The effects of surgical cytoreduction prior to imatinib therapy on the prognosis of patients with advanced GIST

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.

The long-term efficacy of imatinib with hepatic resection or other local treatment for gastrointestinal stromal tumours liver metastases：a retrospective cohort study

BACKGROUND

The liver is the most common site of metastasis from gastrointestinal stromal tumours (GISTs). We aimed to evaluate imatinib (IM) combined with hepatic resection (HR) or other local treatments such as radiofrequency ablation (RFA) and transarterial chemoembolization (TACE), compared to IM monotherapy in long-term survival benefits in patients suffering from GIST liver metastases.

METHODS

Our research encompassed 238 patients diagnosed with liver metastases of GISTs from January 2002 to April 2022 at the XXX Hospital of XXX University. The oncological outcomes of concern included overall survival (OS), progression-free survival (PFS) and liver-specific PFS.

RESULTS

Of all 238 patients, 126 were treated with IM alone (IM group), 81 with IM combined with HR (IM+HR group), and 31 with IM combined with RFA/TACE (IM+RFA/TACE group). The median follow-up time was 44.83 months. The median OS in the IM group was 132.60 months and was not reached in either the IM+HR group or the IM+RFA/TACE group. The 10-year OS rate in the IM+HR group was significantly superior to the IM group and the IM+RFA/TACE group (91.9% vs. 61.1% vs. 55.2%, respectively, P=0.015), and the liver-specific PFS (P=0.642) and PFS (P=0.369) in the three groups showed a beneficial trend in the combined treatment group. Multivariate analyses showed that age ≤60 years (HR 0.280, P<0.001) and IM+HR (HR 0.361, P=0.047) were independently associated with better OS. Achieving no evidence of disease (NED) through surgical intervention was independently correlated with enhanced OS (HR 0.099, P=0.034), liver-specific PFS (HR 0.388, P=0.014), and PFS (HR 0.402, P=0.004).

CONCLUSIONS

In patients with GIST liver metastases, IM combined with HR might improve OS in selected patients compared with IM alone and IM combined with RFA/TACE. Achieving NED status with surgical treatment of patients results in significant prolonging of OS, liver-specific PFS and PFS.

Local treatment in metastatic GIST patients: A multicentre analysis from the Dutch GIST Registry

BACKGROUND

The added value of local treatment in selected metastatic GIST patients is unclear. This study aims to provide insight into the usefulness of local treatment in metastatic GIST by use of a survey study and retrospective analyses in a clinical database.

METHODS

A survey study was conducted among clinical specialists to select most relevant characteristics of metastatic GIST patients considered for local treatment, defined as elective surgery or ablation. Patients were selected from the Dutch GIST Registry. A multivariate Cox-regression model for overall survival since time of diagnosis of metastatic disease was estimated with local treatment as a time-dependent variable. An additional model was estimated to assess prognostic factors since local treatment.

RESULTS

The survey's response rate was 14/16. Performance status, response to TKIs, location of active disease, number of lesions, mutation status, and time between primary diagnosis and metastases, were regarded the 6 most important characteristics. Of 457 included patients, 123 underwent local treatment, which was associated with better survival after diagnosis of metastases (HR = 0.558, 95%CI = 0.336-0.928). Progressive disease during systemic treatment (HR = 3.885, 95%CI = 1.195-12.627) and disease confined to the liver (HR = 0.269, 95%CI = 0.082-0.880) were associated with worse and better survival after local treatment, respectively.

CONCLUSION

Local treatment is associated with better survival in selected patients with metastatic GIST. Locally treated patients with response to TKIs and disease confined to the liver have good clinical outcome. These results might be considered for tailoring treatment, but should be interpreted with care because only specific patients are provided with local treatment in this retrospective study.

Outcomes of Patients with Gastrointestinal Stromal Tumors in the Past Decade

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms of the gastrointestinal tract (GIT) that represent approximately 1 to 2 percent of primary gastrointestinal (GI) cancers. Owing to their rarity, very little is known about their overall epidemiology, and the prognostic factors of their pathology. The current study aimed to evaluate the independent determinants of mortality in patients diagnosed with GISTs over the past decade.

METHODS

Our study comprised 2374 patients diagnosed with GISTs from 2000 to 2017 from the Surveillance, Epidemiology, and End Results (SEER) database. We analyzed the baseline characteristics, and overall mortality (OM), as well as the cancer-specific mortality (CSM) of GISTs. Variables with a p value < 0.01 in the univariate Cox regression were incorporated into the multivariate Cox model, to determine the independent prognostic factors.

RESULTS

Multivariate Cox proportional hazard regression analyses of factors affecting the all-cause mortality and GIST-related mortality among US patients between 2010 and 2017 revealed a higher overall mortality in non-Hispanic Black patients (HR = 1.516, 95% CI 1.172-1.961, p = 0.002), patients aged 80+ (HR = 9.783, 95% CI 4.185-22.868, p = 0), followed by those aged 60-79 (HR = 3.408, 95% CI 1.488-7.807, p = 0.004); male patients (HR = 1.795, 95% CI 1.461-2.206, p < 0.001); patients with advanced disease with distant metastasis (HR = 3.865, 95% CI 2.977-5.019, p < 0.001), followed by cases with regional involvement via both direct extension and lymph node involvement (HR = 3.853, 95% CI 1.551-9.57, p = 0.004); and widowed patients (HR = 1.975, 95% CI 1.494-2.61, p < 0.001), followed by single patients (HR = 1.53, 95% CI 1.154-2.028, p = 0.003). The highest CSM was observed in the same groups, except widowed patients and patients aged 60-79. The highest CSM was also observed among patients that underwent chemotherapy (HR = 1.687, 95% CI 1.19-2.392, p = 0.003).

CONCLUSION

In this updated study on the outcomes of patients with GISTs, we found that non-Hispanic Black patients, male patients, and patients older than 60 years have a higher mortality with GISTs. Furthermore, patients who have received chemotherapy have a higher GIST-specific mortality, and married patients have a lower mortality. However, we do not know to what extent these independent prognostic factors interact with each other to influence mortality. This study paves the way for future studies addressing these interactions. The results of this study may help treating clinicians to identify patient populations associated with a dismal prognosis, as those may require closer follow-up and more intensive therapy; furthermore, with married patients having a better survival rate, we hope to encourage clinicians to involve family members of the affected patients early in the disease course, as the social support might impact the prognosis.

Surgical Options for Peritoneal Surface Metastases from Digestive Malignancies-A Comprehensive Review

The peritoneum is a common site for the dissemination of digestive malignancies, particularly gastric, colorectal, appendix, or pancreatic cancer. Other tumors such as cholangiocarcinomas, digestive neuroendocrine tumors, or gastrointestinal stromal tumors (GIST) may also associate with peritoneal surface metastases (PSM). Peritoneal dissemination is proven to worsen the prognosis of these patients. Cytoreductive surgery (CRS), along with systemic chemotherapy, have been shown to constitute a survival benefit in selected patients with PSM. Furthermore, the association of CRS with hyperthermic intraperitoneal chemotherapy (HIPEC) seems to significantly improve the prognosis of patients with certain types of digestive malignancies associated with PSM. However, the benefit of CRS with HIPEC is still controversial, especially due to the significant morbidity associated with this procedure. According to the results of the PRODIGE 7 trial, CRS for PSM from colorectal cancer (CRC) achieved overall survival (OS) rates higher than 40 months, but the addition of oxaliplatin-based HIPEC failed to improve the long-term outcomes. Furthermore, the PROPHYLOCHIP and COLOPEC trials failed to demonstrate the effectiveness of oxaliplatin-based HIPEC for preventing peritoneal metastases development in high-risk patients operated for CRC. In this review, we discuss the limitations of these studies and the reasons why these results are not sufficient to refute this technique, until future well-designed trials evaluate the impact of different HIPEC regimens. In contrast, in pseudomyxoma peritonei, CRS plus HIPEC represents the gold standard therapy, which is able to achieve 10-year OS rates ranging between 70 and 80%. For patients with PSM from gastric carcinoma, CRS plus HIPEC achieved median OS rates higher than 40 months after complete cytoreduction in patients with a peritoneal cancer index (PCI) ≤6. However, the data have not yet been validated in randomized clinical trials. In this review, we discuss the controversies regarding the most efficient drugs that should be used for HIPEC and the duration of the procedure. We also discuss the current evidence and controversies related to the benefit of CRS (and HIPEC) in patients with PSM from other digestive malignancies. Although it is a palliative treatment, pressurized intraperitoneal aerosolized chemotherapy (PIPAC) significantly increases OS in patients with unresectable PSM from gastric cancer and represents a promising approach for patients with PSM from other digestive cancers.

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.

Debulking surgery for malignant tumors: the current status, evidence and future perspectives

Debulking surgery, also called cytoreductive surgery, is a resection of the tumor as much as possible and an intended incomplete resection for unresectable malignant tumors. Since the most important principle in surgical oncology is complete R0 resection, debulking surgery goes against the basic principle and obscures the concept of operability. However, debulking surgery has been advocated for various types of advanced malignant tumors, including gynecological cancers, urological cancers, gastrointestinal cancers, breast cancers and other malignancies, with or without adjuvant therapy. Positive data from randomized trials have been shown in subsets of ovarian cancer, renal cell carcinoma, colorectal cancer and breast cancer. However, recent trials for renal cell carcinoma, colorectal cancer and breast cancer have tended to show controversial results, mainly according to the survival improvement of nonsurgical systemic therapy alone. On the other hand, debulking surgery still has a therapeutic role for slow-growing and borderline malignant tumors, such as pseudomyxoma peritonei and thymomas. The recent understanding of tumor heterogeneity and clonal evolution responsible for malignancy and drug resistance indicates that select patients may obtain prolonged survival by the synergistic effect of debulking surgery and novel systemic therapy. This review aimed to describe the current status and evidence of debulking surgery in a cross-organ manner and to discuss future perspectives in the current era with advances in systemic therapy.

Primary Tumor Resection Improves Survival in Patients With Metastatic Gastrointestinal Stromal Tumors: A Preliminary Population-Based Analysis

Background: Surgery has been the primary treatment in patients with localized gastrointestinal stromal tumors (GISTs) for many decades, whereas it remains controversial regarding the efficacy of primary tumor resection for metastatic GISTs treated with chemotherapy, and likewise it is unclear who would benefit from the surgical resection.

Methods: GISTs patients with distant metastases were identified from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2016. Cox proportional hazards regression models were used to identify prognostic factors of overall survival (OS) and cancer-specific survival (CSS). Kaplan-Meier analyses and log-rank tests were conducted to assess the effectiveness of surgery on survival.

Results: In total, of 455 patients with metastatic GISTs, 235 patients (51.6%) underwent primary tumor resection and 220 patients (48.4%) did not. Median survival of patients in resection group was 72 (95% CI: 62.90–81.10) months vs. 40 (95% CI: 29.53–50.47) months for those in non-resection group (p < 0.001). Similarly, surgery in conjunction with chemotherapy led to a favorable impact on survival than chemotherapy alone (OS: 72 vs. 40 months, p < 0.001; CSS: 74 vs. 44 months, p < 0.001). Multivariable analysis showed that both OS (HR: 0.581, 95% CI: 0.386–0.874, p = 0.009) and CSS (HR: 0.663, 95% CI: 0.439–0.912, p = 0.042] were dramatically improved in patients with surgical removal of primary site, as well as primary tumor size between 5 and 10 cm, while increasing age was predictive of poorer survival. Stratified analysis revealed that patients with tumor locations in the stomach demonstrated a prolonged survival after surgery, with no significant differential surgical effect between the stomach and small intestine.

Conclusions: Our study preliminarily suggests that carefully selected patients with metastatic GISTs might prolong survival after treatment of surgery, especially those with a primary tumor between 5 and 10 cm and a tumor located in the stomach.

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

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

Role of Resection Following Focal Progression with Standard Doses of Imatinib in Patients with Advanced Gastrointestinal Stromal Tumors: Results of Propensity Score Analyses

BACKGROUND

There are limited data on the clinical benefits of adding surgical resection in patients with focally progressive gastrointestinal stromal tumor (GIST). This study aims to compare the clinical outcomes of resection plus imatinib dose escalation or maintenance (S group) with imatinib dose escalation alone (NS group) in patients with advanced GIST following focal progression (FP) with standard doses of imatinib.

MATERIALS AND METHODS

A total of 90 patients with advanced GISTs who experienced FP with standard doses of imatinib were included in this retrospective analysis. The primary endpoints were time to imatinib treatment failure (TTF) and overall survival (OS).

RESULTS

Compared with the NS group (n = 52), patients in the S group (n = 38) had a higher proportion of primary tumor site involvement and lower tumor burden at FP. With a median follow-up duration of 31.0 months, patients in the S group had significantly better TTF and OS than patients in the NS group (median TTF: 24.2 vs. 6.5 months, p < .01; median OS: 53.2 vs. 35.1 months, p = .009). Multivariate analysis showed that S group independently demonstrated better TTF (hazard ratio [HR], 0.29; p < .01) and OS (HR, 0.47; p = .01). Even after applying inverse probability of treatment-weighting adjustments, S group demonstrated significantly better TTF (HR, 0.36; p < .01) and OS (HR, 0.58; p = .049).

CONCLUSION

Our results suggested that resection following FP with standard doses of imatinib in patients with advanced GIST provides additional benefits over imatinib dose escalation alone.

IMPLICATIONS FOR PRACTICE

This is the first study to compare the clinical outcomes of resection plus imatinib dose escalation or maintenance (S group) with imatinib dose escalation alone (NS group) in patients with advanced gastrointestinal stromal tumor (GIST) following focal progression (FP) with standard doses of imatinib. These findings suggest that resection can be safely performed following FP, and the addition of surgical resection provides further clinical benefit over imatinib dose escalation alone. Based on these results, the authors recommend resection following FP in patients with advanced GIST provided that an experienced multidisciplinary team is involved in the patient's treatment.

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.

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

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

Role for targeted resection in the multidisciplinary treatment of metastatic gastrointestinal stromal tumor

The management of advanced gastrointestinal stromal tumors (GISTs) has evolved in the modern era due to the discovery of c-kit mutations and the development of tyrosine kinase inhibitors (TKIs). Until the advent of TKIs such as imatinib, the median survival reported for patients with advanced GIST was 19 months. Although surgery is the treatment of choice for resectable primary GIST, its role in cases of recurrence and metastasis remains to be unclear. This review outlines the potential beneficial role of repeat surgical resection in the multidisciplinary treatment of advanced GIST in the era of TKIs.

Liver surgery prolongs the survival of patients with gastrointestinal stromal tumor liver metastasis: a retrospective study from a single center

Objectives

Gastrointestinal stromal tumor (GIST) liver metastasis (GLM) is a special subset of advanced GIST, because its lesions are easier to define and assess. We aim to determine the role of liver metastasectomy for patients with GLM in the era of tyrosine kinase inhibitor (TKI) therapy.

Methods

We reviewed patients with metastatic GIST who received surgery or other treatments in Sun Yat-sen University Cancer Center between January 1991 and December 2017. Patients with metastases confined to the liver and with no previous metastasis to other locations were included into the study and were classified into surgical and non-surgical groups. All patients received 400 mg/d imatinib after the operation. We compared progression-free survival (PFS) and overall survival (OS) between the two groups.

Results

A total of 102 patients were included into the study. Of them, 21 (20.1%) underwent surgery for liver metastases and 81 (79.9%) received TKI therapy alone. During the operation, six patients received radiofrequency ablation for suspicious or unresectable lesions. Three-year PFS rate was 77.5% in the surgical group and 65.5% in the non-surgical group (P=0.027); 5-year OS rate was 85.7% and 59.6%, respectively (P=0.008). About 22.1% of patients had metastases of less than three in the surgical group, while the rate was 42.9% in the non-surgical group (P=0.011). Patients with metastases of less than three had longer PFS than those with three or more, with a 3-year PFS rate of 72.8% and 65.8%, respectively (P=0.019). But their difference in 5-year OS rate was not significant (91.7% vs 55.3%, P=0.08).

Conclusion

Followed by continuous TKI therapy, R0 surgery significantly prolongs the survival of patients with GLM, regardless of the extent of disease or the phase of metastasis.

Treatment of metastatic, imatinib refractory, gastrointestinal stroma tumor with image-guided high-dose-rate interstitial brachytherapy

PURPOSE

Evaluation of efficacy and safety of CT- or MRI-guided high-dose-rate interstitial brachytherapy (iBT) in the treatment of advanced, imatinib refractory, metastatic gastrointestinal stroma tumors (GISTs) was the objective of this retrospective study.

METHODS AND MATERIALS

A cumulative number of 40 unresectable metastases (30 hepatic, 10 peritoneal) were treated with iBT in 10 selected patients with histologically proven GISTs. Six patients had peritoneal disease, and 5 patients were even progressing under sunitinib (second line)-thus iBT was applied as a salvage maneuver. IBT uses an interstitially introduced ¹⁹²iridium source in a high-dose-rate irradiation regime to destroy vital cells in a single fraction. Response to treatment was assessed clinically and with acquisition of MRI/CT every 3 months.

RESULTS

Local tumor control was reached in 97.5% of all treated metastases during a median time of 25 months-only one local relapse was observed during followup. The median diameter of the irradiated lesions was 2.4 cm (range 0.6-11.2 cm); a median dose of 15 Gy (range 6.7-21.96 Gy) was applied. The median progression-free survival after iBT was 6.8 (range 3.0-20.2) months; the median overall survival was 37.3 months (range 11.4-89.7). Two major complications (Common Terminology for Adverse Events grade 3) occurred following the intervention: local hemorrhage and pneumothorax, successfully dealt with by angiographic embolization and pleural drainage, respectively.

CONCLUSIONS

In selected patients with metastatic, imatinib refractory GISTs, iBT safely enables high rates of local tumor control and presents an alternative, anti-neoplastic treatment option even in a salvage situation.

Cytoreductive surgery for metastatic gastrointestinal stromal tumors followed by sunitinib compared to followed by imatinib-a multi-center cohort study

BACKGROUND

The progression-free survival (PFS) is not optimal when imatinib was recommended for treatment of gastrointestinal stromal tumor (GIST) undergoing surgery after tumor local or multifocal progression.

METHODS

We evaluate PFS of patients undergoing R0 resection or optimal cytoreductive surgery followed by sunitinib therapy compared with imatinib after tumor unifocal or multifocal progression.

RESULTS

From January 2006 to June 2017, ninety-seven patients from thirteen medical centers were enrolled. Fifty-six patients continued imatinib therapy and 41 patients switched sunitinib treatment directly after R0 resection or optimal cytoreductive surgery. The PFS of sunitinib group was longer than that of imatinib group (30.0 months vs 12.0 months, p = 0.009). In subgroup analysis, the PFS of the sunitinib and imatinib groups were 25.5 months and 12.0 months in patients with tumor multifocal progression (p = 0.008), and 39.0 months and 13.0 months in patients with unifocal progression (p = 0.156), respectively. PFS of postoperative sunitinib group was also superior to the total PFS of postoperative imatinib group (PFS of postoperative imatinib plus PFS of subsequent sunitinib therapy (30.0 months vs 21.0 months, p = 0.012). The overall survival in the sunitinib and imatinib groups were 37.0 months and 33.0 months, respectively (p = 0.794).

CONCLUSIONS

Surgery followed by sunitinib in GIST patients with unifocal or multifocal progression on imatinib may improve PFS, compared with surgery followed by imatinib.

Surgery for metastatic gastrointestinal stromal tumor: to whom and how to?

Although imatinib is a standard treatment for metastatic or recurrent gastrointestinal stromal tumors (GISTs), acquired c-kit mutations reportedly cause secondary resistance to imatinib. Sunitinib is a tyrosine kinase inhibitor (TKI) that can be used as second-line therapy in imatinib-resistant or -intolerant GISTs. For sunitinib-resistant or -intolerant GISTs, regorafenib is a standard third-line treatment. Although TKI therapies have revolutionized the treatment of recurrent or metastatic GISTs, they cannot cure GISTs. Therefore, in the era of TKIs, role of cytoreductive surgery for recurrent or metastatic GISTs has been discussed. Retrospective studies of treatment strategies with front-line surgery prior to imatinib have shown that initial cytoreduction confers no benefit in cases of advanced or recurrent GIST, and administering imatinib is the principle treatment. Most retrospective studies report cytoreductive surgery to be feasible in patients with metastatic GIST whose disease is stable or responsive to imatinib. Cytoreductive surgery may be indicated in limited disease progression refractory to imatinib when complete resection is possible, but case selection is critical. Cytoreductive surgery for metastatic GIST treated with sunitinib seems less feasible because of high rates of incomplete resections and complications. The role of cytoreductive surgery for metastatic GISTs would be difficult to establish in a prospective study; individualized treatments need to be carefully designed based on c-kit and platelet-derived growth factor receptor alpha (PDGFRA) mutations and other factors.

Ultrasound-Guided Intraoperative Radiofrequency Ablation and Surgical Resection for Liver Metastasis from Malignant Gastrointestinal Stromal Tumors

Objective

To evaluate the effectiveness, safety, and feasibility of intraoperative radiofrequency ablation (IORFA) under ultrasound guidance for the treatment of liver metastases from gastrointestinal stromal tumors (GISTs).

Materials and Methods

From August 2009 to February 2017, 24 patients with liver metastases of GISTs underwent IORFA, 14 underwent concurrent IORFA and primary GIST resection, and 10 underwent IORFA to treat hepatic recurrence after previous primary GIST resection. Seventy-six hepatic metastases were treated, of which 47 were surgically resected and 29 underwent IORFA. All included patients received imatinib therapy as standard treatment before and after IORFA or surgical resection. A retrospective medical record review was conducted, and follow-up data were collected. Technical success and effectiveness, overall and GIST-specific survival, and complications were assessed.

Results

The mean follow-up duration was 50.7 ± 34.7 months. The technical success rate of IORFA was 100%. New metastases developed in three of the 24 patients (12.5%) following a complete response 16, 51, and 95 months after IORFA, respectively. The cumulative one-, three-, and five-year overall survival rates were 100, 94.4, and 87.7%, respectively. The one-, three-, and five-year GIST-related survival rates were 100, 94.4, and 94.4%, respectively. Two major complications (biliary stricture and hepatic abscess) were observed.

Conclusion

IORFA appears to be a feasible and safe treatment option for liver metastasis in patients with primary GISTs. In addition, IORFA and surgical resection may be complementary, helping to obtain complete response in cases of otherwise inoperable liver metastases secondary to GISTs.

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.

The Role of Surgery in Metastatic Gastrointestinal Stromal Tumors

OPINION STATEMENT

Gastrointestinal stromal tumors (GISTs) are the most common sarcomas and mesenchymal neoplasms of the gastrointestinal tract. Macroscopically complete (R0/R1) resection is the standard treatment for localized resectable GIST with adjuvant imatinib therapy recommended for patients with intermediate or high-risk disease. In patients with advanced unresectable or metastatic GIST, imatinib has significantly improved outcomes. However, while most patients achieve partial response (PR) or stable disease (SD) on imatinib (with maximal response typically seen by 6 months on treatment), approximately half will develop secondary resistance by 2 years. Available data suggest that cytoreductive surgery may be considered in patients with metastatic GIST who respond to imatinib, particularly if a R0/R1 resection is achieved. The benefit of surgery in patients with focal tumor progression on imatinib is unclear, but may be considered. Patients with multifocal progression undergoing surgery generally have poor outcomes. Thus, surgery should be considered in patients with metastatic GIST whose disease responds to imatinib with a goal of performing R0/R1 resection. Optimal timing of surgery is unclear but should be considered between 6 months and 2 years after starting imatinib. Although surgery in patients with metastatic GIST treated with sunitinib is feasible, incomplete resections are common, complication rates are high, and survival benefit is unclear. Therefore, a careful multidisciplinary consultation is required to determine optimal treatment options on a case-by-case basis. Finally, patients with metastatic GIST should resume tyrosine kinase inhibitor treatment postoperatively.

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.

Combined Therapy of Gastrointestinal Stromal Tumors

Radical surgery is the mainstay of therapy for primary resectable, localized gastrointestinal stromal tumors (GIST). Nevertheless, approximately 40% to 50% of patients with potentially curative resections develop recurrent or metastatic disease. The introduction of imatinib mesylate has revolutionized the therapy of advanced (inoperable and/or metastatic) GIST and has become the standard of care in treatment of patients with advanced GIST. This article discusses the proper selection of candidates for adjuvant and neoadjuvant treatment in locally advanced GIST, exploring the available evidence behind the combination of preoperative imatinib and surgery.

Indications for surgery in advanced/metastatic GIST

Gastrointestinal stromal tumours (GISTs) are a relatively rare entity and often present as a locally advanced tumour or with metastatic disease. Complete surgical resection is the only means of cure in localised disease; however, imatinib therapy has greatly advanced the management of GIST and is established as both an adjunct to surgery in high-risk cases and as principle therapy in metastatic disease. Surgery in advanced GIST has undergone a renaissance in recent years with the potential for a combined treatment approach with either neoadjuvant imatinib in locally advanced primary disease or as an adjunct to imatinib in those with metastases or recurrent disease. Neoadjuvant imatinib can render a locally advanced primary GIST resectable, allow less invasive procedures or promote preservation of function, especially if the tumour is located in an anatomically difficult position. The role of surgery in metastatic or recurrent disease is more controversial and case selection is critical. The potential benefit is difficult to quantify, although surgery may have a limited favourable impact on progression-free survival and overall survival for those patients whose disease is responding to imatinib or those with limited focal progression. Patients with imatinib resistant disease should not be offered surgery unless as an emergency where palliative intervention may be justified.

Present and future role of surgery in metastatic gastrointestinal malignancies

PURPOSE OF REVIEW

Metastases from gastrointestinal malignancies are systemic or abdominal disseminations of cancer cells. From a biological perspective surgical resections are questionable but case series show that for some tumour types, surgery influences survival outcome. This review focuses on management and indications for surgery in recent literature of these metastatic gastrointestinal malignancies.

RECENT FINDINGS

A few gastrointestinal malignancies have emerged to be candidates for surgery in case of metastatic disease. Surgery can be considered in selected cases with liver metastases or abdominal dissemination of colorectal cancer, metastases from gastrointestinal stromal tumours or neuroendocrine tumours. On the contrary, recent publications do not support surgery for metastatic disease of any other gastrointestinal origin. The literature has ample examples of small series and anecdotal cases of successful surgical interventions for most tumour types but no new evidence has been presented to support broader indications for surgery.

SUMMARY

The evidence base for surgery of different metastatic gastrointestinal malignancies is unchanged. There are some clarifications when to perform surgery and the timing of surgery in regard to combined treatments. No new tumour types are added to potential candidates for surgery.

Feasibility and Timing of Cytoreduction Surgery in Advanced (Metastatic or Recurrent) Gastrointestinal Stromal Tumors During the Era of Imatinib

The prognosis of advanced gastrointestinal stromal tumors (GISTs) was dramatically improved in the era of imatinib. Cytoreduction surgery was advocated as an additional treatment for advanced GISTs, especially when patients having poor response to imatinib or developing resistance to it. However, the efficacy and benefit of cytoreduction were still controversial. Likewise, the sequence between cytoreduction surgery and imatinib still need evaluation. In this study, we tried to assess the feasibility and efficiency of cytoreduction in advanced GISTs. Furthermore, we analyzed the impact of timing of the cytoreduction surgery on the prognosis of advanced GISTs. We conducted a prospective collecting retrospective review of patients with advanced GISTs (metastatic, unresectable, and recurrent GISTs) treated in Chang Gung memorial hospital (CGMH) since 2001 to 2013. We analyzed the impact of cytoreduction surgery to response to imatinib, progression-free survival (PFS), and overall survival (OS) in patients with advanced GISTs. Moreover, by the timing of cytoreduction to imatinib, we divided the surgical patients who had surgery before imatinib use into early group and those who had surgery after imatinib into late. We compared the clinical response to imatinib, PFS and OS between early and late cytoreduction surgical groups. Totally, 182 patients were enrolled into this study. Seventy-six patients underwent cytoreduction surgery. The demographic characteristics and tumor presentation were similar between surgical and non-surgical groups. The surgical group showed better complete response rate (P <  .001) and partial response rate (P = 0.008) than non-surgical group. The 1-year, 3-year, and 5-year PFS were significantly superior in surgical group (P = 0.003). The 1-year, 3-year, and 5-year OS were superior in surgical group, but without statistical significance (P = 0.088). Dividing by cytoreduction surgical timing, the demographic characteristics and tumor presentation were comparable in early and late groups. The late cytoreduction group presented higher R0 resection rate (59.1% vs 31.5%, P = 0.025). However, the PFS and OS were comparable in both groups.Combining imatinib with cytoreduction increased the response rate to imatinib and prolonged PFS in patients with advanced GISTs. Moreover, early and late cytoreduction surgery was comparable in prognosis, although late cytoreduction revealed higher complete resection rate.

State of the Art in the Treatment of Gastrointestinal Stromal Tumors

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are the most frequently diagnosed mesenchymal neoplasms of the gastrointestinal tract. Despite their biological and clinical heterogeneity, the majority of these tumors are positive for the receptor tyrosine kinase KIT and are driven by KIT- or platelet-derived growth factor receptor alpha (PDGFRA)-activating mutations. There are still uncertainties regarding their clinical and molecular characterization and the optimal treatment regimens, making it difficult to establish a universal treatment algorithm for these tumors.

SUMMARY

From a clinical perspective, the main difference between GISTs and other gastrointestinal neoplasms is that the benign or malignant behavior of GISTs cannot be predicted from histopathology, but instead relies on empirically established scoring systems. Clinical data suggest that malignant potential may be an inherent quality of some GISTs rather than a feature acquired by the tumor during disease progression. Thus, some patients may require prolonged anti-tumor treatment even after complete surgical removal of the tumor.

KEY MESSAGE

Although GISTs are the most frequently occurring mesenchymal neoplasms in the gastrointestinal tract, no universal treatment algorithms exist. This paper reviews the current evidence that guides the management of GISTs.

PRACTICAL IMPLICATIONS

The management of localized GISTs involves the use of surgical resection, with the inclusion of preoperative tyrosine kinase inhibitor treatment for locally advanced, primarily unresectable tumors and for resectable cases requiring extensive surgery. Imatinib is also indicated as adjuvant therapy after complete surgical removal of GISTs with a high estimated risk of recurrence unless specific mutations conferring imatinib resistance are present. The optimal duration of adjuvant treatment is still controversial. For patients with metastatic imatinib-sensitive GISTs, imatinib constitutes the first-line standard treatment. Molecular characterization of the tumor (with respect to the PDGFRA and KIT genes) is mandatory prior to imatinib therapy. Sunitinib and regorafenib are established as alternative treatments for patients demonstrating generalized disease progression on imatinib. New tyrosine kinase inhibitors such as ponatinib and crenolanib as well as drugs targeting alternative pathways are currently under investigation. Surgery and locally ablative treatments may be indicated in some metastatic patients.

microRNA-218 increase the sensitivity of gastrointestinal stromal tumor to imatinib through PI3K/AKT pathway

To detect the expressions of microRNA-218 (miR-218) in an imatinib mesylate-sensitive human gastrointestinal stromal tumor (GIST) cells (GIST882) and an imatinib mesylate-resistant cell line (GIST430) and explore the roles of miR-218 and GIST cells in the sensitivity of gastrointestinal stromal tumor to imatinib mesylate and its potential signaling pathways, with an attempt to provide new insights for the treatment of GIST. The GIST cell lines (GIST882 and GIST430) were cultured in vitro. Quantitative real-time PCR (qRT-PCR) was utilized to determine the expression profiles of miR-218 in both GIST cell lines. Forty-eight hours after the transfection of the miR-218 mimic or miR-218 inhibitor in the GIST cells, the changes in the expression of miR-218 in the GIST cells were detected with qRT-PCR. The effects of the ectopic expression of miR-218 in GIST882 or GIST430 cells on the imatinib mesylate-induced GIST cell viability were determined by MTT. The effects of miR-218 ectopic expression on the apoptosis of imatinib mesylate-induce GIST cells were determined by Annexin V/PI double staining method and flow cytometry. The effects of miR-218 ectopic expression on the AKT and phospho-AKT (p-AKT) expressions of imatinib mesylate-induce GIST cells were determined by Western blot and flow cytometry with the PI3K pathway inhibitor Wortmannin. As shown by qRT-PCR, compared with that in the imatinib mesylate-sensitive GIST882, the expression of miR-218 in imatinib mesylate-resistant GIST430 was significantly decreased (P < 0.01). Compared with the control group, the expression of miR-218 significantly increased in the GIST882 48 h after the transfection of miR-218 mimic (P < 0.01) and significantly declined after the transfection of miR-218 inhibitor (P < 0.01). As shown by MTT and flow cytometry, after the expression of miR-218 was inhibited in GIST882 under the effect of imatinib mesylate, the cell viability significantly increased (P < 0.01) and the number of apoptotic cells significantly decreased (P < 0.05); on the contrary, the over-expression of miR-218 in GIST430 under the effect of imatinib mesylate resulted in the significantly decreased cell viability (P < 0.01) and the significantly increased number of apoptotic cells (P < 0.05). Western blot and flow cytometry showed that, in comparison to the control group, Wortmannin could significantly inhibit the expression of p-AKT in GIST430 cells (P < 0.01) and stimulated apoptosis (P < 0.01). The expression of miR-218 is down-regulated in an imatinib mesylate-resistant GIST cell line (GIST430), whereas miR-218 over-expression can improve the sensitivity of GIST cells to imatinib mesylate, with PI3K/AKT signaling pathway possibly involved in the mechanism.