The cut-off value of tumor size and appropriate timing of follow-up for management of minimal EUS-suspected gastric gastrointestinal stromal tumors. BMC Gastroenterol. 2017;17:8. [PMID: 28077094 PMCID: PMC5225611 DOI: 10.1186/s12876-016-0567-4]

Results of the interim analysis of a prospective, multicenter, observational study of small subepithelial lesions in the stomach

OBJECTIVES

Long-term outcomes of gastric subepithelial lesions have not been elucidated. To reveal the natural history, we initiated a prospective, 10-year follow-up of patients with small (≤20 mm) gastric subepithelial lesions in September 2014. Here, we report the results of an interim analysis of a prospective observational study.

METHODS

In total, 567 patients with 610 lesions were prospectively registered between September 2014 and August 2016. The location, size, morphology, and number of subepithelial lesions were recorded on a web-based case report form. This study has been conducted as an Academic Committee Working Group of the Japan Gastroenterological Endoscopy Society.

RESULTS

The endoscopic follow-up period was 4.60 ± 1.73 years (mean ± standard deviation), and survival data were investigated for 5.28 ± 1.68 years. This interim analysis revealed that the estimated cumulative incidence of a size increase ≥5 mm, after accounting for patients' death and resection of the tumor as competing risk events, was 4.5% at 5 years. In addition, the estimated cumulative incidence of lesion size increase ≥5 mm or resection of lesions was 7.9% at 5 years, and that of size increase ≥10 mm or resection of lesions was 4.5% at 5 years.

CONCLUSION

These results indicate that approximately one in 13 patients with small (≤20 mm) gastric subepithelial lesions may require resection or further investigation for increased tumor size (≥5 mm) within 5 years.

Precutting endoscopic band ligation-assisted resection versus endoscopic submucosal dissection in patients with small gastric submucosal tumors originating from the muscularis propria: study protocol of a randomized controlled trial

BACKGROUND

The management of small gastric submucosal tumors (SMTs) originating from the muscularis propria layer (SMT-MPs) remains a subject of debate. Endoscopic submucosal dissection (ESD) is currently considered the optimal treatment for resection. However, high expenses, complex procedures, and the risk of complications have limited its application. Our previously proposed novel operation, precutting endoscopic band ligation (precutting EBL), has been demonstrated in a long-term, single-arm study to be an effective and safe technique for removing small gastric SMTs. However, the absence of a pathological examination and the potential for delayed perforation have raised concerns. Thus, we modified the precutting EBL by adding endoscopic resection to the snare after ligation and closure, yielding the precutting endoscopic band ligation-assisted resection (precutting EBLR). Moreover, the initial pilot study confirmed the safety and efficacy of the proposed approach and we planned a randomized controlled trial (RCT) to further validate its clinical feasibility.

METHODS

This was a prospective, single-center, open-label, parallel group, and randomized controlled trial. Approximately 40 patients with SMT-MPs will be included in this trial. The patients included were allocated to two groups: ESD and precutting EBLR. The basic clinical data of the patients were collected in detail. To better quantify the difference between ESD and precutting EBLR, the primary outcome was set as the operation duration. The secondary outcomes included total operation cost and hospitalization, intraoperative adverse events, and postoperative recurrence. The primary outcome was tested for superiority, while the secondary outcomes were tested for noninferiority. SPSS is commonly used for statistical analysis.

DISCUSSION

This study was designed to validate the feasibility of a novel operation for removing gastric SMT-MPs. To intuitively assess this phenomenon, the operation durations of precutting EBLR and ESD were compared, and other outcomes were also recorded comprehensively.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2200065473 . Registered on November 5, 2022.

Prevalence, natural progression, and clinical practices of upper gastrointestinal subepithelial lesions in Korea: a multicenter study

BACKGROUND/AIMS

This study aimed to evaluate the prevalence and natural progression of subepithelial lesions (SELs) in the upper gastrointestinal (UGI) tract.

METHODS

The medical records of patients with UGI SELs who underwent endoscopic screening at eight university hospitals between January and December 2010 were retrospectively investigated. The follow-up evaluations were performed until December 2016.

RESULTS

UGI SELs were found in 1,044 of the 65,233 participants screened (endoscopic prevalence, 1.60%; the total number of lesions, 1,062; mean age, 55.1±11.2 years; men, 53.6%). The median follow-up period was 48 (range, 8-74) months. SELs were most frequently found in the stomach (63.8%) and had a mean size of 9.9±6.1 mm. Endoscopic ultrasonography (EUS) was performed in 293 patients (28.1%). The most common lesions were leiomyomas, followed by gastrointestinal stromal tumors (GISTs), and ectopic pancreas. The proportions of SELs with malignant potential according to size were 3% (<1 cm), 22% (1-2 cm), 27% (2-3 cm), and 38% (≥3 cm). In gastric SELs larger than 1 cm, resections were performed in 20 patients because of an increase in size, of which 12 were found to be GISTs.

CONCLUSION

The prevalence of UGI SELs was 1.60%. Further, 23% of gastric SELs ≥1 cm were precancerous lesions, most followed by EUS and clinical decisions without initial pathological confirmation.

Efficacy and safety of endoscopic "calabash" ligation and resection for small gastric stromal tumors originating from the muscularis propria

AIM

We compared endoscopic "calabash" ligation and resection (ECLR) and endoscopic submucosal excision (ESE) in treating endophytic gastric stromal tumors (GSTs) ≤15 mm in diameter originating from the muscularis propria.

METHODS

We performed a retrospective study and included patients who visited our hospital for removal of small endophytic GSTs (diameter ≤ 15 mm) confirmed by postoperative pathological reports between February 2019 and December 2020. Patients were assigned to the study (received ECLR) or control (accepted ESE) groups, and their medical records were reviewed. Age, sex, GST size, resection outcomes, procedure measurements, lengths of hospital stays, medical expenses, intraoperative and postoperative complications, and follow-up outcomes were documented and compared between the two groups. Propensity score matching was used to avoid retrospective biases.

RESULTS

A total of 277 patients were included in the analysis, with 135 in the study group and 142 in the control group. After propensity score matching, 119 cases in each group were finally included in the study. Compared to the control group, the study group had significantly shorter procedure durations and lengths of hospital stays, as well as reduced medical expenses. Compared to the control group, the study group also had significantly lower incidence rates of intraoperative stomach perforation, postoperative intraperitoneal infection, and postoperative electrocoagulation syndrome, as well as a lower intensity of postoperative pain. There were no significant differences in the other measurements between the two groups.

CONCLUSION

ECLR is an effective and safe procedure for treating patients with endophytic GSTs ≤15 mm in diameter originating from the muscularis propria.

Small Gastric Stromal Tumors: An Underestimated Risk

BACKGROUND AND OBJECTIVES

Small gastrointestinal stromal tumors (GISTs) are defined as tumors less than 2 cm in diameter, which are often found incidentally during gastroscopy. There is controversy regarding the management of small GISTs, and a certain percentage of small GISTs become malignant during follow-up. Previous studies which used Sanger targeted sequencing have shown that the mutation rate of small GISTs is significantly lower than that of large tumors. The aim of this study was to investigate the overall mutational profile of small GISTs, including those of wild-type tumors, using whole-exome sequencing (WES) and Sanger sequencing.

METHODS

Thirty-six paired small GIST specimens, which were resected by endoscopy, were analyzed by WES. Somatic mutations identified by WES were confirmed by Sanger sequencing. Sanger sequencing was performed in an additional 38 small gastric stromal tumor samples for examining hotspot mutations in KIT, PDGFRA, and BRAF.

RESULTS

Somatic C-KIT/PDGFRA mutations accounted for 81% of the mutations, including three novel mutation sites in C-KIT at exon 11, across the entire small gastric stromal tumor cohort (n = 74). In addition, 15% of small GISTs harbored previously undescribed BRAF-V600E hotspot mutations. No significant correlation was observed among the genotype, pathological features, and clinical classification.

CONCLUSIONS

Our data revealed a high overall mutation rate (~96%) in small GISTs, indicating that genetic alterations are common events in early GIST generation. We also identified a high frequency of oncogenic BRAF-V600E mutations (15%) in small GISTs, which has not been previously reported.

Efficacy of endoscopic ultrasound in the evaluation of small gastrointestinal stromal tumors

BACKGROUND

Gastrointestinal stromal tumors (GISTs) with a diameter of < 2 cm are called small GISTs. Currently, endoscopic ultrasound (EUS) is widely used as a regular follow-up method for GISTs, which can also provide a preliminary basis for judging the malignancy potential of lesions. However, there are no studies on the accuracy of EUS to assess the malignant potential of small GISTs.

AIM

To evaluate the efficacy of EUS in the diagnosis and risk assessment of small GISTs.

METHODS

We collected data from patients with small GISTs who were admitted to Shengjing Hospital of China Medical University between October 2014 and July 2019. The accurate diagnosis and risk classifications of patients were based on the pathological assessment according to the modified National Institute of Health criteria after endoscopic resection or laparoscopic surgery. Preoperative EUS features (marginal irregularity, cystic changes, homogeneity, ulceration, and strong echogenic foci) were retrospectively analyzed. The assessment results based on EUS features were compared with the pathological features.

RESULTS

A total of 256 patients (69 men and 187 women) were enrolled. Pathological results included 232, 16, 7, and 1 very low-, low-, intermediate-, and high-risk cases, respectively. The most frequent tumor location was the gastric fundus (78.1%), and mitoses were calculated as > 5/50 high power field in 8 (3.1%) patients. Marginal irregularity, ulceration, strong echo foci, and heterogeneity were detected in 1 (0.4%), 2 (0.8%), 22 (8.6%), and 67 (65.1%) patients, respectively. However, cystic changes were not detected. Tumor size was positively correlated with the mitotic index (P < 0.001). Receiver operating curve analysis identified 1.48 cm as the best cut-off value to predict malignant potential (95% confidence interval: 0.824–0.956). EUS heterogeneity with tumor diameters > 1.48 cm was associated with higher risk classification (P < 0.05).

CONCLUSION

Small GISTs (diameters > 1.48 cm) with positive EUS features should receive intensive surveillance or undergo endoscopic surgery. EUS and dissection are efficient diagnostic and therapeutic approaches for small GISTs.

Advances in endoscopic resection techniques of small gastric tumors originating from the muscularis propria

Gastrointestinal stromal tumors are common gastrointestinal tumors typically originating from the muscularis propria layer of the stomach. Small gastric stromal tumors are usually detected incidentally during routine endoscopic examination. Although they may have malignant potentially, controversies remain regarding the need for endoscopic resection of small gastric stromal tumors originating from the muscularis propria. According to the guidelines of the European Society of Medical Oncology, all gastrointestinal stromal tumors >2 cm in size should be resected with endoscopic surveillance recommended for tumors <2 cm. Endoscopic resection including endoscopic mucosal dissection (EMD), endoscopic submucosal dissection (ESD), submucosal tunneling endoscopic resection and snare assisted endoscopic resection. However, EMD and ESD procedures may be accompanied with serious complications including perforation, bleeding, and abdominal infection. Snare-assisted endoscopic resection is an alternative approach and has the advantages of a shorter procedure time and a low rate of perforation or bleeding. This study summarizes the safety and feasibility of a novel snare-assisted endoscopic resection technique and highlights the pros and cons of the different endoscopic approaches currently used for subepithelia small gastric tumors.

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.

Efficiency of an endoscopic resection strategy for management of submucosal tumors < 20 mm in the upper gastrointestinal tract

Background and study aims  The histologic diagnosis of submucosal tumors (SMTs) < 20 mm is challenging. Monitoring is the main option offered, but compliance is debatable. Endoscopic resection (ER) of malignant SMTs or those with an uncertain diagnosis is an alternative that has already been reported about and proposed in our center. The aims of this study were to confirm the safety of this resection strategy and to perform long-term follow-up of malignant SMTs after resection. Patients and methods  All patients who underwent ER for SMTs < 2 cm in a single center between 2007 and 2019 were included retrospectively. Patients were classified into two groups according to the need for postresection follow-up: benign SMTs (B-SMTs) and follow-up SMTs (FU-SMTs). Results  One hundred and one patients were included. The mean tumor size was 16.7 mm. In total, 92 of 101 SMTs had an uncertain diagnosis. Macroscopic resection was completed for 95 SMTs (93.1 %), with en bloc resection in 94 (92.1%). The morbidity rate was 3 %, with no mortality. A total of 84 of 101 SMTs (84 %) were B-SMTs and did not need monitoring, and 17 SMTs (19.7 %) were FU-SMTs (8 gastrointestinal stromal tumors, 6 neuroendocrine tumors, and 3 others). No relapse was reported in the FU-SMT group, with a median follow-up duration of 33 months [4-127] (61 months [17-127] for the gastrointestinal stroma tumor group). Conclusions  The study results suggest ER is a potentially reliable and effective strategy for upper gastrointestinal tract SMTs < 20 mm. Although the strategy needs further validation in advanced care units, it could eliminate the need for long-term monitoring, therefore targeting such follow-up efforts to patients with FU-SMTs.

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

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

Efficacy and safety of endoscopic resection in treatment of small gastric stromal tumors: A state-of-the-art review

Gastrointestinal stromal tumors can occur in any part of the gastrointestinal tract, but gastric stromal tumors (GSTs) are the most common. All GSTs have the potential to become malignant, and these can be divided into four different grades by risk from low to high: Very low risk, low risk, medium risk, and high risk. Current guidelines all recommend early complete excision of GSTs larger than 2 cm in diameter. However, it is not clear whether small GSTs (sGSTs, i.e., those smaller than 2 cm in diameter) should be treated as early as possible. The National Comprehensive Cancer Network recommends that endoscopic ultrasonography-guided (EUS-guided) fine-needle aspiration biopsy and imaging (computed tomography or magnetic-resonance imaging) be used to assess cancer risk for sGSTs detected by gastroscopy to determine treatment. When EUS indicates a higher risk of tumor, surgical resection is recommended. There are some questions on whether sGSTs also require early treatment. Many studies have shown that endoscopic treatment of GSTs with diameters of 2-5 cm is very effective. We here address whether endoscopic therapy is also suitable for sGSTs. In this paper, we try to explain three questions: (1) Does sGST require treatment? (2) Is digestive endoscopy a safe and effective means of treating sGST? and (3) When sGSTs are at different sites and depths, which endoscopic treatment method is more suitable?

Preoperative imaging of gastric GISTs underestimates pathologic tumor size: A retrospective, single institution analysis

BACKGROUND

How well imaging size agrees with pathologic size of gastric gastrointestinal stromal tumors (GISTs) is unknown. GIST risk stratification is based on pathologic size, location, and mitotic rate. To inform decision making, the size discrepancy between imaging and pathology for gastric GISTs was investigated.

METHODS

Imaging and pathology reports were reviewed for 113 patients. Bland-Altman analyses and intraclass correlation (ICC) assessed agreement of imaging and pathology. Changes in clinical risk category due to size discrepancy were identified.

RESULTS

Computed tomography (CT) (n = 110) and endoscopic ultrasound (EUS) (n = 50) underestimated pathologic size for gastric GISTs by 0.42 cm, 95% confidence interval (CI): (0.11, 0.73), p = 0.008 and 0.54 cm, 95% CI: (0.25, 0.82), p < 0.001, respectively. ICCs were 0.94 and 0.88 for CT and EUS, respectively. For GISTs ≤ 3 cm, size underestimation was 0.24 cm for CT (n = 28), 95% CI: (0.01, 0.47), p = 0.039 and 0.56 cm for EUS (n = 26), 95% CI: (0.27, 0.84), p < 0.0001. ICCs were 0.72 and 0.55 for CT and EUS, respectively. Spearman's correlation was ≥0.84 for all groups. For GISTs ≤ 3 cm, 6/28 (21.4% p = 0.01) on CT and 7/26 (26.9% p = 0.005) on EUS upgraded risk category using pathologic size versus imaging size. No GISTs ≤ 3 cm downgraded risk categories. Size underestimation persisted for GISTs ≤ 2 cm on EUS (0.39 cm, 95% CI: [0.06, 0.72], p = 0.02, post hoc analysis).

CONCLUSION

Imaging, particularly EUS, underestimates gastric GIST size. Caution should be exercised using imaging alone to risk-stratify gastric GISTs, and to decide between surveillance versus surgery.

Over-the-Scope Clip-Associated Endoscopic Muscular Dissection for Seven Cases of Small Gastric Submucosal Tumor: A Video-Based Case Series

Objectives

To evaluate the methodology, feasibility, safety, and efficacy of a novel method called over-the-scope clip- (OTSC-) associated endoscopic muscular dissection for small GSMT.

Methods

A pilot study on small GSMT diameter ≤ 1 cm was performed. OTSC-associated endoscopic muscular dissection was based on the requirement of OTSC apparatus and ESD technique; after ligaturing the bottom of small GSMT by OTSC, ESD was performed to resect the tumors, and the wounds of ESD were closed by clips finally. All the patients were followed up for more than 3 months, and the complications during and after OTSC-associated endoscopic muscular dissection were recorded.

Results

A total of 7 consecutive patients with small GSMT were included. All tumors were completely dissected without any perforation or infection during and after the procedure in all cases, while three patients had mild abdominal pain, and one experienced postoperative bleeding after the procedure which was treated by the endoscopy with titanium clips. All the patients were followed by endoscopy three months later, all the wounds healed well, and all the OTSCs were still in the gastric wall.

Conclusions

OTSC-associated endoscopic muscular dissection as a novel endoscopic interventional therapy should be a convenient, safe, and effective therapy for small GSMT. The short-time outcome is excellent, whereas long-term effect is unclear, and the further follow-up is needed to schedule.

Controversies in EUS: Do we need miniprobes?

This is the fifth in a series of papers entitled "Controversies in EUS." In the current paper, we deal with high-resolution catheter probes, otherwise known as EUS miniprobes (EUS-MPs). The application of miniprobes for early carcinomas in the entire intestinal tract, for subepithelial lesions, and for findings in the bile duct and pancreatic duct as well as endobronchial use is critically discussed. Submucous lesions, especially in the colon, but also early carcinomas in special cases are considered the most important indications. The argument is illustrated by numerous examples.

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.

Gastrointestinal stromal tumor of the excluded stomach after Roux-en-Y gastric bypass: A case report and literature review

•

This is the second reported case of GIST post-RYGB.

•

GISTs generally present good prognosis after surgical resection.

•

The case reported after RYGB did not present the patient follow-up.

•

The case reported after gastric banding presented recurrence 3 years after resection.

Background

Gastric cancer is an extremely rare condition to occur after bariatric surgery, and most of the reported cases are adenocarcinomas. Regarding gastrointestinal stromal tumors (GISTs), there are only two reported cases occurring after bariatric surgery (one after gastric banding and the other following Roux-en-Y gastric bypass (RYGB)).

Case presentation

A 48-year-old woman with previous history of obesity and type 2 diabetes, treated with a Roux-en-Y gastric bypass 2 years earlier, was referred to our center due to complains of diffuse abdominal pain and distension associated with asthenia. Magnetic resonance imaging showed a cystic-solid mass located in the right hypochondrium, measuring 19.5 × 13.5 × 16 cm, suggesting the diagnosis of a retroperitoneal tumor. Based on these findings, a laparotomy, evidencing that the larger cystic-solid tumor was originating from the excluded stomach post-RYGB. The gastrectomy of the excluded stomach was performed aside with a conventional cholecystectomy. Histopathology and immunohistochemistry confirmed to be a gastric GIST with epithelioid cells. Currently, 12 months after surgery, the patient presents no signs of recurrence.

Conclusion

This is the second case of gastric GIST occurring after RYGB to be reported in the literature.

Which size is the best cutoff for primary small gastric gastrointestinal stromal tumor?

Background

The biological behavior of primary small gastric gastrointestinal stromal tumor (gGIST) is indolent. The cutoff size categorizing small gGIST continues to be controversial. To date, there is no consensus regarding whether it should be 1 cm, 2 cm, or another size. We aimed to find a new cutoff size.

Methods

Retrospective clinicopathological and prognosis data of patients with small gGIST from January 1998 to January 2015 were collected among five medical centers in southern China. Tumor size was divided into two groups: <1 cm (Mirco group) and 1-2 cm (Small group). We compared the clinicopathological index and prognosis between these two groups and identified a new cutoff size to define small gGIST.

Results

During this 18-year period, there were 276 patients with primary small gGIST treated at these five medical centers. The range of tumor size was 0.2-2.0 cm. The median tumor size was 1.0 cm. The range of the mitotic count was 0-70/50 high power fields (HPFs) with counts ≤5/50 HPFs in 259 patients (93.8%), 5< counts ≤10/50 HPFs in 7 patients (2.5%), and counts >10/50 HPFs in 10 patients (3.6%). The median follow-up time was 38 months (3-156 months). The 5-year overall survival rate was 98.7% in the entire group. Using Pearson correlation analysis, there was a positive correlation between the mitotic count and tumor size as a continuous variable (r=0.164, P=0.006). There were 137 patients in the Micro group and 139 cases in the Small group. In the Micro group, mitotic counts were ≤5/50 HPFs in 134 patients, 5< counts ≤10/50 HPFs in 0 patients, and counts >10/50 HPFs in 3 patients; mitotic counts in the Small group were counts ≤5/50 HPFs in 125 patients, 5< counts ≤10/50 HPFs in 7 patients, >10/50 HPFs in 7 patients. There was a statistically significant difference between these two groups (P=0.002); the Small group had more intermediate/high-risk cases. Using the receiver operating characteristic curve (ROC curve), we observed that 1.15 cm was the new cutoff size to separate low-risk cases and intermediate/high-risk cases (AUC =0.707, P=0.004, sensitivity =0.824, 1-specificity =0.429).

Conclusions

Primary small gGIST has a good prognosis; gGIST <1 cm can be regarded as benign tumors that only requires endoscopic ultrasonography (EUS) follow-up. The proportion of potential intermediate/high-risk disease is high for patients with 1-2 cm gGIST. These patients should be treated with caution and the tumors should be resected if necessary. These results indicate that 1.15 cm may be the new cutoff size to separate small gGIST from large gGIST, but further studies are needed for verification.

Clinicopathological Features and Prognosis of Small Gastric Gastrointestinal Stromal Tumors (GISTs)

BACKGROUND

The aim of the present study was to evaluate the safety of endoscopic surgery, the clinicopathological features, and prognoses of small gastric gastrointestinal stromal tumors (GISTs).

METHODS

Small gastric GIST patients (diameter: 0.10-2.00 cm) resected endoscopically in Zhongshan Hospital were retrospectively identified and clinicopathological features and outcomes were collected. The relationship between clinicopathological characteristics and tumor recurrence was analyzed. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal tumor diameter for predicting malignant potential.

RESULTS

All lesions were completely removed by endoscopy and En bloc resection was 98.5%. The most frequent location was the gastric fundus (60.3%) and the average diameter of all lesions was 1.20 cm (range: 0.10-2.00 cm). Mitoses were calculated as more than 5/50 HPF in 44 (6.8%) patients and nuclear atypia was moderate in 243 (37.5%) patients, severe in 1 (0.2%). Necrosis, mucosal infiltration, and vascular infiltration were detected in 8 (1.2%), 5 (0.7%), and 3 (0.5%) patients, respectively. Tumor size was positively correlated with mitotic index (P < 0.001) and nuclear atypia (P < 0.001). After a median follow-up of 54 months, four patients were confirmed local recurrence. ROC curve analysis identified 1.45 cm as the best cut-off value to predict malignant potential (95% CI: 0·694-0·774). Survival analysis showed that patients with tumor diameters larger than 1.45 cm were associated with more local recurrences after resection (P = 0.011).

CONCLUSIONS

Endoscopic surgery is feasible and safe for small gastric GISTs, especially those in favorable locations. Small gastric GISTs bear a good prognosis as a whole but those with diameters larger than 1.45 cm should receive more intensive surveillance or undergo endoscopic surgery.

Endoscopic full-thickness resection (EFTR) without laparoscopic assistance for nonampullary duodenal subepithelial lesions: our clinical experience of 32 cases

BACKGROUND

Standard treatment for nonampullary duodenal tumors has not yet been established. In case of tumors originated from the muscularis propria (MP) layer and adherent to the serosa layer, the lesions can not be completely removed by ESD. However, with the development of the endoscopic suture technique, endoscopic full-thickness resection (EFTR) of duodenal subepithelial lesions has become possible.

METHODS

We retrospectively analyzed 32 patients with nonampullary duodenal subepithelial lesions who underwent EFTR between February 2012 and January 2017. The suturing method, complications that occurred during and after the operations, perioperative management, tumor characteristics, and pathological findings were analyzed in all patients.

RESULTS

The complete resection rate was 100%; all patients successfully received EFTR except for one patient who required conversion to open surgery. Severe abdominal pain was observed after the operation in one patient who then received laparoscopic exploration, and the possibility of delayed perforation was considered. Another patient showed a decline in blood oxygen saturation (SO₂) and was transferred to the intensive care unit (ICU) for further management. Delayed bleeding and fistula were not observed. All patients achieved complete remission.

CONCLUSION

EFTR is a safe, minimally invasive treatment modality that ensures complete eradication of the duodenal subepithelial lesions.

Clinicopathological features and prognosis of 276 cases of primary small (≤ 2 cm) gastric gastrointestinal stromal tumors: a multicenter data review

BACKGROUND

Till present, there are still controversies over the epidemiology, pathological features, types of surgical treatment, and prognoses of primary small gastric GISTs (gGISTs).

METHODS

From January 1998 to January 2015, patients with primary small gGIST admitted from four high-volume medical centers of the Southern China were enrolled and their data were analyzed to evaluate their clinicopathological features, treatment and prognostic factors to provide evidence-based medical experience for clinical practice.

RESULTS

A total of 276 primary small gGIST cases over a period of 18 years were investigated and had a median age of 60 years (range 27-91 years old). Regarding the tumor sites, 24 (8.7%) cases were in the cardia of the stomach, 107 (38.8%) in the fundus, 117 (42.4%) in the gastric body, and 28 (10.1%) in the gastric antrum. Eleven patients (4.0%) underwent a preoperative biopsy. A total of 137 (49.6%), 75 (27.2%), and 64 (23.2%) patients underwent laparoscopic, open resection, and endoscopic resection, respectively. Sixty-four patients (23.2%) had local endoscopic resection, 172 (62.3%) had wedge resection, 7 (2.5%) had proximal gastrectomy, 19 (6.9%) had distal gastrectomy, and 14 (5.1%) had total gastrectomy. Mitotic counts were ≤ 5/50, (5-10)/50, and > 10/50 per HPF in 259 (93.8%), 7 (2.5%), and 10 (3.6%) cases, respectively. There were 259 cases (97.1%) of spindle cell type, 7 (2.5%) epithelial cell types and one case (0.4%) of mixed type. Immunohistochemistry showed 74.6% (206/276), 98.2% (271/276), and 97.4% (269/276) of the patients had co-expression of CD34+, CD117+, and DOG-1+, respectively. Thirty-nine patients underwent genetic testing (39/276, 14.1%). Three patients (1.1%) had positive resection margin. Five high-risk patients received follow-up treatment with imatinib with a median follow-up time of 38 months (range 3-156 months). The overall 1-, 3-, and 5-year overall survival rates were 100%, 99.6%, and 99.1%, respectively.

CONCLUSION

Though the incidence of primary small gGISTs increased per annum, the overall survival prognoses were high. Surgery or endoscopic resection was the primary mode of treatment. Pathological features of primary small gGISTs were similar to large gGISTs, and to achieve a timely surgical intervention, the identification of intermediate- and high-risk cases should be a future focus of study.

Evaluation of pancreatic tumor development in KPC mice using multi-parametric MRI

Background

Pancreatic ductal adenocarcinoma (PDA) is a fatal disease with very poor prognosis. Development of sensitive and noninvasive methods to monitor tumor progression in PDA is a critical and unmet need. Magnetic resonance imaging (MRI) can noninvasively provide information regarding underlying pathophysiological processes such as necrosis, inflammatory changes and fibrotic tissue deposition.

Methods

A genetically engineered KPC mouse model that recapitulates human PDA was used to characterize disease progression. MR measures of T₁ and T₂ relaxation times, magnetization transfer ratio (MTR), diffusion and chemical exchange saturation transfer were compared in two separate phases i.e. slow and rapid growth phase of tumor. Fibrotic tissue accumulation was assessed histologically using Masson’s trichrome staining. Pearson correlation coefficient (r) was computed to assess the relationship between the fibrotic tissue accumulation and different MR parameters.

Results

There was a negative correlation between amide proton transfer signal intensity and tumor volume (r = − 0.63, p = 0.003) in the slow growth phase of the tumor development. In the terminal stage of rapid growth phase of the tumor development MTR was strongly correlated with tumor volume (r = 0.62, p = 0.008). Finally, MTR was significantly correlated with % fibrosis (r = 0.87; p < 0.01), followed by moderate correlation between tumor volume (r = 0.42); T₁ (r = − 0.61), T₂ (r = − 0.61) and accumulation of fibrotic tissue.

Conclusions

Here we demonstrated, using multi-parametric MRI (mp-MRI), that MRI parameters changed with tumor progression in a mouse model of PDA. Use of mp-MRI may have the potential to monitor the dynamic changes of tumor microenvironment with increase in tumor size in the transgenic KPC mouse model of pancreatic tumor.

Electronic supplementary material

The online version of this article (10.1186/s40644-018-0172-6) contains supplementary material, which is available to authorized users.

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.

Chinese consensus guidelines for diagnosis and management of gastrointestinal stromal tumor

In order to further promote the standardization of diagnosis and treatment of gastrointestinal stromal tumor (GIST) in China, the members of Chinese Society of Clinical Oncology (CSCO) Expert Committee on GIST thoroughly discussed the key contents of the consensus guidelines, and voted on the controversial issue. In final, the Chinese consensus guidelines for the diagnosis and management of GIST (2017 edition) was formed on the basis of 2013 edition consensus guidelines, which is hereby announced. The consensus included the pathological diagnosis, recurrence risk classification evaluation, targeted agent therapy, surgery and principles of surveillance of GIST.