Surgical intervention following imatinib treatment in patients with advanced gastrointestinal stromal tumors (GISTs)

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.

Radiotherapy in the Management of Gastrointestinal Stromal Tumors: A Systematic Review

Gastrointestinal stromal tumors (GISTs) are considered insensitive to radiotherapy. However, a growing number of case reports and case series have shown that some lesions treated by radiotherapy achieved an objective response. The aim of the study was to perform a systematic review of all reported cases, case series, and clinical studies of GISTs treated with radiotherapy to reevaluate the role of radiotherapy in GISTs. A systematic search of the English-written literature was conducted using PubMed, Web of Science, and Embase databases. Overall, 41 articles describing 112 patients were retrieved. The included articles were of low to moderate quality. Bone was the most common site treated by radiotherapy, followed by the abdomen. In order to exclude the influence of effective tyrosine kinase inhibitors (TKIs), a subgroup analysis was conducted on whether and which TKIs were concurrently applied with radiotherapy. Results showed that radiotherapy alone or combined with resistant TKIs could help achieve objective response in selected patients with advanced or metastatic GISTs; however, survival benefits were not observed in the included studies. Pain was the most common symptom in symptomatic GISTs, followed by neurological dysfunction and bleeding. The symptom palliation rate was 78.6% after excluding the influence of effective TKIs. The adverse reactions were mainly graded 1-2. Radiotherapy was generally well-tolerated. Overall, radiotherapy may relieve symptoms for GIST patients with advanced or metastatic lesions and even help achieve objective response in selected patients without significantly reducing the quality of life. In addition to bone metastases, fixed abdominal lesions may be treated by radiotherapy. Publication bias and insufficient quality of included studies were the main limitations in this review. Further clinical studies are needed and justified.

Neuroendocrine Tumor with Metachronous Gastrointestinal Stromal Tumor in a Patient: A Case Report

Neuroendocrine tumors (NETs) that arise from neuroendocrine cells can develop in most organs; however, it is rarely found in the duodenal papilla. Conversely, gastrointestinal stromal tumors (GISTs), which are mostly asymptomatic and detected incidentally, are usually found in the stomach and very rarely occur metachronously with NETs. A 42-year-old female with no specific underlying disease underwent gastroscopy due to epigastric pain. Biopsy of enlarged major and minor duodenal papilla confirmed the diagnosis of a NET. Endoscopic papillectomy of the major and minor papillae was performed. Multiple duodenal and jejunal submucosal nodules were seen on biliary CT performed at the 30 months follow-up. Pylorus-preserving pancreaticoduodenectomy was performed due to the suspicion of multiple recurrent NETs and muscularis propria involvement on endoscopic ultrasound. Surgical specimen biopsy confirmed the diagnosis of multiple duodenal and jejunal GIST lesions and a metastatic NET in the duodenal lymph node. We report a rare case of a GIST detected in the duodenum during follow-up after the diagnosis and papillectomy of duodenal papilla NET.

The Landmark Series: Systemic Therapy for Resectable Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. Complete resection is the only potentially curative treatment, although recurrence is common, occurring in approximately 40–50% of patients. The introduction of effective molecularly targeted therapies for GISTs has dramatically changed the clinical management paradigms for, and prognosis of, patients with intermediate- and high-risk GISTs, as well as those with locally advanced and metastatic disease. In this article, we review landmark studies that evaluated the use and efficacy of the tyrosine kinase inhibitors imatinib and sunitinib in the adjuvant and neoadjuvant settings for resectable primary and limited resectable metastatic GISTs.

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.

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.

Long-term survival outcome with tyrosine kinase inhibitors and surgical intervention in patients with metastatic or recurrent gastrointestinal stromal tumors: A 14-year, single-center experience

The long‐term effects of tyrosine kinase inhibitors (TKIs), including imatinib, and surgical intervention on advanced gastrointestinal stromal tumor (GIST) were evaluated. All 379 patients had metastatic or recurrent GIST and started 400 mg/d imatinib at the Asan Medical Center in periods 1 and 2 [2001‐2007 (33.2%) and 2008‐2014 (66.8%), respectively]. Men constituted 60.4%; median patient age and tumor size at the initiation of imatinib were 58.6 (14.6‐85.5) years and 51 (0‐324) mm, respectively, without differences between periods except for older age and less preimatinib surgery in period 2. Response and disease control rates with imatinib in measurable GIST were 63.1% and 94.3%, respectively, without differences between periods. More patients in period 2 underwent surgical resection for TKI‐responsive diseases within the first 2 years (24.9%, P = 0.006). With a median follow‐up of 6.1 years (2.5‐16.0) in survivors, median progression‐free survival (PFS) was 5.4 years [95% confidence interval (CI), 4.0‐6.9]. Subsequent sunitinib (P = 0.066) and regorafenib (P = 0.003) were more commonly administered in period 2. Median overall survival (OS) was 8.8 years (95% CI, 7.8‐9.7). PFS with imatinib (P = 0.002) and OS (P = 0.019) were significantly longer in period 2. Young age, smaller tumor size at the initiation of imatinib, KIT exon 11 mutation, surgical intervention, and period 2 were favorable factors for PFS and OS. Patients with advanced GIST showed better prognosis with the optimal use of imatinib, along with active surgical intervention and more common use of subsequent TKIs in period 2.

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.

Role of surgical resection for patients with recurrent or metastatic gastrointestinal stromal tumors: A systematic review and meta-analysis

BACKGROUND

The role of surgical resection for patients with recurrent or metastatic gastrointestinal stromal tumors is still controversial. This meta-analysis aims to investigate the clinical outcomes of surgery combined with tyrosine kinase inhibitors among patients with recurrent or metastatic gastrointestinal stromal tumors.

METHODS

We systematically searched PubMed, EMBASE, the Cochrane Library and Wanfangdata without language restriction. Random effect models were used to estimate pooled hazard ratio and the corresponding 95% confidence intervals. Subgroup analyses, sensitivity analysis and trim and fill analysis were also performed.

RESULTS

A total of 1416 patient from 9 studies were finally enrolled in this meta-analysis. The summary results showed that surgery combined with tyrosine kinase inhibitors showed a tendency of a longer overall survival compared with tyrosine kinase inhibitors treatment alone (HR by random-effects model 0.68, 95% CI 0.54-0.85, I2 = 44.7%) and improved progress-free survival (HR by random-effects model 0.50,95% CI, 0.33-0.76, I2 = 17.9%). The trim and fill analysis and sensitive analysis indicated the relatively robust result.

CONCLUSION

Surgery combined with tyrosine kinase inhibitors therapy is associated with a better overall survival and progression free survival for patients with recurrent or metastatic gastrointestinal stromal tumors as compared with TKIs treatment alone.

Outcomes After Surgical Resection Differ by Primary Tumor Location for Metastatic Gastrointestinal Stromal Tumors (GISTs): a Propensity Score Matching Population Study

PURPOSE

Primary tumor location has been identified as an important prognostic factor among patients with gastrointestinal stromal tumors (GISTs). The purpose of this study is to identify how primary tumor location may affect outcomes after resection for patients with metastatic GISTs.

METHODS

Patients with GISTs and distant metastases at diagnosis were identified in the Surveillance Epidemiology and End Results (SEER) database. Patients that underwent surgery were matched to patients that did not undergo surgery using propensity score matching (PSM) analysis.

RESULTS

After PSM, 570 patients were identified (males 334 [58.6%], females 236 [41.4%], age 62 ± 13.9 years). Gastric tumors constituted the majority (325 [57%]), followed by small intestinal (136 [23.9%]), colorectal (19 [3.3%]), and retroperitoneal/peritoneal tumors (23 [4%]). Median follow-up was 25.5 months (95% CI 23-29 months). Undergoing surgery was associated with improved disease-specific survival (DSS) on both univariate (median not reached vs. 51 months, p < 0.001) and multivariate analyses (HR 4.98, 95% CI 2.23-11.12, p < 0.001). A sub-analysis of patients with gastric GISTs showed that undergoing surgery was the only significant factor associated with improved DSS (median not reached vs. 39 months, p < 0.001, HR 2.95, 95% CI 1.92-4.53). In contrast, undergoing surgery was not associated with improved survival for small intestinal, colorectal, or retroperitoneal/peritoneal tumors.

CONCLUSIONS

Surgery for gastric metastatic GISTs is associated with improved survival. No discernible benefit after surgical resection was identified for patients with small intestinal, colorectal, retroperitoneal, or peritoneal metastatic GISTs.

Prediction of morbidity following cytoreductive surgery for metastatic gastrointestinal stromal tumour in patients on tyrosine kinase inhibitor therapy

BACKGROUND

Although cytoreductive surgery has been shown to be beneficial in carefully selected patients with metastatic gastrointestinal stromal tumours (GISTs) treated with tyrosine kinase inhibitors (TKIs), factors predictive of postoperative morbidity have not been investigated previously.

METHODS

A surgical complexity score for GIST metastasectomy (GM-SCS) composed of patient-related and surgical factors was assigned retrospectively to patients with metastatic GIST treated with TKI therapy and surgery at two institutions between 2002 and 2014. The ability of clinicopathological factors and GM-SCS to predict postoperative morbidity was assessed by means of a multivariable logistic regression model. Postoperative complications were categorized using the Clavien-Dindo classification.

RESULTS

Some 400 operations on 323 patients with metastatic GIST on TKIs were included. Complications were observed following 110 operations (27·5 per cent) including 70 major complications (grade III-V) (17·5 per cent of 400 operations). Patients were divided into low (5 points or less; 100 patients, 25·0 per cent), intermediate (6-9 points; 191, 47·8 per cent) and high (at least 10 points; 109, 27·3 per cent) complexity scoring groups based on the GM-SCS. An intermediate (odds ratio (OR) 2·88; P = 0·008) and high (OR 5·40; P < 0·001) GM-SCS were independent predictors of overall complications, whereas only a high GM-SCS was independently predictive of a major complication (OR 3·65; P = 0·018). Metastatic mitotic index was also an independent predictor of overall complications (OR 2·55; P = 0·047). GM-SCS did not predict progression-free or overall survival.

CONCLUSION

A gastrointestinal stromal tumour metastastectomy surgical complexity score can predict morbidity, which may help in preoperative risk stratification and optimal treatment planning.

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.

Efficacy of Surgery and Imatinib Mesylate in the Treatment of Advanced Gastrointestinal Stromal Tumor: A Systematic Review

Aims and background

In patients with localized gastrointestinal stromal tumors, surgery remains the elective treatment. Nowadays, imatinib therapy has been standardized in advanced gastrointestinal stromal tumors, showing continuous improvements in progression-free and overall survival. A combination of imatinib therapy and surgery may also be effective in a subset of patients with metastatic or unresectable gastrointestinal stromal tumors. In this review, the authors analyzed the role of imatinib mesylate associated to surgery in unresectable and/or metastatic gastrointestinal stromal tumors.

Methods and study design

We searched for all published and unpublished randomized controlled clinical trials and controlled clinical trials. We conducted the review according to the recommendations of The Cochrane Collaboration. We used Review Manager 5 software for the statistical analysis.

Results

There are currently no randomized controlled clinical trials or controlled clinical trials on this issue. We performed a subgroup analysis in the patients pre-operatively treated with imatinib mesylate. This subgroup revealed a minor incidence of recurrent or metastatic gastrointestinal stromal tumors and a greater incidence of locally unresectable gastrointestinal stromal tumors in the responsive disease group (P = 0.001). In this patient group, more complete resections were observed (P = 0.00001). Furthermore, in the same patient group we observed a more significant 12 and 24-month disease-free survival after imatinib treatment and complete resection (respectively P = 0.06 and P = 0.003) and also a better 24-month overall survival (P = 0.004).

Conclusions

There is actually only one ongoing European randomized study evaluating surgery of residual disease in patients with metastatic gastrointestinal stromal tumors responding to imatinib mesylate. Imatinib mesylate represents the standard treatment as preoperative supplement for locally unresectable and/or metastatic gastrointestinal stromal tumors, and a trial to compare the approach versus surgery alone is not necessary. For patients responding to imatinib or patients with prolonged stable disease, resection of residual disease should be considered. A phase III randomized study evaluating surgery of residual disease in patients with metastatic gastrointestinal stromal tumor responding to imatinib mesylate, EORTC 62063, has been opened. Moreover, surgery should be considered for patients at higher risk of complications during pharmacological debulking. In advanced gastrointestinal stromal tumors, the advantages of the integrated treatment are significant in the complete or partial response disease group in terms of more complete resections and better disease-free and overall survival.

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.

Endoscopic versus laparoscopic resection of gastric gastrointestinal stromal tumors: a multicenter study

Despite endoscopic resection has been performed to treat gastric gastrointestinal stromal tumor (GISTs). However, the safety and long-term outcomes remains controversial. This study aims to compare the safety and surgical outcomes of endoscopic versus laparoscopic resection of gastric GISTs. A total of 335 patients that were pathologically confirmed with gastric GISTs (tumor size ≤ 3.5 cm) were surgically treated with endoscopic resection (endoscopic group) or laparoscopic resection (laparoscopic group) in three institutions from March 1, 2011 to October 1 2014. These demographics, tumor characteristics, and outcomes were retrospectively analyzed for identification of outcomes and feasibility of endoscopic or laparoscopic resection. Of 335 patients, 262 and 73 patients underwent endoscopic and laparoscopic resection, respectively. The average tumor size was 1.33±0.78 cm in the endoscopic group and 1.97±0.93 cm in the laparoscopic group. The average operating time was 62.40±36.94 min in the endoscopic group and 112.81±55.69 cm in the laparoscopic group. Days of realimentation was 2.76±1.67 in the endoscopic group and 4.89±2.03 in the laparoscopic group. The average cost was $ 3246.01±1017.61 in the endoscopic group and $ 4884.81±1339.51 in the laparoscopic group. There was no postoperative mortality. Endoscopic resection for gastric GISTs is safe and feasible in tumors ≤ 3.5 cm. Because endoscopic resection showed good results with lower operating time, realimentation days, length of hospital stay and mean total cost, it is a minimally invasive and safe alternative approach which can achieve fast recovery and satisfactory outcomes for appropriately selected patients with gastric GISTs.

Small intestinal stromal tumors: Clinical features and factors related to misdiagnosis

AIM

To analyze the clinical characteristics of small intestinal stromal tumors (SISTs) and identify factors related to their misdiagnosis.

METHODS

Clinical data of 104 patients with pathologically proved SISTs were retrospectively analyzed at our hospital from January 2010 to January 2015, with regard to clinical features, tumor location, tumor size, diagnostic methods, and risk classification.

RESULTS

Common clinical symptoms included abdominal mass (67/104, 64.5%), gastrointestinal bleeding (47/104, 52.8%), and abdominal pain (47/104, 52.8%). The lesions were seen mainly in the jejunum (45.2%), followed by the ileum (29.8%) and duodenum (25%). The misdiagnosis rate was as high as 34.6%, and SISTs were often misdiagnosed as gynecological tumors (15/36), digestive tract leiomyomas (6/36) and other diseases. The misdiagnosis was related, to a certain extent, to clinical manifestations, tumor location, tumor size, growth mode, examination methods and other factors, but had nothing to do with sex, age of onset, risk classification, or metastasis.

CONCLUSION

SISTs frequently occur in the jejunum, with gastrointestinal bleeding and abdominal mass being common clinical manifestations. Its clinical misdiagnosis rate is high. Therefore, for patients with recurrent gastrointestinal bleeding and abdominal mass that cannot be clearly diagnosed by color Doppler ultrasound, CT and digestive endoscopy, timely surgical biopsy and immunohistochemistry examination should be performed to achieve early diagnosis and avoid misdiagnosis.

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.

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.

The role of surgical resection following imatinib treatment in patients with recurrent or metastatic gastrointestinal stromal tumors: results of propensity score analyses

BACKGROUND

Although benefits of surgical resection of residual gastrointestinal stromal tumors (GISTs) after imatinib therapy have been suggested, those benefits over imatinib alone have not been proven. We compared the clinical outcomes of surgical resection of residual lesions after imatinib treatment (S group) with imatinib treatment alone (NS group) in patients with recurrent or metastatic GISTs.

METHODS

A total of 134 patients (42 in the S group, 92 in the NS group) with recurrent or metastatic GIST who had stable disease for more than 6 months after responding to imatinib were included.

RESULTS

There were no statistically significant differences in the baseline characteristics of the S and NS groups except for age and number of peritoneal metastases. The median follow-up period was 58.9 months. Progression-free survival (PFS) and overall survival (OS) were significantly longer in the S group compared with the NS group (median PFS: 87.7 vs. 42.8 months, p = 0.001; median OS: not reached vs. 88.8 months, p = 0.001). Multivariate analysis revealed that S group, female sex, KIT exon 11 mutations, and low initial tumor burden were associated with longer PFS, and S group and low initial tumor burden were associated with a longer OS. Even after applying inverse probability of treatment weighting adjustment, the S group demonstrated significantly better outcomes in terms of PFS (HR 2.326; 95 % confidence interval [CI] 1.034-5.236; p = 0.0412) and OS (HR 5.464; 95 % CI 1.460-20.408; p = 0.0117).

CONCLUSION

Surgical resection of residual lesions after disease control with imatinib is likely to be beneficial to patients with recurrent or metastatic GISTs.

The economic impact of cytoreductive surgery and tyrosine kinase inhibitor therapy in the treatment of advanced gastrointestinal stromal tumours: a Markov chain decision analysis

PURPOSE

The current first-line treatment for patients with recurrent or metastatic gastrointestinal stromal tumours (GIST) is management with tyrosine kinase inhibition (TKI). There is an undefined role for surgery in the management of these patients. This study uses a cost analysis to examine the economic impact of treating patients with TKI in combination with surgery at different time-points in their treatment trajectories.

METHODS

A Markov chain decision analysis was modelled over a 2-year time horizon to determine costs associated with surgery in combination with imatinib mesylate (IM) or sunitinib malate (SU) in seven scenarios varied by TKI agent, dose and disease status (stable versus localised progressive disease). Rates of disease progression, surgical morbidity, mortality and adverse drug reactions were extracted from the existing literature. Deterministic sensitivity analyses were performed to examine changes in cost due to variations in key variables.

RESULTS

The least-costly scenario was to perform no surgery. The most costly scenario was to perform surgery on patients with localised progressive disease on IM 800 mg. The overall range of costs clustered within approximately $47,000 (USD). Variations in surgical cost, surgical mortality and cost of IM demonstrated thresholds for changing the least-costly scenario within plausible tested ranges.

CONCLUSION

Costs of surgical intervention at different time-points within the treatment course of patients with advanced GIST fluctuate within a relatively narrow range, suggesting that costs arise primarily from the administration of TKI. The decision to pursue cytoreductive surgery should not be based on cost alone. Future studies should incorporate health-state utilities when available.

Metastasectomy for gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the intestinal tract. Improvements in understanding the molecular pathogenesis of GIST have resulted in novel treatment strategies combining surgery with tyrosine kinase inhibitors (TKIs). Metastasectomy in carefully selected patients who have stable or responsive disease on imatinib should be considered in the multidisciplinary setting. We review existing data on surgical cytoreduction in metastatic GIST while on targeted therapy and compare outcomes with either treatment alone.

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

BACKGROUND

Baseline tumor size is one of important prognostic factors for imatinib therapy in patients with advanced gastrointestinal stromal tumor (GIST). The purpose of this study was to determine whether surgical cytoreduction before imatinib therapy can improve the prognosis.

METHODS

A total of 249 patients with advanced GIST were reviewed retrospectively. Patients were categorized into two groups according to the degree of initial cytoreduction: 35 patients with ≥75 % of initial tumor bulk removed (cytoreduction group) and the other 214 patients (no cytoreduction group). The median follow-up was 44.0 months.

RESULTS

Patients in the cytoreduction group were younger, in better performance, showed more initially metastatic disease, peritoneal metastases, but fewer liver metastases. The baseline tumor size when starting imatinib became significantly reduced in the cytoreduction group, which made significant difference between the two groups. By multivariate analyses, mutational status, tumor size, and granulocyte count at presentation were associated with progression-free survival. Age and tumor size were associated with overall survival. However, initial cytoreduction was not significantly related to the prognosis.

CONCLUSIONS

Cytoreduction before imatinib therapy appears not to improve the prognosis. Imatinib therapy should still represent the initial treatment for advanced GIST.

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.

A multidisciplinary approach to the diagnosis and treatment of gastrointestinal stromal tumor

Management of patients with gastrointestinal stromal tumor (GIST) typically involves a combination of surgical, pathologic, and pharmacologic interventions. Gastroenterologists are often the first specialists to encounter patients presenting with GIST and are therefore responsible for facilitating early intervention strategies. Although patients with gastric or small-bowel GISTs typically present with symptoms, a diagnosis of GIST should be considered whenever a submucosal lesion is seen endoscopically. Visualization by standard endoscopy often can determine tumor location and size, although endoscopic ultrasound (EUS) is the most accurate imaging technique for submucosal lesions. Biopsy techniques that yield sufficient tumor samples for diagnostic studies, such as EUS-guided fine needle aspiration, are essential, although other approaches such as EUS-guided core needle biopsy may increase diagnostic yield for subepithelial lesions. Pathology assessment should include immunohistochemical staining for KIT and possibly DOG1 expression, and mutational analysis can have prognostic and predictive value for certain patients. R0 resection is the goal for patients with localized or potentially resectable tumors, which often can be accomplished by laparoscopic resection, even for larger tumors. Medical oncologists play a key role in assessing risk of recurrence after resection and optimizing tyrosine kinase inhibitor therapy in the adjuvant or metastatic setting. Cytoreductive surgery may have value for patients with recurrent or metastatic GIST who exhibit stable disease or respond to tyrosine kinase inhibitor therapy. A coordinated multidisciplinary approach over the course of the disease will serve to enhance communication among GIST team members, reduce risk of progression, and optimize outcomes.

A gist of gastrointestinal stromal tumors: A review

Gastrointestinal stromal tumors (GISTs) have been recognized as a biologically distinctive tumor type, different from smooth muscle and neural tumors of the gastrointestinal tract (GIT). They constitute the majority of gastrointestinal mesenchymal tumors of the GIT and are known to be refractory to conventional chemotherapy or radiation. They are defined and diagnosed by the expression of a proto-oncogene protein detected by immunohistochemistry which serves as a crucial diagnostic and therapeutic target. The identification of these mutations has resulted in a better understanding of their oncogenic mechanisms. The remarkable antitumor effects of the molecular inhibitor imatinib have necessitated accurate diagnosis of GIST and their distinction from other gastrointestinal mesenchymal tumors. Both traditional and minimally invasive surgery are used to remove these tumors with minimal morbidity and excellent perioperative outcomes. The revolutionary use of specific, molecularly-targeted therapies, such as imatinib mesylate, reduces the frequency of disease recurrence when used as an adjuvant following complete resection. Neoadjuvant treatment with these agents appears to stabilize disease in the majority of patients and may reduce the extent of surgical resection required for subsequent complete tumor removal. The important interplay between the molecular genetics of GIST and responses to targeted therapeutics serves as a model for the study of targeted therapies in other solid tumors. This review summarizes our current knowledge and recent advances regarding the histogenesis, pathology, molecular biology, the basis for the novel targeted cancer therapy and current evidence based management of these unique tumors.

Gastrointestinal stromal tumors: diagnosis, therapy and follow-up care in Austria

Optimal treatment for patients suffering from gastrointestinal stromal tumors (GIST) is based on an interdisciplinary treatment approach. Austrian representatives of Medical and Surgical Oncology, Pathology, Radiology, Nuclear Medicine, Gastroenterology, and Laboratory Medicine issued this manuscript on a consensual base within the context of currently available and published literature. This paper contains guidelines and recommendations for diagnosis, therapy, and follow-up of GIST patients in Austria.

Imatinib as preoperative therapy in Chinese patients with recurrent or metastatic GISTs

OBJECTIVE

Imatinib has dramatically altered the options for management of patients with gastrointestinal stromal tumours. However, it has become clear that secondary resistance to the drug develops during long-term therapy. The purpose of our study was to retrospectively analyze safety and long-term outcomes in Chinese patients with recurrent or metastatic GISTs treated with imatinib preoperatively.

METHODS

Between June 2003 and June 2011, 22 patients underwent surgery for recurrent or metastatic GISTs after preoperative treatment with imatinib.

RESULTS

Complete resection was accomplished in 8 of the 10 responsive disease (RD) patients (80%), and in 3 of the 12 patients (25%) who had progression disease (PD). The amount of blood loss during the operation in PD patients was higher than in RD patients. There was 1 hospital death in PD group related to surgery, while the other patients recovered with conservative therapy because complications were mild. The difference in median PFS between patients with RD and those with PD was significant (24.8 vs. 2.81 months, P<0.001). The difference in 2-year OS rate between patients with RD and those with PD was not significant (100% vs. 87.5%, P>0.05).

CONCLUSIONS

Our study indicates that surgical intervention can improve the PFS of Chinese patients with recurrent or metastatic GISTs responsive to imatinib, but does not prolong OS as well as in patients who develop imatinib resistance. Surgical resection following imatinib treatment is feasible and can be considered for patients with advanced GISTs responsive to imatinib.

Modern treatment of gastric gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GIST) are rare mesenchymal smooth muscle sarcomas that can arise anywhere within the gastrointestinal tract. Sporadic mutations within the tyrosine kinase receptors of the interstitial cells of Cajal have been identified as the key molecular step in GIST carcinogenesis. Although many patients are asymptomatic, the most common associated symptoms include: abdominal pain, dyspepsia, gastric outlet obstruction, and anorexia. Rarely, GIST can perforate causing life-threatening hemoperitoneum. Most are ultimately diagnosed on cross-sectional imaging studies (i.e., computed tomography and/or magnetic resonance imaging in combination with upper endoscopy. Endoscopic ultrasonographic localization of these tumors within the smooth muscle layer and acquisition of neoplastic spindle cells harboring mutations in the c-KIT gene is pathognomonic. Curative treatment requires a complete gross resection of the tumor. Both open and minimally invasive operations have been shown to reduce recurrence rates and improve long-term survival. While there is considerable debate over whether GIST can be benign neoplasms, we believe that all GIST have malignant potential, but vary in their propensity to recur after resection and metastasize to distant organ sites. Prognostic factors include location, size (i.e., > 5 cm), grade (> 5-10 mitoses per 50 high power fields and specific mutational events that are still being defined. Adjuvant therapy with tyrosine kinase inhibitors, such as imatinib mesylate, has been shown to reduce the risk of recurrence after one year of therapy. Treatment of locally-advanced or borderline resectable gastric GIST with neoadjuvant imatinib has been shown to induce regression in a minority of patients and stabilization in the majority of cases. This treatment strategy potentially reduces the need for more extensive surgical resections and increases the number of patients eligible for curative therapy. The modern surgical treatment of gastric GIST combines the novel use of targeted therapy and aggressive minimally invasive surgical procedures to provide effective treatment for this lethal, but rare gastrointestinal malignancy.

Clinical practice guideline for accurate diagnosis and effective treatment of gastrointestinal stromal tumor in Korea

Despite their rarity in incidence and prevalence, gastrointestinal stromal tumors (GISTs) have emerged as a distinct and noteworthy pathogenetic entity. The clinical management of GISTs has rapidly evolved due to the recent elucidation of their oncogenic signal transduction pathway and the introduction of molecular-targeted therapies. Successful management of GISTs requires a multidisciplinary approach firmly based on an accurate histopathologic diagnosis. In 2007, the Korean GIST study group published the first guideline for optimal diagnosis and treatment of GISTs in Korea. The second version of the guideline was published in 2010. Herein, we provide the results of relevant clinical studies for the purpose of further revision to the guideline. We expect this new guideline will enhance the accuracy of diagnosis, as performed by members of the Korean associate of physicians involved in GIST patient care, thus improving the efficacy of treatment.

Hypoglycaemia in a 63-year-old female with a large, recurrent, metastatic gastrointestinal stromal tumour (GIST)

INTRODUCTION

Non-islet cell tumour-induced hypoglycaemia (NICTH) is rare, with few cases reported in patients with gastrointestinal stromal tumour (GIST).

CASE REPORT

A 63-year-old Chinese female with known metastatic GIST presents with persistent hypoglycaemia. Investigations revealed a likely diagnosis of NICTH, and she underwent debulking surgery. There was complete resolution of her hypoglycaemia post-operatively

DISCUSSION

NICTH should be considered in patients with GIST and hypoglycaemia. Surgical debulking is recommended as part of the management of NICTH.

Clinicopathologic change of gastrointestinal stromal tumor after neoadjuvant imatinib followed by surgical resection

A 53-year-old woman was diagnosed with gastrointestinal stromal tumor (GIST) of the stomach. Computed tomography (CT) revealed a huge mass (12 cm in diameter), likely to invade pancreas and spleen. In the operation field, the tumor was in an unresectable state. The patient was then started on imatinib therapy for 4 months. On follow-up imaging studies, the tumor almost disappeared. We performed total gastrectomy and splenectomy upon which two small-sized residual tumors were found on microscopy. In this paper, we describe a case of clinicopathologic change in unresectable GIST after neoadjuvant imatinib mesylate.

A decade of tyrosine kinase inhibitor therapy: Historical and current perspectives on targeted therapy for GIST

The introduction of molecularly targeted therapies has ushered in a considerable transformation in the management of gastrointestinal stromal tumors (GIST) that currently defines the paradigm of targeted therapy for solid tumors. Indeed, in the past decade the management of GIST has evolved from a disease only effectively treatable by surgery to the archetype of a tumor treatable with a molecularly targeted therapy. Better understanding of the molecular and genetic characteristics that underlie the aberrant behavior of GIST has increased the accuracy of its diagnosis and allowed for the identification of distinct genetic hallmarks, prognostic groups, and treatment strategies. Collectively, this has resulted in the development of the targeted tyrosine kinase inhibitors (TKIs) imatinib and sunitinib, and continues to prompt studies of novel agents in this disease. Since approval in 2002, imatinib has been shown to provide a high level of clinical efficacy in patients with advanced GIST, including a median progression-free survival (PFS) of 2 years and median overall survival approaching 5 years, with some patients progression-free after 10 years of treatment. Imatinib is now also approved in adult patients following resection of KIT-positive GIST. In 2006, sunitinib was approved for the treatment of advanced GIST after failure of imatinib. Sunitinib provides significant benefit in this setting, with a median PFS close to 6 months after imatinib failure. Following progression on these agents, patients have limited treatment options. This critical unmet need is being addressed by the development of new TKIs and the use of novel regimens with approved agents.

Clinical practice guideline for accurate diagnosis and effective treatment of gastrointestinal stromal tumor in Korea

Despite the rarity in incidence and prevalence, gastrointestinal stromal tumor (GIST) has emerged as a distinct pathogenetic entity. And the clinical management of GIST has been evolving very rapidly due to the recent recognition of its oncogenic signal transduction pathway and the introduction of new molecular-targeted therapy. Successful management of GIST requires a multidisciplinary approach firmly based on accurate histopathologic diagnosis. However, there was no standardized guideline for the management of Korean GIST patients. In 2007, the Korean GIST study group (KGSG) published the first guideline for optimal diagnosis and treatment of GIST in Korea. As the second version of the guideline, we herein have updated recent clinical recommendations and reflected changes in diagnosis, surgical and medical treatments for more optimal clinical practice for GIST in Korea. We hope the guideline can be of help in enhancing the quality of diagnosis by members of the Korean associate of physicians involving in GIST patients's care and subsequently in achieving optimal efficacy of treatment.

NCCN Task Force report: update on the management of patients with gastrointestinal stromal tumors

The standard of care for managing patients with gastrointestinal stromal tumors (GISTs) rapidly changed after the introduction of effective molecularly targeted therapies involving tyrosine kinase inhibitors (TKIs), such as imatinib mesylate and sunitinib malate. A better understanding of the molecular characteristics of GISTs have improved the diagnostic accuracy and led to the discovery of novel immunomarkers and new mechanisms of resistance to TKI therapy, which in turn have resulted in the development of novel treatment strategies. To address these issues, the NCCN organized a task force consisting of a multidisciplinary panel of experts in the fields of medical oncology, surgical oncology, molecular diagnostics, and pathology to discuss the recent advances, identify areas of future research, and recommend an optimal approach to care for patients with GIST at all stages of disease. The task force met for the first time in October 2003 and again in December 2006 and October 2009. This supplement describes the recent developments in the field of GIST as discussed at the October 2009 meeting.

Role of surgery combined with kinase inhibition in the management of gastrointestinal stromal tumor (GIST)

BACKGROUND

Surgery is the standard treatment for primary, gastrointestinal stromal tumor (GIST); however, surgical resection often is not curative, particularly in large GIST. Five years after complete removal of their tumor, approximately half of treated patients relapse. Imatinib, an oral tyrosine kinase inhibitor (TKI), is first-line treatment in patients with metastatic or unresectable GIST. It has resulted in durable objective responses or stable disease in 84% of patients and is well tolerated. The efficacy of imatinib in advanced GIST has created interest in a variety of potential multimodal approaches to management that combine surgery with systemic therapy.

RESULTS

Recently, a large, randomized, Phase III, US cooperative group trial that compared adjuvant imatinib, for 1 year after primary complete surgical resection, with placebo in primary GIST, reported a significantly shorter time to relapse for those in the placebo group. This led to the approval of imatinib for this new indication in the US and Europe. Several studies evaluating the efficacy of adjuvant imatinib in patients with primary GIST who are at high risk for postoperative relapse are ongoing; in particular two large European studies are expected to yield preliminary results in the near future. Neoadjuvant therapy with imatinib is also being investigated for its effect on surgical outcomes, with first trial results reported.

CONCLUSION

This article provides an update on the rapidly evolving role of surgery, treatment with TKI therapy, and their combination in the management of GIST as well as further reviews pertinent to current clinical research findings.

NCCN Task Force report: update on the management of patients with gastrointestinal stromal tumors

The standard of care for managing patients with gastrointestinal stromal tumors (GISTs) rapidly changed after the introduction of effective molecularly targeted therapies involving tyrosine kinase inhibitors (TKIs), such as imatinib mesylate and sunitinib malate. A better understanding of the molecular characteristics of GISTs have improved the diagnostic accuracy and led to the discovery of novel immunomarkers and new mechanisms of resistance to TKI therapy, which in turn have resulted in the development of novel treatment strategies. To address these issues, the NCCN organized a task force consisting of a multidisciplinary panel of experts in the fields of medical oncology, surgical oncology, molecular diagnostics, and pathology to discuss the recent advances, identify areas of future research, and recommend an optimal approach to care for patients with GIST at all stages of disease. The task force met for the first time in October 2003 and again in December 2006 and October 2009. This supplement describes the recent developments in the field of GIST as discussed at the October 2009 meeting.

Towards global consensus in the treatment of gastrointestinal stromal tumor

The contemporary clinical landscape of gastrointestinal stromal tumor (GIST) has evolved rapidly over the past several years. Widely used treatment guidelines--from the European Society of Medical Oncology (ESMO) and the National Comprehensive Cancer Network--have recently been updated and represent the most up-to-date, comprehensive tools guiding the optimal management of GIST. In these, and in other published guidelines, close alignment among recommendations now exists for many of the clinical issues relevant to GIST management--surgery, use of the tyrosine kinase inhibitors imatinib and sunitinib and the role of pre- and post-operative imatinib, among others. This trend towards a global consensus in the treatment of GIST is the result of a relatively large amount of new data across the spectrum of its management. However, for some clinical considerations, recommendations still partially deviate. This review examines clinical recommendations and opinions on the management of GIST in the context of the latest data in the field and with an eye towards a multidisciplinary approach including surgical oncology, medical oncology, pathology and diagnostic radiology. Points of consensus are highlighted. Expert opinion is presented on management areas where no scientific evidence or firm recommendations currently exist; lingering and unresolved questions or issues are included. Within this framework, we present an evaluation of current global guidelines on the following areas in GIST management: surgery in the metastatic setting; neoadjuvant therapy; adjuvant therapy; mutational analysis; maintenance tyrosine kinase inhibitor therapy; and radiological imaging in GIST. A summary of consensus across these guidelines based on clinical trial data is juxtaposed with expert opinion where gaps in data still remain.

Gastrointestinal stromal tumors: Recommendations on diagnosis, therapy and follow-up care in Austria

Adequate treatment of gastrointestinal stromal tumors (GISTs) is linked to an interdisciplinary treatment approach. Austrian representatives of medical oncology, surgery, pathology, radiology and gastroenterology have issued this consensus manuscript within the context of currently available and published literature. The paper contains guidelines and recommendations for diagnosis, therapy and follow-up of GIST patients in Austria.

[Aspects of surgical treatment for gastro-intestinal stromal tumors]

Gastro-intestinal stromal tumors (GIST) form the commonest subgroup of soft tissue sarcomas. They arise in the muscular layer of the esophagus, stomach, small intestines and rectum. Characteristic and important for the assessment of the extent of tumors is the peripheral rim vascularization of primary tumors and metastases. Indications for resection are given for tumors larger than 2 cm in size. Locally advanced GISTs can be advantageously treated with imatinib/sunitinib as neoadjuvant and it is often possible to select a low level of resection for this size of tumor and when the rim area is not hypervascularized. Even in the metastasizing stage surgical treatment can be used for elimination of resistant metastases or for removal of residual tumor tissue in an attempt to counteract secondary tumor progression. The effect of this treatment is currently being tested in a randomized phase III study.

Gastrointestinal stromal tumors I: pathology, pathobiology, primary therapy, and surgical issues

Gastrointestinal stromal tumor (GISTs) are the most common connective tissue malignancies of the gastrointestinal (GI) tract, with an incidence on the order of 10-13 per million people per year. Primary therapy is usually surgical, but the recurrence rate of large, so-called high-risk tumors, with a high mitotic rate, or those arising from small bowel and colon/rectum is particularly high. The natural history, pathology, and molecular biology of GISTs are discussed in this review, as are features of increasing our analytical power of the genes altered in these tumors, surgical issues, and the translation of research findings into clinical practice. The biological features of GIST make it a model for the examination of kinase-targeted therapeutics in solid tumors.

[Gastrointestinal stromal tumors: recommendations for diagnosis, treatment and aftercare in Austria]

Diagnosis and treatment of gastrointestinal stromal tumors (GIST) requires an interdisciplinary treatment approach. This strategy should be reflected by the content of this article. Austrian representatives of 'GIST relevant' specialties authored this publication on a consensual base. This manuscript should be regarded as a guideline for 'GIST involved' colleagues in Austria.

[Surgical treatment of gastrointestinal stromal tumors]

Interdisciplinary management is required in the therapy of gastrointestinal stromal tumors, in consideration of complex strategies in the treatment of patients with GIST. Endoscopy, histopathology - mutation analysis included - but also radio diagnostic, surgery and oncology are topics in treating patients suffering from GIST. Especially in cases of advanced gastrointestinal stromal tumor or metastatic disease our multidisciplinary knowledge is required, because information about these entities are rather rare.