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

Development and validation of a machine-learning model for preoperative risk of gastric gastrointestinal stromal tumors

BACKGROUND

Gastrointestinal stromal tumors (GISTs) have malignant potential, and treatment varies according to risk. However, no specific protocols exist for preoperative assessment of the malignant potential of gastric GISTs (gGISTs). This study aimed to use machine learning (ML) to develop and validate clinically relevant preoperative models to predict the malignant potential of gGISTs.

METHODS

This study screened patients diagnosed with gGISTs at the Affiliated Hospital of North Sichuan Medical College. Moreover, this study employed the Least Absolute Shrinkage and Selection Operator (LASSO) and logistic regression to identify risk factors. Subsequently, an ensemble of ML models was used to determine the optimal classifier. In addition, this study used SHapley Additive exPlanations (SHAP) for tailored risk profiling.

RESULTS

This study included 318 patients with gGISTs. Using LASSO regression and multifactorial logistic regression, this study analyzed the training dataset, revealing that the presence of endoscopic ultrasound (EUS) high-risk features, tumor border clarity, tumor diameter, and monocyte-to-lymphocyte ratio (MLR) were significant predictors of high malignancy risk in gGIST. As determined by our ML approach, the logistic classification model demonstrated optimal performance, with area under the receiver operating characteristic curves of 0.919 for the training set and 0.925 for the test set. Furthermore, decision curve analysis confirmed the clinical relevance of the model.

CONCLUSION

High-risk EUS features, ill-defined tumor margins, larger tumor diameters, and elevated MLR independently predicted increased malignant potential in gGIST. This study developed logistic regression models based on these factors, which were further interpreted using the SHAP methodology. This analytical approach facilitated personalized therapeutic decision-making among diverse patient populations.

Patterns of Care and Outcomes of Patients with Small Gastrointestinal Stromal Tumors at a High-Volume Sarcoma Center

BACKGROUND

The course of subclinical gastrointestinal stromal tumors (GISTs) is variable. The management of small GISTs is not well-defined.

METHODS

Records of patients presenting with small GISTs with documented follow-up appointment at our institution between 2016 and 2022 were identified and reviewed. Comparative univariate analysis to compare patient and tumor characteristics and outcomes was performed.

RESULTS

Eighty-six patients were followed for a median of 3.7 years (range 0.1-20 years). The median size at presentation was 1.7 (range 0.1-2.5) cm. A total of 51.2% (n = 44) underwent surgery before or immediately after initial presentation for pain (18.2%), bleeding (15.9%), or patient preference (6.8%). Another 17.4% (n = 15) had delayed surgery for tumor growth (40%), patient preference (2.7%), bleeding (6.7%), or pain (6.7%). The remaining 31.4% (n = 27) of patients never underwent surgery for reasons that included no growth/stability (44.4%), concomitant cancer diagnosis/treatment (29.6%), comorbidities (14.8%), and patient preference (3.7%). Patients who underwent surveillance without intervention compared with those who had delayed surgery were older (71.1 vs. 60.8 years, p < 0.001) with multiple comorbidities or a concurrent cancer diagnosis (70.3% vs. 20%, p = 0.005). There were no differences in survival or rate of distant metastases. Average time to surgery in the delayed group was 2 (range 0.1-10.3) years, and 86% of these patients underwent surgery by 5.5 years after diagnosis.

CONCLUSIONS

In older patients with comorbidities or concurrent cancer diagnoses, opting out of surgery does not affect survival. Conversely, younger patients, free from significant comorbidities or other diagnoses, may consider surgery or active surveillance for up to 5 years, with comparable outcomes.

Development and validation of a preoperative risk nomogram prediction model for gastric gastrointestinal stromal tumors

BACKGROUND AND STUDY AIMS

Gastrointestinal stromal tumors (GIST) carry a potential risk of malignancy, and the treatment of GIST varies for different risk levels. However, there is no systematic preoperative assessment protocol to predict the malignant potential of GIST. The aim of this study was to develop a reliable and clinically applicable preoperative nomogram prediction model to predict the malignant potential of gastric GIST.

PATIENTS AND METHODS

Patients with a pathological diagnosis of gastric GIST from January 2015 to December 2021 were screened retrospectively. Univariate and multivariate logistic analyses were used to identify independent risk factors for gastric GIST with high malignancy potential. Based on these independent risk factors, a nomogram model predicting the malignant potential of gastric GIST was developed and the model was validated in the validation group.

RESULTS

A total of 494 gastric GIST patients were included in this study and allocated to a development group (n = 345) and a validation group (n = 149). In the development group, multivariate logistic regression analysis revealed that tumor size, tumor ulceration, CT growth pattern and monocyte-to- lymphocyte ratio (MLR) were independent risk factors for gastric GIST with high malignancy potential. The AUC of the model were 0.932 (95% CI 0.890-0.974) and 0.922 (95% CI 0.868-0.977) in the development and validation groups, respectively. The best cutoff value for the development group was 0.184, and the sensitivity and specificity at this value were 0.895 and 0.875, respectively. The calibration curves indicated good agreement between predicted and actual observed outcomes, while the DCA indicated that the nomogram model had clinical application.

CONCLUSIONS

Tumor size, tumor ulceration, CT growth pattern and MLR are independent risk factors for high malignancy potential gastric GIST, and a nomogram model developed based on these factors has a high ability to predict the malignant potential of gastric GIST.

Endoscopic resection for the treatment of gastric gastrointestinal stromal tumors: a retrospective study from a large tertiary hospital in China

BACKGROUND AND AIMS

With the continuous development of endoscopic technology, endoscopic resection (ER) has gradually become an optional method for the treatment of gastric gastrointestinal stromal tumors (GISTs). However, studies with a large sample or a long follow-up are lacking. Therefore, this research aims to evaluate the efficacy and safety of ER for gastric GISTs in the real-world setting with more than 300 enrolled patients and a follow-up period longer than 45 months.

METHODS

From January 2013 to February 2023, 409 patients with a pathological diagnosis of GISTs after ER were retrospectively enrolled in this study. After excluding 86 patients with non-gastric GISTs, we assessed 323 patients with gastric GISTs. The main outcome measures were en bloc resection, complete resection, residual disease, recurrence, and complications.

RESULTS

There were 194 (60.06%) females and 129 (39.94%) males, and the median age of the included patients was 58 years (51, 63). The median tumor size was 15.0 (10.0, 20.0) mm. According to the modified NIH criteria, 246 (75.85%) patients were classified as very low risk, 62 (19.20%) were classified as low risk, 12 (3.72%) were classified as moderate risk, and 3 (0.93%) were classified as high risk. A total of 287 (88.85%) patients achieved en bloc resection, and 287 (88.85%) also achieved complete resection. Only one patient showed residual and no recurrent lesions were noted during the follow-up. Regarding complications, three patients had complications, with a complication rate of 0.93%, and no severe complications requiring surgical intervention occurred.

CONCLUSION

ER is an appropriate alternative method for the treatment of gastric GISTs, with an en bloc resection rate of 88.85% and a complication rate of 0.93%. No recurrence was noted during follow-up, even for GISTs with piecemeal resection.

Endoscopic resection for the treatment of non-gastric gastrointestinal stromal tumors: A retrospective study from a large tertiary hospital in China

BACKGROUND AND AIMS

Few studies on endoscopic resection (ER) for the treatment of non-gastric gastrointestinal (GI) stromal tumors (GISTs) have been conducted, and most have been case reports or case series. The aim of this study was to evaluate the effectiveness and safety of ER for non-gastric GISTs.

METHODS

From January 2010 to December 2022, 329 patients who were diagnosed with GISTs underwent ER. After excluding 302 patients with gastric GISTs, we retrospectively assessed the data of 27 patients with non-gastric GISTs. The main outcome measures were en bloc resection, complete resection, residual disease, recurrence, and complications.

RESULTS

A total of 15(55.6%) females and 12(44.4%) males with a mean age of 53.8 ± 11.0 years were assessed. There were 19 (70.4%) GISTs in the esophagus, 2 (7.4%) in the duodenum, 3 (11.1%) in the colon and 3 (11.1%) in the rectum. The median tumor size was 12.0 mm (range 4.0-35.0 mm). Most of the GISTs (20, 74.1%) were very low risk, and the remaining 7(25.9%) were low risk. Both en bloc resection and complete resection were achieved in 25(92.6%) patients. Piecemeal resection mainly resulted from a larger tumor size, an irregular shape, and an extraluminal growth pattern. No residual disease or recurrence was noted during the follow-up period. The median operation time was 23 min (range 2-125 min). After excluding the operation time of EER, the operation time was prolonged to 37 min (range 12-125 min). Only one patient experienced mild abdominal pain, leading to a complication rate of 3.7%. No severe complications requiring for surgical interventions occurred.

CONCLUSION

ER was an effective and safe method for non-gastric GISTs in selected cases. GISTs of a small size and regular shape with an intraluminal growth pattern require complete resection.

Incidence Trends and Main Features of Gastro-Intestinal Stromal Tumours in a Mediterranean Region: A Population-Based Study

Gastro-Intestinal Stromal Tumours (GISTs) are a kind of neoplasm whose diagnosis in common clinical practice just started in the current century, implying difficulties for proper registration. Staff from the Cancer Registry of Murcia, in southeastern Spain, were commissioned by the EU Joint Action on Rare Cancers into a pilot study addressing GIST registration that also yielded a population-based depiction of GISTs in the region, including survival figures. We examined reports from 2001 to 2015 from hospitals as well as cases already present in the registry. The variables collected were sex, date of diagnosis, age, vital status, primary location, presence of metastases, and risk level according to Joensuu's Classification. In total, 171 cases were found, 54.4% occurred in males, and the mean age value was 65.0 years. The most affected organ was the stomach, with 52.6% of cases. Risk level was determined as "High" for 45.0%, with an increment of lower levels in recent years. Incidence for the year 2015 doubled that of 2001. Overall, the 5-year net survival estimation was 77.0%. The rising incidence magnitude is consistent with trends in other European countries. Survival evolution lacked statistical significance. A more interventional approach in clinical management could explain the increase in the proportion of "Low Risk GISTs" and the first occurrence of "Very Low Risk" in recent years.

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.

Endoscopic Resection of Gastrointestinal Stromal Tumor: Is It Safe?

Recently, results from clinical studies of endoscopic resection of gastrointestinal stromal tumor (GIST) in the stomach are being reported. This procedure has several advantages, such as the provision of a definite diagnosis and therapeutic plan, avoidance of frequent follow-up examination, and reduction of patients’ anxiety. However, several concerns also exist such as a limited number of studies, low R0 resection rate, and relatively shorter follow-up period compared with surgical resection. Nevertheless, it is encouraging that most of the post-procedural complications have been treated with conservative management and that some of the patients did not show recurrence of the tumor during long-term follow-up. The selection of suitable cases and the experience of the endoscopists are the most important factors for successful endoscopic resection of gastric GIST. Development of novel procedures as well as collaboration with laparoscopic surgeons are currently in progress.

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.

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.

Gastrointestinal Stromal Tumours (GIST): A Review of Cases from Nigeria

PURPOSE

Gastrointestinal stromal tumours (GIST) are rare and studies on GIST in Nigeria are extremely uncommon. This study aims to achieve a comprehensive systematic review of the cases of this tumour in Nigerians.

METHODS

A systematic search of all available literature on GIST published from Nigeria between January 2000 and December 2018 was done and reviewed. Simple descriptive data on all the cases are presented.

RESULTS

The search yielded 15 publications but 13 publications with a total of 67 patients were analysed. The other two studies centred on imatinib therapy and overall survival, and molecular characteristics respectively and were therefore reviewed independently. Age at diagnosis ranged from 9 to 75 years, with mean age being in the 50s and 60s across most studies. There is no gender disparity. Anatomical location of primary tumours showed gastric location as the most frequent (61%) followed by large intestine accounting for 15%, the small intestine (9%) and other locations (15%). Tumour size ranged from 5-39.5 cm. Over 85% of patients had tumour size greater than 10 cm at presentation, hence fell into intermediate or high-risk group irrespective of location of tumour. The overall survival of a cohort of 27 patients that had imatinib therapy was 69.5% after 4 years of follow-up. KIT exon 11 mutations were the only mutations detected from a small cohort of 12 patients.

CONCLUSIONS

Characteristics of GIST in Nigerians are fairly similar to other parts of the world. However, most of our patients present with large masses which are of poor prognostic characteristics.