Gastrointestinal Stromal Tumors

Germline SDHB-inactivating mutation in gastric spindle cell sarcoma

Gastrointestinal stromal tumors (GISTs) are the most frequent mesenchymal tumors of the gastrointestinal tract. Inactivating mutations or epigenetic deregulation of succinate dehydrogenase complex (SDH) genes are considered defining features of a subset of GIST occurring in the stomach. Based on comprehensive molecular profiling and biochemical analysis within a precision oncology program, we identified hallmarks of SDH deficiency (germline SDHB-inactivating mutation accompanied by somatic loss of heterozygosity, lack of SDHB expression, global DNA hypermethylation, and elevated succinate/fumarate ratio) in a 40-year-old woman with undifferentiated gastric spindle cell sarcoma that did not meet the diagnostic criteria for other mesenchymal tumors of the stomach, including GIST. These data reveal that the loss of SDH function can be involved in the pathogenesis of non-GIST sarcoma of the gastrointestinal tract.

Prognostic significance of preoperative plasma fibrinogen levels in primary gastrointestinal stromal tumours: a retrospective cohort study

BACKGROUND

Improved prediction of prognosis for gastrointestinal stromal tumours (GISTs) has become increasingly important since the introduction of targeted therapy. Here, we aimed to evaluate the prognostic significance of preoperative plasma fibrinogen (Fib) levels in patients with primary GISTs and to analyse their correlations with clinicopathological characteristics.

METHODS

A total of 201 previously untreated patients with primary GISTs who had undergone radical surgery at our institution between October 2004 and July 2018 were enrolled. The optimal cut-off value for Fib levels was calculated using time-dependent receiver-operating characteristic curve analysis. RFS, the primary endpoint, was calculated by the Kaplan-Meier method and compared by the log-rank test. Univariate and multivariate Cox regression models were calculated.

RESULTS

High preoperative plasma Fib levels were detected as an independent adverse prognostic factor (p = 0.008, hazard ratio 3.136, 95% CI 1.356‒7.256). Furthermore, high preoperative plasma Fib levels also indicated a poor prognosis within the modified National Institutes of Health (mNIH) high-risk subgroup (p = 0.041). In addition, preoperative plasma Fib levels showed a positive correlation with several prognostic factors and even a linear relationship with tumour size (Spearman correlation coefficient [r] = 0.411, p < 0.001).

CONCLUSIONS

Our results suggest that high preoperative plasma Fib levels may indicate a poor prognosis in patients with primary GISTs. As a cost-effective biomarker, preoperative assessment of plasma Fib levels may help to further risk stratify patients with mNIH high-risk GISTs and instruct the application of targeted therapy.

Long-term survival among patients with gastrointestinal stromal tumors diagnosed after another malignancy: a SEER population-based study

Background

To explore overall survival (OS) and GISTs-specific survival (GSS) among cancer survivors developing a second primary gastrointestinal stromal tumors (GISTs).

Methods

We conducted a cohort study, where patients with GISTs after another malignancy (AM-GISTs, n = 851) and those with only GISTs (GISTs-1, n = 7660) were identified from the Surveillance, Epidemiology, and End Results registries (1988–2016). Clinicopathologic characteristics and survival were compared between the two groups.

Results

The most commonly diagnosed first primary malignancy was prostate cancer (27.7%), followed by breast cancer (16.2%). OS among AM-GISTs was significantly inferior to that of GISTs-1; 10-year OS was 40.3% vs. 50.0%, (p < 0.001). A contrary finding was observed for GSS (10-year GSS 68.9% vs. 61.8%, p = 0.002). In the AM-GISTs group, a total of 338 patients died, of which 26.0% died of their initial cancer and 40.8% died of GISTs. Independent of demographics and clinicopathological characteristics, mortality from GISTs among AM-GISTs patients was decreased compared with their GISTs-1 counterparts (HR, 0.71; 95% CI, 0.59–0.84; p < 0.001), whereas OS was inferior among AM-GISTs (HR, 1.11; 95% CI, 0.99–1.25; p = 0.085).

Conclusions

AM-GISTs patients have decreased risk of dying from GISTs compared with GIST-1. Although another malignancy history does not seemingly affect OS for GISTs patients, clinical treatment of such patients should be cautious.

Retrospective Analysis of Chilean and Mexican GI Stromal Tumor Registries: A Tale of Two Latin American Realities

PURPOSE

Like other malignancies, GI stromal tumors (GIST) are highly heterogeneous. This not only applies to histologic features and malignant potential, but also to geographic incidence rates. Several studies have reported GIST incidence and prevalence in Europe and North America. In contrast, GIST incidence rates in South America are largely unknown, and only a few studies have reported GIST prevalence in Latin America.

PATIENTS AND METHODS

Our study was part of a collaborative effort between Chile and Mexico, called Salud con Datos. We sought to determine GIST prevalence and patients' clinical characteristics, including survival rates, through retrospective analysis.

RESULTS

Overall, 624 patients were included in our study. Our results found significant differences between Mexican and Chilean registries, such as stage at diagnosis, primary tumor location, CD117-positive immunohistochemistry status, mitotic index, and tumor size. Overall survival (OS) times for Chilean and Mexican patients with GIST were 134 and 156 months, respectively. No statistically significant differences in OS were detected by sex, age, stage at diagnosis, or recurrence status in both cohorts. As expected, patients categorized as being at high risk of recurrence displayed a trend toward poorer progression-free survival in both registries.

CONCLUSION

To the best of our knowledge, this is the largest report from Latin America assessing the prevalence, clinical characteristics, postsurgery risk of recurrence, and outcomes of patients with GIST. Our data confirm surgery as the standard treatment of localized disease and confirm a poorer prognosis in patients with regional or distant disease. Finally, observed differences between registries could be a result of registration bias.

Linsitinib (OSI-906) for the Treatment of Adult and Pediatric Wild-Type Gastrointestinal Stromal Tumors, a SARC Phase II Study

PURPOSE

Most gastrointestinal stromal tumors (GIST) have activating mutations of KIT, PDGFRA, or uncommonly BRAF. Fifteen percent of adult and 85% of pediatric GISTs are wild type (WT), commonly having high expression of IGF-1R and loss of succinate dehydrogenase (SDH) complex function. We tested the efficacy of linsitinib, an oral TKI IGF-1R inhibitor, in patients with WT GIST.

PATIENTS AND METHODS

A multicenter phase II trial of linsitinib was conducted. The primary endpoint was objective response rate. Secondary endpoints were clinical benefit rate: complete response, partial response, and stable disease (SD) ≥ 9 months, and quantitative 2[18F]fluoro-2-deoxy-D-glucose (FDG) metabolic response (MR) at week 8. Serum levels for glucose, insulin, IGF-1R ligand IGF1, and binding proteins were obtained to explore correlations to patient outcomes and FDG-PET results.

RESULTS

Twenty patients were accrued in a 6-month period. Grade 3-4 toxicities possibly related to linsitinib were uncommon (8.5%). No objective responses were seen. Clinical benefit rate (CBR) at 9 months was 40%. Intense FDG uptake was observed at baseline, with partial MR of 12% and stable metabolic disease of 65% at week 8; these patients had RECIST 1.1 SD as their best response. Progression-free survival (PFS) and overall survival Kaplan-Meier estimates at 9 months were 52% and 80%, respectively. SDHA/B loss determined by IHC was seen in 35% and 88% of cases, respectively.

CONCLUSIONS

Linsitinib is well tolerated in patients with WT GIST. Although the 9-month CBR was 40%, and PFS at 9 months was 52%, no objective responses were observed. Rapid accrual to this study demonstrates that clinical trials of experimental agents in selected subtypes of GIST are feasible.

Correlations between imatinib plasma trough concentration and adverse reactions in Chinese patients with gastrointestinal stromal tumors

BACKGROUND

Imatinib is the standard treatment for patients with gastrointestinal stromal tumors (GISTs), but there is significant variation in imatinib plasma trough concentrations (C_min ) among patients. The imatinib C_min distribution at different doses and the correlation of adverse reactions with C_min in Chinese patients with GIST from a high-volume center were evaluated.

METHODS

From July 1, 2017 to December 31, 2018, patients who were receiving imatinib treatment for GIST were prospectively enrolled. Steady-state blood samples were obtained from patients who had received same-dose imatinib treatment for ≥1 month with good compliance. Adverse reactions were recorded during regular follow-up, and blood samples were collected 24 ± 2 hours after dosing. Liquid chromatography-tandem mass spectrometry was used to measure drug concentrations.

RESULTS

In total, 307 patients who received 367 dose levels were investigated. The imatinib C_min was 1315 ± 716 ng/mL, 2117 ± 597 ng/mL, and 3844 ± 987 ng/mL in patients who were receiving imatinib 400 mg, 600 mg, and 800 mg daily, respectively. The C_min was significantly correlated with periorbital and limb edema (P < .001), anemia (P < .001), and rash (P = .037). Nausea and vomiting, diarrhea, and conjunctival hemorrhage also were correlated, but not significantly. A much higher C_min was observed with severe adverse reactions. There was no correlation between the imatinib C_min and leukopenia, muscle cramps, or hepatobiliary dysfunction.

CONCLUSIONS

In Chinese patients with GIST, the imatinib C_min was higher than that reported for Western populations, especially at higher doses. The C_min was correlated with periorbital and limb edema, anemia, and rash, suggesting that monitoring the imatinib C_min should be considered when patients develop severe adverse reactions caused by excessive imatinib plasma concentrations.

Pharmacogenomics Biomarkers of Soft Tissue Sarcoma Therapies

Soft tissue sarcomas (STS) are heterogeneous rare malignancies comprising ~1% of all solid cancers in adults and including more than 70 histological and molecular subtypes with different pathological and clinical development characteristics. Over the last two decades, the increased knowledge of the new molecular and genomic mechanisms of different STS histotypes allowed for a reclassification of these tumors and consequently to the development of novel chemotherapeutic agents. Generally, surgery, in combination with radiotherapy only in selected cases of localized disease, represents the most common treatment of primary STS, whereas the principal treatment modality for locally advanced or metastatic disease is first-line chemotherapy. The principal treatment for the preponderance of STS patients is usually an anthracycline (epirubicin and doxorubicin) in monotherapy or in combination with other drug novel chemotherapeutic agents. However, survival for treated patients with metastatic disease is poor, and a 2-years survival rate is about 30%. In this scenario, Pharmacogenomics (PGx) biomarkers that can predict drug response play an important role in the improvement of molecular diagnostics in clinical routines and contribute to elucidating the genetic basis for the differences in treatment efficacy and toxicity among STS patients. This review focuses on recent insight in the PGx biomarkers that have been described to modulate responsiveness and toxicity parameters of conventional and new chemotherapeutics drugs in several STS histotypes.

Progress in determining response to treatment in gastrointestinal stromal tumor

Introduction: Gastrointestinal stromal tumor (GIST) is the most common malignant mesenchymal tumor of the gastrointestinal system. Multiple advances in the management of GIST from the discovery of KIT/PDGRA and other genetic alterations have led to the development of multiple tyrosine kinase inhibitors. Response assessment in GIST is determined with iRECIST (Response Evaluation Criteria in Solid Tumors), PERCIST (PET response criteria in solid tumors), or Choi criteria. Molecular genotyping of the tissue samples is the recent standard for diagnosis, treatment, and response to treatment.Areas covered: In this study, we provide a brief overview of the history of the GIST, molecular sequencing, available treatment options and clinical trials, radiologic response assessment, and the role of ctDNA in response evaluation.Expert opinion: Future GIST management is related to the development of sensitive assays to detect genetic alterations for initial diagnosis, treatment selection, monitoring the response to treatment, resistant mutations, and predicting survival.

The Pharmacokinetic-Pharmacodynamic (PKPD) Relationships of AZD3229, a Novel and Selective Inhibitor of KIT, in a Range of Mouse Xenograft Models of GIST

PURPOSE

The emergence of secondary mutations is a cause of resistance to current KIT inhibitors used in the treatment of patients with gastrointestinal stromal tumors (GIST). AZD3229 is a selective inhibitor of wild-type KIT and a wide spectrum of primary and secondary mutations seen in patients with GIST. The objective of this analysis is to establish the pharmacokinetic-pharmacodynamic (PKPD) relationship of AZD3229 in a range of mouse GIST tumor models harboring primary and secondary KIT mutations, and to benchmark AZD3229 against other KIT inhibitors.

EXPERIMENTAL DESIGN

A PKPD model was developed for AZD3229 linking plasma concentrations to inhibition of phosphorylated KIT using data generated from several in vivo preclinical tumor models, and in vitro data generated in a panel of Ba/F3 cell lines.

RESULTS

AZD3229 drives inhibition of phosphorylated KIT in an exposure-dependent manner, and optimal efficacy is observed when >90% inhibition of KIT phosphorylation is sustained over the dosing interval. Integrating the predicted human pharmacokinetics into the mouse PKPD model predicts that an oral twice daily human dose greater than 34 mg is required to ensure adequate coverage across the mutations investigated. Benchmarking shows that compared with standard-of-care KIT inhibitors, AZD3229 has the potential to deliver the required target coverage across a wider spectrum of primary or secondary mutations.

CONCLUSIONS

We demonstrate that AZD3229 warrants clinical investigation as a new treatment for patients with GIST based on its ability to inhibit both ATP-binding and A-loop mutations of KIT at clinically relevant exposures.

The Use of Molecular Subtypes for Precision Therapy of Recurrent and Metastatic Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor in the digestive tract. Tyrosine kinase inhibitors (TKIs), represented by imatinib, sunitinib, and regorafenib, have become the main treatment for recurrent and metastatic GISTs. With the wide application of mutation analysis and the precision medicine, molecular characteristics have been determined that not only predict the prognosis of patients with recurrent and metastatic GISTs, but also are closely related to the efficacy of first-, second- and third-line TKIs for GISTs, as well as other TKIs. Despite the significant effects of TKIs, the emergence of primary and secondary resistance ultimately leads to treatment failure and tumor progression. Currently, due to the signal transmission of KIT/PDGFRA during onset and tumor progression, strategies to counteract drug resistance include the replacement of TKIs and the development of new drugs that are directed towards carcinogenic mutations. In addition, it is also the embodiment of precision medicine for GISTs to explore new carcinogenic mechanisms and develop new drugs relying on new biotechnology. Surgery can benefit specific patients but its major purpose is to diminish the resistant clones. However, the prognosis of recurrent and metastatic patients is still unsatisfactory. Therefore, it is worth paying attention to how to maximize the benefits for patients.

MicroRNA-30a targets BECLIN-1 to inactivate autophagy and sensitizes gastrointestinal stromal tumor cells to imatinib

Gastrointestinal stromal tumors (GISTs), the most widespread type of sarcoma, contain driver gene mutations predominantly of receptor tyrosine kinase and platelet-derived growth factor receptor alpha. However, the inevitable development of resistance to imatinib (IM) cannot be fully attributed to secondary driver gene mutations. In this study, we investigated the role of microRNA-30a in sensitization of GIST cells to IM in vivo and in vitro. Higher levels of miR-30a were detected in GIST-T1 cells, which were more sensitive to IM than GIST-882 cells. IM treatment also reduced miR-30a levels, indicating the possible role of miR-30a in GIST IM resistance. Subsequently, miR-30a was confirmed to be an IM sensitizer via a mechanism that was attributed to its involvement in the regulation of cell autophagy. The interaction of miR-30a and autophagy in IM treated GIST cells was found to be linked by beclin-1. Beclin-1 knockdown increased IM sensitivity in GIST cell lines. Finally, miR-30a was confirmed to enhance IM sensitivity of GIST cells in mouse tumor models. Our study provides evidence for the possible role of miR-30a in the emergence of secondary IM resistance in GIST patients, indicating a promising target for overcoming this chemoresistance.

[Wild-type gastroinestinal stromal tumors]

Gastrointestinal stromal tumors (GIST) are the most common non-epithelial tumors of the gastrointestinal tract. Wild-type GISTs (WT-GIST) consist of a rare heterogeneous group characterized by the lack of activating mutations in the tyrosine kinase receptor (Kit) and/or platelet derived growth factor receptor A (PDGFRA). However, WT-GIST is characterized by other genomic alterations, including dehydrogenase succinate (SDH) deficiency or mutations in the Ras pathway. Recent studies have reported many mutations in others genes that may be incriminated in the development of WT-GISTs. Moreover, WT-GIST is frequently associated with hereditary cancer syndromes such as the Carney Triad and Type 1 Neurofibromatosis (NF1). WT-GIST affects usually young and pediatric patients. Most WT-GIST subtypes are insensitive to imatinib; therefore, their therapeutic management is somewhat different from usual GISTs. This review resumes the molecular and therapeutic features of this rare entity.

Preoperative imatinib treatment in patients with locally advanced and metastatic/recurrent gastrointestinal stromal tumors: A single-center analysis

The advent of imatinib mesylate (IM) has dramatically revolutionized the prognosis of advanced and metastatic/recurrent gastrointestinal stromal tumors (GISTs). The objective of this retrospective study is to investigate the safety and efficacy of combination of surgery following IM treatment in the management of advanced and metastatic/recurrent GISTs. We further explore the long-term clinical outcomes in these who underwent therapy of preoperative IM.Eligible patients with GISTs before the onset of the IM therapy and were periodically followed up in the outpatient clinic were included in this study. Detailed clinical and pathologic characteristics were obtained from the medical records of our institution. Univariate and multivariate regression analyses were performed to use for the evaluation of potential prognostic factors.A total of 51 patients were included in the study, of these patients, 36 patients underwent surgery and median duration of preoperative IM is 8.2months (range 3.5-85 months). Significant median tumor shrinkage rate was 29.27% (95% confidence interval 21.00%-34.00%) observed in these patients who responded to IM, and partial response and stable disease were achieved in 24 patients (47.06%) and 23 patients (45.10%), respectively, in light of the RECIST guideline (version 1.1). After the median follow-up of 43.70 months (range 14.2-131.1 months), 1- and 3-year overall survival (OS) were estimated to be 96.1% and 94.0%, respectively, and there was a significant improvement in OS for patients who received surgical intervention versus those who did not.Our study consolidates that patients were received preoperative IM therapy could shrink the size of tumors and facilitate organ-function preservation. The long-term analysis on this study supports that surgical intervention following IM therapy benefits for patients with primary advanced and recurrent or metastatic GISTs on long-term prognosis.

Open transanal resection of low rectal stromal tumor following neoadjuvant therapy of imatinib mesylate: Report of 11 cases and review of literature

OBJECTIVE

The global burden of rectal gastrointestinal stromal tumor (GIST) is increasing. However, a limited number of reports hinder our ability to reach a definitive conclusion regarding the current treatment and prognosis. In this study, we outline our experience with open transanal resection of rectal GIST following neoadjuvant therapy with imatinib mesylate (IM).

PATIENTS AND METHODS

We retrospectively analyzed 11 patients with rectal GISTs treated with neoadjuvant IM therapy and open transanal resection between April 2011 and April 2017 in Shanghai Changzheng Hospital.

RESULTS

The patients had 400-600 mg/day IM once daily for a median of 7 months (range: 3-9 months). Tumor size, distance from the lower margin of the tumor to the anal verge (AV), mitotic rates and mutation analysis were assessed on pretreatment biopsy. After reassessment, all 11 patients underwent transanal R0 resection. With median follow-up of 28 months (range: 8-80 months), there was no tumor recurrence or metastasis.

CONCLUSION

Open transanal resection of rectal GIST after neoadjuvant treatment with IM has good surgical and survival outcomes.

Adherence to Adjuvant Imatinib Therapy in Patients with Gastrointestinal Stromal Tumor in Clinical Practice: A Cross-Sectional Study

BACKGROUND

Adherence to imatinib therapy has been significantly associated with disease progression and direct medical costs in gastrointestinal stromal tumor (GIST) patients. However, adherence to oral anticancer drugs is frequently hindered by the influence of various factors. The aim of this study was to evaluate the prevalence of imatinib adherence and its influencing factors among GIST patients in the adjuvant setting.

METHODS

Adherence of GIST patients (receiving imatinib for ≥1 month) was assessed using the 8-item Morisky Medication Adherence Scale (MMAS), with a score <8 indicating nonadherence. Quality of life and social support were evaluated by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 (EORTC QLQ C30) and Social Support Rating Scale (SSRS). Factors associated with nonadherence were identified by multivariate logistic regression analysis. Imatinib plasma concentrations were determined and compared between adherent and nonadherent groups.

RESULTS

A total of 158 GIST patients were enrolled, 92 (58.2%) patients were considered nonadherent. Intentional nonadherence, especially feeling hassled by treatment plan (34.2% of patients), was common. In the multivariate logistic regression analysis, gender (OR 2.68, 95% CI 1.33-5.41; p = 0.0058), place of residence (OR 3.20, 95% CI 1.39-7.35; p = 0.0061), and global health status (OR 1.02, 95% CI 1.00-1.04; p = 0.0378) were significantly associated with nonadherence. Moreover, imatinib plasma concentrations in nonadherent patients were significantly lower than that in the good adherence group (p = 0.0338).

CONCLUSIONS

Poor adherence to imatinib is a notable problem in Chinese GIST patients in the adjuvant therapy setting. The predominant indicators of nonadherence in this study were gender (female), living in a rural area, and harboring a low global health status score. These indicators may aid clinicians in determining where increased efforts in promoting adherence may be beneficial.

Targeting Non-Oncogene Addiction: Focus on Thyroid Cancer

Thyroid carcinoma (TC) is the most common malignancy of endocrine organs with an increasing incidence in industrialized countries. The majority of TC are characterized by a good prognosis, even though cases with aggressive forms not cured by standard therapies are also present. Moreover, target therapies have led to low rates of partial response and prompted the emergence of resistance, indicating that new therapies are needed. In this review, we summarize current literature about the non-oncogene addiction (NOA) concept, which indicates that cancer cells, at variance with normal cells, rely on the activity of genes, usually not mutated or aberrantly expressed, essential for coping with the transformed phenotype. We highlight the potential of non-oncogenes as a point of intervention for cancer therapy in general, and present evidence for new putative non-oncogenes that are essential for TC survival and that may constitute attractive new therapeutic targets.

Oncological Outcome After Diagnostic Biopsies in Gastrointestinal Stromal Tumors: A Retrospective Cohort Study

OBJECTIVE

To analyze whether the route of preoperative biopsy influences oncological outcome in GIST patients.

SUMMARY OF BACKGROUND DATA

Preoperative biopsies are widely used for diagnosing GIST. Little is known about the risk of tumor seeding after different routes of biopsy.

METHODS

Patients who underwent resection of a primary GIST between 1996 and 2014 were identified from 2 databases from 2 tertiary referral centers. Survival data were obtained using the Kaplan-Meier method. Possible confounders were identified using Cox regression analysis. The primary endpoint was local recurrence free survival (RFS) and the secondary endpoint was DSS.

RESULTS

A total of 228 patients were included, with a median age of 62 years (range 17-86) and a median follow-up time of 53 months (range 1-204). From these patients, 42 patients did not have a biopsy (18%), 70 underwent a transcutaneous biopsy (31%), and 116 a transluminal biopsy (51%). A total of 42 patients (19.0%) had a local and/or distant recurrence. From the 70 patients with a transcutaneous biopsy, only 1 patient developed a needle tract recurrence (1.4%). Local RFS and DSS were both significantly shorter in the transcutaneous biopsy group on univariate analysis compared to the other groups; however, in multivariate analysis the route of biopsy did not influence local RFS (P = 0.128) or DSS (P = 0.096).

CONCLUSIONS

Transluminal or transcutaneous biopsies for diagnosing GIST do not significantly alter the risk of local recurrent disease or DSS in multivariate Cox regressions. The risk of needle tract seeding after transcutaneous biopsy was low.

Comparing about three types of endoscopic therapy methods for upper gastrointestinal submucosal tumors originating from the muscularis propria layer

Background: Endoscopic submucosal excavation (ESE), endoscopic full-thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER) have been widely applied to upper gastrointestinal submucosal tumors (SMTs) originating from the muscularis propria (MP) layer in recent years. But until now, there are few studies that comparing the efficacy and safety of three endoscopic therapy methods.Method: From January 2013 to August 2018, a total of 218 patients with SMTs who underwent ESE, EFTR or STER were enrolled in this retrospective study. Clinicopathological characteristics, endoscopic features, complication and follow-up data were analyzed.Result: There were 114 patients underwent ESE, 61 underwent EFTR and 43 underwent STER, respectively. The en bloc and complete resection rates in STER group (83.7% and 90.0%) were significantly lower and postoperative complication rate (62.8%) was significantly higher than those of the other 2 methods. Furthermore, for lesions <40 mm, no significant differences were found in the en bloc rate, complete rate and postoperative complication rate among 3 methods. The perforation rate decreased in the order of EFTR (100%), ESE (23.7%), STER (7.0%). The median number of clips, fasting time and hospital stay were lowest in ESE group (5, 2 days, and 7 days). And the cost was highest in EFTR group ($4993.1). There were no differences in the bleeding and recurrence rates among three groups.Conclusion: For SMTs <40 mm, the efficacy among 3 ER methods are comparative. The choice of ER methods mainly based on the comprehensive consideration of lesion size, location, growth pattern and clinical experience of endoscopists. For benign SMTs ≥40 mm in stomach, ESE and EFTR becomes alternative choices.

A Phase II Trial of Vandetanib in Children and Adults with Succinate Dehydrogenase-Deficient Gastrointestinal Stromal Tumor

PURPOSE

Gastrointestinal stromal tumors (GIST) are resistant to cytotoxic chemotherapy and radiotherapy. Most GIST in children are wild-type for KIT and PDGFRA (WT GIST) and deficient in expression of succinate dehydrogenase (dSDH GIST). We tested the activity of vandetanib, an oral small-molecule inhibitor of VEGFR2, EGFR, and RET, in patients with dSDH GIST.

PATIENTS AND METHODS

Phase II study of vandetanib (300 mg orally once daily to patients ≥18 years, and 100 mg/m2/dose to patients < 18 years) on a continuous dosing schedule (1 cycle = 28 days) to assess the clinical activity (partial and complete response rate RECIST v1.1) in patients with dSDH GIST. A Simon optimal two-stage design (target response rate 25%, rule out 5%) was used: If ≥1 of 9 patients in stage 1 responded, enrollment would be expanded to 24 patients, and if ≥3 of 24 responded, vandetanib would be considered active.

RESULTS

Nine patients (7 female and 2 male; median age, 24 years; range, 11-52) with metastatic disease were enrolled. Three of the initial 5 adult patients developed treatment-modifying toxicities. After a protocol amendment, two adults received vandetanib at 200 mg/dose with improved tolerability. The two children (<18 years old) enrolled did not experience treatment-modifying toxicities. No partial or complete responses were observed (median number of cycles, 4; range, 2-18).

CONCLUSIONS

Vandetanib at a dose of 300 mg daily was not well tolerated by adults with dSDH GIST. Two of 9 patients had prolonged stable disease, but no partial or complete responses were observed, and vandetanib is thus not considered active in dSDH GIST.

[Imatinib and beyond-what is important for surgery?]

The treatment of gastrointestinal stromal tumors (GIST) has dramatically improved since the introduction of small molecule KIT proto-oncogene receptor tyrosine kinase inhibitors. Nevertheless, the cure of patients is still based on surgical treatment of the primary tumor. The chance of long-term tumor control by tyrosine kinase inhibitors (TKI) even in the metastatic setting also appears to be improved after achieving a surgical complete resection. The decision on which patients will most likely profit from multimodal treatment approaches is increasingly based on complex molecular predictors in addition to clinical factors and also a profound understanding of the biology of GIST that requires discussion in a multidisciplinary, highly experienced treatment team. Novel, more potent inhibitors enable a response to treatment in so far treatment-refractory GIST subtypes, such as the platelet-derived growth factor receptor (PDGFR) D842V mutated GIST subtype and also appear to show treatment benefits even in KIT mutated GIST after the failure of all approved treatments. These treatments are expected to profoundly change treatment algorithms in the near future.

Intestinal tumors in neurofibromatosis 1 with special reference to fatal gastrointestinal stromal tumors (GIST)

Background

Type 1 neurofibromatosis (NF1) is a genetic tumor predisposing Rasopathy. NF1 patients have an increased risk for developing benign and malignant tumors, but the occurrence of intestinal tumors has not been investigated at the population level.

Methods

In this retrospective register‐based total population study, diagnoses of gastrointestinal tract tumors were retrieved from the Finnish Care Register for Health Care for 1,410 NF1 patients and 14,030 reference persons. We also reviewed the death certificates of 232 NF1 patients who died during years 1987–2013, and specifically searched for diagnosis of gastrointestinal stromal tumor (GIST).

Results

The register analysis revealed an increased overall hazard ratio (HR) of 2.6 (95% CI 1.9–3.6) for intestinal tumors in NF1 compared to general population. The highest HR of 15.6 (95% CI 6.9–35.1) was observed in the small intestine. The focused analysis of NF1 death certificates and GISTs demonstrated that the GIST was the primary cause of death in seven patients.

Conclusion

This study emphasizes the need for careful evaluation of NF1 patients with gastrointestinal complaints. The challenge in diagnosis is that the tumors preferably occur at the small intestine, which is difficult target for diagnostic procedures. We also show that the NF1 GISTs may lead to fatal outcome despite of benign histopathological findings at the time of the diagnosis.

TP53 in bone and soft tissue sarcomas

Genomic and functional study of existing and emerging sarcoma targets, such as fusion proteins, chromosomal aberrations, reduced tumor suppressor activity, and oncogenic drivers, is broadening our understanding of sarcomagenesis. Among these mechanisms, the tumor suppressor p53 (TP53) plays significant roles in the suppression of bone and soft tissue sarcoma progression. Although mutations in TP53 were thought to be relatively low in sarcomas, modern techniques including whole-genome sequencing have recently illuminated unappreciated alterations in TP53 in osteosarcoma. In addition, oncogenic gain-of-function activities of missense mutant p53 (mutp53) have been reported in sarcomas. Moreover, new targeting strategies for TP53 have been discovered: restoration of wild-type p53 (wtp53) activity through inhibition of TP53 negative regulators, reactivation of the wtp53 activity from mutp53, depletion of mutp53, and targeting of vulnerabilities in cells with TP53 deletions or mutations. These discoveries enable development of novel therapeutic strategies for therapy-resistant sarcomas. We have outlined nine bone and soft tissue sarcomas for which TP53 plays a crucial tumor suppressive role. These include osteosarcoma, Ewing sarcoma, chondrosarcoma, rhabdomyosarcoma (RMS), leiomyosarcoma (LMS), synovial sarcoma, liposarcoma (LPS), angiosarcoma, and undifferentiated pleomorphic sarcoma (UPS).

Future directions in soft tissue sarcoma treatment

Sarcoma is a broad term for mesenchymal malignancies that arise from soft tissue or bone. Despite classification by histologic subtype, clinical behavior and response to therapy have great variability. Modern genetic sequencing techniques have been able to identify additional genetic variability and subsequently new targeted therapies. In this review, we discuss the current state of STS diagnostics and treatment and explore some of the more promising areas in which progress is being made. We discuss therapies targeting PDGFRα/KIT, β-Catenin/APC/NOTCH, IDH-1/2 mutations, MDM2 amplifications, EZH2/INI1 expression loss, ALK fusion, and ASPSCR1-TFE3 fusion. We also discuss the progress that has been made within immunotherapies. While soft tissue sarcomas still portend a poor prognosis, these targeted therapies and immunotherapies provide treatment with less toxic side effects.

A Phase I Study of Binimetinib (MEK162) Combined with Pexidartinib (PLX3397) in Patients with Advanced Gastrointestinal Stromal Tumor

Lessons Learned.

The combination of pexidartinib and binimetinib was safe and tolerable and demonstrated encouraging signs of efficacy in two patients with advanced gastrointestinal stromal tumor (GIST) refractory to tyrosine kinase inhibitors (TKIs).

Molecular profiling of GISTs at diagnosis and upon progression may provide insight into the mechanisms of response or resistance to targeted therapies.

Additional trials are needed to further explore combined KIT and MEK inhibition in treatment‐naïve and TKI‐refractory patients with advanced GIST.

Background.

Nearly all patients with advanced gastrointestinal stromal tumor (GIST) develop resistance to imatinib, and subsequent treatments have limited efficacy. Dual inhibition of KIT and MAPK pathways has synergistic antitumor activity in preclinical GIST models.

Methods.

This was an investigator‐initiated, phase I, dose escalation study of the MEK inhibitor binimetinib combined with pexidartinib, a potent inhibitor of CSF1R, KIT, and FLT3, in patients with advanced or metastatic GIST who progressed on imatinib. The primary endpoint was phase II dose determination; secondary endpoints included safety, tolerability, and efficacy. An expansion cohort to further evaluate safety and efficacy was planned.

Results.

Two patients were treated at dose level one (binimetinib 30 mg b.i.d. and pexidartinib 400 mg every morning and 200 mg every evening), after which the study was terminated by the manufacturer. No dose‐limiting toxicities (DLTs) were reported, and treatment was well tolerated. The only grade ≥3 treatment‐emergent adverse event (TEAE) was asymptomatic elevated creatine phosphokinase (CPK). Both patients had a best response of stable disease (SD) by RECIST. Progression‐free survival (PFS) and overall survival (OS) were 6.1 and 14.6 months, respectively, in one patient with five prior lines of therapy. The second patient with NF1‐mutant GIST had a 27% decrease in tumor burden by RECIST and remains on study after 19 months of treatment.

Conclusion.

Pexidartinib combined with binimetinib was tolerable, and meaningful clinical activity was observed in two imatinib‐refractory patients.

Imatinib Mesylate

Imatinib mesylate (Gleevec, Glivec [Novartis, Basel, Switzerland], formerly referred to as STI571 or CGP57148B) represents the paradigm of a new class of anticancer agents, so-called small molecules. They have a high selectivity against a specific molecular target known to be the cause for the establishment and maintenance of the malignant phenotype. Imatinib is a rationally designed oral signal transduction inhibitor that specifically targets several protein tyrosine kinases, Abl, Arg (Abl-related gene), the stem cell factor receptor (c-KIT), platelet-derived growth factor receptor (PDGF-R), and their oncogenic forms, most notably BCR-ABL. Imatinib has been shown to have remarkable clinical activity in patients with chronic myeloid leukemia (CML) and malignant gastrointestinal stroma tumors (GIST) leading to its approval for treatment of these diseases. Treatment with imatinib is generally well tolerated with a low incidence of severe side effects. The most common adverse events include mild to moderate edema, muscle cramps, diarrhea, nausea, skin rashes, and myelosuppression. Several mechanisms of resistance have been identified. Clonal evolution, amplification, or overexpression of BCR-ABL as well as mutations in the catalytic domain, P-loop, and other mutations have been demonstrated to play a role in primary and secondary resistance to imatinib, respectively. Understanding of the underlying mechanisms of resistance has led to the development of new second- and third-generation tyrosine kinase inhibitors (see chapters on dasatinib, nilotinib, bosutinib, and ponatinib).

Gastrointestinal Stromal Tumors of the Stomach and Esophagus

Gastrointestinal stromal tumors (GISTs) arise anywhere along the gastrointestinal tract, most commonly as a result of c-kit or PDGFRA proto-oncogene mutations. Surgical resection is an important component of treatment. However, molecular profiling of GISTs has provided many insights into adjuvant and neoadjuvant therapy options. Imatinib, the most frequently studied medical therapy, has been shown in numerous studies to provide benefit to patients in both the neoadjuvant and adjuvant setting. Interval imaging is an important component of the treatment of GISTs and national surveillance recommendations should be followed.

Association between CT imaging features and KIT mutations in small intestinal gastrointestinal stromal tumors

Small intestinal gastrointestinal stromal tumors (GISTs) have different clinical outcomes when KIT mutations are in exons 11 or 9, which are also the most common sites of neoplastic KIT mutations. The purpose of this study is to evaluate the CT imaging features in those two groups. A total of 35 patients were enrolled, and both quantitative and qualitative CT imaging features were compared between patient groups with KIT exon 9 mutations (KIT–9) and exon 11 mutations (KIT–11). The KIT–9 group was statistically associated with a tumor size larger than 10 cm and a higher enhancement ratio when compared with those of the KIT–11 group (both P < 0.05). For the enhancement ratio, the receiver operating characteristic curve indicated a cut-off value of 1.60 to differentiate KIT–9 from KIT–11 tumors. Additionally, tumor necrosis was more commonly seen in the KIT-9 group. In multivariate analysis, tumor size (β = 0.206; P = 0.022) and KIT–9 (β = 0.389; P = 0.006) were independent factors associated with tumor necrosis. Taken together, KIT–9 mutant tumors tended to have CT imaging features indicative of more aggressive neoplasms. These findings may be helpful in identifying more aggressive small intestinal GISTs and optimizing treatment.

Analysis of risk factors of gastrointestinal stromal tumors in different age groups based on SEER database

Objective: To investigate the risk factors affecting the survival of patients with gastrointestinal stromal tumors (GISTs) in different age groups. Methods: Information on 6089 GIST patients was screened from the Surveillance, Epidemiology, and End Results (SEER) database. Risk factor analysis was performed using a chi-square test (univariate analysis). Survival analysis was performed using the Kaplan-Meier method (log-rank test) and the COX proportional hazard model. p Value < .05 was considered statistically significant. Results: Analyzed statistically to reveal that in addition to tumor size, mitotic index, and primary location, age, gender, race, and surgical treatment also were independent risk factors for GISTs. Gender, race, and location of disease influenced the survival rate of patients, which was higher in the young group (≤60 years old) than the elderly group (>60 years). Risk factors such as primary location, tumor diameter, and mitotic index varied significantly between the different age groups. Conclusions: Age, gender, race, and surgical treatment are independent risk factors that influence the prognosis in patients with GISTs. Some risk factors affecting prognosis are age dependent.

Differentiation of duodenal gastrointestinal stromal tumors from hypervascular pancreatic neuroendocrine tumors in the pancreatic head using contrast-enhanced computed tomography

PURPOSE

To determine useful contrast-enhanced computed tomography (CE-CT) features in differentiating duodenal gastrointestinal stromal tumors (duodenal GISTs) from hypervascular pancreatic neuroendocrine tumors in the pancreatic head (pancreatic head NETs).

METHODS

Seventeen patients with pathologically confirmed duodenal GISTs and 25 with pancreatic NETs underwent preoperative CE-CT. CT image analysis included tumor size, morphology, and contrast enhancement. Receiver operating characteristic curves were performed, and cutoff values were calculated to determine CT findings with high sensitivity and specificity.

RESULTS

CT imaging showed duodenal GISTs with higher frequencies of tumor central location close to the duodenum and a predominantly solid tumor type when compared with pancreatic head NETs (p < 0.05 for both). Duodenal GISTs were larger than pancreatic head NETs (3.3 ± 0.9 cm vs. 2.5 ± 1.1 cm, p = 0.03). Duodenal GISTs had significantly lower CT attenuation values (112.9 ± 17.9HU vs. 137.4 ± 32.1HU, p < 0.01) at the arterial phase and higher CT attenuation values at the delayed phase (94.3 ± 7.9HU vs. 84.9 ± 10.4HU, p < 0.01) when compared with pancreatic head NETs. A CT attenuation value of ≤ 135 HU at the arterial phase (30 s) was 76% sensitive, 94.1% specific, and 83.3% accurate for the diagnosis of duodenal GISTs, while a CT attenuation value of ≥ 89.5 HU at the delayed phase (120 s) was 93.3% sensitive, 81.8% specific, and 76.2% accurate for the diagnosis of duodenal GISTs.

CONCLUSION

Tumor central location, size, texture, and contrast enhancement are valuable characteristics for the differentiation between duodenal GISTs and hypervascular pancreatic head NETs during preoperative examination.

Data-Independent Acquisition Mass Spectrometry To Quantify Protein Levels in FFPE Tumor Biopsies for Molecular Diagnostics

Mass spectrometry-based protein quantitation is currently used to measure therapeutically relevant protein biomarkers in CAP/CLIA setting to predict likely responses of known therapies. Selected reaction monitoring (SRM) is the method of choice due to its outstanding analytical performance. However, data-independent acquisition (DIA) is now emerging as a proteome-scale clinical assay. We evaluated the ability of DIA to profile the patient-specific proteomes of sample-limited tumor biopsies and to quantify proteins of interest in a targeted fashion using formalin-fixed, paraffin-embedded (FFPE) tumor biopsies ( n = 12) selected from our clinical laboratory. DIA analysis on the tumor biopsies provided 3713 quantifiable proteins including actionable biomarkers currently in clinical use, successfully separated two gastric cancers from colorectal cancer specimen solely on the basis of global proteomic profiles, and identified subtype-specific proteins with prognostic or diagnostic value. We demonstrate the potential use of DIA-based quantitation to inform therapeutic decision-making using TUBB3, for which clinical cutoff expression levels have been established by SRM. Comparative analysis of DIA-based proteomic profiles and mRNA expression levels found positively and negatively correlated protein-gene pairs, a finding consistent with previously reported results from fresh-frozen tumor tissues.

Approach to wild-type gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) arise from the intestinal pacemaker cells of Cajal. Wild-type gastrointestinal stromal tumors (WT-GIST) are a unique and uncommon subtype of GISTs that lack activating mutations in the tyrosine kinase c-KIT or platelet derived growth factor receptor alpha (PDGFRA) receptors. The lack of these growth-stimulating mutations renders tyrosine kinase receptor inhibitors, such as imatinib mesylate, relatively ineffective against these tumors. WT-GIST arises most commonly due to underlying alternate proliferative signals associated with germ-line, genetic mutations. WT-GIST frequently arises in patients with BRAF mutations, Carney's Triad or neurofibromatosis type-1 (NF-1). All patients with WT-GIST require a careful examination for germ-line mutations and very close observation for recurrent tumors. Surgery remains a mainstay therapy for these patients. This review aims to discuss the most recent data available on the diagnosis and treatment of WT-GIST.

Gastrointestinal stromal tumors: A multidisciplinary challenge

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors located in the alimentary tract. Its usual manifestation is gastrointestinal bleeding. However, small asymptomatic lesions are frequently detected as incidental finding. Characteristically, most GISTs (> 95%) are positive for the KIT protein (CD117) by IHC staining and approximately 80%-90% of GISTs carry a mutation in the c-KIT or PDGFRA genes. Mutational analysis should be performed when planning adjuvant and neoadjuvant therapy, due to its possible resistance to conventional treatment. The arise of tyrosine kinase inhibitor has supposed a revolution in GISTs treatment being useful as adjuvant, neoadjuvant or recurrence disease treatment. That is why a multidisciplinary approach to this disease is required. The correct characterization of the tumor at diagnosis (the diagnosis of recurrences and the evaluation of the response to treatment with tyrosine kinase inhibitors) is fundamental for facing these tumors and requires specialized Endoscopist, Radiologists and Nuclear Medicine Physician. Surgery is the only potentially curative treatment for suspected resectable GIST. In the case of high risk GISTs, surgery plus adjuvant Imatinib-Mesylate for 3 years is the standard treatment. Neoadjuvant imatinib-mesylate should be considered to shrink the tumor in case of locally advanced primary or recurrence disease, unresectable or potentially resectable metastasic tumors, and potentially resectable disease in complex anatomic locations to decrease the related morbidity. In the case of Metastatic GIST under Neoadjuvant treatment, when there are complete response, stable disease or limited disease progression, complete cytoreductive surgery could be a therapeutic option if feasible.

Management of hemorrhage in gastrointestinal stromal tumors: a review

Gastrointestinal stromal tumors (GISTs) are relatively common mesenchymal tumors. They originate from the wall of hollow viscera and may be found in any part of the digestive tract. The prognosis of patients with stromal tumors depends on various risk factors, including size, location, presence of mitotic figures, and tumor rupture. Emergency surgery is often required for stromal tumors with hemorrhage. The current literature suggests that stromal tumor hemorrhage indicates poor prognosis. Although the optimal treatment options for hemorrhagic GISTs are based on surgical experience, there remains controversy with regard to optimum postoperative management as well as the classification of malignant potential. This article reviews the biological characteristics, diagnostic features, prognostic factors, treatment, and postoperative management of GISTs with hemorrhage.