Prospective multicentric randomized phase III study of imatinib in patients with advanced gastrointestinal stromal tumors comparing interruption versus continuation of treatment beyond 1 year: the French Sarcoma Group

Discontinuation versus continuation of imatinib in patients with advanced gastrointestinal stromal tumours (BFR14): exploratory long-term follow-up of an open-label, multicentre, randomised, phase 3 trial

BACKGROUND

The long-term impact of tyrosine kinase inhibitor (TKI) discontinuation on resistance and survival in patients with advanced gastrointestinal stromal tumours (GIST) is unclear. We report the exploratory long-term outcomes of patients with advanced GIST stopping imatinib in the BFR14 trial.

METHODS

BFR14, an open-label, randomised, phase 3 trial, was done in 17 comprehensive cancer centres or hospitals across France. Patients with advanced GIST aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0-3, no previous treatment with imatinib, and no previous malignancy were eligible. Patients were treated with oral imatinib 400 mg daily. Patients with a complete or partial response, or stable disease, according to Response Evaluation Criteria in Solid Tumours (1.0) at 1 year, 3 years, and 5 years from the start of treatment were randomly assigned (1:1) to treatment discontinuation until progression (interruption group) or treatment continuation until progression (continuation group). Randomisation was done centrally with computer-generated permuted blocks of two and six patients stratified by participating centre and presence or absence of residual disease on CT scan. The primary endpoint was progression-free survival. Secondary endpoints included time to imatinib resistance and overall survival. Analyses were conducted on an intention-to-treat basis in all randomly assigned patients who were not lost to follow-up. This trial is registered with ClinicalTrial.gov, NCT00367861.

FINDINGS

Between May 12, 2003, and March 16, 2004, after 1 year of imatinib, 32 patients were randomly assigned to the interruption group and 26 to the continuation group. Between June 13, 2005, and May 30, 2007, after 3 years of imatinib, 25 patients were randomly assigned to the interruption group and 25 to the continuation group. Between Nov 9, 2007, and July 12, 2010, after 5 years of imatinib, 14 patients were randomly assigned to the interruption group and 13 to the continuation group. Median follow-up was 235·2 months (IQR 128·8-236·6) after the 1-year randomisation, 200·9 months (190·2-208·4) after the 3-year randomisation, and 164·5 months (134·4-176·4) after the 5-year randomisation. Median progression-free survival in the interruption group versus the continuation group after 1 year of imatinib was 6·1 months (95% CI 2·5-10·1) versus 27·8 months (19·5-37·9; hazard ratio [HR] 0·36 [95% CI 0·20-0·64], log-rank p=0·0003), after 3 years of imatinib was 7·0 months (3·5-11·7) versus 67·0 months (48·8-85·6; 0·15 [0·07-0·32], log-rank p<0·0001), and after 5 years of imatinib was 12·0 months (9·0-16·6) versus not reached (NR; NR-NR; 0·13 [0·03-0·58], log-rank p=0·0016). The median time to imatinib resistance after 1 year of imatinib was 28·7 months (95% CI 18·1-39·1) versus 90·6 months (25·3-156·1; HR 0·93 [95% CI 0·51-1·71], log-rank p=0·82), after 3 years was 66·2 months (43·0-89·6) versus 127·3 months (15·0-239·7; 0·35 [0·17-0·72, log-rank p=0·0028), and after 5 years was 58·6 months (0·0-167·4) versus NR (NR-NR; 0·24 [0·05-1·12], log-rank p=0·049). Median overall survival after 1 year of imatinib was 56·0 months (95% CI 30·3-82·9) versus 105·0 months (20·6-189·6; HR 0·84 [95% CI 0·46-1·54], log-rank p=0·57), after 3 years was 104·0 months (90·7-118·7) versus 134·0 months (89·7-178·3; 0·40 [0·20-0·82], log-rank p=0·0096), and after 5 years was NR (NR-NR) versus 110·4 months (82·7-154·1; 1·28 [0·41-3·99]; log-rank p=0·67), INTERPRETATION: Imatinib interruption in patients with GIST without progressive disease is not recommended. Imatinib interruption in non-progressing patients with GIST was associated with rapid progression, faster resistance to imatinib, and shorter overall survival in the long-term follow-up when compared with imatinib continuation in patients after 3 years and 5 years of imatinib.

FUNDING

Centre Léon Bérard, INCa, CONTICANET, Ligue Contre le Cancer, and Novartis.

Neoadjuvant Imatinib in Gastrointestinal Stromal Tumors (GIST): The First Analysis of a Mexican Population

Introduction Gastrointestinal stromal tumors (GISTs) are neoplasms originating from the interstitial cells of Cajal, pacemaker cells responsible for intestinal motility. Patients with locally advanced GISTs and those with borderline resections due to the proximity of vital anatomical structures, which could result in unacceptable post-surgical morbidity, require special therapeutic consideration. Imatinib, a tyrosine kinase inhibitor, has demonstrated significant success in the non-surgical management of metastatic GIST, and its favorable impact on overall survival in the adjuvant setting makes it logical to speculate on the benefit it could provide as a neoadjuvant medication in patients with locally advanced disease. Methods Patients aged 18-90 years with a diagnosis of GIST confirmed by immunohistochemistry (CD117 positivity) who were treated at the Oncology Hospital of Centro Médico Nacional Siglo XXI in Mexico City from January 2012 to December 2016 were included in the study. It is a retrospective study with a duration of four years. Clinical data were collected from the medical records, which included sex, age, tumor location, initial resectability, reason for unresectability, initial tumor size, and mitotic rate. In the case of unresectable disease, patients who were evaluated by medical oncology and who had received treatment with 400 mg of imatinib daily were evaluated. Results A total of 312 patients diagnosed with GIST were analyzed. One hundred thirty-one were men (42%) with a mean age of 57 years, and 181 were women (58%) with a mean age of 59 years. The most frequent anatomical location was the stomach (n=185, 59.2%). At the time of diagnosis, 210 patients (67.3%) presented with resectable disease, while n=102 patients (32.7%) had unresectable disease. A total of 102 patients with unresectable disease received therapy with 400 mg of imatinib per day. Sixteen patients (15.7%) presented a reduction in tumor dimensions and underwent surgery. Conclusion The study highlights the importance of complete surgical resection and the potential benefit of neoadjuvant imatinib therapy in converting unresectable to resectable disease. The results suggest that imatinib can be effective in converting unresectable GISTs to resectable ones, allowing for a complete resection to be performed and obtaining an R0 resection in 93.7% of these cases.

English version of Japanese Clinical Practice Guidelines 2022 for gastrointestinal stromal tumor (GIST) issued by the Japan Society of Clinical Oncology

The Japan Society of Clinical Oncology Clinical Practice Guidelines 2022 for gastrointestinal stromal tumor (GIST) have been published in accordance with the Minds Manual for Guideline Development 2014 and 2017. A specialized team independent of the working group for the revision performed a systematic review. Since GIST is a rare type of tumor, clinical evidence is not sufficient to answer several clinical and background questions. Thus, in these guidelines, we considered that consensus among the experts who manage GIST, the balance between benefits and harms, patients' wishes, medical economic perspective, etc. are important considerations in addition to the evidence. Although guidelines for the treatment of GIST have also been published by the National Comprehensive Cancer Network (NCCN) and the European Society for Medical Oncology (ESMO), there are some differences between the treatments proposed in those guidelines and the treatments in the present guidelines because of the differences in health insurance systems among countries.

Discontinuation of imatinib in patients with oligometastatic gastrointestinal stromal tumour who are in complete radiological remission: a prospective multicentre phase II study

INTRODUCTION

Metastatic gastrointestinal stromal tumour (GIST) is considered incurable, and life-long treatment with tyrosine kinase inhibitors is recommended. We investigated whether selected patients with metastatic GIST may remain in durable remission despite imatinib discontinuation.

PATIENTS

In this 1-group, prospective, multicentre phase II trial selected patients with oligometastatic (≤3 metastases) GIST discontinued imatinib treatment. Eligible patients had been treated with imatinib >5 years without progression and had no radiologically detectable metastases after metastasectomy, radiofrequency ablation (RFA) or complete response to imatinib. The primary endpoint was progression-free survival (PFS) 3-years after stopping imatinib. Overall survival (OS) and quality of life (QoL) were secondary endpoints.

RESULTS

The trial closed prematurely due to slow accrual. Between January 5, 2017, and June 5, 2019, 13 patients were enrolled, of whom 12 discontinued imatinib. The median follow-up time was 55 months (range, 36 to 69) after study entry. Five (42%) of the 12 eligible patients remained progression free, and seven (58%) progressed with a median time to progression 10 months. Median PFS was 23 months and the estimated 3-year PFS 41%. Six of the seven patients who progressed restarted imatinib, and all six responded. Three-year OS was 100%, and all patients were alive at the time of the study analysis. QoL measured 5 and 11 months after discontinuation of imatinib demonstrated improvement compared to the baseline.

INTERPRETATION

A substantial proportion of selected patients with oligometastatic GIST treated with imatinib and metastasis surgery/RFA may remain disease-free for ≥3 years with improved QoL after stopping of imatinib.

The GIST of it all: management of gastrointestinal stromal tumors (GIST) from the first steps to tailored therapy. A bibliometric analysis

PURPOSE

Improvement of patient care is associated with increasing publication numbers in biomedical research. However, such increasing numbers of publications make it challenging for physicians and scientists to screen and process the literature of their respective fields. In this study, we present a comprehensive bibliometric analysis of the evolution of gastrointestinal stromal tumor (GIST) research, analyzing the current state of the field and identifying key open questions going beyond the recent advantages for future studies to assess.

METHODS

Using the Web of Science Core Collection, 5040 GIST-associated publications in the years 1984-2022 were identified and analyzed regarding key bibliometric variables using the Bibliometrix R package and VOSviewer software.

RESULTS

GIST-associated publication numbers substantially increased over time, accentuated from year 2000 onwards, and being characterized by multinational collaborations. The main topic clusters comprise surgical management, tyrosine kinase inhibitor (TKI) development/treatment, diagnostic workup, and molecular pathophysiology. Within all main topic clusters, a significant progress is reflected by the literature over the years. This progress ranges from conventional open surgical techniques over minimally invasive, including robotic and endoscopic, resection techniques to increasing identification of specific functional genetic aberrations sensitizing for newly developed TKIs being extensively investigated in clinical studies and implemented in GIST treatment guidelines. However, especially in locally advanced, recurrent, and metastatic disease stages, surgery-related questions and certain specific questions concerning (further-line) TKI treatment resistance were infrequently addressed.

CONCLUSION

Increasing GIST-related publication numbers reflect a continuous progress in the major topic clusters of the GIST research field. Especially in advanced disease stages, questions related to the interplay between surgical approaches and TKI treatment sensitivity should be addressed in future studies.

Liver resection for metastatic GIST tumor improves survival in the era of tyrosine kinase inhibitors: a systematic review and meta-analysis

INTRODUCTION

Survival for gastrointestinal stromal tumor (GIST) has been increasing over the years after the introduction of tyrosine kinase inhibitors. However, the role of metastasectomy for GIST is still controversial. Patients are currently treated with imatinib or sunitinib in case of imatinib failures as optimal medical therapy for metastatic GIST.

METHODS

The Pubmed, EMBASE, and Cochrane Library were systematically searched. Overall survival following liver resection ± tyrosine kinase inhibitor treatment for metastatic GIST was compared to treatment with tyrosine kinase inhibitors alone.

RESULTS

Eleven studies including both randomized control trials and retrospective cohort studies were included in the final analysis with a total of 988 patients. Seven studies encompassed data on 556 patients with isolated liver metastases (219 surgery ± drug groups and 337 drug-only groups) were included. Overall survival was significantly improved in patients undergoing liver resection ± drug therapy in comparison to drug therapy alone. [HR (95%CI) = 2.10 (1.58, 2.79); p<0.00001]. Subgroup analysis showed that patients also had improved progression free survival based on 4 studies. [HR (95%CI) = 1.92 (1.43, 2.56); p<0.00001]. In case of concurrent liver and peritoneal metastases, patients showed improved overall survival with aggressive surgical approaches based on 10 studies. [HR (95%CI) = 1.90 (1.56, 2.31); p<0.00001].

CONCLUSION

This meta-analysis found that liver resection for patients with metastatic GIST regardless of peritoneal metastases improved progression free and overall survival in conjunction with tyrosine kinase inhibitors as compared with medical therapy alone. Furthermore, liver resections did not have any immediate detrimental impact on survival in the group of patients selected.

Interruption of imatinib in advanced gastrointestinal stromal tumor after prolonged imatinib maintenance in the absence of gross tumor lesions

BACKGROUND

Current guidelines recommend indefinite imatinib treatment for advanced gastrointestinal stromal tumor (GIST) patients. Imatinib-refractory progression-free survival (PFS) and overall survival were previously reported not to differ between GIST patients who interrupted imatinib and those who did not.

METHODS

Clinical outcomes of 77 consecutive patients with recurrent or metastatic GIST who interrupted imatinib treatment after maintaining years of imatinib treatment in the absence of gross tumor lesions were retrospectively analyzed. Associations between clinical factors and progression-free survival (PFS) following imatinib interruption were analyzed.

RESULTS

The median time from the absence of gross tumor lesions to imatinib interruption was 61.5 months. Since imatinib interruption, the median PFS was 19.6 months, and 4 patients (26.3%) remained progression-free for longer than 5 years. Among the patients who had progressive disease following the interruption, imatinib re-introduction led to an 88.6% objective response rate and a 100% disease control rate. Complete removal of the initial gross tumor lesion(s) and complete removal of the residual gross tumor lesion(s) by local treatment (vs. no local treatment or residual lesions after local treatment) were independently associated with favorable PFS.

CONCLUSION

Interruption of imatinib following prolonged maintenance in the absence of gross tumor lesions led to disease progression in the majority of cases. However, re-introduction of imatinib resulted in effective tumor control. Unmaintained remission seems to be possible in some patients with metastatic or recurrent GIST after a prolonged remission with imatinib if there is complete removal of any gross tumor lesions.

The multifaceted landscape behind imatinib resistance in gastrointestinal stromal tumors (GISTs): A lesson from ripretinib

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal sarcomas and the gold-standard treatment is represented by tyrosine kinase inhibitors (TKIs). Unfortunately, first-line treatment with the TKI imatinib usually promotes partial response or stable disease rather than a complete response, and resistance appears in most patients. Adaptive mechanisms are immediately relevant at the beginning of imatinib therapy, and they may represent the reason behind the low complete response rates observed in GISTs. Concurrently, resistant subclones can silently continue to grow or emerge de novo, becoming the most representative populations. Therefore, a slow evolution of the primary tumor gradually occurs during imatinib treatment, enriching heterogeneous imatinib resistant clonal subpopulations. The identification of secondary KIT/PDGFRA mutations in resistant GISTs prompted the development of novel multi-targeted TKIs, leading to the approval of sunitinib, regorafenib, and ripretinib. Although ripretinib has broad anti-KIT and -PDGFRA activity, it failed to overcome sunitinib as second-line treatment, suggesting that imatinib resistance is more multifaceted than initially thought. The present review summarizes several biological aspects suggesting that heterogeneous adaptive and resistance mechanisms can also be driven by KIT or PDGFRA downstream mediators, alternative kinases, as well as ncRNAs, which are not targeted by any TKI, including ripretinib. This may explain the modest effect observed with ripretinib and all anti-GIST agents in patients.

Patient-reported outcomes in individuals with advanced gastrointestinal stromal tumor treated with ripretinib in the fourth-line setting: analysis from the phase 3 INVICTUS trial

BACKGROUND

Ripretinib is a novel switch-control kinase inhibitor that inhibits KIT and PDGFRA signaling. In the INVICTUS phase 3 trial, ripretinib increased median progression-free survival and prolonged overall survival vs. placebo in ≥ fourth-line advanced GIST. Here, we report prespecified analysis of quality of life (QoL) as assessed by patient-reported outcome (PRO) measures and an exploratory analysis evaluating the impact of alopecia on QoL.

METHODS

In the INVICTUS trial (NCT03353753), QoL was assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30; physical function, role function, overall health, and overall QoL) and the EuroQoL 5-Dimension 5-Level (EQ-5D-5 L; visual analogue scale). Analysis of covariance (ANCOVA) models compared changes in scores from baseline to treatment cycle 2, day 1 within and between ripretinib and placebo. Within the ripretinib arm, repeated measures models assessed the impact of alopecia on QoL.

RESULTS

Patients receiving ripretinib maintained QoL (as assessed by the EORTC QLQ-C30 and EQ-5D-5 L PRO measures) from baseline to cycle 2, day 1 whereas QoL declined with placebo, resulting in clinically significant differences between treatments (nominal P < 0.01). The most common treatment-emergent adverse event with ripretinib was alopecia; however, QoL was similarly maintained out to treatment cycle 10, day 1 in patients receiving ripretinib who developed alopecia and those who did not.

CONCLUSION

PRO assessments in the INVICTUS trial suggest that patients on ripretinib maintain their QoL out to C2D1, unlike patients receiving placebo. Longitudinal QoL was maintained for patients receiving ripretinib out to cycle 10, day 1 (approximately 8 months; past the point of median progression-free survival with ripretinib [6.3 months]), even if the patients developed alopecia.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03353753 ; first posted: November 27, 2017.

Case report: 10-year survival of a patient with a primary hepatic gastrointestinal stromal tumor

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the gastrointestinal tract. Extra-gastrointestinal stromal tumors (EGISTs) predominantly arise outside the gastrointestinal tract, although primary hepatic GISTs are extremely rare. GISTs are highly aggressive; they often grow to a large size. Here, we report the 10-year survival of a patient with a primary hepatic GIST following sequential response therapy.

CASE PRESENTATION

A 50-year-old Chinese man complained of fatigue and slight abdominal pain, and presented with a large lump in the liver, which was detected by computed tomography (CT). He was subsequently diagnosed with a primary hepatic GIST, based on CT-guided fine needle aspiration cytology and immunohistochemistry analyses. The presence of GIST or EGIST metastases was excluded using CT, esophagogastroduodenoscopy, colonoscopy, and ultrasound. Cytological examination showed that the tumor was composed of epithelioid and spindle cells. Immunohistochemistry analysis revealed positive staining for CD117 (KIT) and DOG1, and negative staining for CD34, S-100, and α-smooth muscle actin (SMA). Following tumor ablation with argon-helium cryosurgery, the patient received imatinib mesylate for 61 months. However, this treatment was discontinued because of disease progression, at which point interventional therapy was administered once. One month later, sunitinib malate was administered for 71 months. The patient achieved long-term survival for 135 months.

CONCLUSIONS

EGISTs can be easily misdiagnosed as other types of tumors because they have no specific characteristics to distinguish them during imaging examinations. However, our case study demonstrates that the long-term survival of patients with EGISTs can be achieved with molecular targeted therapy.

Health-Related Quality of Life and Side Effects in Gastrointestinal Stromal Tumor (GIST) Patients Treated with Tyrosine Kinase Inhibitors: A Systematic Review of the Literature

BACKGROUND

The introduction of tyrosine kinase inhibitors (TKIs) has revolutionized the treatment of gastrointestinal stromal tumors (GISTs), resulting in a substantial gain in median overall survival. Subsequently, health-related quality of life (HRQoL) has become more relevant. Here, we systematically review the available literature on HRQoL issues and side effects of different TKIs registered for the treatment of GIST.

METHODS

A search through five databases was performed. Full reports in English describing HRQoL outcomes and/or side effects in GIST patients on TKI therapy were included.

RESULTS

A total of 104 papers were included; 13 studies addressed HRQoL, and 96 studies investigated adverse events. HRQoL in patients treated with imatinib, regorafenib, and ripretinib remained stable, whereas most sunitinib-treated patients reported a decrease in HRQoL. Severe fatigue and fear of recurrence or progression were specifically assessed as HRQoL issues and had a negative impact on overall HRQoL as well as psychological and physical well-being. The majority of studies focused on physician-reported side effects. Nearly all GIST patients treated with a TKI experienced at least one adverse event, mostly mild to moderate.

CONCLUSIONS

Despite the fact that almost all patients treated with a TKI experienced side effects, this did not seem to affect overall HRQoL during TKI therapy. In daily practice, it are the side effects that hamper a patient's HRQoL resulting in treatment adjustments, suggesting that the reported side effects were underestimated by physicians, or the measures used to assess HRQoL do not capture all relevant issues that determine a GIST patient's HRQoL.

Development and external validation of a nomogram for individualized adjuvant imatinib duration for high-risk gastrointestinal stromal tumors: A multicenter retrospective cohort study

Introduction

The main emphasis of the research about adjuvant imatinib for high‐risk gastrointestinal stromal tumors (GISTs) is prolonging the treatment duration and ignores the heterogeneous that 10‐year recurrence rates ranged from about 20%–100%. Thus, this study evaluated the effect of different durations of adjuvant imatinib on outcomes in high‐risk GISTs to explore the feasibility of individual treatment.

Methods

We analyzed 855 high‐risk GIST patients from three centers who underwent macroscopically complete resection between December 2007 and September 2020. The patients were divided into training (n =564) and two validation cohorts (n = 238 and53) based on their source. Recurrence‐free survival (RFS) was the primary point. Cox multivariate analysis was used to develop the nomogram. C‐index, time‐dependent area under the curves, and calibration plots were used to assess the performance of the nomogram.

Results

Univariate analysis showed that longer adjuvant imatinib was significantly associated with better 5‐year RFS (p < 0.0001). Further investigation identified that the same high‐risk patients with lower tumor‐associated recurrence risk benefitted little from prolonged treatment and that the recommended adjuvant imatinib duration was insufficient for those with higher recurrence risk. A nomogram for predicting 2‐, 3‐, and 5‐year RFS based on different treatment durations and four major risk factors, namely, tumor site, size, mitotic count, and rupture status, was built and validated, with a C‐index of 0.82, 0.74, and 0.70 in training and two external validation cohorts, respectively. An online dynamic nomogram was further developed for clinical applications (https://ruolinliu666.shinyapps.io/GIST/), offering predictive recurrence rates based on different treatment durations and tumor features.

Conclusions

We developed a nomogram to predict the recurrence risk for high‐risk patients according to tumor features and treatment durations of imatinib to help physicians on decision‐making for individualized treatment duration.

Medical Oncological Treatment for Patients with Gastrointestinal Stromal Tumour (GIST) - a Systematic Review

BACKGROUND

Chemotherapy is ineffective in treating patients with Gastrointestinal Stromal Tumour (GIST). However, several types of tyrosine kinase inhibitors have been investigated since the approval of imatinib in 2001. The purpose of this report was to systematically review studies on the efficacy of neoadjuvant, adjuvant, and lifelong medical oncological treatment of GIST.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed throughout the review process. The protocol was submitted to the International prospective register of systematic reviews database (ID 251724). A systematic literature search was performed, including phase II- and III studies of biological treatment, reporting on treatment effect in patients with GIST.

RESULTS

Of 308 identified publications, 42 studies were included in this review.

CONCLUSION

This review gives an overview of the existing evidence for approved lines of oncological treatments and potential alternatives for patients with GIST in the neoadjuvant-, adjuvant- and life-long setting.

Ripretinib and MEK Inhibitors Synergize to Induce Apoptosis in Preclinical Models of GIST and Systemic Mastocytosis

The majority of gastrointestinal stromal tumors (GIST) harbor constitutively activating mutations in KIT tyrosine kinase. Imatinib, sunitinib, and regorafenib are available as first-, second-, and third-line targeted therapies, respectively, for metastatic or unresectable KIT-driven GIST. Treatment of patients with GIST with KIT kinase inhibitors generally leads to a partial response or stable disease but most patients eventually progress by developing secondary resistance mutations in KIT. Tumor heterogeneity for secondary resistant KIT mutations within the same patient adds further complexity to GIST treatment. Several other mechanisms converge and reactivate the MAPK pathway upon KIT/PDGFRA-targeted inhibition, generating treatment adaptation and impairing cytotoxicity. To address the multiple potential pathways of drug resistance in GIST, the KIT/PDGFRA inhibitor ripretinib was combined with MEK inhibitors in cell lines and mouse models. Ripretinib potently inhibits a broad spectrum of primary and drug-resistant KIT/PDGFRA mutants and is approved by the FDA for the treatment of adult patients with advanced GIST who have received previous treatment with 3 or more kinase inhibitors, including imatinib. Here we show that ripretinib treatment in combination with MEK inhibitors is effective at inducing and enhancing the apoptotic response and preventing growth of resistant colonies in both imatinib-sensitive and -resistant GIST cell lines, even after long-term removal of drugs. The effect was also observed in systemic mastocytosis (SM) cells, wherein the primary drug-resistant KIT D816V is the driver mutation. Our results show that the combination of KIT and MEK inhibition has the potential to induce cytocidal responses in GIST and SM cells.

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.

Assessment of Adherence to Imatinib and Health-Related Quality of Life Among Patients with Gastrointestinal Stromal Tumor: A Cross-Sectional Study in an Oncology Clinic in Malaysia

PURPOSE

To evaluate the rate and predictors of non-adherence to imatinib in gastrointestinal stromal tumor (GIST) patients, as well as to compare the difference in health-related quality of life (HRQOL) between adherent and non-adherent patients.

PATIENTS AND METHODS

A cross-sectional study at the Oncology Clinic, Hospital Kuala Lumpur was conducted from March to August 2018. All patients with metastatic and/or unresectable GIST aged ≥18 years old and on at least 3 months of imatinib were included. Adherence to imatinib was assessed using the 10-item validated Medication Compliance Questionnaire, with a score of <100% indicating non-adherence. Non-adherence predictors were determined by multiple logistic regressions. HRQOL was evaluated by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). The difference in the mean HRQOL scores between adherent and non-adherent groups was determined by multivariate analysis of variance.

RESULTS

A total of 89 patients were enrolled, of which 49 (55.1%) were considered non-adherent. The significant predictors of non-adherence were age (adjusted odds ratio [OR] 0.93; CI 0.89-0.98; P = 0.007), presence of nausea and vomiting (OR 5.63; CI 1.25-25.27; P = 0.024), and presence of comorbidities (OR 4.56; CI 1.44-14.40; P = 0.010). Patients who were in the adherent group showed significantly better score in overall HRQOL, F (15, 73) = 2.09, P < 0.02; Pillai's trace = 0.3, partial eta squared = 0.30.

CONCLUSION

Non-adherence to long-term treatment with imatinib among patients with GIST should not be underestimated. Significant predictors of non-adherence among this population are younger age, presence of nausea and vomiting, as well as comorbidities. Patients with good adherence portrayed better HRQOL.

Gastrointestinal Stromal Tumor – An Overview

Gastrointestinal stromal tumors (GISTs) are rare tumors but are most common mesenchymal tumors of the digestive tract. They are commonly seen in the stomach (60%) and small intestine (30%). GISTs are likely derived from the interstitial cells of Cajal or their stem cell precursors. They are best characterized by computerized tomography and have a specific staining pattern on immunohistochemistry, i.e., C-Kit and DOG-1. The treatment of GIST is based on the risk assessment for relapse, and patients with localized GIST require resection with or without adjuvant imatinib mesylate (IM). Advanced unresectable tumors are usually treated with IM, with a number of further options available for patients post progression on IM. There is an increasing emphasis on identifying C-Kit and platelet-derived growth factor receptor alpha mutations in all patients with GIST, as these are driver mutations with current and future therapeutic implications.

Surgical Management of Sarcoma Metastatic to Liver

Sarcomas are rare mesenchymal tumors with a propensity for hematogenous metastasis. Gastrointestinal stromal tumor (GIST) is the most common histologic subtype and the most common source of hepatic metastases. In the case of metastatic GIST, neoadjuvant imatinib can be used as a selection tool for the judicious application of surgery, where treatment-responsive patients who undergo resection to prevent the development of treatment-resistant clones have associated 10-year actuarial survival of 40%. Further advances for many of the non-GIST sarcoma subtypes will depend on the development of improved systemic therapies and evaluation of their activity in subtype or molecularly defined trials.

Maintenance therapy and drug holiday in sarcoma patients: systematic review

Purpose: Overall prognosis of advanced sarcoma remains poor, optimization of systemic treatment is urgently needed in this setting.Materials and methods: We systematically reviewed fully published English-speaking literature about maintenance therapy and drug holiday in sarcoma patients management.Results: We found that switch maintenance therapy with cyclophosphamide/vinorelbine improves the outcome of localized high-risk rhabdomyosarcoma. There is no other maintenance therapy recommended in sarcoma patients. After classical chemotherapy, maintenance therapy with immune-stimulating agents for localized osteosarcoma, bevacizumab for advanced angiosarcoma or pediatric advanced sarcoma, or mTOR inhibitors for metastatic sarcoma does not improve the outcome. Drug holiday has been assessed for metastatic gastrointestinal stromal tumor treated with imatinib as the first-line therapy or for metastatic soft-tissue sarcoma treated with trabectedin. Drug holiday has been found to lead to rapid disease progression and should be avoided.Conclusions: Data about both maintenance and drug holiday are spare in sarcoma management.

High expression of proenkephalin is associated with favorable outcomes in patients with gastrointestinal stromal tumors

Purpose

The aim of this study was to elucidate the prognostic value of proenkephalin (PENK) in gastrointestinal stromal tumors (GISTs).

Patients and methods

We collected data on 268 eligible postoperative patients diagnosed with GIST between January 1, 2002, and December 31, 2011. PENK expression was detected in GIST tissues classified using the United States National Institutes of Health (NIH) risk classification system. The associations between high PENK expression and the clinicopathological characteristics were assessed. Overall survival (OS) and recurrence-free survival (RFS) were estimated by Kaplan–Meier analysis, and the log-rank test was used to compare the differences between groups. Univariate and multivariate Cox regression analyses were conducted to assess the prognostic value of PENK in GIST patients.

Results

High PENK expression was more common in the low- and intermediate-risk GIST groups compared with the high-risk group (P<0.05). Additionally, PENK expression was associated with tumor size, mitosis count per 50 high-power fields, and tumor rupture (P<0.05). Kaplan–Meier analysis revealed that high PENK expression was associated with superior OS and RFS, while low PENK expression was associated with worse OS and RFS. Furthermore, PENK was shown to be an independent predictor of OS and RFS in the overall population (for OS, hazard ratio [HR], 1.596, 95% confidence interval [CI], 1.006–2.914, P<0.001; for RFS, HR, 1.910, 95% CI, 0.977–3.089, P<0.001).

Conclusion

PENK expression in GIST is closely associated with NIH risk grade and prognosis, indicating that PENK may act as a tumor suppressor and may serve as a new biomarker for predicting prognosis in postoperative GIST patients.

New frontiers in the medical management of gastrointestinal stromal tumours

The tyrosine kinase inhibitor (TKI) imatinib has radically changed the natural history of KIT-driven gastrointestinal stromal tumours (GISTs). Approved second-line and third-line medical therapies are represented by the TKIs sunitinib and regorafenib, respectively. While imatinib remains the cardinal drug for patients with GISTs, novel therapies are being developed and clinically tested to overcome the mechanisms of resistance after treatments with the approved TKI, or to treat subsets of GISTs driven by rarer molecular events. Here, we review the therapy of GISTs, with a particular focus on the newest drugs in advanced phases of clinical testing that might soon change the current therapeutic algorithm.

Genomic aberrations in cell cycle genes predict progression of KIT-mutant gastrointestinal stromal tumors (GISTs)

BACKGROUND

Activating mutations of the receptor tyrosine kinase KIT are early events in the development of most gastrointestinal stromal tumors (GISTs). Although GISTs generally remain dependent on oncogenic KIT during tumor progression, KIT mutations alone are insufficient to induce malignant behavior. This is evidenced by KIT-mutant micro-GISTs, which are present in up to one-third of normal individuals, but virtually never progress to malignancy.

METHODS

We performed whole exome sequencing on 29 tumors obtained from 21 patients with high grade or metastatic KIT-mutant GIST (discovery set). We further validated the frequency and potential prognostic significance of aberrations in CDKN2A/B, RB1, and TP53 in an independent series of 71 patients with primary GIST (validation set).

RESULTS

Using whole exome sequencing we found significant enrichment of genomic aberrations in cell cycle-associated genes (Fisher's Exact p = 0.001), most commonly affecting CDKN2A/B, RB1, and TP53 in our discovery set. We found a low mutational tumor burden in these 29 advanced GIST samples, a finding with significant implications for the development of immunotherapy for GIST. In addition, we found mutation of spliceosome genes in a minority of cases, implicating dysregulation of splicing as a potential cancer promoting mechanism in GIST. We next assessed the prognostic significance of CDKN2A, RB1 or TP53 mutation/copy loss in an independent cohort of 71 patients with primary GIST. Genetic events (mutation, deletion, and/or LOH) involving at least one of the three genes examined were found in 17% of the very low-risk, 36% of the low-risk, 42% of the intermediate risk, 67% of the high-risk/low mitotic-count, and in 86% of the high-risk/high mitotic-count group. The presence of cell cycle-related events was associated with a significantly shorter relapse-free survival (median 67 months versus not reached; p < 0.0001) and overall survival (Log Rank, p = 0.042).

CONCLUSION

Our results demonstrate that genomic events targeting cell cycle-related genes are associated with GIST progression to malignant disease. Based on this data, we propose a model for molecular pathogenesis of malignant GIST.

Long-term adjuvant imatinib treatment for a patient who underwent complete resection of a localized recurrent gastrointestinal stromal tumor after preoperative imatinib treatment: A case report

RATIONALE

The efficiency and tolerance of long-term adjuvant imatinib treatment for patient who underwent complete resection of a localized recurrent gastrointestinal stromal tumor (GIST) was unknown.

PATIENT CONCERNS

A 45-year-old man underwent complete resection of an intestinal GIST in August 2001. Four years later, a giant (11 × 8 × 6 cm) recurrent GIST located in the retroperitoneum was detected.

DIAGNOSIS

The recurrent tumor was positive for CD117 by immunohistochemistry.

INTERVENTIONS

The recurrent tumor was completely resected after 4 months of effective imatinib treatment (400 mg/day), and the patient continued imatinib treatment postoperatively. In June 2011, imatinib treatment was stopped for 3 weeks because of hepatitis B infection, and resumed with a reduced dose level of 300 mg/day when liver function recovered. In March 2017, imatinib treatment was interrupted again for 12 days because the patient underwent cholecystectomy.

OUTCOMES

In December 2017, a computed tomography scan showed no signs of tumor recurrence. To date, the patient has been under adjuvant imatinib treatment for >12 years without severe side effects. The plasma concentration of imatinib (detected in February 2018) was trough concentration (Cmin) 1015.7 ng/mL and peak concentration (Cmax) 1550.5 ng/mL.

LESSONS

This case report highlights the active role of long-term (>12 years) imatinib treatment after complete resection of localized recurrent GIST.

Long-Term Imatinib Treatment for Patients with Unresectable or Recurrent Gastrointestinal Stromal Tumors

BACKGROUND

Only limited data are available concerning the long-term outcomes of imatinib treatment among Japanese or Asian patients with advanced or recurrent gastrointestinal stromal tumors (GIST). Our multicenter study, which was conducted in northern Kanto, Japan, aimed to assess the efficacy of imatinib mesylate against advanced or recurrent GIST.

SUMMARY

The clinicopathological data of 234 GIST patients who were treated at one of the 11 participating hospitals from 2001 to 2011 were retrospectively reviewed (GREAT study). Imatinib was administered as a first-line therapy in cases involving unresectable disease or postoperative recurrence (41 cases). The patients treated with imatinib (n = 41) exhibited 1-, 3-, and 5-year overall survival (OS) rates of 92.3, 74.9, and 53.8% respectively. In univariate and multivariate analyses, imatinib continuation with dose reduction and achieving a complete or partial response were found to be associated with increased OS. The results of 2 large-scale, long-term trials demonstrate that the risk of tumor progression decreases with increased treatment duration. Furthermore, the interruption of imatinib treatment in responsive and controlled patients results in a high risk of disease progression. Key Messages: Long-term imatinib treatment is recommended for patients with nonprogressive disease. If patients experience significant toxicities, temporary dose reduction and treatment continuation might be useful.

miR-125a-5p regulation increases phosphorylation of FAK that contributes to imatinib resistance in gastrointestinal stromal tumors

The use of imatinib mesylate has greatly improved the clinical outcome for gastrointestinal stromal tumor (GIST) patients. However, imatinib resistance is still a major clinical challenge, and the molecular mechanisms are not fully understood. We have previously shown that miR-125a-5p and its mRNA target PTPN18 modulate imatinib response in GIST cells. Herein, we evaluated phosphorylated FAK (pFAK) as a candidate downstream target of PTPN18 and the possible association of this regulation with imatinib resistance in GIST. FAK and pFAK expressions were evaluated in GIST882 cells transfected with short hairpin RNA or short interfering RNA targeting PTPN18 or miR-125a-5p mimic, imatinib-resistant GIST882R subclones and clinical samples using Western blot analyses. FAK phosphorylation was blocked using the FAK inhibitor 14 (FAKi) and the effects on cell viability and apoptosis were evaluated using WST-1 assay and cleaved PARP expression. Clinical associations of FAK and pFAK expression with imatinib resistance, KIT mutation and patient outcome were assessed by Fisher's exact test or log-rank test. Over-expression of miR-125a-5p and silencing of PTPN18 increased pFAK, but not FAK, expression in GIST cells. Higher pFAK expression was observed in the GIST882R subclones with acquired imatinib resistance compared to their imatinib-sensitive parental cells. Treatment with FAKi in imatinib-resistant GIST882R cells reduced cell viability and increased apoptosis upon imatinib treatment. Additionally, FAKi could rescue the imatinib resistance effect mediated by miR-125a-5p over-expression. In clinical samples, high FAK and pFAK expressions were associated with KIT mutation status, and high FAK expression was also associated with metastasis in GIST. Higher pFAK was found in cases with shorter overall survival. Our findings highlight an important role for miR-125a-5p regulation and its downstream target pFAK for imatinib resistance in GIST. pFAK and FAK may have prognostic values in GIST.

Comparing the long-term outcomes among patients with stomach and small intestine gastrointestinal stromal tumors: An analysis of the National Cancer Database

BACKGROUND AND OBJECTIVES

Gastrointestinal stromal tumors (GIST) are the most common sarcoma arising from the gastrointestinal tract. Data regrading long-term prognosis based on tumor location (stomach vs small intestine) are mixed, so we aimed to analyze their outcomes using a large national oncology database.

METHODS

The National Cancer Database was queried for cases of stomach and small intestine GIST between the years 2004 and 2014. Survival analysis was performed using the Kaplan-Meier method, and factors related to survival were compared using the Cox proportional hazards model.

RESULTS

Of 18 900 total patients, those with small intestine GIST had larger median tumor size (6.2 cm; interquartile range [IQR], 3.8 to 10.0 vs stomach: 5.0 cm; IQR, 3.0 to 9.0; P < 0.001) and a higher incidence of tumors with ≥5 mitoses/50 HPF (29.3% vs stomach: 24.2%; P < 0.001). Unadjusted median overall survival (OS) was longer for patients with stomach GIST (10.3 years) as compared to small intestine GIST (9.4 years) (P = 0.01). After controlling for patient and tumor-related factors, however, OS did not differ between stomach and small intestine GIST (hazard ratio, 1.19; 95% confidence interval, 0.88 to 1.61; P = 0.26).

CONCLUSIONS

Patients with small intestine GIST more commonly have larger, high mitotic rate tumors, but despite these worse prognostic features, tumor location did not independently impact OS.

Perspectives on the evolving state of the art management of gastrointestinal stromal tumours

Gastrointestinal stromal tumours (GISTs) represent a very exciting tumour entity for the medical oncologist. There has been extensive clinical and preclinical research dissecting the natural behaviour, molecular landscape and therapeutic responsiveness of this rare mesenchymal tumour. Various molecular subtypes of GIST have a differing prognostic and predictive relevance in the state of the art management of the disease. Emerging mature clinical trial data gathered over the last one and half decade provided substantial molecular profiling information in understanding the success and eventual failure of treatment. In our review of the most relevant literature we aim to guide the clinician in tailoring neoadjuvant, adjuvant and palliative treatment of GIST alongside the different, now well established molecular subgroups of GISTs.

Advances and Challenges on Management of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) originate from interstitial cells of Cajal and account for over 5,000 newly diagnosed cases in the United States. The discovery of activated KIT and PDGFRA mutations and introduction of imatinib revolutionized the treatment strategy and opened up the new era of target therapy for solid tumors. Although surgery remains the primary modality of treatment for curative purpose, almost half of the patients experienced disease recurrence. Tailoring (neo)-adjuvant treatment with imatinib is ongoing to meet the need for an effective therapy. Currently, two drugs (sunitinib and regorafenib) have obtained Food and Drug Administration approval for GISTs after imatinib failure. However, most of the patients eventually progress due to primary or secondary resistance. Deeper understanding of the molecular mechanisms will guide us to develop personalized strategies in the future. Discussion in this review includes current standard management and the most recent advances and multiple ongoing clinical trials with different approaches. This review will provide further steps to be taken to conquer refractory disease.

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.

Prognostic factors of primary gastrointestinal stromal tumors: a cohort study based on high-volume centers

Objective

We aimed to evaluate the clinicopathologic characteristics, immunohistochemical expression and prognostic factors of patients with primary gastrointestinal stromal tumors (GISTs).

Methods

Data from 2,570 consecutive GIST patients from four medical centers in China (January 2001-December 2015) were reviewed. Survival curves were constructed by the Kaplan-Meier method, and Cox regression models were used to identify independent prognostic factors.

Results

Of the included patients, 1,375 (53.5%) were male, and the patient age range was 18 to 95 (median, 58) years. The tumors were mostly found in the stomach (64.5%), small intestine (25.1%) and colorectal region (5.1%). At the time of diagnosis, the median tumor size was 4.0 (range: 0.1-55.0) cm, and the median mitotic index per 50 high power fields (HPFs) was 3 (range: 0-254). Of the 2,168 resected patients, 2,009 (92.7%) received curative resection. According to the modified National Institutes of Health (NIH) classification, 21.9%, 28.9%, 14.1% and 35.1% were very low-, low-, intermediate- and high-risk tumors, respectively. The rate of positivity was 96.4% for c-Kit, 87.1% for CD34, 96.9% for delay of germination 1 (DOG-1), 8.0% for S-100, 31.0% for smooth muscle actin (SMA) and 5.1% for desmin. However, the prognostic value of each was limited. Multivariate analysis showed that age, tumor size, mitotic index, tumor site, occurrence of curative resection and postoperative imatinib were independent prognostic factors. Furthermore, we found that high-risk patients benefited significantly from postoperative imatinib (P<0.001), whereas intermediate-risk patients did not (P=0.954).

Conclusions

Age, tumor size, mitotic index, tumor site, occurrence of curative resection and postoperative imatinib were independent prognostic factors in patients with GISTs. Moreover, determining whether intermediate-risk patients can benefit from adjuvant imatinib would be of considerable interest in future studies.

Clinical benefit of sunitinib in gastrointestinal stromal tumors with different exon 11 mutation genotypes

Aim: To assess the efficacy of second-line sunitinib therapy in gastrointestinal stromal tumor patients with different exon 11 mutation genotypes. Patients & methods: Thirty eight of the 75 patients received imatinib (IM) dose escalation followed by sunitinib (IM escalation group), while 37 were switched to sunitinib directly after the failure of first-line IM treatment (sunitinib group). Progression-free survival and overall survival were compared. Results: The median progression-free survival in the sunitinib group was significantly longer than in the IM escalation group (14 vs 4 months; p < 0.001), so was in patients with exon 11 deletions (16 vs 3 months; p < 0.001). Conclusion: Patients who have an exon 11 deletion mutation are more likely to benefit from switching to sunitinib directly than from IM dose escalation.

Prediction of long-term survival in patients with metastatic gastrointestinal stromal tumor: analysis of a large, single-institution cohort

BACKGROUND

A subset of patients with metastatic GIST become long-term survivors, and a more precise prediction of outcome could improve clinical decision-making.

MATERIAL AND METHODS

One-hundred and thirty-three patients diagnosed with metastatic GIST from 1995 to 2013 were identified from the sarcoma database at Oslo University Hospital. Clinical data prospectively registered in the database were supplemented with retrospective review of medical records. Factors associated with survival were analyzed using Kaplan-Meier curves, log-rank test, univariate and multivariate Cox regression analyses.

RESULTS

One-hundred and fifteen patients with metastatic GIST were included in the final study cohort. Median overall survival (OS) was 6.9 years (95% CI 5.6-8.3). Factors associated with long-term survival in univariate analysis were good baseline performance status (ECOG ≤1; p < .001), young age (p = .022), oligometastatic disease (OMD) (≤3 metastases; p < .001), maximum tumor diameter <5 cm (p < .001), surgery for metastatic disease (p = .005), surgery of the primary tumor (p < .001), normal baseline hemoglobin level (p = .05), normal baseline albumin level (p = .001) and normal baseline neutrophil count (p = .03). On multivariate analysis, good performance status, small tumor diameter and, OMD were the factors associated with long-term survival. Five and 10-year OS for patients with OMD were 89% and 71%, respectively, compared to 38% and 20% for patients with polymetastatic disease (p < .001).

CONCLUSIONS

In this single-institution cohort of patients, OMD was as a strong prognostic factor in patients with metastatic GIST. Patients with OMD had an outcome similar to patients with high-risk localized disease, and should be regarded as a separate category among patients with metastatic GIST.

Randomized Clinical Trials in Gastrointestinal Stromal Tumors

This review explores the current standard of care for the surgical management of gastrointestinal stromal tumors, highlights important studies in the medical management of gastrointestinal stromal tumors, and provides guidance in how these studies changed the standard of care in clinical practice.

Recent advances in managing gastrointestinal stromal tumor

Constitutive activating mutations in KIT and platelet-derived growth factor receptor α ( PDGFRα) are heavily involved in the pathobiology of gastrointestinal stromal tumors (GISTs). This disease has served as an effective "proof-of-concept" model for targeting gain-of-function kinase mutations in cancer. This review discusses the current standard of care in terms of pharmacotherapy in the management of localized and metastatic GISTs.

Safeguarding the future of independent, academic clinical cancer research in Europe for the benefit of patients

Cancer is a complex disease that is constantly evolving. It is now the most common cause of death in Europe after cardiovascular diseases. There are inequalities among European countries, potentially unsustainable healthcare systems impacting quality of cancer care and increasing number of patients with cancer with rare conditions. Clinical and translational research are the backbone in establishing scientific advances as novel treatments and advancing progress to the benefit of patients. Commercially sponsored clinical trials are responsible for developing new medicines that can treat various disease areas, including cancer. It is important to note, however, that these clinical trials only assess the viability of compounds that are chosen by a commercial entity that funds the entire process. By their design and focus, these trials need to fulfil commercial interests and market expectations, which do not always coincide with patients' needs. As soon or even before novel treatments and compounds obtain formal market authorisation, academia will take these existing and new medicines to further conduct research in order to optimise their use, develop new combinations and with a strong focus on the patients and their needs. Established standard of care most commonly relies on clinical cancer research stemming from non-commercial entities, cooperative groups or academic clinical research. This article provides a consensus on the definition of academic research, illustrates its added value and suggests and calls to European Union institutions to support this type of research for the benefit of patients.

Unravelling the pharmacologic opportunities and future directions for targeted therapies in gastro-intestinal cancers part 2: Neuroendocrine tumours, hepatocellular carcinoma, and gastro-intestinal stromal tumours

Until the 1990s, cytotoxic chemotherapy has been the cornerstone of medical therapy for gastrointestinal (GI) cancers. Better understanding of the cancer cell molecular biology has led to the therapeutic revolution of targeted therapies, i.e. monoclonal antibodies or small molecule inhibitors directed against proteins that are specifically overexpressed or mutated in cancer cells. These agents, being more specific to cancer cells, were expected to be less toxic than conventional cytotoxic agents. However, their effects have sometimes been disappointing, due to intrinsic or acquired resistance mechanisms, or to an activity restricted to some tumour settings, illustrating the importance of patient selection and early identification of predictive biomarkers of response to these therapies. Targeted agents have provided clinical benefit in many GI cancer types. Particularly, some GI tumours are considered chemoresistant and targeted therapies have offered a new therapeutic base for their management. Hence, somatostatin receptor-directed strategies, sorafenib, and imatinib have revolutioned the management of neuroendocrine tumours (NET), hepatocellular carcinoma (HCC), and gastrointestinal stromal tumours (GIST), respectively, and are now used as first-line treatment in many patients affected by these tumours. However, these agents face problems of resistances and identification of predictive biomarkers from imaging and/or biology. We propose a comprehensive two-part review providing a panoramic approach of the successes and failures of targeted agents in GI cancers to unravel the pharmacologic opportunities and future directions for these agents in GI oncology. In this second part, we will focus on NET, HCC, and GIST, whose treatment relies primarily on targeted therapies.

Principles of Kinase Inhibitor Therapy for Solid Tumors

OBJECTIVE

We aimed to identify key principles of targeted therapy of protein kinases and their application to the management of solid tumors.

BACKGROUND

Concurrent advances in tumor genomic analysis and molecular inhibitor development have dramatically impacted the diagnosis and treatment of solid tumors, and common themes regarding the use of kinase inhibitors are developing.

METHODS

The list of kinase inhibitors that have been approved by the US Food and Drug Administration was reviewed and articles related to the agents were searched in the PubMed database up until December 2015. We included pivotal, randomized controlled phase 2 and 3 trials, and also pertinent preclinical studies.

RESULTS

Small molecule inhibitors targeted against driver kinases, overactive in selected subsets of solid tumors, elicit improved response rates and survival compared with standard chemotherapy. Disease control has been proven in the metastatic and, to a limited extent, the adjuvant setting. However, tumor eradication is rare, and duration of treatment response is limited by the development of drug resistance.

CONCLUSIONS

Kinase inhibitors induce response in diverse types of solid tumors. Although the agents are often effective in defined molecular subsets, cure is rare and resistance is common. This broad review provides rationale for further investigation of multimodality therapy combining kinase inhibitors with additional systemic and local therapies, including surgery.

Extragastrointestinal stromal tumour of the lesser omentum: A case report and literature review

•

EGISTs are very rare mesenchymal tumours which originate from cells outside the gastrointestinal tract and tend to have an aggressive biological behaviour.

•

There have been only a few previous reports of EGISTs arising in the lesser omentum.

•

Complete surgical resection is the most effective treatment associated with the use of imatinib in the presence of adverse prognostic factors.

Introduction

Extragastrointestinal stromal tumours (EGISTs) are very uncommon compared to their gastrointestinal counterparts. Most of them originate from the intestinal mesentery and the omentum.

Case report

A 70 year-old Caucasian woman presented with a bulky abdominal mass which on laparotomy was found to originate from the lesser omentum and was completely resected. Histological examination revealed spindle cells with severe pleomorphism and high mitotic activity. Immunohistochemically, the tumour cells showed strong positivity for c-kit (CD117), DOG-1 and human haematopoietic progenitor cell antigen (CD34). An exon 11 deleterious mutation was identified and thus regular dosing of 400 mg imatinib mesylate was initiated.

Discussion

There have been only a few previous reports of EGISTs arising in the lesser omentum. Although EGISTs seem to have morphological and immunohistochemical similarities with GISTs, their pathogenesis, incidence, genetic background and prognosis are not completely known because they are extremely rare. It is strongly believed that such tumours originate from cells, which have similar pathological characteristics and biological behaviour as the intestinal cells of Cajal. In most series of EGISTs, a female predominance, a greater size and a higher mitotic index than GISTs were observed.

Conclusion

EGISTs are very rare mesenchymal tumours which originate from cells outside the gastrointestinal tract and tend to have a more aggressive biological behaviour than their GI counterparts. Complete surgical resection is the most effective treatment associated with the use of imatinib in the presence of adverse prognostic factors. In any case a strict follow-up is necessary due to high recurrence rates.

Management of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasm of the gastrointestinal tract. The stomach is the most common site of origin. Management of GISTs changed after the introduction of molecularly targeted therapies. Although the only potentially curative treatment of resectable primary GISTs is surgery, recurrence is common. Patients with primary GISTs at intermediate or high risk of recurrence should receive imatinib postoperatively. Imatinib is also first-line therapy for advanced disease. Cytoreductive surgery might be considered in advanced GIST for patients with stable/responding disease or limited focal progression on tyrosine kinase inhibitor therapy. GIST requires multidisciplinary management.

Unveiling changes in the landscape of patient populations in cancer early drug development

The introduction of new Molecularly Targeted Agents (MTA) has changed the landscape in Early Drug Development (EDD) over the last two decades, leading to an improvement in clinical trial design. Previous Phase 1 (Ph1) studies with cytotoxics focused on safety objectives, only recruiting heavily pre-treated cancer patients, have been left behind. In this review, we will illustrate the slow although unstoppable change that has increasingly been observed in those populations candidate to participate in EDD trials with the advent of MTA. As more evidence regarding oncogene addiction becomes available, molecular-biomarker driven selection has been implemented among Molecularly-Selected Population (MSP) studies. New Window-Of-Opportunity (WOO) and Phase 0 (Ph0) studies have been developed in order to assess whether a MTA produces the hypothetical proposed biological effect. The rising need of getting early pharmacokinetics and pharmacodynamics data has led to the conduction of Healthy Volunteer (HV) studies, in part favoured for the particular and different toxicity profile of these MTA. However, several challenges will need to be addressed in order to boost the implementation of these new clinical trial designs in the forthcoming years. Among the problems to overcome, we would highlight a better coordination effort between centers for ensuring adequate patient accrual among small patient populations and a deepening into the ethics implied in enrolling patients in studies with no therapeutic intent. However, these tribulations will be certainly compensated by the possibility of opening a new horizon of treatment for diseases with dismal prognosis.

Clinical implications of repeated drug monitoring of imatinib in patients with metastatic gastrointestinal stromal tumour

BACKGROUND

Imatinib mesylate (IM) is the preferred treatment for the majority of patients with metastatic gastrointestinal stromal tumour (GIST). Low trough IM concentration (C_min) values have been associated with poor clinical outcomes in GIST patients. However, there are few studies of repeated measurements of IM levels, and therapeutic drug monitoring is not yet a part of routine clinical practice. This study was conducted to reveal clinical scenarios where plasma concentration measurement of IM trough level (C_min) is advantageous.

METHODS

Patients with advanced GIST receiving IM were included from January 2011 to April 2015. Heparin plasma was collected at each follow-up visit. Ninety-six samples from 24 patients were selected for IM concentration measurement. Associations between IM plasma concentration and clinical variables were analyzed by Students' t test, univariate and multivariate linear regression analyses.

RESULTS

The mean IM C_min plasma concentrations for patients taking <400, 400 and >400 mg daily were 782, 1132 and 1665 ng/mL, respectively (p = 0.010). High IM C_min levels were correlated with age, low body surface area, low haemoglobin concentration, low creatinine clearance, absence of liver metastasis and no prior gastric resection in univariate analysis. In multivariate analysis age, gastric resection and liver metastasis were included in the final model. Eight patients had disease progression during the study, and mean IM levels were significantly lower at time of progression compared to the previous measurement for the same patients (770 and 1223 ng/mL, respectively; p = 0.020).

CONCLUSIONS

Our results do not support repeated monitoring of IM levels on a routine basis in all patients. However, we have revealed clinical scenarios where drug measurement could be beneficial, such as for patients who have undergone gastric resection, suspicion of non-compliance, subjectively reported side effects, in elderly patients and at the time of disease progression.

A lower dosage of imatinib in patients with gastrointestinal stromal tumors with toxicity of the treatment

This study investigated the efficiency and safety of imatinib in the lower dose (300 mg/d) in patients with gastrointestinal stromal tumor (GIST) who cannot tolerate imatinib in the standard dose (400 mg/d).Steady-state imatinib trough concentration (Cmin) values in 18 patients with GIST who were taking 300 mg/d or 400 mg/d imatinib were measured. The clinical features, toxicity data, and follow-up data were collected.Around 18 patients with GIST were investigated in which 9 patients received 300 mg/d imatinib. The mean imatinib Cmin value of the 18 patients was 1841 ng/mL (1018-3897 ng/mL). The difference between the patients treated with 400 mg/d (n=9) and those treated with 300 mg/d (n = 9), which have imatinib Cmin values of 2122±1003 ng/mL and 1559±478 ng/mL, respectively, was not significant (P = 0.148). In total, 12 of the 18 patients had complete resection of the primary tumor, 8 of whom received postoperative imatinib 300 mg/d. After the average follow-up of 15.4 months, no recurrence was documented. Of the 6 patients with unresected GIST, 1 received imatinib 300 mg/d for 13 months. The tumor size of this patient continued to decrease. In contrast to patients treated with imatinib 400 mg/d, patients treated with imatinib 300 mg/d notably exhibited lesser drug-related side effects.Patients with GIST who exhibited intolerance to the standard dose of imatinib (400 mg/d), a lower dose of 300 mg/d could provide not only sufficient plasma Cmin and good disease control but also the alleviation of the side effects.

SEOM Clinical Guideline for gastrointestinal sarcomas (GIST) (2016)

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the digestive tract, and this disease has served as a paradigmatic model for successful rational development of targeted therapies. The introduction of tyrosine kinase inhibitors with activity against KIT/PDGFRA in both localized and advanced stages has remarkably improved the survival in a disease formerly deemed resistant to all systemic therapies. The Spanish Society of Medical Oncology (SEOM) guidelines provide a multidisciplinary and updated consensus for the diagnosis and treatment of GIST patients. We strongly encourage that the managing of these patients should be performed within multidisciplinary teams in reference centers.

Continuing EGFR inhibition beyond progression in advanced non-small cell lung cancer

The majority of patients with epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC) respond to first-line EGFR tyrosine kinase inhibitors (TKIs), but nearly all inevitably acquire resistance and develop disease progression. Conventional practice would be to switch treatments to second-line therapy. However, continuing TKIs beyond progression is becoming increasingly commonplace in patients with indolent, small volume asymptomatic growth, who may potentially continue to derive ongoing clinical benefit and to avoid a 'withdrawal tumour flare'. Nevertheless, there are limitations to our current criteria for assessing disease response, which are based on radiological assessments without considering symptomatic benefit, or the complex molecular and clinical heterogeneity of tumour growth and drug response patterns. In this article, we review the rationale for continuing EGFR inhibitors in patients with EGFR mutant NSCLC beyond disease progression and discuss strategies that have been pursued in the context of molecularly and clinically heterogeneous populations of tumour growth depending on the different clinical scenarios encountered. We discuss the management of systemic disease progression, including continuing EGFR TKIs alone, introducing a drug holiday, or combining TKIs with chemotherapy or other molecularly targeted agents. We also focus on approaches in managing patients with indolent, small volume asymptomatic growth (non-CNS oligometastatic disease progression) and those with oligometastatic EGFR mutant NSCLC with involvement of the central nervous system. We envision future precision medicine strategies through the use of next generation sequencing strategies of serial tumour rebiopsies and circulating plasma DNA to individualise the management for such patients during disease progression.

Preoperative imatinib treatment in patients with advanced gastrointestinal stromal tumors: patient experiences and systematic review of 563 patients

Preoperative IM therapy for GIST is now a research focus. Due to the low incidence of the disease, there are few RCTs on the preoperative treatment for advanced GIST, let alone relevant meta-analysis. Efficacy of this therapy and targeting population are still undetermined. Therefore, the first part of this article is composed of a controlled retrospective study and demonstrates that preoperative therapy with IM can significantly improve the outcome of advanced GIST. In the second part of the paper, we further investigated what portion of advanced GIST patients benefit more from the therapy, based on a meta-analysis. As the disease is relatively rare, we involved 563 cases in the meta-analysis, much higher than in the controlled clinical studies (51 cases). The objective of this paper is to investigate effects of surgical resection on imatinib-treated advanced GIST. Twenty-two consecutive advanced GIST patients (Group A) with preoperative IM treatment were compared to 29 patients (Group B) who underwent initial tumor resection during the same period. Subsequently, a systematic review of 563 patients was applied to identify the benefit of the advanced GIST patients receiving imatinib before surgery. Compared with Group B, less patients in Group A underwent multivisceral resection (18.2% versus 48.3%, P = 0.026) or suffered tumor rupture at time of surgery (0% versus 17.2%, P = 0.04). The 3-year estimated progression-free survival of Group A (94.4%) was also superior to that of Group B (61.4%; P = 0.045). Subsequent meta-analysis indicated that primarily unresectable patients had higher complete resection and 2-year PFS rates than recurrent/metastasis patients (P = 0.005 and 0.20, respectively); (b) stable disease (SD) patients had better outcome in resection including resectability rate (P < 0.0001), PFS (P < 0.00001) and OS (P = 0.0008) than progressive disease (PD) patients; (c) in recurrent/metastatic PD patients, surgery played a minor role, because they had a higher bulky residual disease rate (P = 0.0005) and higher progression risk (P < 0.00001) within 2 years after surgery. Preoperative IM treatment improves prognosis of advanced GISTs. Among recurrent/metastatic patients, postimatinib surgery may benefit those who have SD after IM treatment but not those resistant to IM.

Cessation of targeted therapy after a complete response in BRAF-mutant advanced melanoma: a case series

BACKGROUND

It is unknown whether melanoma patients achieving complete response (CR) with targeted therapy can safely discontinue treatment.

METHODS

All patients treated with BRAF/MEK inhibitors achieving CR and ceasing treatment before progression were identified. Clinical data at treatment initiation, cessation and progression were examined.

RESULTS

A total of 12 eligible patients were identified, with median follow-up of 16 months, of whom 6 (50%) recurred at a median of 6.6 months after treatment cessation. One patient lost to follow-up until presentation with symptomatic recurrence was the only relapser to die. At relapse, the remaining five patients had an LDH <1.2 times ULN, four were ECOG 0 and one ECOG 1. Baseline characteristics and time to CR and to discontinuation did not influence the rate of relapse.

CONCLUSIONS

A large proportion of patients achieving CR with BRAF/MEK inhibitors relapse after treatment cessation. The optimal treatment duration in such patients is unclear, particularly where alternative treatments are available.

Asian Consensus Guidelines for the Diagnosis and Management of Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors originating in the gastrointestinal tract. With the introduction of molecular-targeted therapy for GISTs which has yielded remarkable outcomes, these tumors have become a model of multidisciplinary oncological treatment. Although Western clinical guidelines are available for GISTs, such as those published by the National Comprehensive Cancer Network (NCCN) and the European Society of Medical Oncology (ESMO), the clinical situations in Asian countries are different from those in Western countries in terms of diagnostic methods, surgical approach, and availability of new targeted agents. Accordingly, we have reviewed current versions of several GIST guidelines published by Asian countries (Japan, Korea, China, and Taiwan) and the NCCN and ESMO and discussed the areas of dissensus. We here present the first version of the Asian GIST consensus guidelines that were prepared through a series of meetings involving multidisciplinary experts in the four countries. These guidelines provide an optimal approach to the diagnosis and management of GIST patients in Asian countries.