A guide for the diagnosis and management of gastrointestinal stromal cell tumors

Whole-lesion iodine map histogram analysis in the risk classification of gastrointestinal stromal tumors: comparison with single-slice iodine concentration measurements

PURPOSE

To evaluate and compare the diagnostic performances of whole-lesion iodine map (IM) histogram analysis and single-slice IM measurement in the risk classification of gastrointestinal stromal tumors (GISTs).

METHODS

Thirty-seven patients with GISTs, including 19 with low malignant underlying GISTs (LG-GISTs) and 18 with high malignant underlying GISTs (HG-GISTs), were evaluated with dual-energy computed tomography (DECT). Whole-lesion IM histogram parameters (mean; median; minimum; maximum; standard deviation; variance; 1st, 10th, 25th, 50th, 75th, 90th, and 99th percentile; kurtosis, skewness, and entropy) were computed for each lesion. In other sessions, iodine concentrations (ICs) were derived from the IM by placing regions of interest (ROIs) on the tumor slices and normalizing them to the iodine concentration in the aorta. Both quantitative analyses were performed on the venous phase images. The diagnostic accuracies of the two methods were assessed and compared.

RESULTS

The minimum, maximum, 1st, 10th, and 25th percentile of the whole-lesion IM histogram and the IC and normalized IC (NIC) of the single-slice IC measurement significantly differed between LG- and HG-GISTs (p < 0.001 - p = 0.042). The minimum value in the histogram analysis (AUC = 0.844) and the NIC in the single-slice measurement analysis (AUC = 0.886) showed the best diagnostic performances. The NIC of single-slice measurements had a diagnostic performance similar to that of the whole-lesion IM histogram analysis (p = 0.618).

CONCLUSIONS

Both whole-lesion IM histogram analysis and single-slice IC measurement can differentiate LG-GISTs and HG-GISTs with similar diagnostic performances.

English version of Japanese Clinical Practice Guidelines 2022 for gastrointestinal stromal tumor (GIST) issued by the Japan Society of Clinical Oncology

The Japan Society of Clinical Oncology Clinical Practice Guidelines 2022 for gastrointestinal stromal tumor (GIST) have been published in accordance with the Minds Manual for Guideline Development 2014 and 2017. A specialized team independent of the working group for the revision performed a systematic review. Since GIST is a rare type of tumor, clinical evidence is not sufficient to answer several clinical and background questions. Thus, in these guidelines, we considered that consensus among the experts who manage GIST, the balance between benefits and harms, patients' wishes, medical economic perspective, etc. are important considerations in addition to the evidence. Although guidelines for the treatment of GIST have also been published by the National Comprehensive Cancer Network (NCCN) and the European Society for Medical Oncology (ESMO), there are some differences between the treatments proposed in those guidelines and the treatments in the present guidelines because of the differences in health insurance systems among countries.

The application of artificial intelligence in EUS

Artificial intelligence (AI) is an epoch-making technology, among which the 2 most advanced parts are machine learning and deep learning algorithms that have been further developed by machine learning, and it has been partially applied to assist EUS diagnosis. AI-assisted EUS diagnosis has been reported to have great value in the diagnosis of pancreatic tumors and chronic pancreatitis, gastrointestinal stromal tumors, esophageal early cancer, biliary tract, and liver lesions. The application of AI in EUS diagnosis still has some urgent problems to be solved. First, the development of sensitive AI diagnostic tools requires a large amount of high-quality training data. Second, there is overfitting and bias in the current AI algorithms, leading to poor diagnostic reliability. Third, the value of AI still needs to be determined in prospective studies. Fourth, the ethical risks of AI need to be considered and avoided.

Endoscopic ultrasound-based application system for predicting endoscopic resection-related outcomes and diagnosing subepithelial lesions: Multicenter prospective study

OBJECTIVES

Subepithelial lesions (SELs) are associated with various endoscopic resection (ER) outcomes and diagnostic challenges. We aimed to establish a tool for predicting ER-related outcomes and diagnosing SELs and to investigate the predictive value of endoscopic ultrasound (EUS).

METHODS

Phase 1 (system development) was performed in a retrospective cohort (n = 837) who underwent EUS before ER for SELs at eight hospitals. Prediction models for five key outcomes were developed using logistic regression. Models with satisfactory internal validation performance were included in a mobile application system, SEL endoscopic resection predictor (SELERP). In Phase 2, the models were externally validated in a prospective cohort of 200 patients.

RESULTS

An SELERP was developed using EUS characteristics, which included 10 models for five key outcomes: post-ER ulcer management, short procedure time, long hospital stay, high medication costs, and diagnosis of SELs. In Phase 1, 10 models were derived and validated (C-statistics, 0.67-0.99; calibration-in-the-large, -0.14-0.10; calibration slopes, 0.92-1.08). In Phase 2, the derived risk prediction models showed convincing discrimination (C-statistics, 0.64-0.73) and calibration (calibration-in-the-large, -0.02-0.05; calibration slopes, 1.01-1.09) in the prospective cohort. The sensitivities and specificities of the five diagnostic models were 68.3-95.7% and 64.1-83.3%, respectively.

CONCLUSION

We developed and prospectively validated an application system for the prediction of ER outcomes and diagnosis of SELs, which could aid clinical decision-making and facilitate patient-physician consultation. EUS features significantly contributed to the prediction.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, http://www.chictr.org.cn (ChiCTR2000040118).

Assessing prognostic factors of long-term survival after surgery for colorectal gastrointestinal stromal tumours

AIM

Due to their rarity, the management of colorectal gastrointestinal stromal tumours (CR GISTs) is still under debate. The aim of this study was to assess prognostic factors.

METHOD

We performed a retrospective review of patients who underwent surgery with curative intent for CR GIST at our centre from 2002 to 2019. Factors associated with overall (OS) and recurrence-free survival (RFS) were analysed.

RESULTS

Fifty-six patients were included [median age 63 years, 29 (52%) female, 30 (54%) Miettinen high-risk, 40 (71%) with rectal GIST]. Nineteen (34%) patients received perioperative (neoadjuvant and/or adjuvant) imatinib. All cases of colonic GIST had an R0 resection, compared with 28 (70%) of rectal GISTs. After a median follow-up of 97 months (interquartile range 48-155 months), 14 (25%) deaths and 14 (25%) recurrences occurred. In the high-risk cohort, factors associated with improved RFS were R0 resection (OR 0.19, 95% CI 0.1-0.5, p = 0.002) and perioperative imatinib (OR 0.33, 95% CI 0.42-0.97, p = 0.04). Patients who had received perioperative imatinib had longer RFS (60% vs. 11% at 5 years, p = 0.006) but not OS. In rectal GISTs, 5-year OS was 85% for R0 and 70% for R1 resections (p = 0.164) and 5-year RFS was 85% for R0 and 12% for R1 resection (p < 0.001). When stratifying patients by perioperative imatinib, there were no differences in OS or RFS in the R0 or R1 groups.

CONCLUSION

Perioperative imatinib and R0 resection were associated with improved RFS in high-risk patients with CR GIST. In patients with rectal GIST, R1 resection was associated with worse RFS irrespective of perioperative imatinib treatment.

Comparing clinical characteristics and surgical outcomes of gastric and small bowel GIST: A single center experiences

OBJECTIVE

Gastrointestinal stromal tumor (GIST) is a rare kind of neoplasm at the gastrointestinal tract. There are few studies regarding the comparison of gastric and small bowel GIST in Korea. We aimed to analyze clinical characteristics and outcomes between gastric and small bowel GIST after curative resection.

METHODS

Between May 2005 and Dec 2017, 165 patients who underwent curative resection for gastric GIST (n = 115) and small bowel GIST (n = 50) were retrieved from a retrospective database. They were compared with respect to clinical, pathologic and oncological outcomes.

RESULTS

The mean age at surgery in both two group was similar (58.8 vs. 58.6, p = 0.772). The rate of emergency admission and surgery was higher in small bowel GIST group (p < 0.005). The mitotic rate and risk category were not significantly different between the two groups. However, the T stage was higher in small bowel GIST compared to the T stage of gastric GIST (22.6% vs. 44.0%, p = 0.025). During the follow-up, 5-year disease free survival rate was worse in small bowel GIST (82.0%) compared gastric GIST (93.7%) (p = 0.032). 5-year survival rate was not significantly different between the two groups (100.0% vs. 97.7%, p = 0.578). The T stage, mitotic count, and risk category were independent prognostic factors for disease free survival of Gastric and small bowel GIST in Cox multivariate analysis.

CONCLUSION

Small bowel GIST has more advanced T stage and higher rate of emergency surgery. Disease free survival rate was worse in small bowel GIST. Larger scaled prospective study of small bowel GIST is needed.

Peculiar Presentation of Gastrointestinal Stromal Tumor in a Patient With Early Satiety

Gastrointestinal stromal tumors (GISTs) are one of the most common, potentially malignant, subepithelial lesions identified in the gastrointestinal tract. Hypothesized to derive from the interstitial cells of Cajal (ICC), GISTs commonly demonstrate gain of function mutations in proto-oncogenic receptor tyrosine kinase CD117 (KIT). Depending on mitotic activity and tumor size characteristics, GISTs may transform from benign to malignant neoplasms. Increasing evidence suggests that early identification of a GIST is paramount for optimal prognostic outcomes. We present a rare case of a GIST located in the uncinate pancreas identified via endoscopic ultrasound (EUS) and diagnosed with an EUS-guided fine needle aspiration (EUS-FNA) biopsy.

Endoscopic Ultrasound Advanced Techniques for Diagnosis of Gastrointestinal Stromal Tumours

Gastrointestinal Stromal Tumors (GISTs) are subepithelial lesions (SELs) that commonly develop in the gastrointestinal tract. GISTs, unlike other SELs, can exhibit malignant behavior, so differential diagnosis is critical to the decision-making process. Endoscopic ultrasound (EUS) is considered the most accurate imaging method for diagnosing and differentiating SELs in the gastrointestinal tract by assessing the lesions precisely and evaluating their malignant risk. Due to their overlapping imaging characteristics, endosonographers may have difficulty distinguishing GISTs from other SELs using conventional EUS alone, and the collection of tissue samples from these lesions may be technically challenging. Even though it appears to be less effective in the case of smaller lesions, histology is now the gold standard for achieving a final diagnosis and avoiding unnecessary and invasive treatment for benign SELs. The use of enhanced EUS modalities and elastography has improved the diagnostic ability of EUS. Furthermore, recent advancements in artificial intelligence systems that use EUS images have allowed them to distinguish GISTs from other SELs, thereby improving their diagnostic accuracy.

Might Patients with Metastatic Gastrointestinal Stromal Tumors Benefit from Operative Management? A Population-Based Retrospective Study

Background

With respect to effect of surgery on the therapy of patients with metastatic gastrointestinal stromal tumors (mGISTs), still no consensus has been reached. This research designed to investigate the effect of surgical treatment on prognosis in patients with mGISTs.

Methods

The population-based study consisted of 6282 GIST patients diagnosed between 2001 and 2016, from the Surveillance, Epidemiology, and End Results (SEER) database registry. The Kaplan-Meier method and Cox model were employed for the exploration of the effect of surgery on overall survival (OS) and GIST-specific survival (GSS).

Results

In total, 6282 patients were diagnosed with GISTs, including 1238 (19.7%) mGIST patients and 5044 (80.3%) non-mGIST patients. Compared with the patients with non-mGISTs, metastatic patients assumed relatively lower proportion of surgical management (756 [61.1%] vs. 4666 [92.5%], P < 0.001). Based on unadjusted analysis, mGIST patients with operative management presented higher five years OS together with GSS in comparison with those without operative management (OS: 58.3% vs. 33.1%, P < 0.001; GSS: 61.6% vs. 36.7%, P < 0.001). Multivariable analysis found that no surgery was correlated to more than 2-fold increased death risk (OS, adjusted HR = 2.27, 95% CI: 1.90-2.71; GSS, adjusted HR = 2.42, 95% CI: 2.00-2.93).

Conclusion

Metastatic GIST patients could potentially benefit from operative management with improved GSS and OS.

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.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Comparison of safety and short-term outcomes between endoscopic and laparoscopic resections of gastric gastrointestinal stromal tumors with a diameter of 2-5 cm

BACKGROUND AND AIM

Developments of endoscopic techniques brought the possibility of endoscopic resection for gastrointestinal stromal tumors (GISTs) of larger sizes. We aim to compare safety and short-term outcomes between endoscopic and laparoscopic resections of gastric GISTs with a diameter of 2-5 cm.

METHODS

This is a single-center, retrospective cohort study. The clinical data, perioperative conditions, and the adverse events of patients who underwent endoscopic or laparoscopic resection for gastric GIST of 2-5 cm in Zhongshan Hospital, Fudan University, from January 2016 to December 2020 were retrospectively reviewed.

RESULTS

A total of 346 patients were reviewed; 12 patients who failed to accomplish the planned procedure were excluded; 182 underwent laparoscopic resection; and 152 underwent endoscopic resection. Significant differences exist in the tumor size between the laparoscopic group (3.43 ± 0.86 cm) and the endoscopic group (2.78 ± 0.73 cm) (P < 0.01). Compared with laparoscopic resection, endoscopic resection was associated with faster recovery (P < 0.01), shorter hospital stays (P < 0.01), and lower cost (P < 0.01). The incidence of Clavien-Dindo grade II-V adverse events in the endoscopic group (3/152) was significantly lower than that in the laparoscopic group (12/182) (P = 0.04). After a propensity score matching analysis, the endoscopic group showed similar incidences of complications with the laparoscopic group, while the advantages over laparoscopic resection in postoperative hospital stay, time to first oral intake, and hospitalization expenses remained significant (P < 0.01).

CONCLUSIONS

Endoscopic resection is a safe and cost-effective method for 2-5 cm of gastric GISTs compared with laparoscopic resection.

Current treatment strategies and future perspectives for gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that originate from the gastrointestinal tract, mostly from the stomach. GISTs are derived from the myenteric interstitial cells of Cajal and are caused by several mutations in the c-kit and platelet-derived growth factor receptor genes. Clinically, GISTs are detected by endoscopic and imaging findings and are diagnosed by immunostaining. Surgery is the first line of treatment, and if the tumor is relatively small, minimally invasive surgery such as laparoscopy is performed. In recent years, neoadjuvant therapy has been administered to patients with GISTs that are suspected of having a large size or infiltration to other organs. Postoperative adjuvant imatinib is the standard therapy for high-risk GISTs. It is important to assess the risk of recurrence after GIST resection. However, the effect of tyrosine kinase inhibitor use will vary by the mutation of c-kit genes and the site of mutation. Furthermore, information regarding gene mutation is indispensable when considering the treatment policy for recurrent GISTs. This article reviews the clinicopathological characteristics of GISTs along with the minimally invasive and multidisciplinary treatment options available for these tumors. The future perspectives for diagnostic and treatment approaches for these tumors have also been discussed.

Transvaginal Excision of Rectal Gastrointestinal Stromal Tumor: A Safe Minimally Invasive Approach

Introduction: Gastrointestinal stromal tumors (GISTs), the specific kit-positive mesenchymal tumors, are rarely found in the anorectum and account for 5% of all GIST cases. Surgical excision remains the main treatment for anorectal GIST. The available techniques include enucleation transanal excision or sometimes an abdominoperineal resection for large or low tumors. Case Study: We present a middle-aged female with a complaint of intermittent rectal pain for 1 year. Diagnostic workup detected a mass in the rectovaginal septum. A transvaginal excision was performed. Final histopathology showed rectal GIST. On regular follow-up visits, there was no detectable recurrence, and her anal pain disappeared completely. Discussion: Colorectal GIST accounts for only 0.1% of all colorectal tumors; this infrequency has led to a controversy in its diagnosis and management. Nevertheless, surgery remains a cornerstone element in the management of rectal GISTs. Different resection methods have been described in the literature, ranging from less-invasive approach such as transanal excision to a more radical one like an abdominoperineal resection. As there is no standard approach, choosing which one to perform depends on the tumor size, its location, and the surgeon’s preference. Conclusion: Transvaginal excision could be considered a safe minimally invasive approach for low-lying rectal GISTs.

A new endoscopic technique for specific gastrointestinal stromal tumors: a retrospective cohort study

OBJECTIVES

Surgical resection is recommended for treating gastrointestinal stromal tumors (GISTs) >20 mm. With the emergence of minimally invasive concept, endoscopic techniques are involved. We introduce a new endoscopic technique termed as endoscopic submucosal resection preserving serosa (ESR-PS) for GISTs ≥ 20 mm with mucosal erosion or ulcer locating at deep muscularis propria.

METHODS

This retrospective cohort study collected patients at the endoscopy center of the First Affiliated Hospital of Xi'an Jiaotong University between January 2019 and 2021. The primary outcome was adverse events including pneumoperitoneum, fever and delayed bleeding. The second outcomes included en bloc resection complete en bloc resection, recurrence, operation time, hospital stay time after ESR-PS, postoperative indwelling gastric tube and postoperative eating.

RESULTS

A total of 49 patients were included. One patient experienced pneumoperitoneum. All patients did not experienced fever or delayed bleeding after ESR-PS. All cases achieved en bloc resection and complete en bloc resection. The median operation time of ESR-PS was 49 min (range 43-71). The indwelling gastric tubes were given to patients for 1 d or 2 d after ESR-PS. After 1 d or 2 d, patients started oral diet, staying in hospital for a median of 4 (3-4) d after ESR-PS. During the follow-up time, recurrence was not found.

CONCLUSIONS

Our study indicated that ESR-PS is a feasible, effective and safe technique for GISTs ≥ 20mm with mucosal erosion or ulcer locating at deep muscularis propria. More large, multi-center and prospective studies are needed to evaluate the effectiveness and safety of ESR-PS in the future.

[Surgical and interdisciplinary treatment of gastrointestinal stromal tumors]

Gastrointestinal stromal tumors (GISTs) are the most frequent potentially malignant mesenchymal tumors of the gastrointestinal tract. The treatment of GISTs has been revolutionized since imatinib and other tyrosine kinase inhibitors were introduced for the treatment of GISTs, which inhibit the tyrosine kinases c‑KIT and platelet-derived growth factor receptor (PDGFR) alpha. Even after the introduction of this targeted treatment GISTs can only be cured by surgical resection. With interdisciplinary multimodal treatment the prognosis of metastasized GIST can now be further improved by surgical resection of the primary tumor and the metastases, potentially leading to a cure. Neoadjuvant therapy can reduce the extent of surgical resection and hereby enable organ preservation and reduce surgical morbidity. To evaluate molecular and clinical predictors and to offer an optimal therapeutic plan, patients with GISTs and certainly patients with advanced GISTs should be evaluated by interdisciplinary sarcoma boards.

Transvaginal Resection of a Rectal Gastrointestinal Stromal Tumor: A Case Report

Gastrointestinal stromal tumors (GISTs) are a type of mesenchymal tumors. They are rare in rectum. This location is a surgical challenge due to the high morbidity after aggressive surgeries. We present the case of an 81-year-old female with a high-grade GIST treated with transvaginal excision and adjunctive therapy with imatinib. The postoperative period was uneventful without anal dysfunction. Within the types of surgical treatment available, transvaginal excision is an acceptable procedure in lesions located in the rectovaginal region.

Skeletal muscle metastasis from a gastrointestinal stromal tumor: A case report

RATIONALE

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Common sites for metastasis are the liver and peritoneum, whereas skeletal muscle metastases are rare.

PATIENT CONCERNS

A 59-year-old man with skeletal muscle metastasis was diagnosed during a period of adjuvant imatinib therapy following the recurrence of GIST of the small intestine.

DIAGNOSIS

The patient was diagnosed with skeletal muscle metastasis of GIST based on immunohistochemistry and molecular pathology analysis results.

INTERVENTION

Extensive resection of the left thigh tumor was performed. The patient underwent whole-exome sequencing of tissue examination. The results suggest that resistance to imatinib may have been developed, and the patient was therefore administered sunitinib instead.

OUTCOMES

Complete remission was observed following sunitinib therapy.

LESSONS

In cases of skeletal muscle metastasis diagnosed during a period of adjuvant imatinib therapy following the recurrence of a GIST of the small intestine, whole exome sequencing may be used to discover more gene variations.

Diagnostic yields of endoscopic ultrasound-guided fine-needle tissue acquisition according to the gastric location

The diagnostic accuracy of endoscopic ultrasound-guided fine-needle tissue acquisition (EUS-FNTA) according to the gastric location of subepithelial tumors (SETs) has not been well established. We aimed to evaluate the efficacy of EUS-FNTA for the diagnosis of gastric SETs according to tumor location.Thirty-three patients diagnosed with gastric SETs via EUS-FNTA from January 2016 to May 2018 were analyzed retrospectively. Patient demographics, diagnostic yields, and complications were evaluated.Nineteen patients (57.6%) were female, with a mean age of 57.7 years. Endoscopic ultrasound revealed a mean longitudinal diameter of 25.6 mm. The most common location of SETs was in the gastric body (n = 18, 54.5%), followed by cardia and fundus (n = 10, 30.3%), and antrum (n = 5, 15.2%). A 20-gauge biopsy needle was most frequently used (90.9%). The diagnostic yield was obtained in 23 patients (69.7%). The most common diagnosis was gastrointestinal stromal tumor (73.9%), followed by leiomyoma (17.4%). The diagnostic yield of SETs in gastric antrum (0/5, 0%) was significantly lower than that in the gastric body and cardia (23/28, 82.1%, P = .001). A case of immediate bleeding after EUS-FNTA occurred in 1 patient (3.0%) who recovered uneventfully. According to related literature, the overall diagnostic yield of SETs in gastric antrum was significantly lower than that in the gastric body, fundus, and cardia (29.7% vs 71.4%, P < .001, n = 191).EUS-FNTA is ineffective in the diagnosis of SETs in the gastric antrum. Although EUS-FNTA is an advanced diagnostic tool for gastric SETs, it is essential to develop more effective methods for the diagnosis of antral SETs.

Gastrointestinal stromal tumor: a review of current and emerging therapies

Gastrointestinal stromal tumors (GIST) are rare neoplasms arising from the interstitial cell of Cajal in the gastrointestinal tract. Two thirds of GIST in adult patients have c-Kit mutation and smaller fractions have platelet derived growth factor receptor alpha (PDGFRA) mutation. Surgery is the only curative treatment for localized disease. Imatinib improves survival when used adjuvantly and in advanced disease. Several targeted therapies have also improved survival in GIST patients after progression on imatinib including sunitinib and regorafenib. Recently, United States Federal and Drug Administration (FDA) approved two new tyrosine kinase inhibitors for the treatment of heavily pretreated advanced/unresectable GIST including avapritinib (a selective inhibitor for PDGFRA exon 18 mutation including D842V mutations) and ripretinib (a broad-spectrum kinase inhibitor of c-Kit and PDGFRA). In this article, we will provide a comprehensive review of GIST including the current standard of care treatment and exploring future paradigm shifts in therapy.

Gastrointestinal Stromal Tumor as a Rare Cause of Abdominal Mass: A Case Report and Literature Review

Gastrointestinal stromal tumors (GISTs) are soft tissue sarcomas that can arise from any part of the digestive system. GISTs represent 1% of gastric neoplasms. We report a rare case of a GIST tumor in a 59-year-old woman who presented with abdominal pain and weight loss. Computed tomography (CT) of the abdomen with intravenous contrast revealed a left upper quadrant abdominal mass and biopsy showed GIST. She was treated with imatinib to downsize the tumor prior to undergoing surgical resection of the tumor.

Gastrointestinal stromal tumors: relationship between preoperative CT features and pathologic risk stratification

OBJECTIVE

To investigate a relationship between contrast-enhanced computed tomography (CECT) features of gastrointestinal stromal tumors (GISTs) and risk of relapse according to Miettinen stratified risk classifications.

METHODS

After ethical committee approval, a retrospective analysis was conducted on the preoperative CECT of patients with pathologically proven GIST undergoing surgery between June 2009 and December 2019. Chi-square analysis was used to evaluate the correlation between Miettinen stratified risk categories and the following imaging features: tumor size and location, growth pattern, margins, type and degree of contrast enhancement, presence of calcifications, necrosis, signs of ulceration/fistulation, internal hemorrhagic foci, enlarged feeding or draining vessels (EFDV), ascites, peritoneal implants, lymphadenopathy, or metastasis.

RESULTS

A total of 54 patients (mean age 65 ± 11, 29 men) were included in the study with a total of 56 GISTs. Necrosis, ulceration/fistulation, hemorrhage, margins, enlarged vessels, type of contrast enhancement, and metastasis turned out to be associated with Miettinen risk categories (p < 0.005). Logistic regression analysis identified the presence of necrosis and EFDV as predictors of pathologic risk of relapse (overall accuracy of 89.3%).

CONCLUSION

Preoperative CECT may be helpful in predicting pathologic risk categories of GISTs, as determined by the Miettinen classification system.

Could computed tomography be used as a surrogate of endoscopic ultrasonography in the screening and surveillance of small gastric Gastrointestinal stromal tumors?

PURPOSE

To investigate whether computed tomography (CT) could be used for screening and surveillance of small gastric gastrointestinal stromal tumors (gGISTs).

METHOD

A total of 162 pathologically confirmed small gGISTs (≤2 cm) between September 2007 and November 2019 were retrospectively enrolled. Thirty-six lesions received contrast-enhanced CT after they were identified by endoscopy and EUS, and forty-three lesions received CT alone before surgery. The detection rate of CT for ≤1 cm gGISTs (micro-gGISTs) and 1-2 cm gGISTs (mini-gGISTs) was investigated, and the detection rate of CT alone was compared with that of CT following endoscopy and EUS. The relationship between EUS- and CT-detected high-risk features were assessed.

RESULTS

CT demonstrated a favorable detection rate for mini-gGISTs previously identified by EUS and endoscopy, whereas CT alone showed an inferior detection rate (100 % vs. 75 %, p =  0.02). CT showed a poor detection rate for micro-gGISTs, both for lesions received CT after identified by EUS and endoscopy, and those received CT alone (33.3 % vs. 14.8 %, p =  0.372). CT-detected heterogeneous enhancement pattern and presence of calcification were strongly correlated with heterogeneous echotexture (Spearman's ρ=0.66, p < 0.001) and echogenic foci (Spearman's ρ=0.79, p < 0.001) on EUS, respectively. CT-detected necrosis was moderately correlated with cystic spaces on EUS (Spearman's ρ=0.42, p = 0.02). No correlation was found between EUS- and CT- assessed irregular border.

CONCLUSIONS

CT could potentially be considered as a surrogate of EUS for surveillance of mini-gGISTs instead of micro-gGISTs, whereas couldn't be used as a screening modality for either micro- or mini-gGISTs.

Development of a Malignancy Potential Binary Prediction Model Based on Deep Learning for the Mitotic Count of Local Primary Gastrointestinal Stromal Tumors

Objective

The mitotic count of gastrointestinal stromal tumors (GIST) is closely associated with the risk of planting and metastasis. The purpose of this study was to develop a predictive model for the mitotic index of local primary GIST, based on deep learning algorithm.

Materials and Methods

Abdominal contrast-enhanced CT images of 148 pathologically confirmed GIST cases were retrospectively collected for the development of a deep learning classification algorithm. The areas of GIST masses on the CT images were retrospectively labelled by an experienced radiologist. The postoperative pathological mitotic count was considered as the gold standard (high mitotic count, > 5/50 high-power fields [HPFs]; low mitotic count, ≤ 5/50 HPFs). A binary classification model was trained on the basis of the VGG16 convolutional neural network, using the CT images with the training set (n = 108), validation set (n = 20), and the test set (n = 20). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated at both, the image level and the patient level. The receiver operating characteristic curves were generated on the basis of the model prediction results and the area under curves (AUCs) were calculated. The risk categories of the tumors were predicted according to the Armed Forces Institute of Pathology criteria.

Results

At the image level, the classification prediction results of the mitotic counts in the test cohort were as follows: sensitivity 85.7% (95% confidence interval [CI]: 0.834–0.877), specificity 67.5% (95% CI: 0.636–0.712), PPV 82.1% (95% CI: 0.797–0.843), NPV 73.0% (95% CI: 0.691–0.766), and AUC 0.771 (95% CI: 0.750–0.791). At the patient level, the classification prediction results in the test cohort were as follows: sensitivity 90.0% (95% CI: 0.541–0.995), specificity 70.0% (95% CI: 0.354–0.919), PPV 75.0% (95% CI: 0.428–0.933), NPV 87.5% (95% CI: 0.467–0.993), and AUC 0.800 (95% CI: 0.563–0.943).

Conclusion

We developed and preliminarily verified the GIST mitotic count binary prediction model, based on the VGG convolutional neural network. The model displayed a good predictive performance.

Recent advances in the management of gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is a rare but an important clinical entity seen in our clinical practice. It is the most common mesenchymal tumor of the gastrointestinal tract and most common malignancy of the small intestine. Although the exact prevalence of GIST is not known, the incidence of GIST has been increasing. GISTs arise from interstitial cells of Cajal. Most of the GISTs occur due to mutation in c-kit gene or platelet derived growth factor receptor alpha gene. 15% of GISTs do not have these mutations and they are called wild-type GISTs. Almost all GISTs express KIT receptor tyrosine kinase. Histologically, GISTs look like spindle cell tumors most of the time but they can be epitheloid or mixed type. The median size of GISTs varies from 2.7 cm to 8.9 cm. Clinically, patients with small GISTs remain asymptomatic but as the GIST size increases, patients present with various symptoms depending on the location of the GIST. Most of GISTs are located in the stomach or small bowel. Diagnosis is suspected on imaging and endoscopic studies, and confirmed by tissue acquisition with immunohistochemical staining. The aggressiveness of GISTs depends on the size, mitotic index and location. Surgical resection is the treatment of choice. But various endoscopic modalities of resection are increasingly being tried. Tyrosine kinase inhibitors are extremely useful in the management of large GISTs, unresectable GISTs and metastatic GISTs. Treatment options for metastatic GISTs also include radiotherapy, chemotherapy, hepatic artery embolization, chemoembolization and radiofrequency ablation.

The Impact of Imatinib on Survival and Treatment Trends for Small Bowel and Colorectal Gastrointestinal Stromal Tumors

BACKGROUND

The aim of this study is to assess treatment trends and overall survival (OS) in small bowel (SB) and colorectal (CR) gastrointestinal stromal tumors (GIST) with respect to the introduction of imatinib in 2008.

METHODS

Patients diagnosed with SB and CR GIST were identified from the National Cancer Database (2004-2015). The primary outcome was 5- and 10-year OS. Patients were stratified by tumor site, time period (before and after imatinib), and treatment type. OS was analyzed using Kaplan-Meier survival curves, log-rank test, and Cox proportional hazards models.

RESULTS

A total of 8441 cases were included (SB 81.66%; CR 18.34%). Radical resection was the most common treatment (SB 42.33%; CR 38.69%). The addition of chemotherapy to radical resection for SB GIST increased between the two time periods (31.76 to 40.43%; p < 0.001), and was associated with improved unadjusted and adjusted OS (2009-2015: adjusted HR [AHR] 0.73, 95% CI 0.59-0.89, p = 0.002). Patients with SB GIST had better 5- and 10-year OS compared with CR (SB 69.83% and 47.68%; CR 61.33% and 45.39%; p < 0.001), even after stratifying by treatment type and tumor size and adjusting for other factors (SB 5-year AHR 1.35, 95% CI 1.19-1.53; 10-year AHR 1.23, 95% CI 1.09-1.38; each p < 0.001).

CONCLUSION

CR GIST are associated with lower OS than SB GIST. Radical resection is the most common treatment type for both sites. Chemotherapy with radical resection offers better OS in SB GIST, but not in CR GIST. Further studies are needed to assess the biology of CR GIST to explain the worse OS.

Feasibility of using computed tomography texture analysis parameters as imaging biomarkers for predicting risk grade of gastrointestinal stromal tumors: comparison with visual inspection

PURPOSE

To evaluate the feasibility of using computed tomography texture analysis (CTTA) parameters for predicting malignant risk grade and mitosis index of gastrointestinal stromal tumors (GISTs), compared with visual inspection.

METHOD AND MATERIALS

CTTA was performed on portal phase CT images of 145 surgically confirmed GISTs (mean size: 42.9 ± 37.5 mm), using TexRAD software. Mean, standard deviation, entropy, mean of positive pixels (MPP), skewness, and kurtosis of CTTA parameters, on spatial scaling factor (SSF), 2-6 were compared by risk grade, mitosis rate, and the presence or absence of necrosis on visual inspection. CTTA parameters were correlated with risk grade. Diagnostic performance was evaluated with receiver operating characteristic curve analysis. Enhancement pattern, necrosis, heterogeneity, calcification, growth pattern, and mucosal ulceration were subjectively evaluated by two observers.

RESULTS

Three to four parameters at different scales were significantly different according to the risk grade, mitosis rate, and the presence or absence of necrosis (p < 0.041). MPP at fine or medium scale (r = - 0.547 to - 393) and kurtosis at coarse scale (r = 0.424-0.454) correlated significantly with risk grade (p < 0.001). HG-GIST was best differentiated from LG-GIST by MPP at SSF 2 (AUC, 0.782), and kurtosis at SSF 4 (AUC, 0.779) (all p < 0.001). CT features predictive of HG-GIST were density lower than or equal to that of the erector spinae muscles on enhanced images (OR 2.1; p = 0.037; AUC, 0.59), necrosis (OR, 6.1; p < 0.001; AUC, 0.70), heterogeneity (OR, 4.3; p < 0.001; AUC, 0.67), and mucosal ulceration (OR, 3.3; p = 0.002; AUC, 0.62).

CONCLUSION

Using TexRAD, MPP and kurtosis are feasible in predicting risk grade and mitosis index of GISTs. CTTA demonstrated meaningful accuracy in preoperative risk stratification of GISTs.

New frontiers in the medical management of gastrointestinal stromal tumours

The tyrosine kinase inhibitor (TKI) imatinib has radically changed the natural history of KIT-driven gastrointestinal stromal tumours (GISTs). Approved second-line and third-line medical therapies are represented by the TKIs sunitinib and regorafenib, respectively. While imatinib remains the cardinal drug for patients with GISTs, novel therapies are being developed and clinically tested to overcome the mechanisms of resistance after treatments with the approved TKI, or to treat subsets of GISTs driven by rarer molecular events. Here, we review the therapy of GISTs, with a particular focus on the newest drugs in advanced phases of clinical testing that might soon change the current therapeutic algorithm.

Endoscopic Enucleation Is Effective and Relatively Safe in Small Gastric Subepithelial Tumors Originating from Muscularis Propria

BACKGROUND

Gastric subepithelial tumors originating from muscularis propria (MP) are usually benign, but some have malignant potential.

AIMS

The aim of this study was to evaluate the utility of endoscopic enucleation for the diagnosis and treatment of MP tumors.

PATIENTS AND METHODS

From January 2010 to February 2018, eighty patients with gastric MP tumors underwent endoscopic enucleation at our hospital. Band ligation and resection (BLR) or endoscopic muscularis resection (EMD) was performed based on considerations of tumor size (≤ 12 mm or > 12 mm). Tumor characteristics, procedure times, complete resection rates, adverse events and recurrence were analyzed.

RESULTS

Eighty patients with 82 lesions were eligible for inclusion in this study. BLR was used to treat 41 lesions. For these lesions, mean tumor size was 9.5 mm, median procedural time was 17.6 min (range 4-52), and the endoscopic complete resection rate was 100% (41/41). Perforation was developed in four patients, and was closed by endoscopic clipping. EMD was used to treat 41 lesions. Median procedure time was 66.1 min (range 12-260) and the endoscopic complete resection rate was 85.4% (35/41). Perforation occurred in eight patients, four patients received endoscopic treatment and four underwent surgery. Tumor recurrence was not observed in any patient over follow-up (mean 26.3 months).

CONCLUSION

Endoscopic enucleation appears to offer an effective, relatively safe means for diagnosing and treating gastric subepithelial tumors originating from the MP, and BLR provides a straightforward, effective, and relatively safe treatment for small MP tumors (≤ 12 mm).

Spectrum of the KIT Gene Mutations in Gastrointestinal Stromal Tumors in Arab Patients

Background: Gastrointestinal stromal tumors are the most common mesenchymal tumors of the gastrointestinal tract, which originate from the interstitial cells of Cajal. These tumors are characterized by expression of CD117 and CD34 antigens and activating mutations in the KIT and PDGFRA genes. While KIT and PDGFRA mutations have been extensively studied in other populations, the spectrum of mutations in Arab patients remains unknown. The study aimed at determining the distribution of KIT and PDGFRA mutations and phenotypic characterization of the gastrointestinal stromal tumors in Arab patients. Methods: Sanger sequencing was used to analyze 52 archived gastrointestinal stromal tumors for mutations in the KIT and the PDGFRA genes. Tumor descriptions were obtained from the clinical reports of patients. Results: In these patients, most tumors occur in the stomach, followed by the rest of the digestive tract. A vast majority of tumors express the CD117 and CD34 antigens. Sequencing of the KIT and PDGFRA genes identified five non-synonymous mutations and 26 deletions (25 novel) in exon 11 of the KIT gene. All non-synonymous mutations and deletions affect the juxta-membrane domain, which is known to inhibit ligand-independent activation of the KIT receptor. No mutations were found in the PDGFRA gene. Conclusions: Molecular profiling of the gastrointestinal stromal tumors in Arab patients identified a unique spectrum of mutations in exon 11 of the KIT gene. These data are important for the diagnosis and management of patients of Arab ethnic origin.

Endoscopic Full-thickness Resection for Gastric Subepithelial Tumors Originating From the Muscularis Propria: A 69-Case Series

OBJECTIVE

This report describes a mini-invasive technique called endoscopic full-thickness resection (EFR) for the treatment of gastric subepithelial tumors (SETs) originating from the muscularis propria (MP).

MATERIALS AND METHODS

We retrospectively analyzed 69 patients with gastric SETs originating from the MP at our hospital between September 2009 and July 2016. The data from each patient were reviewed, including patient information, tumor characteristics, procedure-related data, and recurrence rates.

RESULTS

Successful complete resection by EFR was achieved in 69 cases. The complete resection rate was 100%, and the mean resected tumor size was 2.25±1.40 (range, 0.6 to 6) cm. No residual tumor recurrence was detected during the follow-up period in 57 patients. The other 12 patients were lost to follow-up.

CONCLUSIONS

EFR seems to be a safe and effective technique for the treatment of patients with gastric SETs originating from the MP.

Clinicopathologic features and outcomes of gastrointestinal stromal tumors arising from the esophagus and gastroesophageal junction

Background

Our aim was to characterize the clinicopathological features and outcomes of gastrointestinal stromal tumors (GISTs) arising from the esophagus and gastroesophageal junction (GEJ) and describe the survival of patients treated at our institution as well as from a national hospital-based registry.

Methods

Twenty-eight cases were identified using the Mayo Clinic Cancer Registry from 1997 to 2016, and 1,010 cases from the National Cancer Database (NCDB) between 2004 and 2014, with analysis of TNM staging, histopathological features, mitotic index, immunohistochemical studies, and KIT mutational analysis.

Results

At Mayo Clinic, the tumors ranged in size from 0.3-13 cm (mean 5.40 cm). IHC results were: CD117 (KIT) in 100% (23/23 cases) and DOG1 in 100% (6/6), followed by CD34 (85.7%, 12/14), smooth muscle actin (27.8%, 5/18), desmin (18.2%, 2/11), and S-100 protein (13.3%, 2/15). Mutational analysis (performed in 10 cases) showed KIT exon 11 mutations in 8 cases; KIT mutation was not identified in 2 cases (presumed wild-type). Two-thirds of patients underwent surgery, of which 70% had an esophagectomy. Fourteen patients received adjuvant imatinib mesylate. Five patients had liver metastases at the time of diagnosis; none had lymph node metastases. A total of 38.9% of cases had recurrent or metastatic disease. Complete clinical follow-up was available for 10 patients (median follow-up duration 31.5 months; range, 10-145 months): one (male) had a local recurrence at the anastomotic site and one (female) suffered a liver metastasis; the others were either disease-free or had stable disease at the time of last follow-up. There was a significant association seen among metastatic disease and mitotic count >5/50 high-powered field (HPF) (P=0.016), with median mitotic rate 90/50 HPF (range, 7-500) for metastatic tumors versus 6/50 HPF (range, 0-100) for non-metastatic tumors. For metastatic disease, median tumor size was 7.3 cm (range, 1-66 cm) compared to 4.8 cm (range, 0.02-71 cm) for non-metastatic disease, which was also statistically significant (P≤0.0001). Two hundred and fifty-eight NCDB cases were risk stratified using the Joensuu criteria. Among 89 low risk category tumors, only 2 (2.2%) were ultimately metastatic. A total of 10.9% (15/138) of high risk category tumors were metastatic. The median overall survival (OS) from the time of diagnosis for the Mayo Clinic cohort was 129.5 months (95% CI, 55.7-not reached), with 5-year OS 85.7%. Median OS for the NCDB cohort was 135.95 months (95% CI, 104.08-not reached) with 5-year OS 68.2%. Superior OS was seen in females (HR 0.67, 95% CI, 0.49-0.89, P=0.006).

Conclusions

Among esophageal and GEJ GISTs, metastatic disease was associated with increased mitotic count and increased tumor size. Men were found to have inferior OS. The Joensuu risk criteria were validated for risk stratification of esophageal and GEJ GISTs.

Current clinical management of gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GISTs) are the most common malignant subepithelial lesions (SELs) of the gastrointestinal tract. They originate from the interstitial cells of Cajal located within the muscle layer and are characterized by over-expression of the tyrosine kinase receptor KIT. Pathologically, diagnosis of a GIST relies on morphology and immunohistochemistry [KIT and/or discovered on gastrointestinal stromal tumor 1 (DOG1) is generally positive]. The prognosis of this disease is associated with the tumor size and mitotic index. The standard treatment of a GIST without metastasis is surgical resection. A GIST with metastasis is usually only treated by tyrosine kinase inhibitors without radical cure; thus, early diagnosis is the only way to improve its prognosis. However, a GIST is usually detected as a SEL during endoscopy, and many benign and malignant conditions may manifest as SELs. Conventional endoscopic biopsy is difficult for tumors without ulceration. Most SELs have therefore been managed without a histological diagnosis. However, a favorable prognosis of a GIST is associated with early histological diagnosis and R0 resection. Endoscopic ultrasonography (EUS) and EUS-guided fine needle aspiration (EUS-FNA) are critical for an accurate diagnosis of SELs. EUS-FNA is safe and effective in enabling an early histological diagnosis and adequate treatment. This review outlines the current evidence for the diagnosis and management of GISTs, with an emphasis on early management of small SELs.

Cancer biomarker development and two-dimensional difference gel electrophoresis (2D-DIGE)

Cancer results from the accumulation of genomic alterations. As the genome is functionally translated to the proteome and regulates tumor cell behavior, proteomics studies are expected to further the current understanding of the molecular mechanisms underlying carcinogenesis and cancer progression. Biomarkers are potential tools to classify cancers for therapy, predict responses to treatments, and support treatment-related decision-making. Biomarker development has been actively pursued in oncology by proteomic approaches. Two-dimensional difference gel electrophoresis (2D-DIGE) is a proteomics technique based on two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). In 2D-DIGE, protein samples are labeled with distinct fluorescent dyes before fractionation via 2D-PAGE. 2D-DIGE offers advantages to identify biomarker candidates, including reproducibility, high sensitivity, comprehensiveness, and high throughput. 2D-DIGE has contributed to the establishment of tissue biomarkers, which potentially facilitate precision medicine. 2D-DIGE is thus expected to yield major advancements in cancer biomarker identification and development.

Two staging systems for gastrointestinal stromal tumors in the stomach: which is better?

Background

The prognosis of a gastrointestinal stromal tumor (GIST) is influenced by its anatomic site; however, few studies on the prognosis of gastric GISTs have been reported. The aims of this study were to evaluate long-term prognoses of patients who underwent surgical resection for gastric GISTs and to compare the clinical efficacy of two staging systems: the National Institutes of Health (NIH) consensus criteria and the 7th Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) tumor-node-metastasis (TNM) staging system.

Methods

We conducted a retrospective observational study of 145 patients who underwent surgical resection for gastric GISTs between February 2001 and June 2012 at Pusan National University Hospital (Busan, Korea). Recurrence and 5-year recurrence-free survival (RFS) rates were analyzed.

Results

During a median follow-up period of 44 months (range, 6–144 months), 11 recurrent lesions were detected in 9 patients (6.4%). On multivariate analysis, tumor size (>5 cm), mitotic count (>5/50 high-power fields), and epithelioid and mixed pathological type were significantly associated with recurrence. The overall 5-year RFS rate was 93.4%. Although no statistically significant differences were detected (C-statistic difference P = 0.886), all metrics showed lower values for the UICC/AJCC TNM staging system than for the NIH consensus criteria, suggesting that the UICC/AJCC TNM staging system may be a better model.

Conclusions

The 5-year RFS rate in patients who underwent curative resection for gastric GISTs was excellent. The UICC/AJCC TNM staging system may be more useful than the NIH consensus criteria for risk categorization of patients with gastric GISTs.

Submucosal Tunneling Endoscopic Resection vs Thoracoscopic Enucleation for Large Submucosal Tumors in the Esophagus and the Esophagogastric Junction

BACKGROUND

Submucosal tunneling endoscopic resection (STER) is regarded as a promising method for resection of submucosal tumors (SMTs); however, little is known about a comprehensive comparison of STER and thoracoscopic enucleation (TE). The aim of this study was to compare the clinical outcomes of STER and TE for large symptomatic SMTs in the esophagus and esophagogastric junction, as well as to analyze the factors that affect the feasibility and safety of STER.

STUDY DESIGN

We enrolled 166 patients with large symptomatic SMTs in the esophagus and esophagogastric junction from September 2011 to March 2016 in this retrospective study. The clinicopathologic features and treatment results were collected and analyzed.

RESULTS

En bloc resection was achieved in 84.6% of the patients in the STER group and 86.7% of the patients in the TE group (p = 0.708). Notably, the procedure time and hospital stay in the STER group were considerably shorter than those in the TE group. Tumor transverse diameter is a significant risk factor for piecemeal resection, adverse events, and technical difficulties. No recurrence or metastasis was found during a mean follow-up period of more than 2 years.

CONCLUSIONS

Submucosal tunneling endoscopic resection is effective and safe for large SMTs in the esophagus and esophagogastric junction. This procedure has the advantage of being more minimally invasive with a shorter procedure time and hospital stay compared with TE. Submucosal tunneling endoscopic resection for tumors with a transverse diameter ≥3.5 cm and an irregular shape is associated with relatively high risk for piecemeal resection, adverse events, and technical difficulties.

Familial gastrointestinal stromal tumors, lentigines, and café-au-lait macules associated with germline c-kit mutation treated with imatinib

BACKGROUND

Familial lentiginosis syndromes are characterized by a wide array of manifestations resulting from activation of molecular pathways which control growth, proliferation, and differentiation of a broad range of tissues. Familial gastrointestinal stromal tumors (GISTs) are often accompanied by additional features like hyperpigmentation, mastocytosis, and dysphagia. They have been described with mutations in c-kit (most commonly), platelet-derived growth factor receptor A, neurofibromatosis-1, and succinate dehydrogenase genes.

MATERIALS AND METHODS

We report on molecular characterization and tumor histopathology of two siblings in whom lentigines and café-au-lait macules were present along with multifocal GIST. Immuhistochemical analysis of CD34 and CD117 was performed on GIST biopsy samples from both siblings, while c-kit mutational analysis was done by PCR and direct sequencing on DNA from peripheral blood leukocytes of all family members and from paraffin-embedded gastric biopsy specimens of affected siblings.

RESULTS

Histopathology revealed positive expression of CD117 and CD34. Mutational analysis showed the germline c.1676T>C mutation in c-kit exon 11, (p.(Val559Ala)), in the peripheral blood of both siblings and a second exon 11 mutation, c.1669T>A (p.(Trp557Arg)) in the tumor biopsy of one of them. Initiation of imatinib treatment resulted in striking resolution of their hyperpigmentation and a stable gastrointestinal disease in one of them.

CONCLUSIONS

A c-kit mutational test in familial GISTs is indicated before initiation of imatinib therapy, as it can help predict tumor response to treatment.

Effectiveness and safety of endoscopic resection for gastric GISTs: a systematic review

AIMS

To evaluate the effectiveness and safety of endoscopic resection for gastric gastrointestinal stromal tumors (GISTs).

MATERIAL AND METHODS

The effectiveness and safety of endoscopic resection were mainly assessed by complete resection rate, postoperative adverse event rate, and recurrence rate. Moreover, a comparison of endoscopic with laparoscopic resection for gastric GISTs was made through weighted mean difference by STATA 12.0 with regard to operation time, blood loss, and length of stay after including patients who underwent endoscopic or laparoscopic resection for gastric GISTs in the comparative studies.

RESULTS

Eleven studies investigating endoscopic resection for GISTs were included. For stromal tumors <2 cm in average diameters the pooled rates of complete resection, postoperative adverse events and recurrence were 0.97, 0.08, and 0.03, respectively. Only five retrospective studies directly compared endoscopic with laparoscopic resection for gastric GISTs with average diameters from 1.1 cm to 3.8 cm, and endoscopic resection had a shorter operation time than laparoscopic resection, but there were no significant differences in intraoperative blood loss, length of stay, postoperative complications, and postoperative recurrence rates between the two approaches.

CONCLUSIONS

Endoscopic resection is predominantly tried for gastric GISTs of relatively small size. It seems effective and safe for gastric GISTs <2 cm in average diameter, with relatively short operation times.

Gastrointestinal Bleeding Is an Independent Risk Factor for Poor Prognosis in GIST Patients

A retrospective analysis of prognosis of GIST was used to assess the prognostic effects of hemorrhage of digestive tract induced by mucosal invasion of primary gastrointestinal stromal tumors and related mechanisms. The conclusion is that GISTs with gastrointestinal hemorrhage are more likely to recur, which indicates poor prognosis. Therefore, gastrointestinal hemorrhage may be used as a significant indicator to assess the prognosis of patients.

Elective Surgery of Umbilical Hernia as a First Clinical Manifestation of a Gastrointestinal Stromal Tumor (Gist) - Case Report

Gastrointestinal stromal tumor is a rare pathology. GISTs account for 0.3-1% of all tumors of the gastrointestinal tract. At the same time, this type of cancer is the most common, malignant, non-epithelial tumor of the gastrointestinal tube. Over 90% of GISTs are found in the stomach and small intestine. This cancer usually develops without characteristic clinical symptoms and is diagnosed incidentally. This clinical situation, in which the first symptom of a GIST-pattern tumor includes a fully-symptomatic, non-complicated umbilical hernia, is an unprecedented anomaly. This work presents a case report of a 77-year old female patient undergoing elective surgery, in which the contents of the hernial sac included a stromal tumor. Disseminated, multi-focal progression of the disease was found intraoperatively. Postoperative histopathology and immunohistochemistry revealed a gastrointestinal stromal tumor GIST of the spindle cell type, showing a CD-117, CD-34, SMA expression with possible starting point in the small intestine.

Endoscopic submucosal dissection for gastric gastrointestinal stromal tumors: a retrospective cohort study

BACKGROUND AND AIM

Endoscopic submucosal dissection (ESD) has been used to remove submucosal tumors. However, with regard to the potential malignant behavior of gastrointestinal stromal tumors (GISTs), whether ESD can be recommended for treatment is still controversial. Therefore, we evaluated the efficacy and safety of ESD for removal of GISTs in the muscularis propria (MP) layer and to assess the possible risk factors for a gastric-wall defect (GWD).

METHODS

For 168 GISTs located in the MP layer from 168 consecutive patients, the baseline information, complications, and therapeutic outcomes were recorded. Subsequently, risk factors for a GWD were analyzed.

RESULTS

Most GISTs (106/168) were located in the fundus of the stomach. Tumor shapes in 154 patients (91.7%) were regular, and the median size of the tumor was 1.5 (range 0.5-6.0) cm. The en bloc resection rate was 100% and the median procedure time was 46.5 (33-181) min. A GWD was observed in 71 patients (42.3%) and delayed bleeding occurred in 2 patients (1.2%), and they were treated by clips. A total of 117 patients with a GIST were at very low risk, 37 patients were at low risk, and 14 patients were at mild risk. No local recurrences or distant metastases were observed during a median follow-up of 25 (6-67) months. Univariate and multivariate logistic regression analyses identified the tumor type to be an independent risk factor for a GWD during ESD (odds ratio 29.82, 95% confidence interval 10.87-81.80, P < 0.001).

CONCLUSION

ESD is a safe and feasible method for gastric GISTs, especially for tumor types A and B. Endoscopic ultrasound can aid evaluation of the tumor type before ESD, which is an independent risk factor correlated with a GWD upon ESD.

Skeletal Muscle Metastasis of a GIST: A Case Report and Review of the Literature

Gastrointestinal stromal tumors (GISTs) are the most common malignant mesenchymal tumors of the gastrointestinal tract. The most common sites of metastasis are the liver and the peritoneum, whereas metastasis to soft tissue is rare. The authors present the case of a 78-year-old male with a soft tissue metastasis of a GIST and the current literature is reviewed.

Application of laparoscopy, endoscopy and laparoscopic and endoscopic cooperative surgery in gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) constitute the most common mesenchymal neoplasms of the gastrointestinal tract, among which 60%-70% are located in the stomach. All GISTs have malignant potential, varying from small lesions to aggressive sarcomas. Surgical resection with negative margins remains the best treatment for GISTs. Lymphadenectomy is not necessary because GISTs rarely metastasize to lymph nodes. Because of these biological behavior characteristics, the advantages of minimally invasive surgeries such as laparoscopic surgery and endoscopic surgery can be fully reflected in the surgical management of GISTs. The advent of laparoscopic and endoscopic cooperative surgery has broadened the scope and enhanced the safety of minimally invasive surgical treatment of GISTs. In this paper we will discuss the application of laparoscopy, endoscopy and laparoscopic and endoscopic cooperative surgery in the treatment of GISTs.

Application of novel endoloops to close the defects resulted from endoscopic full-thickness resection with single-channel gastroscope: a multicenter study

BACKGROUND

The key step of the endoscopic full-thickness resection (EFTR) procedure is the successful closure of any gastric wall defect which ultimately avoids surgical intervention. This report presents a new method of closing large gastric defects left after EFTR, using metallic clips and novel endoloops by means of single-channel endoscope.

METHODS

We retrospectively analyzed 68 patients who were treated for gastric fundus gastrointestinal stromal tumors originating from the muscularis propria layer at four institutes between April 2014 and February 2015 and consequently underwent EFTR. The large gastric post-EFTR defects were completely closed with metallic clips and novel endoloops using single-channel endoscope, and all the patients were discharged with subsequent endoscopic and clinical follow-up. Patient characteristics, tumor size, en bloc resection rate, closure operation time, and postoperative adverse events were evaluated.

RESULTS

EFTR was successfully performed on 68 patients [41 male (60 %), 27 female (40 %); median age 61 years, range 38-73], and the en bloc resection rate was 100 %. Complete closure of all the gastric post-EFTR defects was achieved (success rate 100 %). The mean closure operation time was 13 min (range 9-21 min). The mean maximum size of the lesions was 2.6 cm (range 2.0-3.5 cm). One Mallory-Weiss syndrome and one delayed bleeding were resolved with nonsurgical treatment. The wounds were healed in all cases 1 month after the procedure.

CONCLUSIONS

The use of metallic clips and novel endoloops with single-channel endoscope is a relatively safe, easy, and feasible method for repairing large gastric post-EFTR defects.