Risk stratification of patients diagnosed with gastrointestinal stromal tumor

Adjuvant treatment of gastrointestinal stromal tumor: State of the art in 2025

The management of gastrointestinal stromal tumors (GISTs) has been revolutionized by the discovery of their sensitivity to imatinib. Most localized GISTs can be cured by surgery alone. The present overview aims to discuss the results of four recent randomized trials or updates assessing adjuvant imatinib. The duration of adjuvant treatments varied in these 4 trials (1 year versus zero, 2 years versus zero, 3 years versus 1 year and 6 years versus 3 years). All these trials showed that adjuvant imatinib improves disease/relapse-free survival in patients at high-risk of GIST relapse. Nevertheless, only one trial showed an overall survival improvement, in favor of 3-year treatment compared to 1-year treatment. But these randomized trials did not assess KIT or PDGFRA mutational status at study entry. Moreover, the definition of high-risk GIST differed across these trials. So, the patient subset that benefits the most from adjuvant imatinib therapy remains undetermined. The optimal duration of adjuvant imatinib therapy remain unclear.

Navigating Ongoing Challenges in GI Stromal Tumors

GI stromal tumors (GISTs) are mesenchymal neoplasms with variable natural histories, originating in the GI tract, most commonly in the stomach. They are frequently characterized by KIT or platelet-derived growth factor receptor alpha (PDGFRA) oncogenic mutations. Surgical resection remains the cornerstone treatment for localized GISTs. Clinical trials have demonstrated the benefits of adjuvant imatinib in patients selected on the basis of recurrence risk and gene mutations, although the optimal duration of therapy is yet to be established. Some data suggest that longer durations of adjuvant imatinib (>3 years) may provide additional benefit, which is being investigated in ongoing trials. Management of imatinib-related adverse effects is essential during treatment, and longitudinal abdominal imaging is mandatory both during and after adjuvant therapy. Once GISTs are more advanced and unresectable, KIT- and PDGFRA-directed tyrosine kinase inhibitors (TKIs) become the key treatment in most patients with KIT mutation. Several TKIs have regulatory approval for advanced GISTs, but in most patients, resistance to TKIs eventually emerges, mainly from secondary resistance mutations in KIT. Each TKI has different coverage of oncogenic KIT mutations, suggested by preclinical and clinical findings, which has given rationale to an ongoing clinical trial that includes molecular selection as eligibility criteria. Furthermore, novel treatment approaches, from TKI combinations to an antibody-drug conjugate, are being investigated. Despite the significant advance in managing GISTs with KIT mutations, those without KIT or PDGFRA mutation, which consists of 10%-15% of patients with GIST, can be a clinical challenge in the advanced setting. These non-KIT/PDGFRA GISTs could be driven by genomic or epigenomic alterations in SDHx, NF1 mutations, and other genomic alterations. Non-KIT/PDGFRA GISTs are less responsive to currently available TKIs than GISTs driven by KIT/PDGFRA mutations, and each subset of non-KIT/PDGFRA GIST has distinctive biology and clinical features. Therefore, individualized, multidisciplinary, biology-based management and consideration for clinical trial enrollment are critical for non-KIT/PDGRFA GISTs.

Efficacy and safety of endoscopic intraperitoneal subserosal dissection for gastric submucosal tumors with extraluminal growth pattern

Endoscopic intraperitoneal subserosal dissection (EISD) has been reported to be a promising modified tunneling technique for gastric submucosal tumors (SMTs) with a predominantly extraluminal growth pattern. We evaluated the safety and efficacy of EISD for gastric extraluminal SMTs.We prospectively enrolled consecutive patients who underwent EISD for gastric extraluminal SMTs between October 2018 and March 2024. Clinicopathological characteristics and procedure-related parameters were analyzed.10 patients with 11 gastric extraluminal SMTs were included. The mean (SD) longest and shortest specimen diameters were 2.1 (0.9) cm (range 0.5-4.0) and 1.8 (0.7) cm (range 0.4-3.0), respectively. All SMTs (100%) were resected en bloc, and 10 (90.9%) were retrieved en bloc. The mean (SD) resection and suture times were 58.9 (31.5) minutes (range 26-125) and 12.4 (10.1) minutes (range 3-25), respectively. Two patients experienced type I mucosal injury at the tumor site, and no major adverse events occurred. The mean postoperative hospital stay was 3.4 (SD 0.8) days (range 3-5). No recurrence or metastasis occurred during a mean follow-up period of 32.1 (SD 18.8) months (range 7-71).EISD appeared to be a feasible and safe method for removing gastric extraluminal SMTs in selected patients.

Concurrent Coprimary KIT Exon 17 and BRAF Mutations in a Small Intestinal GI Stromal Tumor-A Case Report

PURPOSE

Gastrointestinal stromal tumors (GISTs) are rare neoplasms driven by mutations in KIT, PDGFRA, or BRAF. Concomitant KIT/BRAF mutations are exceptionally rare and have historically been regarded as mutually exclusive. We report the first documented instance of a GIST with concurrent KIT exon 17 (D816H) and BRAF exon 15 (V600E) mutations, exploring the implications of these mutations for treatment and prognosis. KIT exon 17 mutations are rare and associated with imatinib resistance, and the literature on concurrent KIT/PDGFRA and BRAF mutations is limited, highlighting the potential of this case to provide valuable insights into the management of similar tumors.

METHODS

A 70-year-old woman presented with abdominal pain and a 20-year history of intermittent melena. Imaging and histopathological examination confirmed a duodenal GIST. The patient underwent en bloc tumor resection, and next-generation sequencing (NGS) identified co-occurring KIT exon 17 (D816H) and BRAF exon 15 (V600E) mutations. Postoperatively, the patient received adjuvant imatinib therapy for a planned duration of 3 years.

RESULTS

The patient tolerated adjuvant imatinib therapy well, experiencing only mild nausea and diarrhea. After 2 years of follow-up, no recurrence of the tumor was detected, and the patient remained in radiological remission with no signs of metastasis or tumor progression.

CONCLUSION

This case demonstrates a favorable outcome in a patient with localized GIST with concomitant KIT exon 17 and BRAF mutations following surgical resection with no evidence of recurrence. These findings underscore the significance of early comprehensive genotyping in GISTs to guide therapy and predict imatinib resistance.

Endoscopic versus laparoscopic resection of gastrointestinal stromal tumors at the esophagogastric junction using propensity score matching analysis

The esophagogastric junction (EGJ) has a complex anatomy and critical physiological functions, making postoperative quality of life an important consideration in the surgical resection of gastrointestinal stromal tumors at this location (EGJ-GISTs). We conducted a propensity score-matched (1:1) analysis to compare the safety and efficacy of endoscopic resection (ER) and laparoscopic resection (LR) for patients with EGJ-GIST treated at the First Affiliated Hospital of Zhengzhou University, China, from December 2013 to November 2023. We reviewed 176 patients (ER 82; LR 94) with EGJ-GIST, of whom 85 patients with a tumor size of 2-5 cm met the matching criteria (ER 42; LR 43), yielding 20 pairs of patients. ER showed advantages over LR, with a shorter postoperative nil per os time (4.0 days (IQRs, 3.0-5.0) vs. 5.5 days (IQRs, 4.3-7.8), p = 0.005) and postoperative hospitalization time (6.0 days (IQRs, 5.0-6.8) vs. 8.5 days (IQRs, 6.0-11.8, p = 0.002). Long-term adverse events were significantly lower in the ER group (15% vs. 55%, p = 0.005). No recurrence or metastasis was observed in either group during a mean follow-up of 42.3 months. These findings suggest that for 2-5 cm EGJ-GISTs, ER is a safe and effective alternative, offering minimal invasiveness, faster recovery, fewer complications, and improved long-term quality of life.

Unraveling the site-specific features in small intestinal stromal tumors: a retrospective study

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are a rare and less well-characterized disease. There is limited information on the clinical features of small intestinal GISTs at different sites.

AIMS

To enhance the understanding of the clinical characteristics and disease behavior of small intestinal GISTs based on their sites.

METHODS

We conducted a retrospective review of medical records for 317 patients diagnosed with primary small intestinal GISTs confirmed by surgical pathology, comparing their clinical features and tumor characteristics.

RESULTS

According to this cohort's data, duodenal GISTs presented with longer disease durations and higher prevalence of melena (44.6%), while jejunal GISTs manifested as abdominal masses (11.5%) and acute gastrointestinal bleeding (GIB) (13.3%), with the highest rate of emergency surgeries (16.8%). Ileal GISTs were associated with an older age of onset and a higher prevalence of hematochezia (19.6%), with one-third of cases discovered incidentally during gynecological procedures. Notably, the biological behavior of small intestinal GISTs varied significantly by sites. Tumors demonstrated different immunochemical markers and a progressive increase in diameter, mitotic activity, T and M stages, and risk classification from the duodenum to the jejunum and ileum. These findings warrant further validation in prospective multicenter studies.

CONCLUSIONS

Small intestinal GISTs might exhibit distinct clinical presentations and oncological features depending on their sites.

Minimally invasive treatment strategies for submucosal tumors of the upper gastrointestinal tract: Advances in innovative endoscopy-based therapies

The increasing detection of submucosal tumors (SMTs) in the upper gastrointestinal tract (UGI) is due to the increased clinical use of endoscopy and imaging technology. Some of these SMTs have malignant potential and may cause clinical symptoms. Thus, it is recommended in clinical guidelines to consider resection of these SMTs. Endoscopic techniques have become widely used in the diagnosis and treatment of SMT in the UGI as compared with traditional surgery due to their advantages of minimally invasive, quick recovery, and economical cost. Recently, new endoscopic techniques and instruments have been continuously implemented, leading to revolutionary innovation in endoscopic treatments. However, the safety and efficacy of these innovative techniques remain unclear. Therefore, we have comprehensively summarized the various techniques used in the treatment of UGI tumors in recent years, evaluated the indications and effects of each technique, and compared their benefits and disadvantages. We hope that this review will provide a more comprehensive reference for clinical and endoscopic practitioners, and help them develop more individualized treatment plans for different patients. This will ultimately expand the patient population that can benefit from these innovative technologies.

Asymptomatic small gastric subepithelial lesions arising from the muscularis propria: outcomes and surveillance in a medical center

BACKGROUND AND AIMS

Gastric subepithelial lesions (SELs) are frequently identified incidentally during endoscopy, with those originating from the muscularis propria (MP) layer posing diagnostic and management challenges. The optimal surveillance duration for these lesions remains debated. This study aimed to assess size changes in SELs from the MP layer and recommend appropriate surveillance intervals.

METHODS

We retrospectively reviewed asymptomatic gastric SELs (≤2 cm) diagnosed via endoscopic ultrasound (EUS) from 2013 to 2018, with follow-up data and no excision within 1 year. Significant progression was defined as a > 20% increase in diameter during EUS surveillance. Lesion-related adverse outcomes, size changes, and histological findings were analyzed.

RESULTS

A total of 561 patients (median surveillance duration: 80 months) were included. One lesion-related adverse outcome (0.2%), liver metastasis from a gastrointestinal stromal tumor, occurred after 62 months. Among the EUS subgroup (n = 313), no differences were observed in progression rates (22.6% vs. 25%) or size increase rates (0.3 mm/year vs. 0.9 mm/year) between micro-SELs (<10 mm) and mini-SELs (10-20 mm). Progressive lesions exhibited faster growth (2.6 mm/year) and more heterogeneous echotexture (43.8%). Most excised lesions were gastrointestinal stromal tumors or leiomyomas.

CONCLUSIONS

Over a mean surveillance period of 25.5 months, 13 lesions grew beyond 20 mm. No lesion-related adverse outcomes occurred within the first three years. Histological diagnosis remains the gold standard, but when tissue acquisition is unfeasible, EUS surveillance may be an alternative. Our findings suggest that for asymptomatic micro-SELs (<10 mm) from the MP layer without high-risk features, the surveillance interval can be safely extended to two years.

Next questions on gastrointestinal stromal tumors: unresolved challenges and future directions

PURPOSE OF REVIEW

Despite remarkable progress in the management of gastrointestinal stromal tumors (GISTs), critical challenges persist. Key aspects such as risk stratification, the optimal duration of adjuvant therapy, and strategies to enhance the efficacy of first-line treatment remain subjects of ongoing debate. This review explores emerging concepts and innovative approaches aimed at refining patient selection and optimizing therapeutic decision-making to further improve clinical outcomes.

RECENT FINDINGS

Molecular and genomic parameters have the potential to enhance traditional risk models, enabling more precise stratification of high-risk patients. Innovations in artificial intelligence and liquid biopsy are emerging as powerful tools for refining predictions of recurrence and treatment response. Meanwhile, the definition and prognostic significance of tumor rupture remain pivotal challenges that influence both risk assessment and adjuvant therapy decisions. Furthermore, transcriptomic and multiomic analyses have unveiled distinct GIST subtypes with significant prognostic and therapeutic implications, paving the way for more tailored treatment strategies.

SUMMARY

Integrating molecular features into clinical decision making may refine risk assessment and personalize the treatment in patients with GIST. Future research should focus on validating these tools and redefine clinical trial designs to accelerate drug development for this rare disease.

An Incidental Finding of Appendiceal Gastrointestinal Stromal Tumor with Abundant Skeinoid Fibers: A Rare Case Report with Insights from a Comprehensive Literature Review

Background and Clinical Significance: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract but are exceedingly rare in the appendix, with only 20 cases reported in the literature. Due to their rarity, clinical behavior, histopathologic features, and management of appendiceal GISTs remain poorly understood. Case Presentation: We present the case of a 74-year-old man who underwent a right hemicolectomy for colonic adenocarcinoma, during which an incidental 1.2 cm appendiceal GIST was discovered. Histopathological examination revealed spindle cell morphology with abundant skeinoid fibers (SF), minimal mitotic activity (<1/50 HPF), and no nuclear atypia. Immunohistochemical staining confirmed positivity for CD117, DOG1, and CD34. The tumor was classified as low risk based on its size and mitotic count, and the patient remained recurrence-free at a 4-month follow-up. Conclusions: Our case expands the limited literature on appendiceal GISTs by demonstrating their histopathological and immunohistochemical features, favorable prognostic outcomes, and potential for incidental detection during surgeries for unrelated conditions. However, additional studies are needed to further elucidate their molecular characteristics and overall clinical behavior.

CT assessed morphological features can predict higher mitotic index in gastric gastrointestinal stromal tumors

OBJECTIVES

To investigate the correlation of the mitotic index (MI) of 1-5 cm gastric gastrointestinal stromal tumors (gGISTs) with CT-identified morphological and first-order radiomics features, incorporating subgroup analysis based on tumor size.

METHODS

We enrolled 344 patients across four institutions, each pathologically diagnosed with 1-5 cm gGISTs and undergoing preoperative contrast-enhanced CT scans. Univariate and multivariate analyses were performed to investigate the independent CT morphological high-risk features of MI. Lesions were categorized into four subgroups based on their pathological LD: 1-2 cm (n = 69), 2-3 cm (n = 96), 3-4 cm (n = 107), and 4-5 cm (n = 72). CT morphological high-risk features of MI were evaluated in each subgroup. In addition, first-order radiomics features were extracted on CT images of the venous phase, and the association between these features and MI was investigated.

RESULTS

Tumor size (p = 0.04, odds ratio, 1.41; 95% confidence interval: 1.01-1.96) and invasive margin (p < 0.01, odds ratio, 4.55; 95% confidence interval: 1.77-11.73) emerged as independent high-risk features for MI > 5 of 1-5 cm gGISTs from multivariate analysis. In the subgroup analysis, the invasive margin was correlated with MI > 5 in 3-4 cm and 4-5 cm gGISTs (p = 0.02, p = 0.03), and potentially correlated with MI > 5 in 2-3 cm gGISTs (p = 0.07). The energy was the sole first-order radiomics feature significantly correlated with gGISTs of MI > 5, displaying a strong correlation with CT-detected tumor size (Pearson's ρ = 0.85, p < 0.01).

CONCLUSIONS

The invasive margin stands out as the sole independent CT morphological high-risk feature for 1-5 cm gGISTs after tumor size-based subgroup analysis, overshadowing intratumoral morphological characteristics and first-order radiomics features.

KEY POINTS

Question How can accurate preoperative risk stratification of gGISTs be achieved to support treatment decision-making? Findings Invasive margins may serve as a reliable marker for risk prediction in gGISTs up to 5 cm, rather than surface ulceration, irregular shape, necrosis, or heterogeneous enhancement. Clinical relevance For gGISTs measuring up to 5 cm, preoperative prediction of the metastatic risk could help select patients who could be treated by endoscopic resection, thereby avoiding overtreatment.

Endoscopic resection for gastric submucosal tumors: A single-center experience in Japan

Objectives

Endoscopic resection (ER) for gastric submucosal tumors (SMTs) has gained prominence in recent years, with studies emerging from various countries. However, there is a paucity of reports from Japan. We aimed to elucidate the efficacy and safety of ER for gastric SMT in Japan.

Methods

In this retrospective observational study, we investigated the outcomes of consecutive patients who underwent ER for gastric SMT from January 2017 to May 2023. The outcome variables assessed included the complete resection rate, procedure time, closure-related outcomes, and the incidence of adverse events.

Results

A total of 13 patients were included in the analysis. The median procedure time was 163 (55-283) min. Complete full-thickness resection was performed in seven cases, while in four cases, the serosa remained, and in two cases, the outer layer of the muscularis propria remained. In two cases where the SMT was located on the anterior side, conversion to laparoscopic surgery became necessary, resulting in a procedural success rate of 84.6% (11/13). Excluding these two cases, endoscopic closure of the defect was successfully accomplished in the remaining 11 cases. R0 resection was achieved in 12 out of 13 cases (92.3%). Although one patient had peritonitis, which was successfully treated conservatively, no other treatment-related adverse events were encountered.

Conclusions

Although ER for SMT on the anterior side may be challenging, our experience revealed that ER is a safe and efficacious approach for gastric SMT.

A case of quadruple wild-type gastrointestinal stromal tumor with CDC42BPB::NTRK3 fusion and abundant lymphoid infiltration

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The most common mutations in GISTs are those in receptor tyrosine kinase (KIT) and platelet-derived growth factor receptor alpha (PDGFRA). GISTs without KIT or PDGFRA mutations are defined as wild-type (WT) GISTs. The molecular changes, prognosis, and treatments of WT GISTs remain uncertain. Among WT GISTs, neurotrophic tyrosine receptor kinase (NTRK) fusions have rarely been reported. We report a case of quadruple wild-type GIST harboring a novel CDC42BPB::NTRK3 fusion. In this study, we described a 66-year-old male patient with intrajejunal lesion. This case showed massive lymphocytic and plasma cell infiltration, which caused diagnostic difficulties in morphology. CDC42BPB::NTRK3 fusion was detected via next-generation sequencing (NGS), and this finding was confirmed by fluorescence in situ hybridization (FISH), which revealed NTRK3 breakage. However, the expression of the Trk protein in tumor tissue was not detected by immunohistochemistry (IHC). This finding expands the genetic spectrum of NTRK rearrangements in GISTs.

Endoscopic treatment outcome of oesophageal gastrointestinal stromal tumours

BACKGROUND

There are few clinicopathologic characteristics and clinical results for oesophageal gastrointestinal stromal tumours (GISTs). Thus, the objective of this study was to identify the clinicopathologic characteristics and clinical results of oesophageal GISTs.

AIM

To investigate endoscopic treatment effective of oesophageal GISTs.

METHODS

It was retrospective research that collected 32 patients with oesophageal GISTs treated by endoscopic resection (ER) between January 2012 and January 2023 in two Hospital. Clinicopathologic, endoscopic records, and follow-up data were collected and analysed.

RESULTS

Thirty-one patients underwent en bloc resection and 24 (75.0%) lesions underwent R0 resection. The size of GISTs was 2.12 ± 1.88 cm. The overall complication rate was 25.0%, including hydrothorax and post-endoscopic submucosal dissection electrocoagulation syndrome. The mean mitotic index was 3.34 ± 5.04 (median, 1.50; range, 1.00-4.00). Eighteen (56.3%), 6 (18.8%), 2 (6.3%), and 6 (18.8%) patients were identified as very low, low, intermediate, and high risk, respectively. Three patients developed recurrence after a median follow-up of 64.69 ± 33.13 months. The 5-year overall survival rate was 100%, and the disease-free survival rate was 90.6%.

CONCLUSION

ER is safe and effective for patients with low-risk oesophageal GISTs. Early detection of oesophageal GISTs is essential to achieve a favourable prognosis.

Inflammatory biomarker correlations and prognosis in high-risk gastrointestinal stromal tumor patients: a multicenter retrospective analysis

BACKGROUND

The accurate prognosis of gastrointestinal stromal tumors (GISTs) has garnered substantial attention, yet a gap persists in understanding the influence of inflammatory markers on the prognosis of high-risk GIST patients. This study investigated the relationship between various factors and the prognosis of high-risk GIST patients, with a specific focus on first recurrence-free survival (RFS) and overall survival (OS) as crucial prognostic indicators.

METHODS

A comprehensive collection of clinical data was conducted on 145 high-risk GIST patients meeting specific inclusion and exclusion criteria at 17 medical centers in Ningxia Hui Autonomous Region, China, covering the period from January 2013 to December 2019. Single-factor analysis and survival curves were used to analyze the variables, while the Cox regression model evaluated independent prognostic factors.

RESULTS

Within the cohort, a balanced male-to-female ratio of 1:1.1 was observed. Univariate analysis revealed compelling associations between RFS and age, preoperative neutrophil-to-lymphocyte ratio (NLR), preoperative platelet-to-lymphocyte ratio (PLR), preoperative systemic immune-inflammatory index (SII), preoperative prognostic nutritional index (PNI), mitotic index, and whether or not imatinib (IM) was taken regularly in high-risk GIST patients (P < 0.05). Except age, these other variables were also significantly correlated with OS (P < 0.05). Cox regression analysis showed that age, preoperative PNI, mitotic index and postoperative IM adjuvant therapy independently affected RFS (P < 0.05). In addition, preoperative PNI and postoperative IM adjuvant therapy were also independent factors of OS, with statistical significance (P < 0.05). Age was negatively correlated with RFS, and early routine IM treatment after operation significantly reduced the risk of recurrence and death. Higher mitotic index is closely related to poor RFS, and higher preoperative PNI indicates a better prognosis.

CONCLUSION

A close correlation between young age, low preoperative PNI, high mitotic index, and lack of IM treatment had an unfavorable prognosis in high-risk GIST patients. Notably, the PNI was identified as a potential additional prognostic factor, enhancing the accuracy of predicting treatment efficacy and patient outcomes in high-risk patients with GISTs. Therefore, we advocate for the serious consideration of the PNI as a valuable addition to standard clinical practice for managing high-risk GIST patients.

Incidentally Discovered Duodenal Gastrointestinal Stromal Tumour (GIST): Operative Treatment and Problems After Surgery-A Case Report and Literature Review

Background: Gastrointestinal stromal tumours (GISTs) are mesenchymal tumours of the digestive tract that can involve any part of the tract. The tumours can be harmless or life-threatening. Materials and Methods: A case report of a surgeon who fell in a Finnish sauna, and he immediately felt that some ribs were broken. Magnetic resonance imaging and ultrasound showed three fractured ribs and an intrasplenic haematoma. Contrast-enhanced computed tomography (CT) demonstrated a small intrasplenic anomaly but no haematoma. Incidentally, an incidentaloma in the left adrenal gland was diagnosed. Three months later, a control CT scan was performed. The radiological findings on the adrenal gland and laboratory examinations matched those of a benign adenoma. Incidentally, a small duodenal tumour was diagnosed. At the same time, anaemia (haemoglobin: 104 g/L) and iron deficiency (ferritin: 8 μg/L) were noticed. An esophagogastroduodenoscopy showed an intramural tumour localised after the bulb-descending junction. Because the tumour was submucosal, the pathological diagnosis failed. Three months later, a radical surgical resection of the tumour with a resection margin of 2 mm and primary closing of the duodenum was performed. Pathological examination showed a well-circumscribed submucosal mesenchymal tumour with spindle cells. A tumour-free margin was uncertain. Immunohistochemistry findings showed a GIST. Due to the uncertain margin, an esophagogastroduodenoscopy control was planned at 2 years postoperatively. The patient disagreed with the decision and ordered a private control CT 3 months after the operation. The new CT found no local recurrence or metastasis. The patient contacted the head surgeon of the clinic, who ordered a 1-year postoperative CT. The 1-year follow-up CT finding agreed with the previous findings. Conclusion: The aftertreatment of a radical-operated GIST is extremely important if histologic examination of the tumour-free margin is uncertain. In that case, CT controls should be considered once a year for at least 3 years.

Impact of Mutation Profile on Outcomes of Neoadjuvant Therapy in GIST

BACKGROUND

Neoadjuvant imatinib therapy plays a crucial role in the management of gastrointestinal stromal tumors (GISTs), but its impact across various mutational profiles remains uncertain.

OBJECTIVE

The aim of this study is to describe the clinicopathological features and to assess the response and surgical outcomes of neoadjuvant imatinib in GIST patients exhibiting diverse mutational profiles.

METHODS

We conducted a retrospective study, extracting data from the Dutch GIST Registry, including patients treated with neoadjuvant imatinib. Response rate was the primary outcome, and secondary outcomes were the time on neoadjuvant treatment and resection margins (R0 vs. R1/R2), respectively.

RESULTS

Between 2009 and 2021, 326 patients were treated with neoadjuvant imatinib, of which 264 (80.9%) underwent resection. A total of 197 (74.6%) of them had a KIT-exon 11 mutation, 19 (7.3%) had other KIT mutations, 10 (3.8%) had PDGFRA D842 mutations, 21 (6.8%) had other PDGFRA mutations, 2 (0.7%) had NTRK mutation, 1 (0.4%) had an SDH mutation, and 17 (6.4%) had WT GISTs. Patients with KIT-exon 11 mutations demonstrated a higher rate of partial response to imatinib (60.5% vs. 33.3%; p = 0.00). A positive resection margin (R1 or R2) was observed in 14 (21.2%) patients with a non-KIT exon 11 mutations and in 11 (5.5%) patients with a KIT-exon 11 mutation (p = 0.00). Moreover, non-KIT exon 11 mutation patients had a shorter median duration of neoadjuvant therapy (5.3 months, range 0.5-21.0) compared to patients with a KIT exon 11 mutation (8.8 months, range 0.2-31.3; p < 0.001).

CONCLUSIONS

Our study highlights the variability in treatment response associated with different GIST mutational profiles. Patients with a KIT-exon-11 mutation tended to respond more favorably to neoadjuvant imatinib in terms of partial response and surgical outcomes.

Patient-derived xenograft models of gastrointestinal stromal tumors provide a ready-to-use platform for translational research

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal malignancy of the gastrointestinal tract. Most GISTs harbor mutations in oncogenes, such as KIT, and are treated with tyrosine kinase inhibitors (TKIs), such as imatinib. Most tumors develop secondary mutations, inducing drug resistance against the available TKIs, requiring novel therapies. We established a GIST patient-derived xenograft (PDX) platform of GIST that can be used for preclinical drug testing. Tumor tissue from consenting GIST patients was transplanted subcutaneously to NMRI nu/nu mice. Once tumor growth was observed, the tumor was re-transplanted to a next generation of mice. Tumors were characterized histopathologically and molecularly at every re-transplantation and compared with the original patient tumor. We transplanted 112 tumor samples from 99 GIST patients, resulting in 12 established and well-characterized GIST models with different mutations and TKI sensitivity. Three models harbor secondary KIT mutations. One model is characterized by a primary, imatinib-resistant PDGFRA exon 18 p.D842V mutation. Our established platform of well-characterized GIST PDX models, covering the most relevant driver mutations, serves as an excellent tool for preclinical drug testing and tumor biology studies.

Mucosal snare resection-endoscopic submucosal excavation for gastric submucosal tumors: a retrospective study (with video)

Aims

This study aimed to compare the clinical outcomes of patients with submucosal tumors treated with endoscopic submucosal excavation (ESE) and those treated with mucosal snare resection-endoscopic submucosal excavation (MSR-ESE).

Methods

We retrospectively analyzed clinical data from patients who underwent ESE or MSR-ESE at the Second Affiliated Hospital of Zhejiang University School of Medicine between January 2023 and January 2024. Factors such as operation time, intraoperative perforation, postoperative adverse events, postoperative fasting time, antibiotic use, hospitalization duration, costs, and pathological diagnosis were compared between the two procedures.

Results

A total of 180 patients with submucosal tumors were included in this study. The MSR-ESE group consisted of 75 patients (41.7%), while the ESE group had 105 patients (58.3%). Propensity score matching (PSM) showed no significant differences in postoperative antibiotic use, fasting time, or intraoperative perforation between the two groups (P>0.05). However, the MSR-ESE group demonstrated shorter operation and hospitalization times, lower hospitalization costs, and a reduced incidence of postoperative peritonitis (P<0.05). Multivariate logistic regression analysis identified operation time as an independent risk factor for unplanned intraoperative perforation, with the likelihood of perforation increasing significantly as operation time increased (P=0.007, OR=1.015, 95% CI, 1.004 to 1.026).

Conclusion

MSR-ESE outperforms ESE with shorter operation times, lower costs, and fewer postoperative complications, making it a safe and effective treatment for gastric submucosal tumors.

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.

Influence of lymph node removal on the prognosis of high malignancy potential gastric gastrointestinal stromal tumors: Insights from population-based study

High malignancy potential gastric gastrointestinal stromal tumors (HMP-gGISTs) generally require surgical resection. However, the necessity of lymph node removal (LR) for patients with such tumors remains unclear. Therefore, we conducted a population-based study to analyze the impact of LR on the long-term prognosis of patients with HMP-gGISTs. Patients with HMP-gGISTs were gathered from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching (PSM) was utilized to address potential selection bias. Overall survival (OS) and cancer-specific survival (CSS) were evaluated using Kaplan-Meier analyses and multivariate Cox proportional hazards models. A total of 840 patients with HMP-gGISTs were included in the study, with 317 undergoing LR and 523 not undergoing LR. The prognosis for OS (P = 0.026) and CSS (P < 0.001) in the LR group was worse compared to the No-LR group. After PSM, 634 patients were matched for comparison. The results showed that the OS (P = 0.028) and CSS (P = 0.006) in the LR group remained poorer than those in the No-LR group. Subgroup analysis further indicated that patients who did not undergo LR had a better prognosis. Our findings suggest that LR may not improve the prognosis of patients with HMP-gGISTs, implying that LR may not be necessary for these patients.

Different radiomics models in predicting the malignant potential of small intestinal stromal tumors

Objectives

To explore the feasibility of different radiomics models for predicting the malignant potential of small intestinal stromal tumors (SISTs), and to select the best radiomics model.

Methods

A retrospective analysis of 140 patients with SISTs was conducted. Radiomics features were extracted from CT-enhanced images. Support vector machine (SVM), Decision tree (DT), Conditional inference trees (CIT), Random Forest (RF), K-nearest neighbors (KNN), Back-propagation neural network (BPNet), and Bayes were used to construct different radiomics models. The clinical data and CT performance were selected using univariate analysis and to construct clinical model. Nomogram model was developed by combining clinical data and radiomics features. Model performances were assessed by using the area under the receiver operator characteristic (ROC) curve (AUC). The models' clinical values were assessed by decision curve analysis (DCA).

Results

A total of 1132 radiomics features were extracted. Among radiomics models, SVM was better than DT, CIT, RF, KNN, BPNet, Bayes because it had the highest AUC with a significant difference (P<0.05). The AUC of the clinical model was 0.781. The AUC of the radiomics model was 0.910. The AUC of nomogram model was 0.938. Clinical models had the lowest AUC. Nomogram AUC were slightly higher than radiomics model, but the difference was not significant (P=0.48). The DCA of the nomogram model and radiomics model showed optimal clinical efficacy.

Conclusions

The model constructed with SVM method was the best model for predicting the malignant potential of SISTs. Radiomics model and nomogram model showed high predictive value in predicting the malignant potential of SISTs.

An ultrasound based method for predicting the malignant potential of primary gastrointestinal stromal tumors preoperatively

OBJECTIVE

Gastrointestinal stromal tumors (GISTs) are difficult to identify the risk level accurately without surgical pathological confirmation. The purpose of our study was to propose a noninvasive prediction method for predicting the malignant potential of GISTs preoperatively by using contrast-enhanced ultrasound (CEUS) with gastric distention.

METHODS

We reviewed 47 GISTs who underwent CEUS from April 2017 to August 2023 retrospectively, all the lesions were certificated by pathology after surgery. The age of the patient, size of the lesion, shape, necrosis, calcification in the lesion, perfusion parameters including arrival time (AT), peak intensity (PI), time to peak (TTP), and area under the curve (AUC) of the lesion and surrounding normal tissue were analyzed. Logistic regression analyses were performed. Of the 47 GISTs, 26 were high-risk and 21 low-risk tumors respectively.

RESULTS

Compared with low-risk GISTs, high-risk GIST had faster AT (7.7s vs. 11.5s, p < 0.05), higher PI (15.2dB vs. 12.5dB, p < 0.05), and larger size (4.4 cm vs. 2.2 cm, p < 0.001). In multivariate logistic regression, AT, PI, and size were significant features. The corresponding regression equation In (p/(1-p)=-5.9 + 4.5 size + 4.6 PI + 4.0 AT).

CONCLUSION

The size, AT, and PI of the GISTs on CEUS can be used as parameters for a noninvasive risk level prediction model of GISTs. This model may help identify the different risk levels of GISTs before surgery.

Interpretable machine learning model based on CT semantic features and radiomics features to preoperatively predict Ki-67 expression in gastrointestinal stromal tumors

To develop and validate a machine learning (ML) model which combined computed tomography (CT) semantic and radiomics features to preoperatively predict Ki-67 expression in gastrointestinal stromal tumors (GISTs) patients. We retrospectively collected the clinical, imaging and pathological data of 149 GISTs patients. We randomly assigned the patients in a ratio of 7:3 to a training set (104 cases) and a validation (45 cases) set. We divided the patients into low and high Ki-67 expression group according to postoperative pathology. CT semantic features were analyzed from preoperative enhancement CT images and radiomics features were extracted from venous phase-enhanced images. We used intraclass correlation coefficient, maximal relevance and minimal redundancy and least absolute shrinkage and selection operator method to screen radiomics features and build radiomics label. 6 ML models were used for model construction. Receiver operating characteristic curves were used to evaluate the predictive efficiency of ML models. SHAP analysis was used to explain the contribution of different variables and their risk threshold. AUC of radscores in predicting Ki-67 expression of GIST patients were 0.749 and 0.729 in training and validation set. Among the 6 ML models, SVM exhibited best prediction accuracy. AUC of SVM model in predicting Ki-67 expression of GIST patients were 0.840, 0.767 and 0.832 in training, validation and test set. SHAP analysis showed that radscores and tumor diameter had highly positive contribution to the model. Therefore, the interpretable SVM model can predict Ki-67 expression of GISTs patients individually before surgery, which can provide reliable imaging biomarkers for clinical treatment decisions.

Pathologic diagnosis and molecular features of gastrointestinal stromal tumors: a mini-review

Gastrointestinal stromal tumors (GISTs) arise from the interstitial cells of Cajal, predominantly affecting the stomach and small intestine, with rare occurrences in the duodenum, rectum, and extraintestinal sites. Histologically, GISTs can present as spindle cells, epithelioid cells, or mixed morphologies, with immunohistochemical staining revealing expression of KIT (CD117) and discovered on GIST 1 (DOG1). Approximately 80% of GISTs harbor activating mutations in KIT or platelet derived growth factor receptor α (PDGFRA), which influence their clinical behavior and treatment response. SDH-deficient GISTs, associated with syndromes such as Carney triad and Carney-Stratakis syndrome, represent a distinct subgroup with unique characteristics and management challenges. The standard treatment includes surgery and imatinib for metastatic cases; however, resistance to tyrosine kinase inhibitors remains a significant hurdle, especially in pediatric and wildtype GISTs. This highlights the need for advanced therapeutic strategies and emphasizes the importance of molecular profiling in guiding treatment decisions and improving outcomes for GIST patients.

An additional gastrojejunostomy may reduce the incidence of moderate and severe delayed gastric emptying after distal segmental duodenectomy for gastrointestinal stromal tumors

BACKGROUND

To investigate whether an additional gastrojejunostomy reduces the incidence of delayed gastric emptying (DGE) following a distal segmental duodenectomy for duodenal and proximal jejunal gastrointestinal stromal tumors (GIST).

MATERIALS AND METHODS

This retrospective review of the GIST database at Peking University Cancer Hospital included 50 patients who underwent distal segmental duodenectomies for primary GIST in the duodenum or proximal jejunum within 20 cm of Treitz's ligament between January 2008 and December 2023. The patients were divided into two groups: non-bypass (without gastrojejunostomy) and bypass (with gastrojejunostomy and Braun's jejunojejunostomy). Perioperative characteristics and postoperative complications were analyzed.

RESULTS

Among the 50 patients, 27 underwent duodenojejunostomies without gastrojejunostomies and 23 with gastrojejunostomies and Braun's jejunojejunostomies. The incidence of grade B-C DGE was significantly lower in the bypass group (43.5% vs. 74.1%, p = 0.028). In addition, non-bypass surgery was an independent risk factor for increased grade B-C DGE (OR 3.67, 95% CI 1.07-12.64, p = 0.039). The bypass group showed a trend towards a shorter postoperative hospital stay (median: 14 days, range: 10-56) compared to the non-bypass group (median: 28 days, range: 6-75), but this difference did not reach statistical significance (p = 0.070). Operative time (min) was significantly longer in the multi-visceral resection group (381.0 ± 108.8 vs. 227.3 ± 87.6, p < 0.001), for tumors ≥ 6.3 cm compared to < 6.3 cm (337.0 ± 116.4 vs. 228.3 ± 99.8, p = 0.002), and in patients with positive preoperative symptoms versus asymptomatic patients (319.9 ± 118.0 vs. 210.2 ± 90.3, p = 0.031).

CONCLUSION

The addition of gastrojejunostomy and Braun's jejunojejunostomy in distal segmental duodenectomy can reduce the incidence of grade B-C DGE, potentially facilitating timely adjuvant imatinib therapy. Future multicenter studies are needed to confirm these findings.

Genomic and transcriptomic landscape of human gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GISTs) are clinically heterogenous exhibiting varying degrees of disease aggressiveness in individual patients. We comprehensively describe the genomic and transcriptomic landscape of a cohort of 117 GISTs including 31 low-risk, 18 intermediate-risk, 29 high-risk, 34 metastatic and 5 neoadjuvant GISTs from 105 patients. GISTs have notably low tumor mutation burden but widespread copy number variations. Aggressive GISTs harbor remarkably more genomic aberrations than low-/intermediate-risk GISTs. Complex genomic alterations, chromothripsis and kataegis, occur selectively in aggressive GISTs. Despite the paucity of mutations, recurrent inactivating YLPM1 mutations are identified (10.3%, 7 of 68 patients), enriched in high-risk/metastatic GIST and functional study further demonstrates YLPM1 inactivation promotes GIST proliferation, growth and oxidative phosphorylation. Spatially and temporally separated GISTs from individual patients demonstrate complex tumor heterogeneity in metastatic GISTs. Finally, four prominent subtypes are proposed with different genomic features, expression profiles, immune characteristics, clinical characteristics and subtype-specific treatment strategies. This large-scale analysis depicts the landscape and provides further insights into GIST pathogenesis and precise treatment.

The R.O.A.D. to precision medicine

We propose a novel framework that addresses the deficiencies of Randomized clinical trial data subgroup analysis while it transforms ObservAtional Data to be used as if they were randomized, thus paving the road for precision medicine. Our approach counters the effects of unobserved confounding in observational data through a two-step process that adjusts predicted outcomes under treatment. These adjusted predictions train decision trees, optimizing treatment assignments for patient subgroups based on their characteristics, enabling intuitive treatment recommendations. Implementing this framework on gastrointestinal stromal tumors (GIST) data, including genetic sub-cohorts, showed that our tree recommendations outperformed current guidelines in an external cohort. Furthermore, we extended the application of this framework to RCT data from patients with extremity sarcomas. Despite initial trial indications of universal treatment necessity, our framework identified a subset of patients who may not require treatment. Once again, we successfully validated our recommendations in an external cohort.

Radiomics-based predictive model for preoperative risk classification of gastrointestinal stromal tumors using multiparametric magnetic resonance imaging: a retrospective study

OBJECTIVE

The aim of this study was to develop and assess a radiomics model utilizing multiparametric magnetic resonance imaging (MRI) for the prediction of preoperative risk assessment in gastrointestinal stromal tumors (GISTs).

MATERIAL AND METHODS

An analysis was performed retrospectively on a group of 121 patients who received a histological diagnosis of GIST. They were then divided into two sets, with 85 in the training set and 36 in the validation set through random partitioning. Radiomics features from five MRI sequences, totaling 600 per patient, were extracted and subjected to feature selection utilizing a random forest algorithm. The discriminatory efficacy of the models was evaluated through receiver operating characteristic (ROC) and precision-recall (P-R) curve analyses. Model calibration was assessed via calibration curves. Subgroup analysis was performed on GISTs with a pathological maximum diameter equal to or less than 5 cm. Furtherly, Kaplan-Meier (K-M) curves and log-rank tests were used to compare the differences in survival status among different groups. Cox regression analysis was employed to identify independent prognostic factors and to construct a prognostic prediction model.

RESULTS

The clinical model (ModelC) displayed limited predictive efficacy in the context of GIST. Conversely, a radiomics model (ModelR) incorporating five parameters exhibited robust discriminative capabilities across both the training and validation sets, yielding area under the ROC curve (AUC) values of 0.893 (95% confidence interval [CI]: 0.807-0.949) and 0.855 (95% CI: 0.732-0.978), respectively. The F1max scores derived from the P‑R curves were 0.741 and 0.842 for the training and validation sets, respectively. Noteworthy was the exclusion of the two-dimensional tumor diameter and tumor location when constructing a hybrid model (ModelCR) that amalgamated radiomics and clinical features. ModelR demonstrated a substantially enhanced discriminative capacity in the training set compared with ModelC (p < 0.005). The net reclassification improvement (NRI) corroborated the superior performance of ModelR over ModelC, thereby enhancing diagnostic accuracy and clinical applicability. Patients in the high-risk group had significantly worse recurrence-free survival (RFS, p < 0.001) and overall survival (OS, p = 0.004), and the radiomics signature is an independent risk factor for RFS. The extended model incorporating the radiomics signature outperformed the baseline model in terms of risk assessment accuracy (p < 0.001).

CONCLUSION

Our investigation underscores the value of integrating radiomics analysis in conjunction with machine learning algorithms for prognostic risk stratification in GIST, presenting promising implications for informing clinical decision-making processes as well as optimizing management strategies.

Performance of radiomics in preoperative determination of malignant potential and Ki-67 expression levels in gastrointestinal stromal tumors: a systematic review and meta-analysis

Empirical evidence for radiomics predicting the malignant potential and Ki-67 expression in gastrointestinal stromal tumors (GISTs) is lacking. The aim of this review article was to explore the preoperative discriminative performance of radiomics in assessing the malignant potential, mitotic index, and Ki-67 expression levels of GISTs. We systematically searched PubMed, EMBASE, Web of Science, and the Cochrane Library. The search was conducted up to 30 September 2023. Quality assessment was performed using the Radiomics Quality Score (RQS). A total of 35 original studies were included in the analysis. Among them, 26 studies focused on determining malignant potential, three studies on mitotic index discrimination, and six studies on Ki-67 discrimination. In the validation set, the sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of radiomics in the determination of high malignant potential were 0.74 (95% CI=0.69-0.78), 0.90 (95% CI=0.83-0.94), and 0.81 (95% CI=0.14-0.99), respectively. For moderately to highly malignant potential, the sensitivity, specificity, and AUC were 0.86 (95% CI=0.83-0.88), 0.73 (95% CI=0.67-0.78), and 0.88 (95% CI=0.27-0.99), respectively. Regarding the determination of high mitotic index, the sensitivity, specificity, and AUC of radiomics were 0.86 (95% CI=0.83-0.88), 0.73 (95% CI=0.67-0.78), and 0.88 (95% CI=0.27-0.99), respectively. When determining high Ki-67 expression, the combined sensitivity, specificity, and AUC were 0.74 (95% CI=0.65-0.81), 0.81 (95% CI=0.74-0.86), and 0.84 (95% CI=0.61-0.95), respectively. Radiomics demonstrates promising discriminative performance in the preoperative assessment of malignant potential, mitotic index, and Ki-67 expression levels in GISTs.

Endoscopic resection of extra-luminal gastric gastrointestinal stromal tumors using a snare assisted external traction technique (with video)

OBJECTIVE

The primary purpose of the study was to explore the clinical efficacy of the novel snare assisted endoscopic resection of extraluminal growing gastric gastrointestinal stromal tumors (gastric GISTs) using external traction, and the secondary purpose was to compare the novel snare assisted endoscopic resection of extraluminal GISTs with the standard laparoscopic procedure.

METHODS

We retrospectively analyzed the patients who underwent novel external traction assisted endoscopic resection or laparoscopic resection for their extraluminal gastric GIST ≤5 cm in diameter.

RESULTS

A total of 111 patients (27 in the endoscopic group and 84 in the laparoscopic group) were included in this study. There was no significant difference in tumor diameter and complication rate between the two groups. The overall procedure time was slightly higher in the endoscopic group compared to the laparoscopic group (P = 0.034). However, postoperative hospitalization time (P < 0.001) and postoperative fasting time (P = 0.005) were shorter in the endoscopic group compared to the laparoscopic group.

CONCLUSION

Snare external traction-assisted endoscopic resection of extraluminal growing gastric GISTs is safe and effective, and it provides a new adjunctive method for endoscopic resection of GIST.

Gastrointestinal Stromal Tumor (GIST) Quiz: Test your knowledge

Having a strong understanding of the epidemiology, pathophysiology, and clinical management of gastrointestinal stromal tumors (GISTs) is crucial for clinicians who may encounter this cancer. The quiz below is designed for medical students, residents, fellows, and practicing physicians to test their knowledge and review key concepts for understanding GIST.

True Mitotic Count Prediction in Gastrointestinal Stromal Tumors: Bayesian Network Model and PROMETheus (Preoperative Mitosis Estimator Tool) Application Development

BACKGROUND

Gastrointestinal stromal tumors (GISTs) present a complex clinical landscape, where precise preoperative risk assessment plays a pivotal role in guiding therapeutic decisions. Conventional methods for evaluating mitotic count, such as biopsy-based assessments, encounter challenges stemming from tumor heterogeneity and sampling biases, thereby underscoring the urgent need for innovative approaches to enhance prognostic accuracy.

OBJECTIVE

The primary objective of this study was to develop a robust and reliable computational tool, PROMETheus (Preoperative Mitosis Estimator Tool), aimed at refining patient stratification through the precise estimation of mitotic count in GISTs.

METHODS

Using advanced Bayesian network methodologies, we constructed a directed acyclic graph (DAG) integrating pertinent clinicopathological variables essential for accurate mitotic count prediction on the surgical specimen. Key parameters identified and incorporated into the model encompassed tumor size, location, mitotic count from biopsy specimens, surface area evaluated during biopsy, and tumor response to therapy, when applicable. Rigorous testing procedures, including prior predictive simulations, validation utilizing synthetic data sets were employed. Finally, the model was trained on a comprehensive cohort of real-world GIST cases (n=80), drawn from the repository of the Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Humanitas Research Hospital, with a total of 160 cases analyzed.

RESULTS

Our computational model exhibited excellent diagnostic performance on synthetic data. Different model architecture were selected based on lower deviance and robust out-of-sample predictive capabilities. Posterior predictive checks (retrodiction) further corroborated the model's accuracy. Subsequently, PROMETheus was developed. This is an intuitive tool that dynamically computes predicted mitotic count and risk assessment on surgical specimens based on tumor-specific attributes, including size, location, surface area, and biopsy-derived mitotic count, using posterior probabilities derived from the model.

CONCLUSIONS

The deployment of PROMETheus represents a potential advancement in preoperative risk stratification for GISTs, offering clinicians a precise and reliable means to anticipate mitotic counts on surgical specimens and a solid base to stratify patients for clinical studies. By facilitating tailored therapeutic strategies, this innovative tool is poised to revolutionize clinical decision-making paradigms, ultimately translating into improved patient outcomes and enhanced prognostic precision in the management of GISTs.

Endoscopic “calabash” ligation and resection for small gastric mesenchymal tumors

BACKGROUND

Gastric mesenchymal tumors (GMT) are identified as soft tissue neoplasms that arise from mesenchymal stem cells within the gastrointestinal tract. GMT primarily encompass gastric stromal tumors (GST), gastric leiomyomas, and gastric schwannomas. Although most GMT are benign, there are still potential malignant changes, especially GST. Thus, early surgical intervention is the primary treatment for GMT. We have designed a simple endoscopic “calabash” ligation and resection (ECLR) procedure to treat GMT. Its efficacy and safety need to be compared with those of traditional endoscopic techniques, such as endoscopic submucosal excavation (ESE).

AIM

To assess the safety and effectiveness of ECLR in managing small GMT (sGMT) with a maximum diameter ≤ 20 mm by comparing to ESE.

METHODS

This retrospective analysis involved patients who were hospitalized in our institution between November 2021 and March 2023, underwent endoscopic resection, and received a pathological diagnosis of GMT. Cases with a tumor diameter ≤ 20 mm were chosen and categorized into two cohorts: Study and control groups. The study group was composed of patients treated with ECLR, whereas the control group was composed of those treated with ESE. Data on general clinical characteristics (gender, age, tumor diameter, tumor growth direction, tumor pathological type, and risk grade), surgery-related information (complete tumor resection rate, operation duration, hospitalization duration, hospitalization cost, and surgical complications), and postoperative follow-up were collected for both groups. The aforementioned data were subsequently analyzed and compared.

RESULTS

Five hundred and eighty-nine individuals were included, with 297 cases in the control group and 292 in the study group. After propensity score matching, the final analysis incorporated 260 subjects in each cohort. The findings indicated that the study group exhibited shorter operation duration and lowered medical expenses relative to the control group. Furthermore, the study group reported less postoperative abdominal pain and had a lower incidence of intraoperative perforation and postoperative electrocoagulation syndrome than the control group. There were no substantial variations observed in other parameters among the two cohorts.

CONCLUSION

ECLR is a viable and effective approach for managing sGMT.

Optimizing Outcomes in Gastrointestinal Stromal Tumors: A Surgeon's Perspective

Gastrointestinal stromal tumors (GISTs) typically originate in the stomach (60%-70%), followed by the small intestine (20%-30%), with less frequent occurrences in the colon, rectum, and esophagus. The location of the tumor significantly affects both its clinical presentation and treatment approach. Gastric GISTs generally have a better prognosis, while tumors in the small intestine or rectum are associated with a higher likelihood of aggressive growth and recurrence. Surgical resection is the cornerstone of treatment for localized GISTs, with the aim of achieving a complete (R0) resection with negative margins. Preserving tumor integrity during surgery is critical, as rupture could lead to peritoneal spread and worsen outcomes. Minimally invasive surgery may be an option for smaller tumors in favorable locations, while larger or more complex cases may require open surgery. In addition to surgery, tyrosine kinase inhibitors are integral to the treatment of GISTs, especially in cases where the tumor is unresectable, metastatic, or at a high risk of recurrence. Agents such as imatinib have revolutionized GIST treatment, offering neoadjuvant therapy to shrink tumors prior to surgery and adjuvant therapy to reduce recurrence risk after surgery. Long-term monitoring with regular imaging is essential, particularly in high-risk patients, due to the potential for late recurrences. Familiarity with these management strategies is vital for optimizing patient outcomes in GIST care.

Common Symptoms and a Rare Diagnosis: A Case of Duodenal Gastrointestinal Stromal Tumor Presenting as Gastrointestinal Bleeding

Duodenal gastrointestinal stromal tumors (D-GISTs) are a rare subtype of GISTs, accounting for only 4% to 5% of all GIST cases. This case report details the presentation, diagnosis, and management of a 48-year-old female who presented with melena and anemia and was eventually diagnosed with a D-GIST. The tumor was identified through imaging studies, and histopathology performed after surgical resection revealed a submucosal neoplasm composed of spindle cells with extensive hemorrhage and necrosis. Given the tumor's rarity and its challenging presentation, which can mimic other conditions such as pancreatic masses, the case underscores the importance of considering D-GIST in differential diagnoses of duodenal or pancreatic lesions. Surgical resection remains the cornerstone of treatment, with adjuvant therapy considered in high-risk cases to prevent recurrence.

Gastrointestinal stromal tumours: incidence, recurrence and mortality. A decade of patients from a New Zealand tertiary surgical centre

BACKGROUND

Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract. The New Zealand (NZ) population incidence has not previously been documented nor has the potential effect of ethnicity been reviewed. We furthermore wanted to assess the difference between those undergoing a wedge resection versus a more extensive operation which we hypothesised would correlate with recurrence and mortality.

METHODS

All patients (n = 103) with a GIST diagnosed and treated at Te Whatu Ora Waitematā (Auckland, New Zealand) between 2012 and 2021 are presented. Patient demographics, method of GIST detection, management approach, index surgery, histological features, use of adjuvant and neoadjuvant imatinib, follow-up, recurrence and mortality rates were analysed.

RESULTS

This paper reports the largest NZ GIST cohort to date and estimates an incidence of 17 cases per million per year. Eighty-four patients underwent surgical resection, 58 received a wedge resection and 17 received a more extensive operation. Five-year disease-free survival rates were 100% in the low/very low risk, 90% in the intermediate and 59% in the high risk groups as determined by the modified NIH criteria. Our overall 5-year GIST-specific survival rate was 83%; it was 91% in those who underwent a wedge resection and 60% in the extensive operation group. There is evidence that Māori have higher rates of GIST recurrence compared to non-Māori and are more likely to require an extensive surgical resection.

Deep Learning-Based Segmentation and Risk Stratification for Gastrointestinal Stromal Tumors in Transabdominal Ultrasound Imaging

PURPOSE

To develop a deep neural network system for the automatic segmentation and risk stratification prediction of gastrointestinal stromal tumors (GISTs).

METHODS

A total of 980 ultrasound (US) images from 245 GIST patients were retrospectively collected. These images were randomly divided (6:2:2) into a training set, a validation set, and an internal test set. Additionally, 188 US images from 47 prospective GIST patients were collected to evaluate the segmentation and diagnostic performance of the model. Five deep learning-based segmentation networks, namely, UNet, FCN, DeepLabV3+, Swin Transformer, and SegNeXt, were employed, along with the ResNet 18 classification network, to select the most suitable network combination. The performance of the segmentation models was evaluated using metrics such as the intersection over union (IoU), Dice similarity coefficient (DSC), recall, and precision. The classification performance was assessed based on accuracy and the area under the receiver operating characteristic curve (AUROC).

RESULTS

Among the compared models, SegNeXt-ResNet18 exhibited the best segmentation and classification performance. On the internal test set, the proposed model achieved IoU, DSC, precision, and recall values of 82.1, 90.2, 91.7, and 88.8%, respectively. The accuracy and AUC for GIST risk prediction were 87.4 and 92.0%, respectively. On the external test set, the segmentation models exhibited IoU, DSC, precision, and recall values of 81.0, 89.5, 92.8, and 86.4%, respectively. The accuracy and AUC for GIST risk prediction were 86.7 and 92.5%, respectively.

CONCLUSION

This two-stage SegNeXt-ResNet18 model achieves automatic segmentation and risk stratification prediction for GISTs and demonstrates excellent segmentation and classification performance.

Imatinib-induced ulcerative colitis

INTRODUCTION

Imatinib, a tyrosine kinase inhibitor, is the first-line therapy for patients with KIT mutation in gastrointestinal stromal tumor (GIST). Nausea, vomiting, diarrhea, dyspepsia and abdominal pain are common gastrointestinal adverse reactions of imatinib, but imatinib-induced ulcerative colitis (UC) is rarely reported.

CASE REPORT

We presented a case of UC induced by imatinib in a 56-year-old male patient who experienced this adverse event after 5 years of imatinib 400 mg/d treatment following GIST resection.

MANAGEMENT AND OUTCOME

The patient's diarrhea and bloody stools showed significant improvement following the discontinuation of imatinib therapy and administration of antidiarrheal medications. Then, imatinib was restarted at a daily dosage of 400 mg.

DISCUSSION

UC is a rare adverse event associated with imatinib. Physicians should consider the possibility of UC induced by imatinib when patients present with diarrhea and bloody stool after receiving imatinib treatment. This case offered objective evidence of UC induced by imatinib.

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.

Gastrointestinal Stromal Tumors (GISTs) in Pediatric Patients: A Case Report and Literature Review

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms that primarily affect adults, with pediatric cases constituting only 0.5-2.7% of the total. Pediatric GISTs present unique clinical, genetic, and pathological features that distinguish them from adult cases. This literature review aims to elucidate these differences, emphasizing diagnostic and therapeutic challenges. We discuss the resistance of pediatric GISTs to conventional chemotherapy and highlight the importance of surgical intervention, especially in emergency situations involving intra-abdominal bleeding. The review also explores the molecular characteristics of pediatric GISTs, including rare mutations such as quadruple-negative wild-type GIST with an FGF3 gene gain mutation. To illustrate these points, we conclude with a case from our clinic involving a 15-year-old female with multiple CD117-positive gastric GISTs and a quadruple-negative wild-type genetic profile who required urgent surgical intervention following a failed tumor embolization. This case underscores the critical need for early diagnosis and individualized therapeutic strategies combining oncologic and surgical care to improve outcomes in pediatric GIST patients.

Follow-up analysis and research of very low-risk and low-risk gastrointestinal stromal tumors after endoscopic resection

Currently, due to limited long-term evidence, there remains some controversy surrounding the recommended postoperative monitoring strategy for primary low-risk gastrointestinal stromal tumors (GISTs). This study recruited a total of 532 patients diagnosed with very low-risk and low-risk GISTs who underwent endoscopic resection from 2015 to 2021, including 460 very low-risk patients and 72 low-risk patients. Descriptive statistical analysis was used to evaluate the clinical and pathological characteristics of GIST patients, and Kaplan-Meier methods were employed for survival analysis. The results showed that the 5-year recurrence-free survival rates for very low-risk and low-risk patients were 98.5% and 95.9%, respectively. The 5-year disease-specific survival rates for both groups were 100%. Additionally, the 5-year overall survival rates were 99.7% for very low-risk patients and 100% for low-risk patients (P = 0.69). Therefore, it is suggested that routine follow-up monitoring, including endoscopic surveillance and imaging, may not be necessary for very low-risk and low-risk GISTs after endoscopic resection.

Deep learning analysis for differential diagnosis and risk classification of gastrointestinal tumors

OBJECTIVES

Recently, artificial intelligence (AI) has been applied to clinical diagnosis. Although AI has already been developed for gastrointestinal (GI) tract endoscopy, few studies have applied AI to endoscopic ultrasound (EUS) images. In this study, we used a computer-assisted diagnosis (CAD) system with deep learning analysis of EUS images (EUS-CAD) and assessed its ability to differentiate GI stromal tumors (GISTs) from other mesenchymal tumors and their risk classification performance.

MATERIALS AND METHODS

A total of 101 pathologically confirmed cases of subepithelial lesions (SELs) arising from the muscularis propria layer, including 69 GISTs, 17 leiomyomas and 15 schwannomas, were examined. A total of 3283 EUS images were used for training and five-fold-cross-validation, and 827 images were independently tested for diagnosing GISTs. For the risk classification of 69 GISTs, including very-low-, low-, intermediate- and high-risk GISTs, 2,784 EUS images were used for training and three-fold-cross-validation.

RESULTS

For the differential diagnostic performance of GIST among all SELs, the accuracy, sensitivity, specificity and area under the receiver operating characteristic (ROC) curve were 80.4%, 82.9%, 75.3% and 0.865, respectively, whereas those for intermediate- and high-risk GISTs were 71.8%, 70.2%, 72.0% and 0.771, respectively.

CONCLUSIONS

The EUS-CAD system showed a good diagnostic yield in differentiating GISTs from other mesenchymal tumors and successfully demonstrated the GIST risk classification feasibility. This system can determine whether treatment is necessary based on EUS imaging alone without the need for additional invasive examinations.

Interpretable artificial intelligence to optimise use of imatinib after resection in patients with localised gastrointestinal stromal tumours: an observational cohort study

BACKGROUND

Current guidelines recommend use of adjuvant imatinib therapy for many patients with gastrointestinal stromal tumours (GISTs); however, its optimal treatment duration is unknown and some patient groups do not benefit from the therapy. We aimed to apply state-of-the-art, interpretable artificial intelligence (ie, predictions or prescription logic that can be easily understood) methods on real-world data to establish which groups of patients with GISTs should receive adjuvant imatinib, its optimal treatment duration, and the benefits conferred by this therapy.

METHODS

In this observational cohort study, we considered for inclusion all patients who underwent resection of primary, non-metastatic GISTs at the Memorial Sloan Kettering Cancer Center (MSKCC; New York, NY, USA) between Oct 1, 1982, and Dec 31, 2017, and who were classified as intermediate or high risk according to the Armed Forces Institute of Pathology Miettinen criteria and had complete follow-up data with no missing entries. A counterfactual random forest model, which used predictors of recurrence (mitotic count, tumour size, and tumour site) and imatinib duration to infer the probability of recurrence at 7 years for a given patient under each duration of imatinib treatment, was trained in the MSKCC cohort. Optimal policy trees (OPTs), a state-of-the-art interpretable AI-based method, were used to read the counterfactual random forest model by training a decision tree with the counterfactual predictions. The OPT recommendations were externally validated in two cohorts of patients from Poland (the Polish Clinical GIST Registry), who underwent GIST resection between Dec 1, 1981, and Dec 31, 2011, and from Spain (the Spanish Group for Research in Sarcomas), who underwent resection between Oct 1, 1987, and Jan 30, 2011.

FINDINGS

Among 1007 patients who underwent GIST surgery in MSKCC, 117 were included in the internal cohort; for the external cohorts, the Polish cohort comprised 363 patients and the Spanish cohort comprised 239 patients. The OPT did not recommend imatinib for patients with GISTs of gastric origin measuring less than 15·9 cm with a mitotic count of less than 11·5 mitoses per 5 mm2 or for those with small GISTs (<5·4 cm) of any site with a count of less than 11·5 mitoses per 5 mm2. In this cohort, the OPT cutoffs had a sensitivity of 92·7% (95% CI 82·4-98·0) and a specificity of 33·9% (22·3-47·0). The application of these cutoffs in the two external cohorts would have spared 38 (29%) of 131 patients in the Spanish cohort and 44 (35%) of 126 patients in the Polish cohort from unnecessary treatment with imatinib. Meanwhile, the risk of undertreating patients in these cohorts was minimal (sensitivity 95·4% [95% CI 89·5-98·5] in the Spanish cohort and 92·4% [88·3-95·4] in the Polish cohort). The OPT tested 33 different durations of imatinib treatment (<5 years) and found that 5 years of treatment conferred the most benefit.

INTERPRETATION

If the identified patient subgroups were applied in clinical practice, as many as a third of the current cohort of candidates who do not benefit from adjuvant imatinib would be encouraged to not receive imatinib, subsequently avoiding unnecessary toxicity on patients and financial strain on health-care systems. Our finding that 5 years is the optimal duration of imatinib treatment could be the best source of evidence to inform clinical practice until 2028, when a randomised controlled trial with the same aims is expected to report its findings.

FUNDING

National Cancer Institute.

Is laparoscopic approach as treatment of large gastric GIST acceptable?

AIM

Laparoscopic surgery is widely used for small gastric gastrointestinal stromal tumors (GISTs) (≤ 5 cm) but remains a controversial approach for larger gastric GISTs (> 5 cm). This study aims to compare short- and long-term outcomes of laparoscopic resection in comparison with open resection for gastric GISTs measuring over 5 cm.

METHOD

All patients receiving surgery for gastric GIST > 5 cm between 2000 and 2021 in a single tertiary hospital were included. Data were collected from prospectively maintained records. Kaplan-Meier method and log rank test were used to compare survival outcomes.

RESULTS

Among 108 included patients, 59 patients had minimally invasive (MI) surgery (54.6%) whereas 49 patients had open surgery (46.4%). The rate of overall postoperative morbidity was 14.8% and the median length was significantly shorter in the MI group [4 (range 2-30) vs. 7 (range 4-33) days; P = 0.007]. The overall R0 resection rate was 98.2% and the rate of tumor rupture was 13%, not different between the two groups. Recurrence occurred in 24% of the whole population without any difference between groups (20.3% vs. 28.7%, p = 0.31). Minimally invasive surgery was not found as a negative prognostic disease-free survival factor.

CONCLUSION

Laparoscopic surgery could be a safe and feasible alternative to open surgery in large gastric GIST, bringing the benefits of minimally invasive surgery without compromising oncologic results.

Development and interpretation of a multimodal predictive model for prognosis of gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal original tumor in gastrointestinal (GI) tract and is considered to have varying malignant potential. With the advancement of computer science, radiomics technology and deep learning had been applied in medical researches. It's vital to construct a more accurate and reliable multimodal predictive model for recurrence-free survival (RFS) aiding for clinical decision-making. A total of 254 patients underwent surgery and pathologically diagnosed with GIST in The First Hospital of China Medical University from 2019 to 2022 were included in the study. Preoperative contrast enhanced computerized tomography (CE-CT) and hematoxylin/eosin (H&E) stained whole slide images (WSI) were acquired for analysis. In the present study, we constructed a sum of 11 models while the multimodal model (average C-index of 0.917 on validation set in 10-fold cross validation) performed the best on external validation cohort with an average C-index of 0.864. The multimodal model also reached statistical significance when validated in the external validation cohort (n = 42) with a p-value of 0.0088 which pertained to the recurrence-free survival (RFS) comparison between the high and low groups using the optimal threshold on the predictive score. We also explored the biological significance of radiomics and pathomics features by visualization and quantitative analysis. In the present study, we constructed a multimodal model predicting RFS of GIST which was prior over unimodal models. We also proposed hypothesis on the correlation between morphology of tumor cell and prognosis.

The influence of lymphadenectomy on the prognosis of small intestinal stromal tumors: a study based on the SEER database

BACKGROUND

Small intestinal stromal tumors (SISTs) typically require surgical treatment. However, the impact of lymphadenectomy (LA) on long-term prognosis in patients remains unclear. Therefore, we plan to analyze the effect of LA on the prognosis of patients with SISTs using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

Data on SISTs patients between 2000 and 2019 were obtained from the SEER database. Multiple imputation (MI) was employed to handle missing data, while propensity score matching (PSM) was conducted to mitigate selection bias in the comparative assessments between the LA group and the No-LA group. Kaplan-Meier analyses and multivariate Cox proportional hazards models were utilized to evaluate both overall survival (OS) and cancer-specific survival (CSS).

RESULTS

A total of 2412 patients diagnosed with SISTs were included in the study, with 879 undergoing LA and 1533 not undergoing LA. There were no significant differences observed between the two cohorts concerning long-term OS (hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.84-1.13, P  = 0.720) and CSS (HR 1.05, 95% CI 0.86-1.29, P = 0.622). After PSM, 1596 patients (798 in the LA group and 789 in the No-LA group) were matched for comparison. There was also no difference in long-term OS and CSS between the two groups. Subgroup analysis revealed that in the age group > 60 years, the CSS in the No-LA group was superior to that in the LA group. Multivariate Cox regression analysis revealed that age, M stage, marital status, and mitotic rate are significant risk factors influencing OS and CSS.

CONCLUSIONS

Conducting LA in patients with SISTs does not enhance long-term prognosis. For patients aged over 60 years, it may be more advisable to refrain from performing LA.

A Predefined Rule-Based Multi-Factor Risk Stratification Is Associated With Improved Outcomes at a Rural Primary Care Practice

This study built a predefined rule-based risk stratification paradigm using 19 factors in a primary care setting that works with rural communities. The factors include medical and nonmedical variables. The nonmedical variables represent 3 demographic attributes and one other factor represents transportation availability. Medical variables represent major clinical variables such as blood pressure and BMI. Many risk stratification models are found in the literature but few integrate medical and nonmedical variables, and to our knowledge, no such model is designed specifically for rural communities. The data used in this study contain the associated variables of all medical visits in 2021. Data from 2022 were used to evaluate the model. After our risk stratification model and several interventions were adopted in 2022, the percentage of patients with high or medium risk of deteriorating health outcomes dropped from 34.9% to 24.4%, which is a reduction of 30%. The medium-complex patient population size, which had been 29% of all patients, decreased by about 4% to 5.7%. According to the analysis, the total risk score showed a strong correlation with 3 risk factors: dual diagnoses, the number of seen providers, and PHQ9 (0.63, 0.54, and 0.45 correlation coefficients, respectively).

Adjuvant imatinib in high-risk resected gastrointestinal stromal tumors: Merely delaying the inevitable?

INTRODUCTION

Patients with high-risk resected gastrointestinal stromal tumors (GIST) receiving adjuvant imatinib have improved recurrence-free survival (RFS), however whether a complete cytocidal effect exists is unknown. We investigated this using a normalized recurrence timeline measured from end of oncologic treatment (EOOT), defined as the later of resection or end of adjuvant therapy.

METHODS

We reviewed patients with resected high-risk GIST at our cancer center from 2003 to 2018. RFS (measured from resection and EOOT), overall survival (OS), and time to imatinib resistance (TTIR) were analyzed using Kaplan-Meier analysis and multivariable Cox proportional hazards modeling. The performance of the Memorial Sloan Kettering (MSK) GIST nomogram was assessed.

RESULTS

We identified 86 patients with high-risk GIST with a median 106 months of postsurgical follow-up. One-third (n = 29; 34%) did not receive adjuvant imatinib, while 57 (66%) did for a median of 3 years. The MSK nomogram-predicted 5-year RFS for patients receiving adjuvant imatinib was similar to those who did not (29% vs. 31%, p = 0.64). When RFS was measured from EOOT, the MSK-predicted RFS was independently associated with EOOT RFS (hazard ratio 0.22, p = 0.02), while adjuvant imatinib receipt and duration were not. Neither receipt nor duration of adjuvant imatinib were associated with TTIR or OS (all p > 0.05).

CONCLUSIONS

Treatment with adjuvant imatinib delays, but does not clearly impact ultimate recurrence, TTIR, or OS, suggesting many patients with high-risk GIST may receive adjuvant imatinib unnecessarily. Additional studies are needed to establish the benefit of adjuvant therapy versus initiating therapy at first radiographic recurrence.