A prospective epidemiological study of new incident GISTs during two consecutive years in Rhône Alpes region: incidence and molecular distribution of GIST in a European region

Gastrointestinal stromal tumour (GIST): British Sarcoma Group clinical practice guidelines

BACKGROUND

British Sarcoma Group guidelines for the management of GIST were initially informed by those published by the European Society of Clinical Oncology. This update was written by a group of experts to includes a discussion of the highlight improvements in our knowledge of the disease and recent treatment developments. The guidelines include sections on Incidence, Aetiology, Diagnosis, including risk assessment, Treatment and Follow-up.

METHODS

A careful review of the literature was performed to ensure that wherever possible recommendations are supported by the results of clinical trials or substantive retrospective reports. Areas of uncertainty are indicated appropriately.

CONCLUSION

Guidelines represent a consensus view of current best clinical practice. Where appropriate, key recommendations are given and the levels of evidence and strength of recommendation gradings are those used by the European Society for Medical Oncology (ESMO).

Clinicopathological Characteristics and the First Mutational Analysis of Gastrointestinal Stromal Tumors From Mexico: A Single Institution Experience

Background Gastrointestinal stromal tumors (GISTs) arise from Cajal's interstitial cell precursors and display a variety of genetic mutations, primarily in the KIT and PDGFRA genes. These mutations are linked to tumor location, prognosis, and response to treatment. This study delves into the mutational patterns of GISTs in a Mexican population and their impact on overall survival (OS) and disease-free survival (DFS). Methodology This retrospective study examined 42 GIST cases diagnosed at the Oncology Hospital of the National Medical Center XXI Century between January 2018 and December 2020. Clinical, histological, and immunohistochemical data were gathered, and mutational analysis of KIT and PDGFRA genes was conducted using second-generation sequencing. Results The study group consisted of 52.4% females and 47.6% males, with an average age of 62.6 years. The most common tumor site was the stomach (59.5%), followed by the small intestine (26.2%). KIT mutations were detected in 71.4% of cases, predominantly involving exon 11. PDGFRA mutations were observed in 7.1% of cases. Recurrence was noted in 9.5% of patients, all with high-risk tumors. No significant link was identified between specific mutations and OS or DFS. Conclusions This investigation sheds light on the genetic landscape of GISTs in the Mexican population. While no significant association was established between particular mutations and survival outcomes, the study emphasizes the importance of molecular profiling in treatment decision-making. Further studies with larger sample sizes and longer follow-up periods are necessary to validate these results and explore their clinical relevance.

Treatment Access for Gastrointestinal Stromal Tumor in Predominantly Low- and Middle-Income Countries

Importance

Gastrointestinal stromal tumor (GIST) is a rare cancer treated with the tyrosine kinase inhibitors imatinib mesylate or sunitinib malate. In general, in low- and middle-income countries (LMICs), access to these treatments is limited.

Objective

To describe the demographic characteristics, treatment duration, and survival of patients with GIST in LMICs treated with imatinib and sunitinib through The Max Foundation programs.

Design, Setting, and Participants

This retrospective database cohort analysis included patients in 2 access programs administered by The Max Foundation: the Glivec International Patient Assistance Program (GIPAP), from January 1, 2001, to December 31, 2016, and the Max Access Solutions (MAS) program, January 1, 2017, to October 12, 2020. Sixty-six countries in which The Max Foundation facilitates access to imatinib and sunitinib were included. Participants consisted of patients with approved indications for imatinib, including adjuvant therapy in high-risk GIST by pathologic evaluation of resected tumor or biopsy-proven unresectable or metastatic GIST. All patients were reported to have tumors positive for CD117(c-kit) by treating physicians. A total of 9866 patients received treatment for metastatic and/or unresectable disease; 2100 received adjuvant imatinib; 49 received imatinib from another source and were only included in the sunitinib analysis; and 53 received both imatinib and sunitinib through The Max Foundation programs. Data were analyzed from October 13, 2020, to January 30, 2024.

Main Outcomes and Measures

Demographic and clinical information was reported by treating physicians. Kaplan-Meier analysis was used to estimate time to treatment discontinuation (TTD) and overall survival (OS). An imputation-based informed censoring model estimated events for patients lost to follow-up after treatment with adjuvant imatinib. Patients who were lost to follow-up with metastatic or unresectable disease were presumed deceased.

Results

A total of 12 015 unique patients were included in the analysis (6890 male [57.6%]; median age, 54 [range, 0-100] years). Of these, 2100 patients were treated with imatinib in the adjuvant setting (median age, 54 [range 8-88] years) and 9866 were treated with imatinib for metastatic or unresectable disease (median age, 55 [range, 0-100] years). Male patients comprised 5867 of 9866 patients (59.5%) with metastatic or unresectable disease and 1023 of 2100 patients (48.7%) receiving adjuvant therapy. The median OS with imatinib for unresectable or metastatic disease was 5.8 (95% CI, 5.6-6.1) years, and the median TTD was 4.2 (95% CI, 4.1-4.4) years. The median OS with sunitinib for patients with metastatic or unresectable GIST was 2.0 (95% CI, 1.5-2.5) years; the median TTD was 1.5 (95% CI, 1.0-2.1) years. The 10-year OS rate in the adjuvant setting was 73.8% (95% CI, 67.2%-81.1%).

Conclusions and Relevance

In this cohort study of patients with GIST who were predominantly from LMICs and received orally administered therapy through the GIPAP or MAS programs, outcomes were similar to those observed in high-resource countries. These findings underscore the feasibility and relevance of administering oral anticancer therapy to a molecularly defined population in LMICs, addressing a critical gap in cancer care.

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

AIM

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

METHOD

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

RESULTS

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

CONCLUSION

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

Hallmarks and novel insights for gastrointestinal stromal tumors: A bibliometric analysis

BACKGROUND

Due to the increasing recognition of gastrointestinal stromal tumor (GIST), novel insights have appeared in both preclinical and clinical research and begun to reshape the field. This study aims to map the research landscape through bibliometric analysis and provide a brief overview for the future of the GIST field.

METHODS

We searched the Web of Science Core Collection without publication data restrictions for GISTs and performed a bibliometric analysis with CiteSpace and VOSviewer software.

RESULTS

In sum, 5,911 of 13,776 records were included, and these studies were published in 948 journals and written by 24,965 authors from 4,633 institutions in 100 countries. Referring to published reviews and bibliometric analysis, we classified the future trends in four groups. In epidemiological study, precise incidence and clinicopathological features in different regions and races might become potential hotspots. Novel therapy, such as drugs, modified strategies, radioligand therapy, was persistent hotspots in GIST fields, and ctDNA-guided diagnosis, monitoring, and treatment might meet future clinical needs. The debate over serosa surgery vs. mucosa surgery will remain active for a long time in GIST surgery, and function reserve surgery, biology-based surgery will play an important role in future. Moreover, rare GIST type, like NF-1-associated GIST, Carney triads and SDH mutant GIST, need more studies in pathogenesis and genetic mutation to provide appropriate treatment for this orphan GIST patients.

CONCLUSIONS

Potential hotspots in future GIST trends might involve epidemiology, agents, resection therapy and rare type GIST, moreover, researchers could pay more attention in these four fields.

A New Online Dynamic Nomogram: Construction and Validation of a Predictive Model for Distant Metastasis Risk and Prognosis in Patients with Gastrointestinal Stromal Tumors

BACKGROUND

Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the digestive tract, among which patients with distant metastases tend to have a poor prognosis. This study aimed to develop a model for predicting distant metastasis in GIST patients and to develop two models for monitoring overall survival (OS) and cancer-specific survival (CSS) in GIST patients with metastasis. This would allow us to develop an optimal, individualized treatment strategy.

METHODS

We reviewed demographic and clinicopathological characteristics data from 2010 to 2017 of patients diagnosed with GIST in the Surveillance, Epidemiology, and End Results (SEER) database. The data of the external validation group was reviewed from the Forth Hospital of Hebei Medical University. Univariate and multivariate logistic regression analyses were used to confirm the independent risk factors for distant metastasis in the GIST patients, and univariate and multivariate Cox regression analyses were performed to identify the independent prognostic factors for OS and CSS in the GIST patients with distant metastasis. Subsequently, three web-based novel nomograms were developed, which were evaluated by the receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).

RESULTS

Of the 3639 patients who met the inclusion criteria, 418 (11.4%) had distant metastases. The risk factors for distant metastasis in GIST patients included sex, primary site, grade, N stage, tumor size, and mitotic count. For OS, the independent prognosis factors for GIST patients with metastasis included age, race, marital, primary site, chemotherapy, mitotic count, and metastasis at the lung, and for CSS, age, race, marital, primary site, and metastasis at the lung were the independent prognosis factors. Three web-based nomograms were constructed based on these independent factors, respectively. The ROC curves, calibration curves, and DCA were performed in the training, testing, and validation sets which confirmed the high accuracy and strong clinical practice power for the nomograms.

CONCLUSION

Population-based nomograms can help clinicians predict the occurrence and prognosis of distant metastases in patients with GIST, which may be helpful for clinicians to formulate clinical management and appropriate treatment strategies.

Unusual Acute, Massive Lower Gastrointestinal Bleeding Secondary to a Proximal Jejunal Gastrointestinal Stromal Tumor: A Case Report

The most common primary non-epithelial neoplasms of the gastrointestinal (GI) tract are gastrointestinal stromal tumors (GISTs). Ten percent (10%) of GISTs arise from the jejunum. Usually, patients complain of abdominal discomfort, but they may present with complications such as intestinal obstruction or bleeding. This report describes a 35-year-old male who presented with unusually massive, acute lower GI bleeding. After resuscitation and investigations (including a contrast-enhanced computed tomography of the abdomen and lower GI endoscopy), the patient underwent diagnostic laparoscopy and bowel resection of the affected section with anastomosis, and he had an eventful postoperative course. Studies suggest that GI bleeding in GIST occurs due to the ulceration and necrosis of the overlying mucosa caused by the pressure effect of the mass. Small-bowel GISTs are categorized based on their size. Many guidelines have advocated conservative management for small GISTs (<2 cm) that are in the jejunum. This patient has a rare case of a small jejunal GIST with a rare presentation of massive lower GI bleeding. A multidisciplinary approach is useful in managing such cases, and our case showed that laparoscopic intervention is a feasible option in a stable patient with massive lower GI bleeding.

Gastrointestinal Stromal Tumors: Recurrence and Survival Analysis of 49 Patients

Background: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor originating from the gastrointestinal tract and have a broad spectrum of clinicopathological features affecting disease management regarding the treatment modalities. Methods: A retrospective study of 49 patients who underwent surgery for gastrointestinal tumors between 2008 and 2016 was conducted. Clinical, pathological, and immunohistochemical features of patients with and without recurrence were statistically analyzed. Results: Twenty-nine (59.1%) patients had gastric; 16 (32.6%) had small intestinal; 3 (6.1%) had mesenteric; and 1 (2.2%) had rectal GISTs. Microscopic tumor necrosis and tumor ulceration were also significant for disease recurrence (P = 0.005, P = 0.049). High-risk patients according to Miettinen's risk classification were more likely to develop a recurrence (P < 0.001). Additionally, high-grade tumors were also a risk factor for recurrence (P < 0.001). Ki-67 levels were available in 40 patients and the mean Ki-67 level was 16.8 in patients with recurrence, which was a significant risk factor in regression analysis (HR: 1.24, 95%, CI: 1.08-1-43). Five-year disease-free survival rates of non-gastric and gastric GISTs were 62.3% and 90%, respectively (P = 0.044). Conclusion: Larger tumors and higher mitotic rates are more likely to develop recurrence. High Ki-67 levels were also associated with recurrence.

Comparison of 22G Fork-Tip and Franseen Needles and Usefulness of Contrast-Enhanced Endoscopic Ultrasound for Diagnosis of Upper Gastrointestinal Subepithelial Lesions

Endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-TA) is less accurate in obtaining samples from gastrointestinal subepithelial lesions (SELs) ≤2 cm than from pancreatic cancers. The present study compared the usefulness of 22G Fork-tip and Franseen needles for EUS-TA and assessed the ability of contrast-enhanced harmonic EUS (CH-EUS) to diagnose SELs ≤2 cm. Fifty-seven patients who underwent EUS-TA for SELs ≤2 cm were evaluated. The primary endpoint was to compare the rate of acquisition of sufficient samples by these two needles. Secondary endpoints included technical success rate, adverse events, numbers of needle passes, and diagnostic ability of CH-EUS for SELs. Of the 57 included patients, 23 and 34 underwent EUS-TA with Fork-tip and Franseen needles, respectively. Technical success rates were 100% with both needles and adverse events occurred in zero (0%) and one (2.9%) patient with Fork-tip and Franseen needles, respectively. The rate of adequate sample acquisition was significantly higher using Fork-tip than Franseen needles (96% vs. 74%; p = 0.038). The hyper- or iso-vascular pattern on CH-EUS correlated significantly with a diagnosis of gastrointestinal stromal tumor (p < 0.001). EUS-TA with Fork-tip needles were superior to EUS-TA with Franseen needles in acquiring sufficient samples and CH-EUS was also useful for the diagnosis of SELs ≤2 cm.

Current Molecular Profile of Gastrointestinal Stromal Tumors and Systemic Therapeutic Implications

Gastrointestinal stromal tumors (GISTs) are malignant mesenchymal tumors arising from the intestinal pacemaker cells of Cajal. They compose a heterogenous group of tumors due to a variety of molecular alterations. The most common gain-of-function mutations in GISTs are either in the KIT (60-70%) or platelet-derived growth factor receptor alpha (PDGFRA) genes (10-15%), which are mutually exclusive. However, a smaller subset, lacking KIT and PDGFRA mutations, is considered wild-type GISTs and presents distinct molecular findings with the activation of different proliferative pathways, structural chromosomal and epigenetic changes, such as inactivation of the NF1 gene, mutations in the succinate dehydrogenase (SDH), BRAF, and RAS genes, and also NTRK fusions. Currently, a molecular evaluation of GISTs is imperative in many scenarios, aiding in treatment decisions from the (neo)adjuvant to the metastatic setting. Here, we review the most recent data on the molecular profile of GISTs and highlight therapeutic implications according to distinct GIST molecular subtypes.

An overview of agents and treatments for PDGFRA-mutated gastrointestinal stromal tumors

Platelet-derived growth factor receptor A (PDGFRA) mutations occur in approximately 10-15% of gastrointestinal stromal tumors (GISTs). These tumors with PDGFRA mutations have a different pathogenesis, clinical characteristics, and treatment response compared to tumors with receptor tyrosine kinase protein (KIT) mutations (60-70%). Many clinical studies have investigated the use of tyrosine kinase inhibitors mainly in patients with KIT mutations; however, there is a lack of attention to the PDGFRA-mutated molecular subtype. The main effective inhibitors of PDGFRA are ripretinib, avapritinib, and crenolanib, and their mechanisms and efficacy in GIST (as confirmed in clinical trials) are described in this review. Some multi-targeted tyrosine kinase inhibitors with inhibitory effects on this molecular subtype are also introduced and summarized in this paper. This review focuses on PDGFRA-mutated GISTs, introduces their clinical characteristics, downstream molecular signaling pathways, and existing resistance mechanisms. We focus on the most recent literature that describes the development of PDGFRA inhibitors and their use in clinical trials, as well as the potential benefits from different combination therapy strategies.

High-frame-rate contrast-enhanced ultrasound findings of liver metastasis of duodenal gastrointestinal stromal tumor: A case report and literature review

BACKGROUND

Liver metastasis of duodenal gastrointestinal stromal tumor (GIST) is rare. Most reports mainly focus on its treatment and approaches to surgical resection, while details on its contrast-enhanced ultrasound (CEUS) findings are lacking. The diagnosis and imaging modalities for this condition remain challenging.

CASE SUMMARY

A 53-year-old Chinese man presented with mild signs and symptoms of the digestive tract. He underwent routine examinations after GIST surgery. Magnetic resonance imaging showed a 2.3 cm hepatic space-occupying lesion. All the laboratory test results were within normal limits. For further diagnostic confirmation, we conducted high frame rate CEUS (H-CEUS) and found a malignant perfusion pattern. Heterogeneous concentric hyper-enhancement, earlier wash-in than the liver parenchyma, and two irregular vessel columns could be observed at the periphery of the lesion during the arterial phase. Ultrasound-guided puncture biopsy was used to confirm the diagnosis of the lesion as liver metastasis of duodenal GIST. Imatinib was prescribed after biopsy, and the patient’s clinical course was monitored.

CONCLUSION

H-CEUS is useful for detecting microcirculation differences, wash-in patterns, and vascular morphogenesis and diagnosing liver metastasis of duodenal GIST.

Novel endoscopic ultrasonography imaging technique for visualizing microcirculation without contrast enhancement in subepithelial lesions: Prospective study

OBJECTIVES

Detective flow imaging for endoscopic ultrasonography (DFI?EUS) is a new imaging modality developed for detecting fine vessels without using ultrasound contrast agents. This study aimed to evaluate its utility by comparing it with a type of directional power Doppler (eFLOW) for subepithelial lesions (SELs).

METHODS

Between January 2019 and January 2020, 28 patients with SELs undergoing DFI?EUS and eFLOW?EUS were enrolled. DFI?EUS and eFLOW?EUS assessing the vascularity in SELs were compared in terms of the rates of identification of intratumoral vessels. We also investigated how large vessels were depicted in both modalities based on surgical specimens as well as the detection rates of intratumoral vessels in gastrointestinal stromal tumors (GISTs) and non?GISTs using either DFI?EUS or eFLOW?EUS.

RESULTS

Among 28 patients, 23 with pathological confirmation by EUS?guided fine?needle aspiration biopsy (EUS?FNAB) specimens were included. Of those 23 patients, the 10 who underwent surgical resection were selected for analysis. The rate of detection of intratumoral vessels in SELs was significantly higher on DFI?EUS (80%) than on eFLOW?EUS (30%) (P\xA0=\xA00.03). Comparison with surgical specimens revealed that detection rate for vessels with maximum size of less 1000\xA0μm was higher in DFI?EUS (66%) than that in eFLOW?EUS (0%). GIST patients had significantly higher positive rates (90%) of intratumoral vessels than non?GIST patients (31%) on DFI in 23 cases including EUS?FNAB specimens (P\xA0=\xA00.045).

CONCLUSIONS

Detective flow imaging?EUS is more sensitive for depicting intratumoral vessels than eFLOW?EUS. Evaluation of intratumoral vessels on DFI?EUS is useful for identifying GISTs without contrast agents.

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

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

Gastrointestinal stromal tumours

Gastrointestinal stromal tumours (GIST) have an incidence of ~1.2 per 10⁵ individuals per year in most countries. Around 80% of GIST have varying molecular changes, predominantly mutually exclusive activating KIT or PDGFRA mutations, but other, rare subtypes also exist. Localized GIST are curable, and surgery is their standard treatment. Risk factors for relapse are tumour size, mitotic index, non-gastric site and tumour rupture. Patients with GIST with KIT or PDGFRA mutations sensitive to the tyrosine kinase inhibitor (TKI) imatinib that are at high risk of relapse have improved survival with adjuvant imatinib treatment. In advanced disease, median overall survival has improved from 18 months to >70 months since the introduction of TKIs. The role of surgery in the advanced setting remains unclear. Resistance to TKIs arise mainly from subclonal selection of cells with resistance mutations in KIT or PDGFRA when they are the primary drivers. Advanced resistant GIST respond to second-line sunitinib and third-line regorafenib, as well as to the new broad-spectrum TKI ripretinib. Rare molecular forms of GIST with alterations involving NF1, SDH genes, BRAF or NTRK genes generally show primary resistance to standard TKIs, but some respond to specific inhibitors of the activated genes. Despite major advances, many questions in both advanced and localized disease remain unanswered.

Nationwide evaluation of mutation-tailored treatment of gastrointestinal stromal tumors in daily clinical practice

BACKGROUND

Molecular analysis of KIT and PDGFRA is critical for tyrosine kinase inhibitor treatment selection of gastrointestinal stromal tumors (GISTs) and hence recommended by international guidelines. We performed a nationwide study into the application of predictive mutation testing in GIST patients and its impact on targeted treatment decisions in clinical practice.

METHODS

Real-world clinical and pathology information was obtained from GIST patients with initial diagnosis in 2017-2018 through database linkage between the Netherlands Cancer Registry and the nationwide Dutch Pathology Registry.

RESULTS

Predictive mutation analysis was performed in 89% of the patients with high risk or metastatic disease. Molecular testing rates were higher for patients treated in expertise centers (96%) compared to non-expertise centers (75%, P < 0.01). Imatinib therapy was applied in 81% of the patients with high risk or metastatic disease without patient's refusal or adverse characteristics, e.g., comorbidities or resistance mutations. Mutation analysis that was performed in 97% of these imatinib-treated cases, did not guarantee mutation-tailored treatment: 2% of these patients had the PDGFRA p.D842V resistance mutation and 7% initiated imatinib therapy at the normal instead of high dose despite of having a KIT exon 9 mutation.

CONCLUSION

In conclusion, nationwide real-world data show that over 81% of the eligible high risk or metastatic disease patients receive targeted therapy, which was tailored to the mutation status as recommended in guidelines in 88% of cases. Therefore, still 27% of these GIST patients misses out on mutation-tailored treatment. The reasons for suboptimal uptake of testing and treatment require further study.

Incidence of gastrointestinal stromal tumor in Chinese urban population: A national population-based study

Background

Information on incidence of gastrointestinal stromal tumor (GIST), the most common type of mesenchymal tumor in gastrointestinal tract, was limited in China. This study aimed to estimate the incidence of GIST in urban population from mainland China in 2016.

Methods

Urban Employee Basic Medical Insurance (UEBMI) and Urban Residence Basic Medical Insurance (URBMI) in China were used. The denominator of incidence was the total person‐years of insured individuals in 2016 in the database, covering approximately 0.43 billion individuals. The numerator was the number of incident GIST cases in 2016.

Results

The crude incidence in 2016 was 0.40 per 100,000 person‐years (95% CI, 0.06–1.03). Male incidence was higher than female incidence (0.44 vs. 0.36, rate ratio: 1.22, p < 0.001). The mean age at diagnosis was 55.20 years (SD = 14.26) and the incidence among those aged 50 years or older was 2.63 times (0.84 vs. 0.32, p < 0.001) higher than those aged under 50. The highest incidence was observed in East China (2.29, 95% CI: 0.46–5.54).

Conclusions

The incidence of GIST in mainland China was lower than Europe, North America and Korea. The mean age at diagnosis of GIST in China was younger than that of Europe and Canada. This study provides useful information to further research, policy formulating and management of GIST.

Nomogram to Predict Preoperative Occult Peritoneal Metastasis of Gastrointestinal Stromal Tumors (GIST) Based on Imaging and Inflammatory Indexes

Background

Preoperative imaging examination is the primary method for diagnosing metastatic gastrointestinal stromal tumor (GIST), but it is associated with a high rate of missed diagnosis. Therefore, it is important to establish an accurate model for predicting occult peritoneal metastasis (PM) of GIST.

Patients and Methods

GIST patients seen between April 2002 and December 2018 were selected from an institutional database. Using multivariate logistic regression analyses, we created a nomogram to predict occult PM of GIST and validated it with an independent cohort from the same center. The concordance index (C-index), decision curve analysis (DCA) and a clinical impact curve (CIC) were used to evaluate its predictive ability.

Results

A total of 522 eligible GIST patients were enrolled in this study and divided into training (n=350) and validation cohorts (n=172). Factors associated with occult PM were included in the model: tumor size (odds ratio [OR] 1.194 95% confidence interval [CI], 1.034-1.378; p=0.016), primary location (OR 7.365 95% CI, 2.192-24.746; p=0.001), tumor capsule (OR 4.282 95% CI, 1.209-15.166; p=0.024), Alb (OR 0.813 95% CI, 0.693-0.954; p=0.011) and FIB (OR 2.322 95% CI, 1.410-3.823; p=0.001). The C-index was 0.951 (95% CI, 0.917-0.985) in the training cohort and 0.946 (95% CI, 0.900-0.992) in the validation cohort. In the training cohort, the prediction model had a sensitivity of 82.8%, a specificity of 93.8%, a positive predictive value of 54.7%, and a negative predictive value of 98.4%; the validation cohort values were 94.7%, 85.0%, 43.9% and 99.2%, respectively. DCA and CIC results showed that the nomogram had clinical value in predicting occult PM in GIST patients.

Conclusion

Imaging and inflammatory indexes are significantly associated with microscopic metastases of GIST. A nomogram including these factors would have an excellent ability to predict occult PM.

Value of endoscopy with narrow-band imaging and probe-based confocal laser endomicroscopy in the diagnosis of preneoplastic lesions of gastrointestinal tract

INTRODUCTION

Amongst all malignant tumors, cancers of the digestive tract rank first in terms of yearly deaths. Patients above 60 years of age are the most affected, as the diagnosis is frequently made in advanced stages of the disease when therapy is less effective. Our study aimed to evaluate the efficiency of narrow-band imaging (NBI) endoscopy and probe-based confocal laser endomicroscopy (pCLE) in the correct diagnosis of preneoplastic lesions in the upper and lower digestive tract.

PATIENTS, MATERIALS AND METHODS

We included 46 patients with digestive preneoplastic lesions, who underwent either upper or lower digestive endoscopy, followed by NBI and pCLE. We recorded 5-10 frames per each lesion, from different angles and distances during white-light endoscopy and selected frames from full recordings of NBI and pCLE. Usual preparation was used for the endoscopic procedures; pCLE required in vivo administration of 10% Sodium Fluorescein as a contrast agent. Pathology was performed in case of solid tumors. Three medical professionals with different levels of training, blinded to the results, interpreted the data.

RESULTS

The experienced physician correlated very well the NBI findings with pathology (0.93, p=0.05), while the resident physician and the experienced nurse obtain lower, albeit still statistically significant, values (0.73 and 0.62, respectively). For pCLE, the experienced physician obtained near-perfect correlation with pathology (0.96), followed closely by the resident physician (0.93). The nurse obtained a modest correlation (0.42). All examiners obtained approximately equal performances in discerning between malignant and benign lesions.

CONCLUSIONS

Digestive endoscopy in NBI mode proved its effectiveness. Even less experienced endoscopists can achieve good results, while an experienced nurse can positively influence the diagnosis. In the case of pCLE, when available, it can greatly reduce diagnostic times, while requiring higher expertise and specialty training.

Preoperative adjuvant therapy for locally advanced and recurrent/metastatic gastrointestinal stromal tumors: a retrospective study

BACKGROUND

Preoperative imatinib mesylate therapy for gastrointestinal stromal tumors (GISTs) is controversial. This study aimed to explore the clinical efficacy and optimal duration of preoperative imatinib mesylate (IM) therapy in patients with locally advanced and recurrent/metastatic GISTs.

METHODS

We retrospectively examined patients who received preoperative imatinib mesylate therapy from January 2013 to December 2018 at Xiangya Hospital, Central South University and the Second Xiangya Hospital of Central South University, China. Clinical data, including the results of tests for mutations in KIT and PDGFR, findings from regularly conducted re-examinations, abdominal-enhanced computed tomography/magnetic resonance imaging data, responses to imatinib, progression-free survival, and overall cancer-specific survival, were recorded.

RESULTS

A total of 25 patients were enrolled in our study, including 18 with a locally advanced GIST and 7 with recurrent or metastatic GISTs. Their ages ranged from 22 to 70 years (M:F = 1.6:0.9), with a mean age of 50.48 ± 12.51 years. The tumor locations included the stomach (56.0%), rectum (16.0%), enterocoelic/retroperitoneal sites (12.0%), and the small intestine (12.0%). Based on testing for mutations in KIT and PDGFR, 22 patients received 400 mg/day KIT, and 3 patients received 600 mg/day PDGFR. The median duration of preoperative IM therapy was 8.96 ± 4.81 months, ranging from 3 to 26 months. According to the Choi criteria, 24 patients achieved a partial response (PR), and 1 patient had stable disease (SD). All patients underwent surgery after preoperative IM therapy, and no postoperative complications appeared. The 2-year PFS and 5-year PFS were 92% and 60%, respectively, and the total 5-year cancer-specific survival (CSS) was 92%.

CONCLUSION

Preoperative imatinib therapy is feasible for locally advanced and recurrent/metastatic GISTs and can effectively shrink the tumor size, allow organ sparing, and avoid extensive organ resection. Moreover, the optimal duration of preoperative IM therapy in patients with locally advanced and recurrent/metastatic GISTs was 8.96 ± 4.81 months, ranging from 3 to 26 months, and gastric GISTs had a better response to preoperative IM therapy than did non-gastric GISTs.

Imatinib in combination with phosphoinositol kinase inhibitor buparlisib in patients with gastrointestinal stromal tumour who failed prior therapy with imatinib and sunitinib: a Phase 1b, multicentre study

Background

The majority of patients with advanced gastrointestinal stromal tumours (GISTs) develop resistance to imatinib and sunitinib, the standard of care for these patients. This study evaluated the combination of buparlisib, an oral phosphoinositide 3-kinase (PI3K) inhibitor, with imatinib in patients with advanced GIST, who have failed prior therapy with imatinib and sunitinib.

Methods

This Phase 1b, multicentre, open-label study aimed to determine the maximum tolerated dose (MTD) and/or a recommended Phase 2 dose of buparlisib in combination with 400 mg of imatinib through a dose-escalation part and a dose-expansion part, and also evaluated the clinical profile of the combination.

Results

Sixty patients were enrolled, including 25 in the dose-escalation part and 35 in the dose-expansion part. In the combination, MTD of buparlisib was established as 80 mg. No partial or complete responses were observed. The estimated median progression-free survival was 3.5 months in the expansion phase. Overall, 98.3% of patients had treatment-related adverse events (AEs), including 45% with grade 3 or 4 AEs.

Conclusions

Buparlisib in combination with imatinib provided no additional benefit compared with currently available therapies. Due to the lack of objective responses, further development of this combination was not pursued for third-line/fourth-line advanced/metastatic GIST.

Trial registration number

NCT01468688.

Sclerosing Tumors of the Gastrointestinal Tract: A Systematic Approach

Some lesions in the gastrointestinal tract have a propensity for sclerosis such that it may mask the actual true nature of the lesion. The purpose of this review is to highlight those lesions of the gastrointestinal tract that can be attended by sclerosis. The sclerosis can mask the cellularity of the lesion; hence, knowledge of the key lesions that are known to have sclerosis will be aid the diagnostic pathologist.

Adjuvant therapy with imatinib in gastrointestinal stromal tumors (GISTs)-review and perspectives

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of the gastrointestinal (GI) tract. Most of them (>75%) are driven by an oncogenic initiating event involving activating mutations of the genes encoding for tyrosine kinase, KIT or platelet derived growth factor receptor alpha (PDGFRA). Efficacy of the tyrosine kinase Inhibitor imatinib is now well established for advanced disease. For localized GISTs, 3 years treatment is the recommended adjuvant therapy for high risk patients. Whether a longer duration and selection of patients for this adjuvant therapy in localized GISTs remains is not yet established (PERSIST-5 study). Similarly, it will be important to further refine the definition of the population of GIST patients at high risk of relapse including molecular criteria (Annals of Oncology, ESMO guidelines 2018). This review aims to describe current knowledges on the issue of adjuvant therapy of primary GISTs in view of available results.

Survival in advanced GIST has improved over time and correlates with increased access to post-imatinib tyrosine kinase inhibitors: results from Life Raft Group Registry

Background

The use of imatinib, sunitinib, and regorafenib has transformed the treatment of advanced GIST. Sunitinib and regorafenib improve progression free-survival in the second (2L) and third (3L) line, respectively, compared with placebo. However, the impact of these agents on overall survival (OS) is unclear.

Methods

The Life Raft Group (LRG) patient registry contains records from 1716 GIST patients; 526 have advanced to at least 2L treatment. Patient-reported treatment and outcome data were examined to determine treatment patterns and their impact on OS.

Results

Median OS from start of 2L therapy was 32.4 months for sunitinib (n = 436) compared with 27.1 months for patients treated with any other 2L drug (n = 74, p = 0.023, HR 1.377) and 16.8 months for patients who never received sunitinib in any treatment line (n = 42, p = 0.028, HR 1.52). In patients reporting progression in 2L, the median OS in patients subsequently receiving 3L regorafenib (n = 53, 26.2 months) was longer than that of 3L patients who never received regorafenib in any line of therapy (n = 174, 14.3 months, p = 0.0002, HR 2.231), and was longer than that of patients who received any other 3L treatment (19.8 months, p = 0.044, HR 1.525). OS for advanced GIST patients in the LRG registry has improved over time (p = 0.0013), correlated with the increased use of TKIs in ≥ 2L settings.

Conclusions

In our analysis, sunitinib and regorafenib significantly improved OS compared with patients who never received these agents. Our data also support the hypothesis that the use of KIT/PDGFRA inhibitors, including non-approved agents, has improved OS for patients with imatinib- and sunitinib-resistant GIST.

Electronic supplementary material

The online version of this article (10.1186/s13569-019-0114-5) contains supplementary material, which is available to authorized users.

Value of contrast-enhanced harmonic endoscopic ultrasonography in differentiating between gastrointestinal stromal tumors: A meta-analysis

OBJECTIVE

Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) is a valuable device to diagnose and determine the malignant potential of gastrointestinal stromal tumors (GIST) as early as possible when making clinical therapeutic decisions. This study aimed to estimate the ability of CH-EUS to discriminate between GIST and benign submucosal lesions (SML) and to predict their malignant potential.

METHODS

PubMed, MEDLINE, EMBASE, the Web of Science, and Cochrane Central Register of Controlled Trials databases were screened. Using the data provided in the literatures, 2 × 2 tables were constructed to obtain the pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio. A receiver operating characteristic (ROC) curve was generated and the area under the ROC curve (AUROC) was calculated.

RESULTS

Four studies with a total of 187 patients were identified to evaluate the value of CH-EUS in discriminating between GIST and benign SML. The pooled sensitivity, specificity, and AUROC were 89% (95% CI 0.82-0.93), 82% (95% CI 0.66-0.92), and 0.89, respectively. Five studies including 143 patients were analyzed to assess the accuracy of CH-EUS in determining the malignant potential of GIST. The pooled sensitivity, specificity, and AUROC curve of CH-EUS were 96% (95% CI 0.90-0.99), 53% (95% CI 0.40-0.66), and 0.92, respectively.

CONCLUSIONS

CH-EUS is a safe, noninvasive method that can distinguish between GIST and benign subepithelial lesions and to predict their malignant potential to a certain extent. Large-scale, multicenter prospective studies are needed in the future.

CDKN2A Depletion Causes Aneuploidy and Enhances Cell Proliferation in Non-Immortalized Normal Human Cells

Aneuploidy is a common feature of cancer cells and may contribute to cellular transformation and cancer development. In this study, we found that significant down-regulation of CDKN2A, CHEK2, CDCA8, TP53BP1, and CCNDBP1 led to chromosome imbalances in two diploid non-immortalized human cell lines; however, only CDKN2A inhibition enhanced cell proliferation and additionally up-regulated three cell cycle control genes: CDCA8, AURKA, and CCND. These results confirm that CDKN2A is a tumor suppressor gene driving human cancer development by inducing cell aneuploidy and cell cycle up-regulation.

Comprehensive molecular screening by next generation sequencing reveals a distinctive mutational profile of KIT/PDGFRA genes and novel genomic alterations: results from a 20-year cohort of patients with GIST from north-western Greece

Introduction

Gastrointestinal stromal tumours (GIST) are mesenchymal neoplasms that usually carry an activating mutation in KIT or platelet-derived growth factor receptor alpha (PDGFRA) genes with predictive and prognostic significance. We investigated the extended mutational status of GIST in a patient population of north-western Greece in order to look at geopraphic/genotypic distinctive traits.

Patient and methods

Clinicopathological and molecular data of 38 patients diagnosed from 1996 to 2016 with GIST in the region of Epirus in Greece were retrospectively assessed. Formalin-fixed paraffin-embedded tumours were successfully analysed for mutations in 54 genes with oncogenic potential. Next generation sequencing was conducted by using the Ion AmpliSeqCancer Hotspot Panel V.2 for DNA analysis (Thermofisher Scientific).

Results

Among 38 tumours, 24 (63.16%) and seven (18.42%) of the tumours harboured mutations in the KIT and PDGFRA genes, respectively, while seven (18.42%) tumours were negative for either KIT or PDGFRA mutation. No mutations were detected in five (13.16%) cases. Concomitant mutations of BRAF and fibroblast growth factor receptor 3 (FGFR3) genes were observed in two patients with KIT gene mutation. Two patients with KIT/PDGFRA wild-type GIST had mutations in either KRAS or phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) genes. There was no significant survival difference regarding the exonic site of mutation in either KIT or PDGFRA gene. The presence of a mutation in pathway effectors downstream of KIT or PDGFRA, such as BRAF, KRAS or PIK3CA, was associated with poor prognosis. Adverse prognosticators were also high mitotic index and the advanced disease status at diagnosis.

Conclusions

We report comparable incidence of KIT and PDGFRA mutation in patients with GIST from north-western Greece as compared with cohorts from other regions. Interestingly, we identified rare mutations on RAS, BRAF and PIK3CA genes in patients with poor prognosis.

The incidence, mutational status, risk classification and referral pattern of gastro-intestinal stromal tumours in the Netherlands: a nationwide pathology registry (PALGA) study

Symptomatic gastrointestinal stromal tumours (GIST) are infrequent with an incidence of 12.7 per million inhabitants in the western population. We studied whether the incidence of GIST has further increased between 2003 and 2012 and assessed the frequency of mutations, risk groups, histological subtypes and immunohistochemistry results. From PALGA, the nationwide Dutch Pathology Registry, pathology excerpts from all patients with a GIST or GIST-like tumour between 2003 and 2012 were retrieved to calculate incidence rates. Full pathology reports were retrieved of resections in 2011 and 2012 to study the frequency of mutations, risk groups, histological subtypes and immunohistochemistry results. The incidence of GIST increased to 17.7 per million inhabitants in 2012 with a median age of 67 years. Mutational analysis was performed in 33.9% of patients with a resection between 2011 and 2012 (KIT mutation 67.5%, PDGFRA 16.3%, wild-type 11.4%). The percentage of high risk patients in the different risk classifications varied from 19.9% to 38.0% depending on the used classification. Only 35.9% of patients had diagnosis or revision of pathology diagnosis within three months in a designated GIST referral centre. No increase in proportion of central pathology reviews was found. Proportion of patients with mutational analysis increased over the years. The registered incidence of GIST, 17.7 per million inhabitants in 2012 in the Netherlands, is still rising. Despite incorporation in the ESMO GIST guidelines since 2008 for mutational testing and since 2010 for central review of pathology, both are performed in a minority of patients.

Imatinib response of gastrointestinal stromal tumor patients with germline mutation on KIT exon 13: A family report

Familial gastrointestinal stromal tumor (GIST) is a rare autosomal dominant disorder associated with mutations in the KIT gene in the majority of cases. Although, exon 11 appears to be the hot spot region for approximately 95% of germline mutations, pathogenic variations have also been identified in exon 8, 13 and 17. Exon 13 germline mutations are extremely rare amongst familial GISTs and seven families with a germline mutation have been reported to date. Moreover, the role of imatinib mesylate in this rare familiar settings is not completely known so far. We describe here clinical, imaging, pathological and genetic findings of a family with four affected members; grandmother, his son and two grand-sons having a germline gain-of-function mutation of KIT in exon 13 and discuss the imatinib mesylate treatment surveillance outcomes towards disease management.

UK clinical practice guidelines for the management of gastrointestinal stromal tumours (GIST)

BACKGROUND

Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues. Gastrointestinal stromal tumour (GIST) is the commonest STS and arises within the wall of the gastrointestinal (GI) tract. While most GISTs occur in the stomach they do occur in all parts of the GI tract. As with other STS, it is important that GISTs are managed by expert teams, to ensure consistent and optimal treatment, as well as recruitment to clinical trials, and the ongoing accumulation of further knowledge of the disease. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field.

METHODOLOGY

British Sarcoma Group guidelines for the management of GIST were initially developed by a panel of physicians experienced in the management of GIST. This current version has been updated and amended with reference to other European and US guidance. We have received input from representatives of all diagnostic and treatment disciplines as well as patient representatives. Levels of evidence and strength of recommendation gradings are those used by ESMO adapted from those published by the Infectious Disease Society of America.

CONCLUSIONS

The guidelines cover aetiology, genetics and underlying molecular mechanisms, diagnosis and initial investigations, staging and risk stratification, surgery, neoadjuvant and adjuvant therapy, the management of advanced disease and follow-up. The importance of mutational analysis in guiding treatment is highlighted, since this can indicate the most effective treatment and avoid administration of ineffective drugs, emphasising the need for management in specialist centres.

Preoperative imatinib mesylate (IM) for huge gastrointestinal stromal tumors (GIST)

Background

Preoperative imatinib mesylate (IM) treatment has not yet been standardized. Here, we aim to further explore such therapy on patients with gastrointestinal stromal tumors (GIST) retrospectively.

Methods

Patients experiencing preoperative IM were identified from January 2009 to February 2015.

Results

A total of 28 GIST patients were identified. The patients received preoperative IM treatment for a median length of 13.5 months, ranging from 5 to 37 months. PR and SD were observed in 24 (85.7%) and 4 (15.3%) patients, respectively. The tumor shrinkage occurred predominantly within 6 to 12 months, and slight tumor shrinkage could be observed after 12 months in certain patients. Nineteen patients (67.9%) received surgery, and R0 resection was acquired in 18 (94.7%) patients. The initial mean maximum diameter was 10.5 (5.2 to 19.0) cm and decreased to 5.9 (2.7 to 19.0) cm after preoperative treatment with a median length of 12 (ranging from 5 to 36) months (P < 0.001) in patients receiving operations. Three in 7 cases of rectum GIST underwent abdominoperineal resection, and four others adopted sphincter-sparing resection. Partial gastrectomy was performed in four patients.

Conclusions

IM prior to surgery can effectively prevent tumor rupture and facilitate surgery with low surgical morbidity for GIST patients. Tumor shrinkage following IM occurred predominantly within 6 to 12 months, and slight tumor shrinkage could be observed after 12 months in certain patients. In selected patients, prolonged exposure to IM is seemingly advisable under close radiological surveillance.

Somatic mutational spectrum analysis in a prospective series of 104 gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors distinguished by driver mutations in proto-oncogenes KIT or PDGFRA in 85-90% of cases. These mutations have been linked to the response to imatinib, a multikinase inhibitor, and have independent prognostic impact. Here, we describe the prospective study of the molecular characteristics of 104 GISTs from French adult patients analyzed routinely through the National Hospital Program of Molecular Cancer Diagnosis. All patients with GISTs diagnosed at the University Hospital of Besançon between August 2005 and October 2014 were prospectively included in the present study. KIT, PDGFRA and KRAS-codons 12 and 13 as well as BRAF codon 600 mutations were analyzed by Sanger sequencing or SNaPshot. KIT and PDGFRA mutations were detected in 71.2 and 19.2% of the cases, respectively. A total of 43 different mutations were detected of which 13 had never been described. As expected, KIT exon 9 and PDGFRA exon 18 mutations were associated with small bowel and gastric localizations respectively. No mutation was found in KRAS and BRAF. Molecular studies are critical to improve the management of GISTs. Our study enhances the current knowledge by describing 13 new mutations in KIT. A common molecular pattern in all KIT exon 11 substitutions is also described for the first time in this study but its significance remains unknown since genetic and environmental risk factors favoring the development of GISTs such as DNA repair defects and exposure to carcinogens are not currently known.

Comparison of Different Risk Classification Systems in 558 Patients with Gastrointestinal Stromal Tumors after R0-Resection

Background: Due to adjuvant treatment concepts for patients with R0-resected gastrointestinal stromal tumors (GIST), a reproducible and reliable risk classification system proved of utmost importance for optimal treatment of patients and prediction of prognosis. The aim of this study was to reevaluate the impact of five widely-applied and well-established GIST risk classification systems (i.e., scores by Fletcher, Miettinen, Huang, Joensuu, and TNM classification) on a series of 558 GIST patients with long-term follow-up after R0 resection. Methods: Tumor size, mitotic count and site were used in variable combination to predict high- and low risk patients by the use of the five risk classification models. For survival analyses disease-specific survival, disease-free survival and overall-survival were investigated. Patients with initial metastatic disease or incompletely resectable tumors were excluded. Results: All GIST classification models distinguished well between patients with high-risk and low-risk tumors and none of the five risk systems was superior to predict patient outcome. The models showed significant heterogeneity. There was no significant difference between the different risk-groups regarding overall-survival. Subdivision of GIST patients with very low- and low-risk appeared to be negligible. Conclusions: Currently applied GIST risk classification systems are comparable to predict high- or low-risk patients with initial non-metastatic and completely resected GIST. However, the heterogeneity of the high-risk group and the absence of differences in overall survival indicate the need for more precise tumor- and patient-related criteria for better stratification of GIST and identification of patients who would benefit best from adjuvant tyrosine kinase inhibitor therapy.

Rectal gastrointestinal stromal tumor with metastasis to the penis: Case report and review of literature

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The first reported case of a rectal GIST with metastasis to the penis is documented by this report.

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The primary cancer was treated with neoadjuvant chemotherapy and abdominoperineal resection.

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Biopsies of lesions identified on follow-up imaging were consistent with metastatic GIST.

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Metastasectomy and adjuvant chemotherapy have been utilized to help prolong survival.

We report the case of a 51-year-old gentleman with previously diagnosed gastrointestinal stromal tumor (GIST) of the rectum with metastasis to the penis. The patient underwent abdominoperineal resection of the primary tumor with negative margins and completed a three-year course of imatinib mesylate (Gleevec). Forty months after resection of his rectal tumor, the patient presented to his urologist with worsening testicular pain, mild lower urinary tract obstructive symptoms, and nocturia. A pelvic MRI revealed the presence of an ill-defined mass in the right perineum extending from the base of the penis to the penoscrotal junction. Biopsy of this mass was consistent with metastatic GIST. To our knowledge, this is the first report of metastatic GIST to the penis.

Targeted therapy of gastrointestinal stromal tumours

Gastrointestinal stromal tumours (GISTs) are mesenchymal neoplasms originating in the gastrointestinal tract, usually in the stomach or the small intestine, and rarely elsewhere in the abdomen. The malignant potential of GISTs is variable ranging from small lesions with a benign behaviour to fatal sarcomas. The majority of the tumours stain positively for the CD-117 (KIT) and discovered on GIST-1 (DOG-1 or anoctamin 1) expression, and they are characterized by the presence of a driver kinase-activating mutation in either KIT or platelet-derived growth factor receptor α. Although surgery is the primary modality of treatment, almost half of the patients have disease recurrence following surgery, which highlights the need for an effective adjuvant therapy. Traditionally, GISTs are considered chemotherapy and radiotherapy resistant. With the advent of targeted therapy (tyrosine kinase inhibitors), there has been a paradigm shift in the management of GISTs in the last decade. We present a comprehensive review of targeted therapy in the management of GISTs.

Synchronous occurrence of gastrointestinal stromal tumors and other digestive tract malignancies in the elderly

BACKGROUND/AIMS

Elderly patients with gastrointestinal stromal tumors (GISTs) synchronous with other digestive tract malignancies have been rarely reported. In this study, clinicopathological characteristics were evaluated among elderly patients with GISTs with or without coexisting digestive tract malignancies.

METHODS

A total of 161 patients (≥65 years) were retrospectively reviewed at the West China Hospital, Sichuan University from January 2009 to June 2014.

RESULTS

Sixty-one patients were diagnosed with synchronous digestive tract malignancies (synchronous group), whereas 100 patients were diagnosed with no synchronous condition (no-synchronous group). The synchronous group exhibited a higher percentage of males (70.49% vs. 53.00%, P = 0.028) and poorer Eastern Cooperative Oncology Group performance status than the no-synchronous group (P = 0.029). The three-year overall survival (OS) rate was significantly lower among patients with synchronous digestive tract malignancies than that among patients without synchronous condition (64.5% vs. 84.0%, P = 0.003). Multivariate analysis showed that the presence of synchronous digestive tract malignancies (P = 0.002), co-morbidity (P = 0.004), and mitotic count ≥10 mitoses/50 high power fields (P = 0.012) were associated with poor OS.

CONCLUSIONS

A synchronous condition with other digestive tract malignancies is common in elderly patients with GISTs. OS primarily depends on synchronous digestive tract malignancies, mitotic count, and co-morbidity.

Metastatic Liver Disease Associated with Gastrointestinal Stromal Tumors: Controversies in Diagnostic and Therapeutic Approach

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are the most frequent mesenchymal lesions of the GI tract. They are considered to originate from neoplastic transformation of either the intestinal pacemaker cells of Cajal or the precursor pluripotential stem cells. The genetic basis of GIST growth is an activating mutation of two receptor tyrosine kinases. Recent epidemiologic studies demonstrate that the GIST prevalence is approximately 20/1000000/year. Although GISTs develop in every part of the GI tract, stomach remains the most common localization. About 80 % of the patients experience tumor recurrence or hepatic metastasis after radical resection. GIST liver metastases are usually multiple, large in diameter, and localized in both lobes. In addition, GISTs are usually completely asymptomatic, discovered incidentally. Symptoms are not typical and depend on the location, size, and aggressiveness of the tumor.

DISCUSSION

Diagnostic evaluation is based on imaging techniques, such as computed tomography, magnetic resonance imaging, positron emission tomography, and endoscopic ultrasound. Despite recent research on the therapeutic strategies against GISTs, surgical resection appears the only potentially curative approach. For the advanced metastatic disease, imatinib, a tyrosine kinase inhibitor, has been proposed neoadjuvantly with the surgery performed after the adequate reduction of tumor burden. The aim of this review was to evaluate the results of surgical treatment for metastatic GIST with special reference to the extent of its histological spread and to present the recent literature in order to provide an update on the current concepts of advanced surgical management of this entity.

Clinico-pathological characteristics and prognostic factors of gastrointestinal stromal tumors among a Chinese population

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms in the gastrointestinal tract, exhibiting wide variability in their biological behavior. The aim of the present study was to investigate the clinicopathological characteristics and prognostic factors of GISTs in Chinese patients. All GIST cases (n=182) retrieved from the pathology database and the archived files in Shanghai Changzheng Hospital between January 2011 and December 2014 were reviewed. The clinical symptoms, preoperative investigations, treatments, pathological characteristics and follow-up data of these patients were reviewed, and univariate and multivariate survival analyses were performed. A total of 73.1% of the GISTs were located in the stomach, and the most common three symptoms included abdominal pain (30.2%), dyspepsia (23.1%) and gastrointestinal bleeding (21.4%). Univariate analysis revealed that larger tumor size (P<0.001), higher mitotic rate (P<0.001), aggressive behavior (P<0.001), negative smooth muscle actin expression (P=0.009) and palliative resection (P<0.001) contributed toward poor overall survival (OS). In addition, non-gastric disease location (P<0.001), larger tumor size (P<0.001), higher mitotic rate (P=0.004), aggressive behavior (P<0.001) and palliative resection (P<0.001) were associated with poor relapse-free survival (RFS). Multivariate analysis indicated that mitotic rate [hazard ratio (HR=3.761, P=0.015)] and aggressive behavior (HR=3.916, P=0.010) were independent risk factors for OS, while non-gastric location (HR=4.740, P=0.002) and aggressive behavior (HR=4.009, P=0.004) were independent risk factors for RFS. The present study provided information on the clinicopathological characteristics and epidemiology of GISTs in the Chinese population. Non-gastric disease location, higher mitotic rate and tumor metastasis or local invasion prior to treatment were identified as predictors of a poor prognosis.

Global epidemiology of gastrointestinal stromal tumours (GIST): A systematic review of population-based cohort studies

BACKGROUND

Gastrointestinal stromal tumours (GISTs) are rare, yet the most common mesenchymal tumour within the digestive tract. Lack of diagnostic criteria and no specific code in the ICD system has prevented epidemiological evaluation except from overt malignant cases in the past. A global estimate of incidence and disease patterns has thus not been available.

METHODS

A systematic literature search of all available population-based studies on GIST published between January 2000 and December 2014 were reviewed. Descriptive epidemiological data are presented.

RESULTS

The search found 29 studies of more than 13,550 patients from 19 countries that reported sufficient data for regional or national population-based statistics. Age at diagnosis ranged from 10 to 100 years, with median age being mid 60s across most studies. Gender distribution was equal across studies. On average, 18% of patients had an incidental diagnosis (range from 5% to 40%). Anatomical location of primary tumour in 9747 GISTs demonstrated gastric location as the most frequent (55.6%) followed by small bowel (31.8%), colorectal (6.0%), other/various location (5.5%) and oesophagus (0.7%). Most studies reported incidence at 10-15 per million per year. Notably, lowest incidence was in China (Shanxi province) with 4.3 per million per year. Highest incidence rates were reported also from China (Hong Kong and Shanghai areas), and in Taiwan and Norway (Northern part), with up to 19-22 per million per year.

CONCLUSIONS

Epidemiology of GIST demonstrates some consistent features across geographical regions. Whether the reported extreme differences in incidence reflect real variation in population risk warrants further investigation.

Clinical activity of regorafenib in PDGFRA-mutated gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is the most frequent mesenchymal tumor of the gastrointestinal tract and one of the most frequent sarcoma. Mutually exclusive KIT and PDGFRA mutations are central events in GIST pathogenesis, and their understanding is crucial because specific treatment targeting oncogenic KIT and PDGFRA activation (especially imatinib) has become available. The most frequent PDGFRA mutation (D842V) is associated with primary resistance to imatinib. Data related to regorafenib efficacy in PDGFRA-mutated GIST are lacking. We report here a case report of a prolonged response with regorafenib in a patient with a PDGFRA-mutated GIST.

This report describes the clinical efficacy of regorafenib in a patient with metastatic gastrointestinal stromal tumor bearing a mutation of the PDGFRA exon 18 gene.

KIT exon 10 variant (c.1621 A > C) single nucleotide polymorphism as predictor of GIST patient outcome

Background

Tumor genotype plays a crucial role in clinical management of GIST. Whether genetic polymorphism of KIT may influence GIST patient outcome is unclear.

Methods

We investigated the biological and clinical significance of the presence of KIT exon 10 variant (c.1621 A > C), KIT^L541, in a transfected cell line (3 T3 L541) and in two retrospectively collected series of 109 GIST patients in total. The control group consisted of 60 healthy donors collected at the French department of blood transfusion.

Results

In the 3 T3 L541 cell line, KIT^L541 protein exhibited a spontaneous phosphorylation status comparable to that of wild-type KIT but displayed a phosphorylation pattern of AKT and ERK1/2 that was found similar to that of the classical mutated forms of the KIT receptor. Of 109 patients enrolled in this retrospective translational research study, 24 (22 %) harboured KIT^L541, similarly to the control group of healthy donors (n = 10 of 60, 17 %). A higher prevalence of the variant KIT^L541 was observed in patients with metastatic status at diagnosis (KIT^L541 correlated nine of 22 versus 15 of 87, p = 0.02). In addition, patients with KIT^L541 and localized GIST had a higher rate of relapse at 5 years and lower relapse free survival at 5 years in univariate, as well as in multivariate analysis. Response rate and duration of response to imatinib was similar in KIT^L541 and KIT^M541 patients.

Conclusion

KIT^L541 genotype is associated with a higher risk of metastasis at diagnosis and a higher risk of relapse in GIST patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1817-5) contains supplementary material, which is available to authorized users.

Frequence, spectrum and prognostic impact of additional malignancies in patients with gastrointestinal stromal tumors

Currently available data on prognostic implication of additional neoplasms in GIST miss comprehensive information on patient outcome with regard to overall or disease specific and disease free survival. Registry data of GIST patients with and without additional neoplasm were compared in retrospective case series. We investigated a total of 836 patients from the multi-center Ulmer GIST registry. Additionally, a second cohort encompassing 143 consecutively recruited patients of a single oncology center were analyzed. The frequency of additional malignant neoplasms in GIST patients was 31.9% and 42.0% in both cohorts with a mean follow-up time of 54 and 65 months (median 48 and 60 months), respectively. The spectrum of additional neoplasms in both cohorts encompasses gastrointestinal tumors (43.5%), uro-genital and breast cancers (34.1%), hematological malignancies (7.3%), skin cancer (7.3%) and others. Additional neoplasms have had a significant impact on patient outcome. The five year overall survival in GIST with additional malignant neoplasms (n = 267) was 62.8% compared to 83.4% in patients without other tumors (n = 569) (P < .001, HR=0.397, 95% CI: 0.298-0.530). Five-year disease specific survival was not different between both groups (90.8% versus 90.9%). 34.2% of all deaths (n = 66 of n = 193) were GIST-related. The presented data suggest a close association between the duration of follow-up and the rate of additional malignancies in GIST patients. Moreover the data indicate a strong impact of additional malignant neoplasms in GIST on patient outcome. A comprehensive follow-up strategy of GIST patients appears to be warranted.

Clinical Observations on Treatment for Chinese Patients with Gastrointestinal Stromal Tumors

BACKGROUND

To investigate the diagnostic and treatment methods for Chinese patients with gastrointestinal stromal tumor (GIST).

MATERIALS AND METHODS

From January 2004 to June 2014, patients diagnosed with primary GIST and treated by a single medical team in the Department of Digestive Disease of XuYi Hospital of Traditional Chinese Medicine were retrospectively recruited. Re-examination and follow-up was conducted regularly and abdominal enhanced CT, blood biochemistry and responses to surgery or imatinib were recorded.

RESULTS

A total of 15 patients were enrolled, including 9 male and 6 female patients, with an average age of 54 years (ranging from 32-81 years). The primary symptoms were abdominal uncomfortable in 5 patients, abdominal pain in 6 patients as well as nausea and vomiting in 4 patients. One patient was diagnosed with bowl obstruction at the first visit. All patients were treated with surgery, and tumor site was confirmed 1 esophagus, 6 stomach, 4 small bowel, and 4 colorectal and all patients were pathologically diagnosed with GIST. Immunochemical test positive for CD 117 was found 12 patients, and positive for CD 34 in7 patients. The median follow-up time was 24 months (range of 3-63). Three metastasis were confirmed 1.5, 2 and 2.6 years postoperatively. Three patients were treatment by imatinib postoperatively.

CONCLUSIONS

Surgery remains the main treatment method for Chinese patients with GIST and imatinib could be feasible and safe for treating Chinese patients with GIST.

Efficacy of Imatinib in Patients with Platelet-Derived Growth Factor Receptor Alpha-Mutated Gastrointestinal Stromal Tumors

Purpose

The incidence of gastrointestinal stromal tumors (GISTs) harboring platelet-derived growth factor receptor alpha (PDGFRA) mutations is low, therefore further investigation of the efficacy of imatinib in this subgroup was needed.

Materials and Methods

Patients with PDGFRA-mutant GISTs who received imatinib as primary therapy for advanced disease between January 2000 and June 2012 were identified from the GIST registry of Asan Medical Center, Seoul, Korea.

Results

KIT and PDGFRA genotyping in 823 patients identified 18 patients (2%) with PDGFRA mutations who were treated with first-line imatinib. Exon 18 D842V substitution, non-D842V exon 18 mutations, and exon 12 mutations were detected in nine (50%), four (22%), and five (28%) patients, respectively. Objective response rate differed significantly between patients with the D842V mutation and those with non-D842V mutations (0% [0/5] vs. 71% [5/7], p=0.03). In all patients, median progression-free survival (PFS) and overall survival (OS) was 24.8 months (95% confidence interval [CI], 0.0 to 57.2) and 51.2 months (95% CI, 37.1 to 65.3), respectively. Significantly, poorer PFS was observed for patients with D842V-mutant GISTs than those with non-D842V PDGFRA-mutant GISTs: median 3.8 months (95% CI, 1.4 to 6.3) versus 29.5 months (95% CI, 18.3 to 40.7) (p < 0.001). Patients with the D842V mutation had poorer OS than those with non-D842V PDGFRA mutations: median 25.2 months (95% CI, 12.7 to 37.8) versus 59.8 months (95% CI, 43.0 to 76.5) (p=0.02).

Conclusion

Imatinib is active against non-D842V PDGFRA-mutant GISTs, whereas GISTs harboring the D842V mutation are primarily resistant to imatinib.

Surgical treatment of gastrointestinal stromal tumour of the rectum in the era of imatinib

BACKGROUND

Gastrointestinal stromal tumours (GISTs) of the rectum often require radical surgery to achieve complete resection. This study investigated the management and outcome of surgery for rectal GISTs and the role of imatinib.

METHODS

A cohort study was undertaken of patients identified from a database at one tertiary sarcoma referral centre over a continuous period, from January 2001 to January 2013.

RESULTS

Over 12 years, 19 patients presented with a primary rectal GIST. Median age was 57 (range 30-77) years. Neoadjuvant imatinib was used in 15 patients, significantly reducing mean tumour size from 7·6 (95 per cent c.i. 6·1 to 9·0) to 4·1 (2·8 to 5·3) cm (P < 0·001). Nine of these patients underwent surgical resection. Imatinib therapy enabled sphincter-preserving surgery to be undertaken in seven patients who would otherwise have required abdominoperineal resection or pelvic exenteration for tumour clearance. Neoadjuvant imatinib treatment also led to a significant reduction in mean(s.d.) tumour mitotic count from 16(16) to 4(9) per 50 high-power fields (P = 0·015). Imatinib was used only as adjuvant treatment in two patients. There were three deaths, all from unrelated causes. Eleven of the 13 patients who underwent resection were alive without evidence of recurrence at latest follow-up, with a median disease-free survival of 38 (range 20-129) months and overall survival of 62 (39-162) months.

CONCLUSION

The use of neoadjuvant imatinib for rectal GISTs significantly decreased both tumour size and mitotic activity, which permitted less radical sphincter-preserving surgery.

Presence of PDGFRA and DOG1 mutations in gastrointestinal stromal tumors among Chinese population

Approximately 15% of gastrointestinal stromal tumors (GIST) do not express KIT mutations and of these about 5 to 7% harbor mutations in PDGFRA. DOG1 was specifically expressed in GISTs. These cases require special attention for PDGFRA and DOG1 mutational status. Hundred cases of GIST were diagnosed between August 2007 and October 2012 at the First Affiliated Hospital of Guangxi Medical University. DNA from tumor tissues and normal adjacent tissues was isolated and amplified for the 22 exons of PDGFRA and 26 exons of DOG1. Each PCR product was sequenced. Amino acid sequences were inferred from DNA and aligned to GenBank reference sequences to determine the position and type of mutations. Overall, 16.0% of the samples had a mutation in PDGFRA, and GISTs with mutations in the DOG1 gene were not found. Of the mutations detected, they were in PDGFRA exon 18 (8 cases, 8%), PDGFRA exon 12 (5 cases, 5%), PDGFRA exon 14 (1 cases, 1.0%), PDGFRA exon 11 (1 cases, 1.0%), and PDGFRA exon 8 (1 cases, 1.0%). Of these, Y392S, L521P and T632K mutant occurred in PDGFRA exon 8, exon 11 and exon 14, respectively. The mutation of PDGFRA has been considered as another causative genetic event as PDGFRA mutations were found in most GISTs lacking a KIT mutation. PDGFRA mutations occurred preferentially in exon 18 and exon 12. Mutations occurring in PDGFRA exon 8 (Y392S), exon 11 (L521P) and exon 14 (T632K) also were first identified. The over-expression of DOG1 was not related to DOG1 gene mutation.

Association of high expression of Groβ with clinical and pathological characteristics of unfavorable prognosis in gastrointestinal stromal tumors

GROβ (CXCL2) is a chemokine produced by endotoxin-treated macrophages that mediates inflammation and tumor development. However, little is known about GROβ expression in gastrointestinal stromal tumors (GIST) or the relationship between GROβ expression and clinical attributes of GIST. GROβ expression was examined via immunohistochemical staining of 173 GIST samples using tissue microarray. The relationship between GROβ expression and relevant patient and tumor characteristics was assessed, using chi-square tests. Univariate and multivariate analysis was carried out using the Cox regression method. High GROβ cytoplasm staining was detected in 56 (32.4%) specimens; high GROβ nuclear staining was detected in 64 (37.0%) specimens. High GROβ cytoplasm staining was significantly associated with patients' age (P = 0.043) and tumor location (P = 0.014), while high GROβ nucleus staining was significantly associated with mitotic index (P = 0.034), tumor location (P = 0.049), and AFIP-Miettinen risk classification (P = 0.048). Kaplan-Meier survival curves showed GIST patients with low GROβ cytoplasm expression (P = 0.023) and mitotic index < 6 per 50 HPFs (P = 0.026) to have a more favorable prognosis. These findings indicate that GROβ expression correlates with malignant GIST phenotypes and could be an unfavorable prognostic marker in patients with GIST.

Correlation between mutational status and survival and second cancer risk assessment in patients with gastrointestinal stromal tumors: a population-based study

BACKGROUND

Gastrointestinal stromal tumors are sarcomas of the digestive tract characterized by mutations mainly located in the c-KIT or in the platelet-derived growth factor receptor (PDGFR)-alpha genes. Mutations in the BRAF gene have also been described. Our purpose is to define the distribution of c-KIT, PDGFR and BRAF mutations in a population-based cohort of gastrointestinal stromal tumors (GIST) patients and correlate them with anatomical site, risk classification and survival. In addition, as most of the GIST patients have a long survival, second cancers are frequently diagnosed in them. We performed a second primary cancer risk assessment.

METHODS

Our analysis was based on data from Tarragona and Girona Cancer Registries. We identified all GIST diagnosed from 1996 to 2006 and performed a mutational analysis of those in which paraffin-embedded tissue was obtained. Observed (OS) and relative survival (RS) were calculated according to risk classifications and mutational status. Multivariate analysis of variables for observed survival and was also done.

RESULTS

A total of 132 GIST cases were found and we analyzed mutations in 108 cases. We obtained 53.7% of mutations in exon 11 and 7.4% in exon 9 of c-KIT gene; 12% in exon 18 and 1.9% in exon 12 of PDGFR gene and 25% of cases were wild type GIST. Patients with mutations in exon 11 of the c-KIT gene had a 5-year OS and RS of 59.6% and 66.3%, respectively. Patients with mutations in exon 18 of the PDGFR gene had a 5-year OS and RS of 84.6% and 89.7%. In multivariate analysis, only age and risk group achieved statistical significance for observed survival. GIST patients had an increased risk of second cancer with a hazard ratio of 2.47.

CONCLUSIONS

This population-based study shows a spectrum of mutations in the c-KIT and PDGFR genes in GIST patients similar to that previously published. The OS and RS of GIST with the exon 18 PDGFR gene mutation could indicate that this subgroup of patients may be less aggressive and have a good prognosis, although less sensitive to treatment at recurrence. In our study, GIST patients have an increased risk of developing a second neoplasm.

Contrast-enhanced endoscopic ultrasonography can predict a higher malignant potential of gastrointestinal stromal tumors by visualizing large newly formed vessels

BACKGROUND

The aim of this study was to elucidate the histologic and clinical implications of detection of intratumoral vessels on contrast-enhanced endoscopic ultrasonography (CE-EUS) in gastrointestinal stromal tumors (GISTs).

METHODS

Thirteen patients with a GIST, all of whom were referred for surgery, underwent presurgical CE-EUS. The malignant potential, assessed according to the modified Fletcher risk classification system, and the histologic degree of angiogenesis were compared with the presence or absence of intratumoral vessels on CE-EUS.

RESULTS

Of the six tumors with intratumoral vessels observed on CE-EUS, five were intermediate- or high-risk GISTs, and the remaining seven negative cases were categorized as very low risk or low risk. The presence of intratumoral vessels on CE-EUS was significantly correlated with a higher-risk classification (p = 0.005). On histologic examination, all GISTs having visualized vessels incorporated vessels of more than 500 μm in diameter. The large intratumoral vessels of the five intermediate- or high-risk GISTs lacked elastic fibers, suggesting that they were neovascular in nature. These higher-risk tumors were also found, by immunohistochemical analysis, to have high expression of vascular endothelial growth factor.

CONCLUSIONS

Intratumoral vessels observed in GISTs on CE-EUS are correlated with a higher degree of angiogenesis, resulting in higher malignant potential.