Advanced or metastatic gastrointestinal stromal tumors: systemic treatment options

Imatinib adherence prediction using machine learning approach in patients with gastrointestinal stromal tumor

BACKGROUND

Nonadherence to imatinib is common in patients with gastrointestinal stromal tumor (GIST), which is associated with poor prognosis and financial burden. The primary aim of this study was to investigate the adherence rate in patients with GIST and subsequently develop a model based on machine learning (ML) and deep learning (DL) techniques to identify the associated factors and predict the risk of imatinib nonadherence.

METHODS

All eligible patients completed four sections of questionnaires. After the data set was preprocessed, statistically significance variables were identified and further processed to modeling. Six ML and four DL algorithms were applied for modeling, including eXtreme gradient boosting, light gradient boosting machine (LGBM), categorical boosting, random forest, support vector machine, artificial neural network, multilayer perceptron, NaiveBayes, TabNet, and Wide&Deep. The optimal ML model was used to identify potential factors for predicting adherence.

RESULTS

A total of 397 GIST patients were recruited. Nonadherence was observed in 185 patients (53.4%). LGBM exhibited superior performance, achieving a mean f1_score of 0.65 and standard deviation of 0.12. The predominant indicators for nonadherent prediction of imatinib were cognitive functioning, whether to perform therapeutic drug monitoring (if_TDM), global health status score, social support, and gender.

CONCLUSIONS

This study represents the first real-world investigation using ML techniques to predict risk factors associated with imatinib nonadherence in patients with GIST. By highlighting the potential factors and identifying high-risk patients, the multidisciplinary medical team can devise targeted strategies to effectively address the daily challenges of treatment adherence.

Two Decades of Gastrointestinal Stromal Tumor Management With First-Line Treatment: A Case Report

Gastrointestinal stromal tumors (GISTs) are rare malignant tumors that arise from the connective tissues of the gastrointestinal tract. Reports about GISTs treated with imatinib for over five years are exceedingly rare. In this case report, we present a patient with GIST who remained alive for two decades after undergoing imatinib treatment. We describe a man in his forties with no significant prior medical issues, who presented in 2004 to the emergency department with severe abdominal pain. A computed tomography scan revealed a ruptured intra-abdominal mass. He underwent surgical resection, leading to the diagnosis of jejunal GIST. Following this, he underwent active surveillance until 2007, when the disease recurred. After completing a two-year course of imatinib, no signs of disease were detected, and medical therapy was stopped. However, in 2011, a pelvic recurrence was observed, leading to the re-introduction of imatinib therapy, which was maintained until 2018. A year later, disease progression was noted, prompting the re-initiation of imatinib. Since then, the patient was receiving imatinib therapy with good tolerance, until March of 2024. This case highlights the potential sensitivity of imatinib for a long duration.

Debulking of Advanced Gastrointestinal Stromal Tumor With Peritoneal Carcinomatosis Refractory to Imatinib and Sunitinib: A Case Report

Gastrointestinal stromal tumors (GISTs) are non-epithelial stromal tumors that arise in the gastrointestinal tract. Pharmacological treatments for GIST are tyrosine kinase inhibitors. For metastatic disease, debulking may be helpful in reducing the tumor burden, thus increasing the effectiveness of tyrosine kinase inhibitors. Debate on whether resection would benefit the patient is still present. Here is a case of a 52-year-old African American male presenting with metastatic malignant GIST with peritoneal carcinomatosis refractory to imatinib and sunitinib. Since this patient had stage IV metastasis it was ultimately decided to proceed with a therapeutic debulking procedure. For this patient, the procedure increased the effectiveness of the medication and reduced mass effect symptoms, improving quality of life.

Prevalence, diagnosis, and treatment of primary hepatic gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GIST), which is the most common mesenchymal tumor of the digestive tract, account for 1%-3% of gastrointestinal tumors. Primary stromal tumors outside the gastrointestinal tract are collectively referred to as extra GISTs, and stromal tumors in different regions often have different prognoses. A primary hepatic GIST is a rare tumor with an unknown origin, which may be related to interstitial Cajal-like cells. Although primary hepatic GIST has certain characteristics on imaging, it lacks specific symptoms and signs; thus, the final diagnosis depends on pathological and genetic evidence. This review summarizes all cases of primary hepatic GIST described in the literature and comprehensively analyzes the detailed clinical data of all patients. In terms of treatment, local resection alone or with adjuvant therapy was the prioritized choice to obtain better disease-free survival and longer survival time. For advanced unresectable cases, imatinib mesylate was applied as the first-line chemotherapy agent. Moreover, transcatheter arterial chemoembolization, radiofrequency ablation, and microwave ablation were shown to improve overall survival for selected patients. Liver transplantation was a final treatment option after resistance to chemotherapy developed.

The prognostic value of gender in gastric gastrointestinal stromal tumors: a propensity score matching analysis

Background

Gastrointestinal stromal tumors (GISTs) of the stomach are the most common GISTs. The risk, incidence, and outcome of cancer are different between the sexes. Whether gender is related to the prognosis of gastric stromal tumors is unclear. Therefore, this study aims to explore the relationship between gender and gastric GIST prognosis.

Methods

Data from gastric GIST patients were collected from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching (PSM) was performed to reduce confounding factors, and the clinicopathological features and prognosis of GIST patients were comprehensively evaluated.

Results

There were 512 male patients and 538 female patients with gastric GIST. The gender of gastric GIST patients was associated with marital status, surgical treatment, tumor size, and mitotic index (P < 0.05). The Kaplan-Meier analysis and log-rank test revealed that male patients had a higher mortality rate than female patients (P = 0.0024). After matching all the potential confounding factors, the survival of the female gastric GIST patients was better than that of the male gastric GIST patients (P = 0.042). Cox regression analysis revealed that gender was an independent risk factor for overall survival. The risk of death was higher for males than for females (HR 1.677, 95% CI 1.150–2.444, P = 0.007).

Conclusion

Gender could be a prognostic factor for gastric GIST survival, and male patients had a higher risk of death.

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.

The Role of Surgical Resection Following Tyrosine Kinase Inhibitors Treatment in Patients with Advanced Gastrointestinal Stromal Tumors: A Systematic Review and Meta-analysis

Background The benefit of surgical resection for advanced gastrointestinal stromal tumors (GISTs) following tyrosine kinase inhibitors (TKIs) treatment was still under debate. The present meta-analysis was designed to assess the value of surgical resection for the prognosis of patients with metastatic, recurrence and unresectable GISTs. Methods A systematic search of PubMed Central, PubMed, EMBASE and the Cochrane Library database was performed. Relevant studies of the role of surgery in advanced GISTs published before 1 May 2019 were identified. The quality of studies was assessed by the Newcastle-Ottawa Quality Assessment Scale. The progression-free survival (PFS) and overall survival (OS) were assessed through software Stata 15.0. Results A total of 6 retrospective studies including 655 patients were analyzed. The pooled result revealed that surgical resection group was associated with better PFS (HR = 2.08; 95% CI: 1.58 to 2.76; P<0.001) and better OS (HR = 2.13; 95% CI: 1.59 to 2.85; P<0.001) compared with TKIs treatment alone group. Conclusions Surgical resection following TKIs treatment could significantly improve the prognosis of patients with advanced GISTs.

Endoscopic ultrasound FNA: An illustrated review of spindle cell neoplasms of the upper gastrointestinal tract including a novel case of gastric plexiform fibromyxoma

Plexiform fibromyxoma (PF) is a recently-described and rare mesenchymal neoplasm of the gastric wall. A few small case series reports of this spindle cell entity exist in the surgical pathology literature, but to our knowledge no prior endoscopic ultrasound guided fine needle aspiration cytology examples have been reported. In clinical practice, mural gastrointestinal (GI) lesions are often initially evaluated by endoscopic ultrasound guided (EUS) fine needle aspiration (FNA). In addition, newer EUS fine needle biopsy techniques also allow for reliable retrieval of core tissue samples with intact cellular architecture, making EUS histopathologic analyses possible. We report a combined EUS FNA and core biopsy case of PF and correlate the findings with imaging results. The cytomorphology of PF is described and illustrated, and important entities in the differential diagnosis of upper GI spindle cell lesions (including GI stromal tumor, leiomyoma, schwannoma, carcinoid tumor, desmoid-type fibromatosis, and inflammatory fibroid polyp) are reviewed. Illustrated examples of relevant cytomorphologic, cell block histomorphologic and immunohistochemical characteristics are emphasized.

Successful Laparoscopic Sleeve Gastrectomy in Emergency for a Gastric Gastrointestinal Stomal Tumor (GIST) with Acute Bleeding: A Case Report

BACKGROUND Gastrointestinal stomal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, and the stomach is the most commonly involved organ. Complete surgical resection with negative margins is the primary and only potentially curative treatment. Surgeon experience with minimally invasive gastric resections in addition to the tumor size and site has to be considered in the choice of laparoscopic or open surgical approach in order to remove the lesion. CASE REPORT A 67-year-old male patient with an history of gastric ulcer presented 2 days after an esophagogastroduodenoscopy with an incidental finding of a 30-mm gastric submucosal lesion that was not histologically defined (biopsies were taken), chest pain in association with hematemesis, and melena. An initial attempt to achieve endoscopic hemostasis with epinephrine injection was followed by the recurrence of the gastric bleeding until the presentation of hemorrhagic shock. An emergent laparoscopic sleeve gastrectomy was then performed for hemorrhage control. There were no intra- or postoperative major complications and the histological findings led to the diagnosis of a gastrointestinal stromal tumor (GIST). CONCLUSIONS Laparoscopic sleeve gastrectomy is a bariatric surgical treatment of morbid obesity. This report describes the application of a bariatric procedure in a life-threatening situation and illustrates how safe and effective it can be when performed by surgeons with excellent laparoscopic skills.

Advanced gastrointestinal stromal tumor patients benefit from palliative surgery after tyrosine kinase inhibitors therapy

The role of palliative surgery is controversial in advanced gastrointestinal stromal tumors (GIST) after tyrosine kinase inhibitors (TKIs) therapy.We evaluated safety and clinical outcomes in a single institution series of advanced GIST patients from January 2002 to December 2008.One hundred and fifty-six patients had been recruited, including 87 patients underwent surgical resection and 69 patients kept on TKIs treatment. Four patients had major surgical complications. Median follow-up was 38.3 months, the overall survival (OS) and progression-free survival (PFS) of the patients in surgical group were longer than the nonsurgical group, PFS: 46.1 versus 33.8 months (P < .01), OS: 54.8 versus 40.4 months. In the subgroup analysis for the patients received surgery, the median PFS for patients with progression disease, stable disease, and partial response was 33.3, 51.5, and 83.0 months, respectively (P < .01). Median OS was 68.0 months in those with only liver or peritoneal metastases, and 45.3 months in those with both metastases. Median PFS of patients underwent R0/R1 resection was 73.6 months compared with 35.8 months in R2 resection patients (P < .01).Patients with advanced GISTs have prolonged OS after debulking procedures. Surgery for patients who have responsive disease after TKIs treatment should be considered.

Gastrointestinal stromal tumours (GISTs): an insight into clinical practice with review of literature

BACKGROUND

Gastrointestinal stromal tumours (GISTs) are rare mesenchymal tumours of the gastrointestinal tract. We retrospectively reviewed the clinical management of all patients with GIST presenting to a regional multidisciplinary upper gastrointestinal cancer group in the north of England.

METHODS

Clinical, pathological, immunohistochemical treatment strategies, follow-up and outcome data on all patients with GIST between 2007 and 2012 were reviewed. Tumours were categorised by risk according to the National Institutes of Health (NIH) and AFIP models.

RESULTS

36 (85.7%) of 42 tumours were located in the stomach, 5 (11.9%) in the small intestine and 1 (2.4%) in the oesophagus. Median age of patients was 68 (range 43-91) years. 24 patients (57.1%) were female. Tumour size ranged from 1.0  to 12.7 cm with mean size of 5.46 cm. Metastasis was present in 19 (45.2%) patients at diagnosis with distant metastases in 12 patients. Liver was the most common site of metastases. Histology and immunohistochemical analysis was available in 32 (76.2%) patients. Most common histology was spindle cell morphology 17/32 (53.1%) followed by epithelioid 9/32 (28.1%) and mixed morphology 5/32 (15.6%). The positive rate for KIT protein (CD117) was 90.6%, while that for CD34 was 75.0%. 12/25 (48.0%) and 8/23 (34.8%) patients were categorised as high risk as per NIH and AFIP risk scores, respectively. 23/42 (54.8%) patients underwent surgical resection, after which 5/23 (21.7%) had adjuvant imatinib therapy. Imatinib was given as primary therapy in 14/42 (33.3%) patients.

CONCLUSIONS

Surgery alone may not be a curative treatment for GISTs. Targeted therapy with imatinib may play an important role in the treatment of GISTs. Further risk categorisation models may be needed to evaluate GIST behaviour and prognosis.

A Phase 2 Study of the Hsp90 Inhibitor AUY922 as Treatment for Patients with Refractory Gastrointestinal Stromal Tumors

BACKGROUND

AUY922 is an inhibitor of heat shock protein 90 (Hsp90). Hsp90 inhibitors induce kit degradation in preclinical gastrointestinal stromal tumor (GIST) models. This trial was designed to determine the progression-free survival (PFS) of patients with GIST refractory to or intolerant of imatinib and sunitinib.

METHODS

Eligible patients received AUY922 70 mg/mg(2) by intravenous (IV) infusion on days 1, 8, and 15 of 21-day cycles. Treatment continued until progression or unacceptable toxicity.

RESULTS

Between December 2011 and January 2015, 25 patients were enrolled (median age, 63 years; 56% male) and received a median of 2 cycles (range: 1-12) of AUY922 treatment. Thirty-four patients were planned, but enrollment was stopped early due to slow accrual. Median PFS was 3.9 months (95% CI: 2.5, 5.3) and median OS was 8.5 months (95% CI: 5.2, 16.7). Radiographic response was evaluated in 21 patients; one patient achieved PR (4%) with another 15 having best response of stable disease (60%). The most common treatment-related adverse event was diarrhea (60% all grades). Reversible ocular toxicities that resulted in drug hold (24%) or reduction (8%) were also observed.

CONCLUSION

AUY922 produced a median PFS which compares favorably to historical controls of placebo (6 weeks) for patients refractory to treatment with imatinib. While diarrhea and ocular toxicities were common, the majority of patients received treatment until disease progression.

Hepatic artery embolization for liver metastasis of gastrointestinal stromal tumor following imatinib and sunitinib therapy

PURPOSE

The purpose of the study is to determine the efficacy of hepatic artery embolization (HAE) as a therapy for gastrointestinal stromal tumor (GIST) in patients who are refractory to imatinib and sunitinib.

METHODS

After institutional review board approval, a retrospective review revealed 11 patients with GIST metastatic to the liver who underwent 15 HAEs between February 2002 and May 2013. These patients were stratified into two groups according to the previous treatment: (a) those treated with HAE as second-line treatment after failing first-line imatinib (n = 3) and (b) those treated with HAE as third-line therapy after failing first-line imatinib and second-line sunitinib (n = 8). Initial therapeutic response, overall survival (OS), progression-free survival (PFS), and safety were evaluated.

RESULTS

Initial therapeutic response rates at 3 months after HAE were 27.3 % (95 % confidence interval (CI), 6.0-61.0 %) by Response Evaluation Criteria in Solid Tumor (RECIST) version 1.0 and 45.5 % (95 % CI, 16.7-76.6 %) by modified RECIST (mRECIST). The median OS and PFS after HAE were 14.9 and 3.9 months in group A and 23.8 and 3.4 months in group B, respectively. No procedure-related mortality or major complication was observed.

CONCLUSIONS

HAE is an effective and well-tolerated therapeutic option for GIST liver metastases. Although larger studies are necessary, HAE should be considered as an alternative or adjuvant to third-line or even second-line systemic treatment.

Beyond standard therapy: drugs under investigation for the treatment of gastrointestinal stromal tumor

INTRODUCTION

Gastrointestinal stromal tumor (GIST) is the most common nonepithelial malignancy of the GI tract. With the discovery of KIT and later platelet-derived growth factor α (PDGFRA) gain-of-function mutations as factors in the pathogenesis of the disease, GIST was the quintessential model for targeted therapy. Despite the successful clinical use of imatinib mesylate, a selective receptor tyrosine kinase (RTK) inhibitor that targets KIT, PDGFRA and BCR-ABL, we still do not have treatment for the long-term control of advanced GIST.

AREAS COVERED

This review summarizes the drugs that are under investigation or have been assessed in trials for GIST treatment. The article focuses on their mechanisms of actions, the preclinical evidence of efficacy, and the clinical trials concerning safety and efficacy in humans.

EXPERT OPINION

It is known that KIT and PDGFRA mutations in GIST patients influence the response to treatment. This observation should be taken into consideration when investigating new drugs. RECIST was developed to help uniformly report efficacy trials in oncology. Despite the usefulness of this system, many questions are being addressed about its validity in evaluating the true efficacy of drugs knowing that new targeted therapies do not affect the tumor size as much as they halt progression and prolong survival.

Fear of progression in patients with gastrointestinal stromal tumors (GIST): Is extended lifetime related to the Sword of Damocles?

BACKGROUND

Gastrointestinal stromal tumors (GIST) are rare and before 2000, patients had a dismal prognosis with a median survival of less than a year after tumor metastasis. However, the median overall survival has increased to more than five years following the introduction of imatinib and other tyrosine kinase inhibitors (TKI). Little is known about the psychosocial consequences of treatment of GIST, but this is important because patients now are treated and live for longer. This cross-sectional study assessed quality of life, distress, and fear of cancer recurrence or progression in patients with GIST.

MATERIAL AND METHODS

Eighty-six patients with localized or metastatic GIST were asked to participate. Patients completed self-report questionnaires including the EORTC-Quality of Life Questionnaire, Hospital Anxiety and Depression Scale, Impact of Event Scale, Cancer Worry Scale, and Fear of Cancer Recurrence Inventory.

RESULTS

Fifty-four patients (median age 63.3 years) completed the questionnaires, 33 (61%) of whom were receiving TKI treatment at the time of the study. Overall, the GIST patients had a good global quality of life, but 28 patients had high levels of fear of cancer recurrence/progression. This high level of fear was not related to patient- or treatment-related variables. These patients experienced significantly higher levels of psychological distress, functional impairments, and difficulty making plans for the future than did patients with lower levels of fear.

CONCLUSIONS

More attention should be paid to specific cancer-related problems, such as fear of cancer recurrence/progression, in addition to general quality of life issues in patients with GIST.

Regorafenib treatment for advanced, refractory gastrointestinal stromal tumor: a report of the UK managed access program

Background

Tyrosine kinase inhibitors (TKI) have revolutionized the treatment of gastrointestinal

stromal tumors (GIST) although most patients develop resistance to first and second-line therapies.

Regorafenib, an oral multi-targeted TKI, has demonstrated benefit in previously treated GIST patients.

Methods

We assessed safety and activity of regorafenib in patients treated within the Managed Access Program (MAP). All consecutive patients with advanced GIST who had progressed on or were intolerant to imatinib and sunitinib were recruited from the Royal Marsden and University College Hospitals. We retrospectively reviewed the data for response, toxicity, treatment duration and survival. Response was assessed by RECIST and Choi criteria. Toxicity was graded according to CTCAE v4.0 criteria.

Results

20 patients were included in the MAP in the UK between 3/2013 and 9/2013. Median age was 68 (range 45–87), 65% of patients were male. Performance Status was 0–1 for 18 patients (90%), 2 for 2 patients (10%). The median treatment duration was 9.25 months (range 0.1-15.33). 18 patients were assessable for response and all patients attained a best response of at least stable disease. At a median follow-up of 12.6 months, there were 2 partial responses (11%) by RECIST and 7 partial responses (39%) according to Choi criteria. 7 patients remain on regorafenib. 3 patients discontinued treatment due to unacceptable adverse events; fistulation, myalgia and fatigue. 10 (50%) patients had grade 3 toxicities and 11 (55%) patients required a dose reduction. Median PFS was 9.4 months (95% Cl: 6.2-not calculable) and median OS was 12.2 months (95% Cl: 10.5-not calculable). Notably, prolonged stable disease was seen in 1 patient with exon 9 mutation and 1 patient with PDGFR D842V mutation.

Conclusions

These data demonstrate encouraging activity and tolerability of regorafenib in routine clinical practice. The documented adverse events are in line with previous trial data.

Endoscopic full-thickness resection and laparoscopic surgery for treatment of gastric stromal tumors

AIM

To assess the effectiveness of endoscopic full-thickness resection (EFR) and laparoscopic surgery in the treatment of gastric stromal tumors arising from the muscularis propria.

METHODS

Out of 62 gastric stromal tumors arising from the muscularis propria, each > 1.5 cm in diameter, 32 were removed by EFR, and 30 were removed by laparoscopic surgery. The tumor expression of CD34, CD117, Dog-1, S-100, and SMA was assessed immunohistochemically. The operative time, complete resection rate, length of hospital stay, incidence of complications, and recurrence rate were compared between the two groups. Continuous data were compared using independent samples t-tests, and categorical data were compared using χ (2) tests.

RESULTS

The 32 gastric stromal tumors treated by EFR and the 30 treated by laparoscopic surgery showed similar operative time [20-155 min (mean, 78.5 ± 30.1 min) vs 50-120 min (mean, 80.9 ± 46.7 min), P > 0.05], complete resection rate (100% vs 93.3%, P > 0.05), and length of hospital stay [4-10 d (mean, 5.9 ± 1.4 d) vs 4-19 d (mean, 8.9 ± 3.2 d), P >0.05]. None of the patients treated by EFR experienced complications, whereas two patients treated by laparoscopy required a conversion to laparotomy, and one patient had postoperative gastroparesis. No recurrences were observed in either group. Immunohistochemical staining showed that of the 62 gastric stromal tumors diagnosed by gastroscopy and endoscopic ultrasound, six were leiomyomas (SMA-positive), one was a schwannoglioma (S-100 positive), and the remaining 55 were stromal tumors.

CONCLUSION

Some gastric stromal tumors arising from the muscularis propria can be completely removed by EFR. EFR could likely replace surgical or laparoscopic procedures for the removal of gastric stromal tumors.

Regorafenib for treatment of advanced gastrointestinal stromal tumors

INTRODUCTION

Gastrointestinal stromal tumors (GISTs) are abdominal sarcomas which are extremely refractory to chemotherapy treatment. The treatment of GISTs has been revolutionized by use of KIT/platelet-derived growth factor receptor-α (PDGFRA) kinase inhibitors. Unfortunately, most tumors develop resistance to front-line (imatinib) or second-line (sunitinib) therapy. Regorafenib, a KIT/PDGFRA/vascular endothelial growth factor receptor (VEGFR) oral kinase inhibitor, has been shown to improve progression-free survival in the third- or fourth-line setting.

AREAS COVERED

This review covers the preclinical and clinical studies of regorafenib for treatment of GIST. A literature search on regorafenib was carried out using the PubMed database up to October 2013.

EXPERT OPINION

Currently, imatinib and sunitinib represent the only proven first- and second-line therapies, respectively, for advanced GISTs. Based on the results of a Phase III study, regorafenib is now established as the only proven third-line therapy. Regorafenib activity in this setting is believed to be due to its activity against oncogenic forms of KIT/PDGFRA. Although side effects are common with this agent, they can be effectively managed with a combination of supportive care, dose interruptions/reductions. The toxicity profile is similar to other oral kinase inhibitors with anti-VEGFR activity. Regorafenib is mainly metabolized by CYP3A4, and concomitant use of strong inducers/inhibitors of this enzyme should be avoided.

A comparison between patients with gastrointestinal stromal tumours diagnosed with isolated liver metastases and liver metastases plus sarcomatosis

OBJECTIVES

This study was conducted to compare overall survival (OS) in patients presenting with isolated hepatic metastases with that of patients with synchronous metastatic disease to the liver and sarcomatosis on a background of gastrointestinal stromal tumours (GISTs).

METHODS

Patients presenting with metastatic GISTs during 1999-2009 were identified. Survival outcomes were compared between groups.

RESULTS

Of the 193 patients with GISTs, 43 patients presented with isolated hepatic metastases and 16 presented with synchronous metastases to the liver and sarcomatosis. Thirteen patients with metastases to the liver and sarcomatosis underwent surgery, and 34 patients with metastatic disease solely to the liver underwent hepatic resection. The proportion of patients treated with preoperative tyrosine kinase inhibitor (TKI) therapy was similar in both groups. Similar OS was observed in both groups (isolated liver metastases group: 40.5 months; liver metastases and sarcomatosis group: 28.7 months; P = 0.620).

CONCLUSIONS

Overall survival in patients with GIST and metastatic disease to the liver and sarcomatosis is similar to that in patients with isolated metastatic liver disease. Although patients with a greater disease burden might be expected to show worse survival, these data do not reflect this assumption.

Endoscopic full-thickness resection of gastric stromal tumor arising from the muscularis propria

BACKGROUND

Gastric stromal tumors are the most common type of tumor originating from mesenchymal tissue. The traditional method for the treatment of gastric stromal tumor is surgical operation or therapeutic laparoscopy. More recently, endoscopic micro-traumatic surgery has become possible for gastric stromal tumors, with any perforation caused by endoscopic therapy mended endoscopically. We assessed the effectiveness of endoscopic full-thickness resection (EFR) in the treatment of gastric stromal tumors arising from the muscularis propria.

METHODS

Of the 42 gastric stromal tumors, each > 2.0 cm in diameter, arising from the muscularis propria, 22 were removed by EFR and 20 by laparoscopic surgery. Tumor expression of CD34, CD117, Dog-1, S-100, and smooth muscle actin (SMA) was assessed immunohistochemically. Operating time, complete resection rate, length of hospital stay, incidence of complications, and recurrence rates were compared between the two groups. Continuous data were compared by using independent samples t-tests and categorical data by using χ(2) tests.

RESULTS

Comparisons of the 22 gastric stromal tumors treated with EFR and the 20 treated with laparoscopic surgery showed similar operation times (60 - 155 minutes (mean, (90 ± 17) minutes) vs. 50 - 210 minutes (mean, (95 ± 21) minutes), P > 0.05), complete resection rates (100% vs. 95%, P > 0.05), and length of hospital stay (4 - 10 days (mean, (6.0 - 1.8) days) vs. 4 - 12 days (mean, (7.3 - 1.7) days), P > 0.05). None of the patients treated with EFR experienced complications, whereas one patient treated with laparoscopy required a conversion to laparotomy and one experienced postoperative gastroparesis. No recurrences were observed in either group. Immunohistochemical staining showed that of the 42 gastric stromal tumors diagnosed by gastroscopy and endoscopic ultrasound, six were leiomyomas (SMA-positive) and the remaining 36 were stromal tumors.

CONCLUSIONS

Gastric stromal tumors arising from the muscularis propria can be completely removed by EFR. EFR may replace surgical or laparoscopic procedures for the removal of gastric stromal tumors.

Efficacy and safety of regorafenib for advanced gastrointestinal stromal tumours after failure of imatinib and sunitinib (GRID): an international, multicentre, randomised, placebo-controlled, phase 3 trial

BACKGROUND

Until now, only imatinib and sunitinib have proven clinical benefit in patients with gastrointestinal stromal tumours (GIST), but almost all metastatic GIST eventually develop resistance to these agents, resulting in fatal disease progression. We aimed to assess efficacy and safety of regorafenib in patients with metastatic or unresectable GIST progressing after failure of at least imatinib and sunitinib.

METHODS

We did this phase 3 trial at 57 hospitals in 17 countries. Patients with histologically confirmed, metastatic or unresectable GIST, with failure of at least previous imatinib and sunitinib were randomised in a 2:1 ratio (by computer-generated randomisation list and interactive voice response system; preallocated block design (block size 12); stratified by treatment line and geographical region) to receive either oral regorafenib 160 mg daily or placebo, plus best supportive care in both groups, for the first 3 weeks of each 4 week cycle. The study sponsor, participants, and investigators were masked to treatment assignment. The primary endpoint was progression-free survival (PFS). At disease progression, patients assigned placebo could crossover to open-label regorafenib. Analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01271712.

RESULTS

From Jan 4, to Aug 18, 2011, 240 patients were screened and 199 were randomised to receive regorafenib (n=133) or matching placebo (n=66). Data cutoff was Jan 26, 2012. Median PFS per independent blinded central review was 4·8 months (IQR 1·4-9·2) for regorafenib and 0·9 months (0·9-1·8) for placebo (hazard ratio [HR] 0·27, 95% CI 0·19-0·39; p<0·0001). After progression, 56 patients (85%) assigned placebo crossed over to regorafenib. Drug-related adverse events were reported in 130 (98%) patients assigned regorafenib and 45 (68%) patients assigned placebo. The most common regorafenib-related adverse events of grade 3 or higher were hypertension (31 of 132, 23%), hand-foot skin reaction (26 of 132, 20%), and diarrhoea (seven of 132, 5%).

INTERPRETATION

The results of this study show that oral regorafenib can provide a significant improvement in progression-free survival compared with placebo in patients with metastatic GIST after progression on standard treatments. As far as we are aware, this is the first clinical trial to show benefit from a kinase inhibitor in this highly refractory population of patients.

FUNDING

Bayer HealthCare Pharmaceuticals.

Advances in the development of cancer immunotherapies

Manipulating the immune system in order to induce clinically relevant responses against cancer is a longstanding goal. Interventions to enhance tumor-specific immunity through vaccination, sustaining effector T cell activation, or increasing the numbers of tumor-specific T cells using ex vivo expansion, have all resulted in clinical successes. Here, we examine recent clinical advances and major ongoing studies in the field of cancer immunotherapy. Single agents have so far benefited a limited proportion of patients, and future studies combining different types of immunotherapies and other therapeutic modalities, such as drugs against specific signaling pathways driving cancer cell growth, are needed to pave the way for the development of effective anticancer treatments causing durable responses.

Diagnostic value of endoscopic ultrasonography combined with CT in gastric stromal tumors

AIM: To evaluate the diagnostic value of endoscopic ultrasonography and CT in gastric stromal tumors.

METHODS: Twenty-seven patients who were found to have gastric protrusion lesions by gastroscopy underwent endoscopic ultrasonography and CT examinations. The results of endoscopic ultrasonography and CT examinations were then compared with postoperative pathological results.

RESULTS: In 11 patients who had lesions less than 3 cm in diameter, the diagnostic yield of endoscopic ultrasonography was 85.2% and that of CT was 62.7%. In 9 patients who had lesions 3-5 cm, the diagnostic yield of endoscopic ultrasonography was 68.4% and that of CT was 76.2%. In 7 patients who had lesions greater than 5 cm, the diagnostic yield of endoscopic ultrasonography was 59.2% and that of CT was 83.7%. The diagnostic yield of endoscopic ultrasonography combined CT was 95.3%.

CONCLUSION: Endoscopic ultrasonography combined with CT is the best method for diagnosis of gastric stromal tumors.

Endoscopic therapy for gastric stromal tumors originating from the muscularis propria

AIM

To explore endoscopic therapy methods for gastric stromal tumors originating from the muscularis propria.

METHODS

For 69 cases diagnosed as gastric stromal tumors originating from the muscularis propria, three types of endoscopic therapy were selected, based on the size of the tumor. These methods included endoscopic ligation and resection (ELR), endoscopic submucosal excavation (ESE) and endoscopic full-thickness resection (EFR). The wound surface and the perforation of the gastric wall were closed with metal clips. Immunohistostaining for CD34, CD117, Dog-1, S-100 and smooth muscle actin (SMA) was performed on the resected tumors.

RESULTS

A total of 38 cases in which the tumor size was less than 1.2 cm were treated with ELR; three cases were complicated by perforation, and the perforations were closed with metal clips. Additionally, 18 cases in which the tumor size was more than 1.5 cm were treated with ESE, and no perforation occurred. Finally, 13 cases in which the tumor size was more than 2.0 cm were treated with EFR; all of the cases were complicated by artificial perforation, and all of the perforations were closed with metal clips. All of the 69 cases recovered with medical treatment, and none required surgical operation. Immunohistostaining demonstrated that among all of the 69 gastric stromal tumors diagnosed by gastroscopy, 12 cases were gastric leiomyomas (SMA-positive), and the other 57 cases were gastric stromal tumors.

CONCLUSION

Gastric stromal tumors originating from the muscularis propria can be treated successfully with endoscopic techniques, which could replace certain surgical operations and should be considered for further application.

Anti-angiogenic drug discovery: lessons from the past and thoughts for the future

INTRODUCTION

Since the pioneering work of Judah Folkman, the discovery of bevacizumab has introduced the use of anti-angiogenic agents as a new modality for the treatment of cancer. Currently, hundreds of clinical trials involving anti-angiogenic agents, targeting different elements of the tumour angiogenesis pathway, are underway. However, thus far, the benefits of anti-angiogenic therapy in unselected patient populations are often marginal with harmful side effects.

AREAS COVERED

This article presents a detailed discussion of the lessons learnt from the use of bevacizumab and other VEGF pathway inhibitors in the clinical setting. Specifically, this article provides a review of the literature on anti-VEGF agents and other angiogenesis inhibitors used in pre-clinical and clinical trials for cancer treatment.

EXPERT OPINION

Future anti-angiogenic drug design centres on multiple protein targets and combinations including: growth factors, hypoxia-inducible factor and tumour endothelial cell markers unique to the tumour vasculature. Furthermore, treatment dosing, scheduling and combination with radiation and chemotherapy require further investigation, as does the potential of treating early disease, and the development of biomarkers which accurately predict response to therapy. These are essential for the future development of these drugs with individualised therapy likely to be the ultimate goal.

Clinical and pathological features of gastrointestinal stromal tumors: an analysis of 138 cases

AIM: To explore the clinical, pathologic and immunohistochemical characteristics of gastrointestinal stromal tumors (GISTs).

METHODS: The clinical, surgical, immunohistochemical and pathologic data for 138 patients with GISTs were retrospectively analyzed. The expression of CD117, CD34, SMA, Desmin and S-100 was detected using the Envision immunohistochemical method.

RESULTS: The lesion was located in the stomach in 90 cases (65.22%), in the small intestine in 36 cases (26.09%), in the colorectum in 9 cases (6.52%), and in the retroperitoneum in 3 cases (2.17%). Of 138 cases, 114 were detected as spindle type, 6 as epithelioid type, 18 as mixture type; 99 had mitotic figures ≤5/50 HPF, 24 had mitotic figures 5-10/50 HPF, 15 had mitotic figures >10/50 HPF; 97.38% were positive for CD117, 73.91% for CD34, 6.52% for SMA, 2.17% for Desmin, 2.17% for S100 (2.17%); 24 (17.39%) were benign, 39 (28.26%) had low tendency of malignancy, 33 (23.91%) had moderate tendency of malignancy, 21 (15.225%) had high tendency of malignancy, 21 (15.22%) were malignant.

CONCLUSION: GISTs have unique clinical and pathologic characteristics. CD117 detection has high specificity and sensitivity in diagnosing GISTs. Detecting CD34, SMA, Desmin, and S100 together can help diagnose GISTs. The malignancy of GISTs depends on the size, location and mitotic count of the lesion.