Clinical and pathological features of "small" GIST (≤2 cm). What is their prognostic value?

Percutaneous ultrasound-guided radiofrequency ablation for patients with liver metastases from gastrointestinal stromal tumors

OBJECTIVES

This study aimed to analyze the survival outcomes and prognostic factors of radiofrequency ablation (RFA) for liver metastases from gastrointestinal stromal tumors (GISTs).

METHODS

Between March 2011 and November 2022, 34 patients (16 males; age range, 25-72 [median age, 52.5] years) who underwent RFA for liver metastasis from GISTs were included. The mean maximum diameter of metastatic lesions was 2.4 ± 1.0 (range, 1.1-5.2) cm. Survival curves were constructed using the Kaplan-Meier method and compared using the log-rank test. Multivariate analyses were performed using a Cox proportional hazards model.

RESULTS

For 79 lesions among 34 patients, all targeted lesions were completely ablated. The mean hepatic progression-free survival (HPFS) period was 28.4 ± 3.8 (range, 1.0-45.7) months. The 1-, 3-, and 5-year HPFS rates were 67.2%, 60.5%, and 20.2%, respectively. Based on the univariate analysis, the number of metastatic tumors and tyrosine kinase inhibitors(TKI) therapy before RFA were prognostic factors for HPFS. Multivariate analysis showed that pre-RFA TKI therapy was associated with a better HPFS(p = 0.030). The mean overall survival (OS) period was 100.5 ± 14.1 (range, 3.8-159.5) months and the 1-, 3-, and 5-year survival rates were 96.9%, 77.1%, and 58.7%, respectively. Both univariate and multivariate analysis indicated that extrahepatic metastasis before RFA (p = 0.044) was a significant prognostic factor for OS.

CONCLUSIONS

Liver metastases from GIST exhibit relatively mild biological behavior. RFA is safe and effective, particularly in patients without pre-RFA extrahepatic metastases. Patients received targeted therapy before RFA can obtain an extended HPFS.

Prediction of the mitotic index and preoperative risk stratification of gastrointestinal stromal tumors with CT radiomic features

OBJECTIVE

The objective is to develop a mitotic prediction model and preoperative risk stratification nomogram for gastrointestinal stromal tumor (GIST) based on computed tomography (CT) radiomic features.

METHODS

A total of 267 GIST patients from 2009.07 to 2015.09 were retrospectively collected and randomly divided into (6:4) training cohort and validation cohort. The 2D-tumor region of interest was delineated from the portal-phase images on contrast-enhanced (CE)-CT, and radiomic features were extracted. Lasso regression method was used to select valuable features to establish a radiomic model for predicting mitotic index in GIST. Finally, the nomogram of preoperative risk stratification was constructed by combining the radiomic features and clinical risk factors.

RESULTS

Four radiomic features closely related to the level of mitosis were obtained, and a mitotic radiomic model was constructed. The area under the curve (AUC) of the radiomics signature model used to predict mitotic levels in training and validation cohorts (training cohort AUC = 0.752; 95% confidence interval [95%CI] 0.674-0.829; validation cohort AUC = 0.764; 95% CI 0.667-0.862). Finally, the preoperative risk stratification nomogram combining radiomic features was equivalent to the clinically recognized gold standard AUC (0.965 vs. 0.983) (p = 0.117). The Cox regression analysis found that the nomogram score was one of the independent risk factors for the long-term prognosis of the patients.

CONCLUSION

Preoperative CT radiomic features can effectively predict the level of mitosis in GIST, and combined with preoperative tumor size, accurate preoperative risk stratification can be performed to guide clinical decision-making and individualized treatment.

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.

Advances of endoscopic and surgical management in gastrointestinal stromal tumors

As one of the most common mesenchymal malignancies in the digestive system, gastrointestinal stromal tumors (GISTs) occur throughout the alimentary tract with diversified oncological characteristics. With the advent of the tyrosine kinase inhibitor era, the treatment regimens of patients with GISTs have been revolutionized and GISTs have become the paradigm of multidisciplinary therapy. However, surgery resection remains recognized as the potentially curative management for the radical resection and provided with favorable oncological outcomes. The existing available surgery algorithms in clinical practice primarily incorporate open procedure, and endoscopic and laparoscopic surgery together with combined operation techniques. The performance of various surgery methods often refers to the consideration of risk evaluation of recurrence and metastases; the degree of disease progression; size, location, and growth pattern of tumor; general conditions of selected patients; and indications and safety profile of various techniques. In the present review, we summarize the fundamental principle of surgery of GISTs based on risk assessment as well as tumor size, location, and degree of progress with an emphasis on the indications, strengths, and limitations of current surgery techniques.

Needle tract seeding and abdominal recurrence following pre-treatment biopsy of gastrointestinal stromal tumors (GIST): results of a systematic review

BACKGROUND

Gastrointestinal stromal tumors (GIST) are rare abdominal tumors. Pretreatment biopsies may be used to diagnose a GIST and enable tailored treatment. Some experts are skeptical about biopsies because they fear tumor cell seeding. The objective of this study was to determine if pretreatment biopsy is associated with increased tumor recurrence.

METHODS

We performed a systematic literature search and included studies assessing the oncological outcome of GIST patients who underwent a pre-treatment core needle biopsy or fine needle aspiration. We assessed methodological quality with the Newcastle-Ottawa-Scale for non-randomized studies. This review was registered in the PROSPERO database (CRD42021170290).

RESULTS

Three non-randomized studies and eight case reports comprising 350 patients were eligible for inclusion. No prospective study designed to answer the review question was found. One case of needle tract seeding after percutaneous core needle biopsy of GIST was reported. None of the studies reported an increased rate of abdominal recurrence in patients with pretreatment biopsy.

CONCLUSIONS

The existing evidence does not indicate a relevant risk of needle tract seeding or abdominal recurrence after pre-treatment biopsy of GIST. Biopsy can safely be done to differentiate GIST from other tumors and to select the most appropriate treatment.

Molecular Portrait of GISTs Associated With Clinicopathological Features: A Retrospective Study With Molecular Analysis by a Custom 9-Gene Targeted Next-Generation Sequencing Panel

Objectives: The study aims to investigate genetic characterization of molecular targets and clinicopathological features with gastrointestinal stromal tumors based on targeted next-generation sequencing.

Materials and Methods: We selected 106 patients with GISTs from Sir Run Run Shaw Hospital between July 2019 and March 2021. FFPE samples and paired blood samples were obtained from these patients who underwent excision of the tumor. A customized targeted-NGS panel of nine GIST-associated genes was designed to detect variants in the coding regions and the splicing sites of these genes.

Results: In total, 106 patients with a GIST were included in the study which presented with various molecular driver alterations in this study. KIT mutations occurred most often in GISTs (94/106, 95.92%), followed by point mutations in PDGFRA. KIT or PDGFRA mutations were detected to be mutually exclusive in the GIST. A total of eight patients with wide-type KIT/PDGFRA were characterized as WT-GISTs, according to clinical diagnosis which included six quadruple-WT GISTs, 1 BRAF-mutant, and 1 NF1-mutant GIST. In KIT exon 11, the most common mutation type was the codon Mutation (in-frame deletion or indels), whereas the missense mutation was the dominant type in KIT exon 13 and KIT exon 17. All variations in KIT exon 11 observed in this study were concentrated at a certain position of codon 550 to codon 576. Mutation in KIT exon 9 was mostly located at codon 502–503. Two germline pathogenic mutations were detected: NF1-R681* and KRAS-T58I. NF1-L591P was a germline mutation to be identified for the first time and is not recorded in the database. The frequency of driving mutations differed between the primary anatomical site in the GIST (p = 0.0206). KIT exon 11 mutants had a lower proliferation index of Ki67 (68.66%,≤5%), while 50.00% of KIT exon 9 mutants had the Ki67 status greater than 10%.

Conclusion: The occurrence and development of a GIST is driven by different molecular variations. Resistance to TKIs arises mainly with resistance mutations in KIT or PDGFRA when they are the primary drivers. Targeted NGS can simultaneously and efficiently detect nine GIST-related gene mutations and provide reference for clinicians’ individualized diagnosis and treatment. Our results have important implications for clinical management.

Gastrointestinal Stromal Tumor

Over the past 20 years, gastrointestinal stromal tumor (GIST) has evolved into an increasingly complex clinical entity with ever more challenges. While surgical resection is the gold standard, advancements in genetic testing, therapeutic options, immunotherapy, and management of metastatic disease necessitate a comprehensive, multimodal approach for these tumors. This chapter highlights the importance of genomic testing of GIST, the use of neoadjuvant and adjuvant therapy for localized disease, surgical principles for GIST, as well as current and new approaches for addressing metastatic disease.

Small-sized gastrointestinal stromal tumors: Is there an association between expectant management and overall survival?

BACKGROUND

Small-sized gastrointestinal stromal tumors (GISTs) have limited malignant potential. Few studies evaluate the safety and efficacy of expectant management (EM) for patients presenting with small GIST.

METHODS

We queried the National Cancer Database to identify patients ≤65 years presenting with GISTs smaller than 3 cm in size between 2004 and 2015. Patients undergoing EM were 1:3 propensity score matched for relevant covariates to patients undergoing resection. Kaplan-Meier (KM) analysis of matched cohorts was used to evaluate the association between EM and overall survival (OS).

RESULTS

1330 patients met inclusion criteria; 966 (72.6%) had gastric GISTs. 1196 (89.9%) underwent resection; 134 (10.1%) EM. 117 patients undergoing EM were propensity-matched to 356 patients undergoing resection. There was no difference in 5-year OS between patients undergoing EM and those undergoing resection (95.7% vs 92.6%, p = 0.4882).

CONCLUSIONS

Survival for small GISTs is similar with expectant management or resection.

MRI Texture-Based Models for Predicting Mitotic Index and Risk Classification of Gastrointestinal Stromal Tumors

BACKGROUND

Treatment regimens and prognoses of gastrointestinal stromal tumors (GIST) are quite different for tumors in different risk categories. Accurate preoperative grading of tumors is important for avoiding under- or overtreatment.

PURPOSE

To develop and validate an MRI texture-based model to predict the mitotic index and its risk classification.

STUDY TYPE

Retrospective.

POPULATION

Ninety-one patients with histologically-confirmed GIST; 64 patients in a training cohort, and 27 patients in a test cohort.

FIELD STRENGTH/SEQUENCE

T₂ -weighted imaging (T₂ WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced three-dimensional volumetric interpolated breath-hold examination (3D-VIBE) at 1.5T.

ASSESSMENT

GIST images were manually segmented by two independent radiologists using ITK-SNAP software and MRI features were extracted using Pyradiomics. Two pathologists reviewed the tissue specimens of the tumors to identify the mitotic index and risk classification in consensus.

STATISTICAL TESTS

The least absolute shrinkage and selection operator (LASSO) regression method was used to select texture features. A logistic regression model was established based on the radiomic score (radscore), tumor location, and maximum diameter to predict tumor classification and develop a nomogram. Receiver operator characteristic (ROC) curves were used to evaluate the ability of the nomogram to distinguish between two tumors with different risk classifications, and a calibration curve was used to evaluate the consistency between the predicted risk and the actual risk.

RESULTS

The texture signature achieved high efficacy in predicting the mitotic index area under the curve ([AUC], 0.906; 95% confidence interval [CI]: 0.813, 0.961). A nomogram for prediction of the risk classification of GIST, which incorporated this texture signature together with maximum tumor diameter and location, allowed good discrimination in the training cohort (AUC, 0.878; 95% CI: 0.769, 0.960) and the validation cohort (AUC, 0.903; 95% CI: 0.732, 0.922).

DATA CONCLUSION

The texture-based model can be used to predict GIST mitotic index and risk classification preoperatively.

LEVEL OF EVIDENCE

2.

TECHNICAL EFFICACY STAGE

3.

Low ETV1 mRNA expression is associated with recurrence in gastrointestinal stromal tumors

Although the majority of gastrointestinal stromal tumors (GISTs) possess KIT mutations that induce constitutive signal transduction, the clinical outcomes are variable. The ETS translocation variant 1 (ETV1) gene encodes a transcription factor that is reported to cooperate with KIT in GISTs. However, the clinical role of ETV1 is largely unknown. The aim of this study was to examine ETV1 expression and its associations with clinical features in GISTs. We conducted a cohort study involving 64 patients with GISTs who underwent surgical resection between October 2008 and February 2015. ETV1 mRNA expression was compared with that in non-GISTs and was analyzed among risk classifications or clinical outcomes. The GIST samples exhibited significantly higher ETV1 mRNA expression than the non-GIST samples (P < 0.0001). Sixty-four GISTs were stratified into high or low ETV1 mRNA expression groups based on the median relative abundance of ETV1 mRNA. The multivariate analysis showed that low ETV1 expression, as well as tumor size and mitotic index, was an independent factor of recurrence (hazard ratio: 8.1). Patients with high ETV1 expression achieved significantly longer recurrence-free survival (RFS) times than those with low ETV1 expression (P = 0.025). Our study revealed that low ETV1 expression is an independent factor of recurrence after surgery in patients with GISTs, and thus, low ETV1 expression might be a marker of more aggressive malignant GISTs.

[Comparative treatment analysis of upper gastroenterology submucosal tumors originating from muscularis propria layer: submucosal tunneling endoscopic resection versus endoscopic submucosal excavation]

OBJECTIVE

To evaluate the efficacy and safety of submucosal tunneling endoscopic resection (STER) and endoscopic submucosal excavation (ESE) for upper gastroenterology submucosal tumors (SMT) originating from the muscularis propria (MP) layer.

METHODS

Clinicopathological and endoscopic data of 42 cases with upper gastroenterology tumors originating from the MP layer who were treated with STER (n=28) or ESE (n=14) between April 2013 and December 2016 in Peking University Third Hospital were retrospectively analyzed. The treatment and complications of the two groups were compared.

RESULTS

In the study, 42 cases were all resected by therapeutic endoscopy successfully．There was no significant difference (STER vs. ESE) in gender, age, mean tumor size [1.5 (1.0-6.0) cm vs. 1.3 (0.5-2.0) cm, P=0.056]. STER was superior to ESE with reduced sutured time [3.5 (1.0-11.0) min vs. 8.0 (2.0-33.0) min, P=0.006], but more resection time [46.5 (11.0-163.0) min vs.19.5 (6.0-56.0) min, P=0.007]. There was statistical difference between the two groups in resection time or sutured time, but no significant difference (STER vs. ESE) in total operative time [52.0 (14.0-167.0) min vs. 31.5 (10.0-88.0) min, P=0.080]. En bloc resection rates (92.9% vs. 85.7%), hospital stay duration and complications (10.7 vs. 0.0) were similar in the STER and ESE groups. One case developed mediastinal emphysema and 2 pneumonia after operation in STER group, and all of them recovered uneventfully after conservative treatments; There were no complications in the ESE group. After operation, 28 cases of leiomyoma and 14 cases of stromal tumor were diagnosed by routine pathological and immunohistochemical staining. Among them, 6 cases of stromal tumors in group STER were all extremely low risk, 4 cases of stromal tumors in group ESE were extremely low risk, 4 cases of stromal tumors in group ESE were medium risk (the size of the lesion was about 1.0-2.0 cm, and mitotic figures counted (6-8)/50 high power field). The median follow-up time of all the patients was 46.5 (24-60) months, and the shortest follow-up time for medium risk stromal tumors was 32 months. No residual tumor, recurrence and implantation in the tunnel were observed.

CONCLUSION

STER or ESE can be used as an effective and safe option for treatment of submucosal tumors originating from the muscularis propria of the upper digestive tract. Compared with STER, ESE had shorter resection time but longer wound closure time. There was no significant difference in total operation time.