absent. Another cohort, comprising 28 patients with pathologically confirmed primary GISTs, was further screened for risk stratification, with a comparison of volumetric ADC parameters between the pathologically very-low-to-low risk and moderate-to-high risk GIST patients.

Results

For identifying GISTs, the sensitivity and specificity of noncontrast MRI were 83.6% and 89.3% for reader 1 respectively, and 81.8% and 92.9% for reader 2 respectively; the sensitivity and specificity of CECT were 76.4% and 89.3% for reader 1 respectively, and 76.4 and 78.6% for reader 2 respectively. Tumor volumetric ADC histogram parameters, including ADC_max, ADC_stdev, 90^th and 95^th percentiles, inhomogeneity, and entropy, were positively correlated with a higher risk grade of GIST (r=0.421-0.758). The receiver operator characteristic curve analysis showed ADC_max achieved the highest area under the curve value of 0.938 for discriminating very-low-to-low risk versus moderate-to-high risk GISTs.

Conclusions

Noncontrast MRI was an efficient technique for identifying GIST patients. The combination of CECT and noncontrast MRI can improve the reliability of diagnosis. For patients with contraindications to CECT, noncontrast MRI may be a comparable alternative. Volumetric ADC histogram parameters may be useful in differentiating very-low-to-low risk from moderate-to-high risk primary GISTs.

Ripretinib in treatment of repeatedly relapsing rectal gastrointestinal stromal tumor: a case report

Gastrointestinal stromal tumor (GIST) is the most common type of gastrointestinal mesenchymal tumor. Fewer than 2% of patients with metastatic GIST treated with imatinib experience a pathologic complete response. Furthermore, response to imatinib and subsequent-line tyrosine kinase inhibitor is limited by most patients developing drug resistance; median time to progression is 2 years for imatinib, and about half a year for sunitinib and regorafenib. In recent years, ripretinib, a fourth-line medicine, is been of the most important advances in the treatment of GIST. The ripretinib in patients with advanced gastrointestinal stromal tumours (INVICTUS): a double-blind, randomised, placebo-controlled, phase 3 trial study showed that ripretinib can significantly reduce the risk of disease progression and mortality in patients with advanced GIST ≥4 lines, and has obvious clinical activity for a variety of KIT/platelet-derived growth factor receptor α (PDGFR α) gene mutations. This paper presents a case of advanced rectal GIST treated with ripretinib in China. In the years preceding, the patient did not respond well to first-third line agent therapies. However, a partial remission (PR) of the tumor was found after 3-courses of ripretinib treatment. For GIST patients with drug-resistant mutations (both primary and secondary), treatment may be a more accurate and reasonable when mutation-inhibitor agents are prescribed at an early stage.

Indocyanine green-labeled dasatinib as a new fluorescent probe for molecular imaging of gastrointestinal stromal tumors

BACKGROUND AND AIM

It is difficult to differentiate gastrointestinal stromal tumors (GISTs) from other subepithelial lesions under gastrointestinal endoscopy. Because most GISTs express tyrosine kinase receptor c-KIT, fluorescence-labeled c-KIT-specific tyrosine kinase inhibitors seem to be useful agents for molecular imaging of GIST. We aimed to develop a near-infrared fluorescent imaging technology for GIST targeting c-KIT using the novel fluorescent probe indocyanine green-labeled dasatinib (ICG-dasatinib) and to investigate the antitumor effect of ICG-dasatinib on GIST cells.

METHODS

Indocyanine green-labeled dasatinib was synthesized by labeling linker-induced dasatinib with ICG derivative 3-indocyanine-green-acyl-1,3-thiazolidine-2-thione. Human GIST cell lines GIST-T1 and GIST-882M were incubated with ICG-dasatinib and observed by fluorescent microscopy. GIST cells were incubated with ICG-dasatinib, unlabeled dasatinib, or imatinib, and cell viabilities were evaluated. Subcutaneous GIST model mice or orthotopic GIST model rats were intravenously injected with ICG-dasatinib and observed using an IVIS Spectrum.

RESULTS

Strong fluorescent signals of ICG-dasatinib were observed in both GIST cell lines in vitro. IC50 values for ICG-dasatinib, unlabeled dasatinib, and imatinib were 13.9, 1.17, and 16.2 nM in GIST-T1 and 26.6, 3.63, and 47.6 nM in GIST-882M cells, respectively. ICG-dasatinib accumulated in subcutaneous xenografts in mice. Fluorescent signals were also observed in liver and gallbladder, indicating biliary excretion; however, fluorescence intensity of tumors was significantly higher than that of intestine after washing. Strong fluorescent signals were observed in orthotopic xenografts through the covering normal mucosa in rats.

CONCLUSIONS

Indocyanine green-labeled dasatinib could visualize GIST cells and xenografted tumors. The antitumor effect of ICG-dasatinib was preserved to the same degree as imatinib.

Small Cell Lung Carcinoma and Synchronous Rectal Adenocarcinoma and Jejunal Gastrointestinal Stromal Tumor Present in a Patient With History of Laryngeal Squamous Cell Carcinoma

BACKGROUND

The synchronous diagnosis of two or more primary malignancies in a patient is overall rare.

CASE REPORT

We report such a case of a 67-year-old male smoker with a history of laryngeal squamous cell carcinoma. He was incidentally identified through follow up computed tomography to have three masses in the lung, rectum and jejunum, respectively. Biopsies were performed and demonstrated synchronous lung small cell carcinoma (pT1bN0) and rectal adenocarcinoma. The patient underwent fractionated stereotactic radiation (FSRT) to the pulmonary tumor and chemotherapy with cisplatin and etoposide followed by laparoscopic rectum low anterior resection and small bowel segmental resection. Final pathology diagnoses confirmed synchronous microsatellite stable (MMS) moderately differentiated adenocarcinoma of the rectum (pT3N1b) and jejunal gastrointestinal stromal tumor (GIST), spindle cell type (pT2N0). At 8 months follow up postsurgery, the patient was doing well and no tumor recurrences were identified.

CONCLUSION

To the best of our knowledge, this is the first documented case of synchronous primary small cell lung carcinoma, rectal adenocarcinoma, and GIST in the English literature. The rarity, diagnosis and treatment challenges of these entities are discussed.

The current status of and prospects in research regarding gastrointestinal stromal tumors in China

China still lacks statistical data regarding the incidence of gastrointestinal stromal tumors (GISTs). Data from 3 regions have demonstrated that the incidence of GISTs in China is similar to that in the United States. Furthermore, no significant differences between both nations with regard to epidemiological characteristics and genotyping of GISTs have been reported. Chinese physicians are demonstrating an increased interest in studies regarding GISTs. Currently, to the authors' knowledge, China publishes the most research articles regarding GIST annually worldwide. Despite the paucity of relevant research regarding the clinical practices for GISTs, a series of studies performed by Chinese physicians in the fields of recurrence risk classification, laparoscopic surgery, and adjuvant therapy have contributed to the diagnosis and treatment of GISTs. The lack of innovative drugs, slow approval of new drugs, and insufficient research funds have limited further advancements in GIST-related research in China. In recent years, increased investment in scientific research has allowed for these advancements to be made by creating conditions for Chinese physicians to conduct high-level clinical research. Chinese researchers hope to further shorten the gap between China and the rest of the world in the field of GIST research within a relatively short period. The purpose of the current review article was to present the most updated information regarding the diagnosis and treatment of GISTs in Chinese medical practice and to suggest prospective research in this field.

Tumor-associated tertiary lymphoid structure predicts postoperative outcomes in patients with primary gastrointestinal stromal tumors

Tumor-infiltrating tertiary lymphoid structures (TLS) are thought to have anti-tumor activity and are believed to indicate a favorable prognosis in cancer patients. However, the prognostic value of TLS in gastrointestinal stromal tumors (GIST) is unknown. We evaluated the prognostic value of TLS using two independent GIST cohorts. Pathological examinations identified TLS in 44.9% of patients in our discovery cohort (DC). TLS was significantly associated with smaller tumor size (P = .011), relatively well morphological classification (P < .001), lower NIH classification (P < .001), lower recurrence (P = .005), longer survival time (P < .001) and lower imatinib resistance (P = .006). Kaplan-Meier curves showed that TLS was remarkably associated with favorable survival (P = .0002) and recurrence (P = .0015) time. In addition, the presence of KIT mutations and the absence of TLS suggested worst prognosis both in terms of overall survival (OS) (P = .0029) and time to recurrence (TTR) (P = .0150), while the presence of PDGFRA mutations and TLS suggested optimal prognosis for OS and TTR. Multivariate analyzes demonstrated that TLS was an independent prognostic factor for OS (HR:0.180, P = .002) and TTR (HR:0.412, P = .023). These results were confirmed using our validation cohort. Multiplexed immunohistochemistry staining was used to determine the composition of TLS. Therapies designed to target TLS may be a novel therapeutic strategy for GIST patients with imatinib resistance.

Endoscopic resection for subepithelial lesions-pure endoscopic full-thickness resection and submucosal tunneling endoscopic resection

Endoscopic full-thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER) are the frontier of therapeutic endoscopic. These two methods rely on the skillset and equipment of endoscopic submucosal dissection (ESD) while going beyond the boundaries of the gastrointestinal lumen. They are both representatives of natural orifice transluminal endoscopic surgery, with STER being a direct off-shoot of peroral endoscopic myotomy (POEM). Both techniques are designed for the removal of gastrointestinal tumors originating from the muscularis propria but tend to be used in different organs and come with respective challenges. In this review we will go over the history, indication, technique and literature of these two techniques.

Gastrointestinal stromal tumor - A review of clinical studies

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. With the advent of Imatinib, the treatment of gastrointestinal stromal tumor has been revolutionized as both the progression-free and overall survival rates have increased dramatically. Unfortunately, gastrointestinal stromal tumor patients on Imatinib do eventually fail due to resistance. Even though sunitinib and regorafenib have been shown to be highly effective as second- and third-line treatments, both have limited effects. New treatments are highly warranted for this reason. In this present review, 25 registered pharmacological clinical trials at ClinicalTrials.gov have been reviewed and show promising and encouraging results.

Pediatric gastrointestinal stromal tumors-a review of diagnostic modalities

Gastrointestinal stromal tumors are exceedingly rare tumors in the pediatric population, as a result many clinicians either may never see this diagnosis or will encounter it only a few times throughout their careers. It is imperative in the pediatric population to follow appropriate steps to ensure a swift diagnosis and referral to specialized centers that are equipped with the multidisciplinary teams accustomed to treating rare diseases. This review aims to discuss the most recent data available on the diagnostic modalities utilized in cases of suspected Pediatric GIST.

Current treatment strategies in pediatric gastrointestinal stromal cell tumor

Gastrointestinal stromal tumors (GIST) are exceedingly rare tumors in the pediatric population. As a result, many clinicians either may never see this diagnosis or will encounter it only a few times throughout their careers. Additionally, the more we discover about this disease, it becomes evident that it represents a distinct clinical entity from adult GIST. Many of the treatments and strategies used to combat the adult tumor are either ineffective or may be harmful to the pediatric population with this disease. The unique tumor biology found in pediatric GIST necessitates unique approaches and treatment strategies in order to achieve the best clinical outcome. This review aims to discuss the most recent data available on the different therapeutic modalities utilized in cases of Pediatric GIST.

Colorectal sarcoma: more than a gastrointestinal stromal tumor

Primary colorectal sarcomas have been defined as a rare and diverse group of mesenchymal cancers distinct from gastrointestinal stromal tumors (GISTs). Primary colorectal sarcomas have been recognized as a distinct entity from GISTs due to the dramatically worse prognosis these sarcomas carry. Also, primary colorectal sarcomas when compared to the more common colorectal adenocarcinoma, demonstrate more aggressive biology, present at a younger age and carry worse outcomes. At this time, surgery remains the mainstay of treatment and adjuvant chemotherapy has an unclear role in treatment of primary colorectal sarcoma. This paper attempts to review the available data regarding primary colorectal sarcomas.

Oncogene mutational analysis in Chinese gastrointestinal stromal tumor patients

Background

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors and exhibit a high frequency of oncogenic KIT or PDGFRA mutations. Tyrosine kinase inhibitors (TKIs) have been mainly used in the treatment of GISTs bearing KIT/PDGFRA mutations. However, other mutation profiles have been found to affect the sensitivity to and effectiveness of TKIs in the treatment of GISTs.

Purpose

The aim of the present study was to describe the mutational status of multiple genes in GIST samples and to provide information for finding potential predictive markers of therapeutic targets in Chinese GIST patients.

Patients and methods

MassARRAY spectrometry was used to test 40 Chinese GIST patients for 238 mutations affecting 19 oncogenes.

Results

A total of 14 oncogenes with 43 mutations were detected in 38 samples, with a mutation frequency of 95%. Among these mutation samples, 26 GISTs were found for KIT or PDGFRA mutations, while 12 were KIT/PDGFRA wild-type. Approximately half of the GIST samples harbored multiple mutations. The most frequent mutations were found in KIT (62.5%), CDK4 (17.5%), NRAS (15%) and EGFR (12.5%). Other mutations included PIK3CA and AKT1 (10%), BRAF and ABL1 (7.5%), PDGFRA, ERBB2 and HRAS (5%), and AKT2, FLT3 and KRAS (2.5%). New mutated genes (CDK4, AKT2, FLT3, ERBB2, ABL1 and AKT1), a higher BRAF mutation frequency (7.5%) and new BRAF mutation sites (G464E) were found in Chinese GIST patients.

Conclusion

This study demonstrated useful mutations in a small fraction of Chinese GIST, but targeted therapeutics on these potential predictive markers need to be investigated in depth especially in Oriental populations.

Gastric inflammatory fibroid polyp tumor with acute intestinal obstruction-Vanek's tumor can mimick a giant gastrointestinal stromal tumor or a gastric lymphoma

An inflammatory fibroid polyp (IFP) is a solitary rare benign neoplasm of the gastrointestinal tract, frequently located in the gastric antrum. IFPs account for about 0.1% of all gastric polyps. We report a case of a giant gastric inflammatory polyp of 2.5 cm × 7 cm that determines a gastric outlet obstruction called "ball valve syndrome" mimicking a gastrointestinal stromal tumor (GIST) and a gastric lymphoma, with an intestinal obstruction of high origin. Therefore, due to acute presentation we have decided to submit the patient to a subtotal gastrectomy. The patient was discharged two weeks later, asymptomatic. At 14 months of follow-up, patient is disease free at abdominal CT and OGDS. Depending on their size and location, IFPs can be associated with unspecific symptoms. Giant IFPs of the gastric antrum or the duodenum can determine an intermittent gastric outlet obstruction called "ball valve syndrome". Endoscopic biopsies are unhelpful and right diagnosis can be reached only with resection. In fact, only about 10% of the gastric lesions are diagnosed correctly prior to resection. Surgical treatment with complete resection with safe margins is curative. Giant IFPs are rare benign lesions whose atypical presentation can mimic GISTs, lymphomas or carcinomas. Clinical and radiological findings may not clarify the right diagnosis until histopathological evaluation aided with immunohistochemical analysis. The resection of IFPs with negative margins is curative with a good clinical outcome. In acute presentation, like in our case, surgery is the mainstay of treatment.

Opposing roles of KIT and ABL1 in the therapeutic response of gastrointestinal stromal tumor (GIST) cells to imatinib mesylate

Most gastrointestinal stromal tumors (GISTs) are caused by activating mutations of the KIT receptor tyrosine kinase. The small molecule inhibitor imatinib mesylate was initially developed to target the ABL1 kinase, which is constitutively activated through chromosomal translocation in BCR-ABL1-positive chronic myeloid leukemia. Because of cross-reactivity of imatinib against the KIT kinase, the drug is also successfully used for the treatment of GIST. Although inhibition of KIT clearly has a major role in the therapeutic response of GIST to imatinib, the contribution of concomitant inhibition of ABL in this context has never been explored. We show here that ABL1 is expressed in the majority of GISTs, including human GIST cell lines. Using siRNA-mediated knockdown, we demonstrate that depletion of KIT in conjunction with ABL1 – hence mimicking imatinib treatment – leads to reduced apoptosis induction and attenuated inhibition of cellular proliferation when compared to depletion of KIT alone. These results are explained by an increased activity of the AKT survival kinase, which is mediated by the cyclin-dependent kinase CDK2, likely through direct phosphorylation. Our results highlight that distinct inhibitory properties of targeted agents can impede antitumor effects and hence provide insights for rational drug development. Novel KIT-targeted agents to treat GIST should therefore comprise an increased specificity for KIT while at the same time displaying a reduced ability to inhibit ABL1.

Gastrointestinal stromal tumor of the esophagus: current issues of diagnosis, surgery and drug therapy

Gastrointestinal stromal tumors (GISTs) often arise in the stomach and small intestine, while esophageal GISTs are rare. Due to their rarity, clinicopathological data on esophageal GISTs are extremely limited, and this results in a lack of clear recommendations concerning optimal surgical management for esophageal GISTs. It is difficult to distinguish esophageal GIST from leiomyoma, the most frequent esophageal mesenchymal tumor, prior to resection, because the two types of tumors appear similar on computed tomography (CT), endoscopic ultrasound (EUS), and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). Fine-needle aspiration biopsy (FNAB) under EUS enables definitive diagnosis, but it is often avoided because scarring could make enucleation more difficult and increase the risk of tumor dissemination by capsule destruction. Esophageal segmental and wedge resections are not usually performed due to the anatomical peculiarity of the esophagus, and the surgical options are limited to the highly invasive esophagectomy or the much less invasive surgical tumor enucleation. The decision as to which surgical procedure should be performed for esophageal GISTs is still under debate. Tumor enucleation may be permitted for smaller tumors, and esophagectomy may be recommended for larger GISTs or high-risk tumors with a high mitotic rate. The purpose of neoadjuvant imatinib administration is downsizing of the GIST to reduce the extent of resection and to reduce the risk of intraoperative complications, including tumor rupture. The efficacy of neoadjuvant/adjuvant imatinib therapy for esophageal GISTs is poorly understood, because the reports are limited to case reports or case series with small numbers. More clinicopathological data and clinical trials for esophageal GIST are expected.

Anti-tumor efficacy of oncolytic reovirus against gastrointestinal stromal tumor cells

Imatinib, a multitargeted receptor tyrosine kinase inhibitor, is used as the standard initial therapy against inoperable gastrointestinal stromal tumor (GIST). However, GIST can acquire resistance to imatinib within several years of therapy. The development of oncolytic reovirus as an anticancer agent has expanded to many clinical trials for various tumors. Here, we investigated whether reovirus has antitumor activity against GIST cells in the setting of imatinib sensitivity in vitro and in vivo. Cell proliferation and apoptosis assays were performed using a human GIST cell line, GIST-T1, and imatinib-resistant GIST (GIST-IR) cells that we established. The molecular pathways responsible for cell damage by reovirus were explored using PCR-arrays and Western blots. Reovirus significantly induced apoptotic cell death in GIST-T1 and GIST-IR cells in vitro, despite differences in the activation of receptor tyrosine kinase pathways between GIST-T1 and GIST-IR. Molecular assays indicated the possibility that reovirus induces apoptotic cell death via Fas signaling. Furthermore, in vivo mouse tumor xenograft models demonstrated a significant anti-tumor effect of reovirus on both GIST-T1 and GIST-IR cells. Our results demonstrate the therapeutic potential of reovirus against GIST.

Endoscopic resection of gastric gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract, and about 60% of them are found in the stomach. With the widespread application of endoscopy and endoscopic ultrasonography (EUS), more and more gastric GISTs are being found in an early stage (with a relative small diameter and no metastasis), giving the chance of complete resection. Endoscopic resection such as endoscopic band ligation (EBL), endoscopic submucosal dissection (ESD), endoscopic submucosal excavation (ESE), endoscopic full-thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER), is a minimally invasive method compared with the conventional surgical approaches (open or laparoscopic), and has been demonstrated to be safe and effective for treating gastric GISTs. This review summarizes the recent advances on endoscopic resection of gastric GISTs, aiming to provide a rational management strategy for gastric GISTs.

Minimally invasive surgery for gastric gastrointestinal stromal tumors

Minimally invasive surgery has been increasingly performed for gastric gastrointestinal stromal tumors (GIST). In this review we discuss and summarize the current evidence on minimally invasive surgery for gastric GISTs. Laparoscopic resection for gastric GIST has been consistently shown to be associated with superior perioperative outcomes with no compromise in oncological outcomes when compared to open resection in numerous retrospective case-control studies. It has also been shown to be safe and feasible for large tumors or tumors located in unfavorable sites. However, to date, there remains a lack of level 1 evidence from prospective randomized control trials in support of laparoscopic resection.

Management of liver metastases from gastrointestinal stromal tumors: where do we stand?

The recommended management of liver metastases (LM) from gastrointestinal stromal tumors (GISTs) disease consists of perioperative administration of tyrosine kinase inhibitors (TKIs) and surgical resection. The aim of our study was to investigate the efficacy of this therapeutic approach. Studies reporting outcomes for patients underwent liver resection from metastatic gastrointestinal stromal tumor (GIST) were overviewed. Eleven studies were included, which enrolled 240 patients with liver metastasis from GISTs. A median overall survival (OS) interval of 41.8 months was calculated while a median disease free interval of 17.9 [17-43] months following resection was also measured. Recurrences were recorded in 63 patients. Prognostic factors identified by the studies included surgical resection, R0 resection, age <55 years, clinical response to TKIs, pre- and postoperative administration of TKIs. The included studies highlight the importance of complete resection and the timing of resection, as well underline the importance of pre- and post-operative administration of TKIs.

Cost-effectiveness of precision medicine in gastrointestinal stromal tumor and gastric adenocarcinoma

Over the past 20 years, with the incorporation of genetic sequencing and improved understanding regarding the mechanisms of cancer growth/metastasis, novel targets and their associated treatments have emerged in oncology and are now regularly incorporated into the clinical care of patients in the US. Novel, more tumor-specific, non-chemotherapy agents, including agents that are commonly used in the treatment of patients with gastric adenocarcinoma (GA) and gastrointestinal stromal tumor (GIST), fall under a broader treatment strategy, termed "precision medicine". While diagnostic testing and associated treatments in metastatic GA (mGA) are costly and may produce marginal benefit, those associated with GIST, despite being costly, produce significant improvements in patient outcomes. Despite the significant difference in impact, the agents associated with these cancers have similar acquisition costs. In this paper, we will review the current literature regarding cost and cost-effectiveness associated with precision medicine diagnosis and treatment strategies for GA and GIST.

Laparoscopic techniques and strategies for gastrointestinal GISTs

The laparoscopic approach is widely accepted surgical treatment for gastrointestinal submucosal tumors (SMTs). In this chapter, we will introduce laparoscopic techniques and strategy for gastrointestinal SMTs, in accordance with those for gastrointestinal stromal tumors (GISTs). The indication for a laparoscopic approach has been related to tumor size. The upper limit of tumor size has increased, according to recent trends, and there is no established guideline for a lower limit. All patients undergoing laparoscopic surgery receive preoperative examinations including gastrofiberscopy, upper gastrointestinal radiography, computed tomography (CT), and endoscopic ultrasonography (EUS). Gastric tumors <20 mm in diameter measured by EUS or CT are preoperatively localized by gastrofiberscopic clipping of the mucosa covering the SMT. While maintaining the principle of local resection with a negative resection margin, different surgical techniques are required depending on the location and configuration of the tumor. A single dose of a second-generation cephalosporin is administered to patients as a prophylactic antibiotic before or immediately after operation. If a patient undergoes wedge resection, a semi-bland diet will be provided within 48-72 hours. However, in cases of proximal or distal gastrectomy, the diet will be restricted for several days. A "no-touch" technique, by which the risk of tumor dissemination can be minimized, includes grasping the surrounding tissues, holding the threads sutured at the normal serosa around the tumor, and using a laparoscopic stapler or bag during laparoscopic resection.

Laparoscopic and endoscopic cooperative surgery for gastrointestinal tumor

With technological progress of endoscopic submucosal dissection (ESD) in the last decade, several laparoscopic and endoscopic cooperative surgeries (LECS) for gastrointestinal tumor have recently been developed. LECS is definitely favorable to the minimization of surgical margin, which leads to functional and anatomical preservation of gastrointestinal tract. LECS for gastrointestinal tumor is mainly sorted by two categories: exposure procedures and non-exposure procedures between endoluminal and extraluminal spaces. Exposure procedures have the potential risk of gastric contents or tumor cells spilling out over the abdominal cavity, because the stomach wall has to be perforated intentionally during the procedure. In order to avoid the potential these risks, non-exposure procedures have been developed. Currently, the LECS concept has rapidly permeated for treatment of gastrointestinal tumor due to its certainty and safety, although there is still room for improvement to lessen its technical difficulty. This review describes the current LECS for gastrointestinal tumor based on the several articles.

Diagnostic and treatment strategy for small gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are considered to be potentially malignant mesenchymal tumors of the gastrointestinal tract. Clinically relevant GISTs are rare; however, subclinical GISTs (mini‐GISTs) (1‐2 cm) and pathologic GISTs (micro‐GISTs) (<1 cm) are frequently reported. Most mini‐GISTs and almost all micro‐GISTs of the stomach may exhibit benign clinical behavior, and only mini‐GISTs with high‐risk features may progress. For this review, a provisional algorithm was used to propose diagnostic and treatment strategies for patients with small GISTs. Because surgery is the only potentially curative treatment, in its application for small GISTs, the principles of sarcoma surgery should be maintained, and cost effectiveness should be considered. Indications for surgery include GISTs measuring ≥2 cm, symptomatic GISTs, and mini‐GISTs with high‐risk features (irregular borders, cystic spaces, ulceration, echogenic foci, internal heterogeneity, and tumor progression during follow‐up); however, a preoperative pathologic diagnosis is infrequently obtained. For small intestinal and colorectal GISTs, surgery is indicated irrespective of size because of their greater malignant potential. Otherwise, mini‐GISTs without high‐risk features, micro‐GISTs, and small submucosal tumors measuring <5 cm without high‐risk features may be followed by periodical endoscopic ultrasonography. Although surgical approaches and operative methods are selected according to tumor size, location, growth pattern, and surgical teams, laparoscopic surgery has produced similar oncologic outcomes and is less invasiveness compared with open surgery. After resection, pathologic examination for diagnosis and risk assessment is mandatory, and genotyping is also recommended for high‐risk GISTs. Endoscopic resection techniques, although feasible, are not routinely indicated for most mini‐GISTs or micro‐GISTs. Cancer 2016;122:3110–8. © 2016 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.

Gastrointestinal stromal tumors (GISTs) are potentially malignant, and endoscopic ultrasonography and endoscopic ultrasound‐guided fine‐needle aspiration may play a major role in the diagnosis of small GISTs and submucosal tumors. Surgery is indicated for all intestinal GISTs and for small gastric GISTs in patients who have symptoms and/or high‐risk features.

Gastric bronchogenic cyst presenting as a gastrointestinal stromal tumor

Bronchogenic cyst (BC) is congenital abnormality of the tracheobronchial bud derived from the primitive foregut which is predominantly found in the mediastinum. Surgery remains the most common treatment when malignancy is suspected, or when there are presenting. Only infrequently, is BC located at an extrathoracic site. Although rarely located in the stomach, BC should be considered as a differential diagnosis of gastric neoplasm. For these cases, surgery remains a common choice. Minimally invasive procedures such as endoscopic ultrasonography-guided fine needle biopsy aspiration (EUS-FNA) and endoscopic submucosal dissection (ESD) should also be considered when the diagnosis of BC is suspected. They are valuable diagnostic methods that can assess and identify the location of the lesion, and facilitate histological examination of the cyst. In some cases of more superficial lesions ESD can take the place of surgery as it avoids unnecessary complications of a more invasive procedure. Here we present a case of gastric BC located in the fundus of the stomach that resembled a gastrointestinal stromal tumor (GIST). We discuss its embryology, pathogenesis, radiological, clinical and treatment modalities. We also provide a thorough review of 14 cases (including our own case), which completely meet pathological criteria has been undertaken focusing on symptom, location, treatment, and histological features.

Increased risk of additional cancers among patients with gastrointestinal stromal tumors: A population-based study

BACKGROUND

Most gastrointestinal stromal tumors (GISTs) are considered nonhereditary or sporadic. However, single-institution studies suggest that GIST patients develop additional malignancies at increased frequencies. It was hypothesized that greater insight could be gained into possible associations between GISTs and other malignancies with a national cancer database inquiry.

METHODS

Patients diagnosed with GISTs (2001-2011) in the Surveillance, Epidemiology, and End Results database were included. Standardized prevalence ratios (SPRs) and standardized incidence ratios (SIRs) were used to quantify cancer risks incurred by GIST patients before and after GIST diagnoses, respectively, in comparison with the general US population.

RESULTS

There were 6112 GIST patients, and 1047 (17.1%) had additional cancers. There were significant increases in overall cancer rates: 44% (SPR, 1.44) before the GIST diagnosis and 66% (SIR, 1.66) after the GIST diagnosis. Malignancies with significantly increased occurrence both before and after diagnoses included other sarcomas (SPR, 5.24; SIR, 4.02), neuroendocrine-carcinoid tumors (SPR, 3.56; SIR, 4.79), non-Hodgkin lymphoma (SPR, 1.69; SIR, 1.76), and colorectal adenocarcinoma (SPR, 1.51; SIR, 2.16). Esophageal adenocarcinoma (SPR, 12.0), bladder adenocarcinoma (SPR, 7.51), melanoma (SPR, 1.46), and prostate adenocarcinoma (SPR, 1.20) were significantly more common only before the GIST diagnosis. Ovarian carcinoma (SIR, 8.72), small intestine adenocarcinoma (SIR, 5.89), papillary thyroid cancer (SIR, 5.16), renal cell carcinoma (SIR, 4.46), hepatobiliary adenocarcinoma (SIR, 3.10), gastric adenocarcinoma (SIR, 2.70), pancreatic adenocarcinoma (SIR, 2.03), uterine adenocarcinoma (SIR, 1.96), non-small cell lung cancer (SIR, 1.74), and transitional cell carcinoma of the bladder (SIR, 1.65) were significantly more common only after the GIST diagnosis.

CONCLUSIONS

This is the first population-based study to characterize the associations and temporal relations between GISTs and other cancers by both site and histological type. These associations may carry important clinical implications for future cancer screening and treatment strategies.

Strongyloidiasis in a diabetic patient accompanied by gastrointestinal stromal tumor: cause of eosinophilia unresponsive to steroid therapy

We report here a case of strongyloidiasis in a 72-year-old diabetic patient (woman) accompanied by gastrointestinal stromal tumor receiving imatinib therapy, first diagnosed as hypereosinophilic syndrome and treated with steroids for uncontrolled eosinophilia. She suffered from lower back pain and intermittent abdominal discomfort with nausea and diagnosed with gastrointestinal stromal tumor. After post-operative imatinib treatment eosinophilia persisted, so that steroid therapy was started under an impression of hypereosinophilic syndrome. In spite of 6 months steroid therapy, eosinophilia persisted. Stool examination was performed to rule out intestinal helminth infections. Rhabditoid larvae of Strongyloides stercoralis were detected and the patient was diagnosed as strongyloidiasis. This diagnosis was confirmed again by PCR. The patient was treated with albendazole for 14 days and her abdominal pain and diarrhea improved. This case highlights the need for thorough investigation, including molecular approaches, to test for strongyloidiasis before and during steroid therapies.

Clinical course of gastrointestinal stromal tumor diagnosed by endoscopic ultrasound-guided fine-needle aspiration

BACKGROUND AND AIM

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumor of the gastrointestinal tract. However, little is known about the clinical presentation of GIST, especially small lesions. The purpose of the present study was to clarify the efficacy of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for the diagnosis of GIST and to determine its clinical course.

METHODS

Pathological and clinical records of GIST extracted from our institutional database between 1996 and 2012 were reviewed. All GIST cases were diagnosed pathologically by surgical specimen or EUS-FNA. To examine the efficacy of EUS-FNA for the diagnosis of GIST, the pathological findings of EUS-FNA were compared with the surgical findings from resected cases. Next, to clarify the clinical presentation of GIST, imaging findings and changes in tumor size over time were evaluated in follow up.

RESULTS

Of 84 cases of GIST, 67 were resected surgically after EUS-FNA; tumor size was <20 mm in 19 patients, and ≥20 mm in 48 patients. For the diagnosis of small GIST<20 mm, sensitivity and positive predictive value of EUS-FNA were 81.3% and 100%, respectively. A total of 27 patients with GIST was follow up for more than 1 year. Tumor size increased significantly during follow up. However, generalized linear analysis showed that there was no significant relationship between tumor size and follow up period.

CONCLUSIONS

The present results showed that even small GIST can be correctly identified by EUS-FNA. Moreover, size of small GIST increased significantly during follow up.

Laparoscopic endoscopic cooperative surgery

Laparoscopic and endoscopic cooperative surgery (LECS) is a newly developed concept for tumor dissection of the gastrointestinal tract that was first investigated for local resection of gastric gastrointestinal stromal tumors (GIST). The first reported version of LECS for GIST has been named 'classical LECS' to distinguish it from other modified LECS procedures, such as inverted LECS, a combination of laparoscopic and endoscopic approaches to neoplasia with a non-exposure technique (CLEAN-NET), and non-exposed endoscopic wall-inversion surgery (NEWS). These modified LECS procedures were developed for dissection of malignant tumors which may seed tumor cells into the abdominal cavity. While these LECS-related procedures might prevent tumor seeding, their application is limited by several factors, such as tumor size, location and technical difficulty. Currently, classical LECS is a safe and useful procedure for gastric submucosal tumors without mucosal defects, independent of tumor location, such as proximity to the esophagogastric junction or pyloric ring. For future applications of LECS-related procedures for other malignant diseases with mucosal lesions such as GIST with mucosal defects and gastric cancer, some improvements in the techniques are needed.

Cowden syndrome complicated by a gastrointestinal stromal tumor

To our knowledge, this is the first report of Cowden syndrome complicated by a gastrointestinal stromal tumor (GIST) of the small bowel. A 42-year-old female patient was found to have an abdominal mass that was diagnosed as the cause of anemia and was surgically extracted. The surgical specimen was found to be a GIST. During the same period, the patient underwent an endoscopic examination of the entire gastrointestinal tract. She was also diagnosed as having Cowden syndrome based on gastrointestinal polyps and skin, thyroid and breast lesions. Cowden syndrome is associated with germline mutations in the tumorsuppressor gene PTEN. PTEN expression may be essential to tumor growth and is a predictive biomarker of the prognosis of both diseases. The present report of such a case is expected to further the analysis of Cowden syndrome.

A comparative study between Embosphere(®) and conventional transcatheter arterial chemoembolization for treatment of unresectable liver metastasis from GIST

OBJECTIVE

Transcatheter arterial chemoembolization (TACE) is a standard treatment for hepatocellular carcinoma (HCC) and/or some unresectable liver metastasis tumors. Hypervascular liver metastatic lesions such as metastasis from gastrointestinal stromal tumor (GIST) are an indication for transcatheter arterial embolization (TAE). The purpose of this study was to evaluate the efficacy and safety of Embosphere(®)-TAE (Embo-TAE) in comparison with conventional TACE (cTACE) for the treatment of liver metastasis from GIST.

METHODS

A total of 45 patients who underwent TACE between Aug 2008 and Feb 2013 were enrolled. Patients with GIST who underwent TAE with Embosphere(®) (n=19) were compared with controls who received cTACE (n=26). The primary end points were treatment response and treatment-related adverse events. The secondary end points were progression-free survival (PFS) and overall survival (OS).

RESULTS

The treatment response of Embo-TAE group was significantly higher than that of the cTACE group (P<0.001). The PFS was significantly better in the Embosphere(®)-group than in the cTACE group (56.6 and 42.1 weeks, respectively; P=0.003). However, there was no statistically significant difference in liver toxicity between the two groups (P>0.05). The median OS in the Embo-TAE group was longer than that in the cTACE group (74.0 weeks, 95% CI: 68.2-79.8 vs. 61.7 weeks, 95% CI: 56.2-67.2 weeks) (unadjusted P=0.045). The use of Embo-TAE significantly reduced the risk of death in patients with GIST with liver metastases according to the Cox proportional hazards regression model [hazard ratio (HR): 0.149; 95% CI: 0.064-0.475].

CONCLUSIONS

TAE with Embosphere(®) showed better treatment response and delayed tumor progression compared with cTACE. There was no significant difference in treatment-related hepatic toxicities. Embo-TAE thus appears to be a feasible and promising approach in the treatment of liver metastasis from GIST.

The benefit of using CT-perfusion imaging for reliable response monitoring in patients with gastrointestinal stromal tumor (GIST) undergoing treatment with novel targeted agents

Solely size-based response criteria may be unreliable in patients with gastrointestinal stromal tumors (GIST) treated with tyrosine kinase inhibitors, because they typically underestimate responses to treatment. As GISTs are generally hypervascularized and novel targeted drugs knowingly affect angiogenic signaling pathways, perfusion measurements are expected to deliver important information about their efficacy. This pictorial essay illustrates the benefit of using complementary CT-perfusion-based measurements for more accurate evaluation of response to therapy in GIST.

Submucosal tumors: comprehensive guide for the diagnosis and therapy of gastrointestinal submucosal tumors

Small submucosal tumors (SMT) without symptoms are frequently found by endoscopic and radiological examinations. To find proper diagnostic measures and therapeutic indications for histologically undiagnosed SMT, we reviewed published articles in PubMed between 1990 and March 2013 using the key words 'submucosal tumor' and the name of a specific disease. SMT is observed in a wide range of gastrointestinal (GI) diseases and conditions, including compression by extra-GI organs and lesions, congenital tumors, inflammation, and benign as well as malignant neoplastic lesions. In the diagnosis of diseases and decision-making for therapy, endoscopic ultrasonography (EUS) and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) may play a key role. Symptomatic SMT and SMT histologically diagnosed as malignant or potentially malignant tumors such as gastrointestinal stromal tumor (GIST) should be treated by surgery. SMT >5 cm, SMT increasing in size and those with'high-risk features' including irregular border, heterogeneous internal echo such as anechoic area, and heterogeneous enhancement by contrast media may also be removed by surgery. Laparoscopic approach is feasible for gastric GIST <5 cm and this is considered less invasive than the open approach. Emerging techniques using flexible endoscopes appear less invasive, but require further evidence and are still under clinical study. Correct diagnosis of SMT is challenging; however, EUS and EUS-FNA are useful in the histological diagnosis and clinical decision-making. In the future, minimally invasive approaches may be a mainstream of surgical treatment for small SMT.

CT and MR imaging of gastrointestinal stromal tumor of stomach: a pictorial review

This pictorial review illustrates CT and MR imaging appearance of gastrointestinal stromal tumor (GIST) of the stomach and other lesions with similar imaging appearance. GIST of the stomach appears as well-defined enhanced masses with characteristics of subeppthial neoplasms. Majority are exophytic growth, but can also be of intra-luminal growth. GIST can growth into a large mass without gastrointestinal tract obstruction. Necrosis is often seen in GIST and results in heterogeneous enhancement and communication with gastrointestinal tract. CT and MRI features of several other neoplasms mimicking GISTs in the stomach are also described in this review.