Population-based incidence and survival of gastrointestinal stromal tumours (GIST) in Girona, Spain

Metabolomic and transcriptomic response to imatinib treatment of gastrointestinal stromal tumour in xenograft-bearing mice

BACKGROUND

Although imatinib is a well-established first-line drug for treating a vast majority of gastrointestinal stromal tumours (GIST), GISTs acquire secondary resistance during therapy. Multi-omics approaches provide an integrated perspective to empower the development of personalised therapies through a better understanding of functional biology underlying the disease and molecular-driven selection of the best-targeted individualised therapy. In this study, we applied integrative metabolomic and transcriptomic analyses to elucidate tumour biochemical processes affected by imatinib treatment.

MATERIALS AND METHODS

A GIST xenograft mouse model was used in the study, including 10 mice treated with imatinib and 10 non-treated controls. Metabolites in tumour extracts were analysed using gas chromatography coupled with mass spectrometry (GC-MS). RNA sequencing was also performed on the samples subset (n=6).

RESULTS

Metabolomic analysis revealed 21 differentiating metabolites, whereas next-generation RNA sequencing data analysis resulted in 531 differentially expressed genes. Imatinib significantly changed the profile of metabolites associated mainly with purine and pyrimidine metabolism, butanoate metabolism, as well as alanine, aspartate, and glutamate metabolism. The related changes in transcriptomic profiles included genes involved in kinase activity and immune responses, as well as supported its impact on the purine biosynthesis pathway.

CONCLUSIONS

Our multi-omics study confirmed previously known pathways involved in imatinib anticancer activity as well as correlated imatinib-relevant downregulation of expression of purine biosynthesis pathway genes with the reduction of respectful metabolites. Furthermore, considering the importance of the purine biosynthesis pathway for cancer proliferation, we identified a potentially novel mechanism for the anti-tumour activity of imatinib. Based on the results, we hypothesise metabolic modulations aiming at the reduction in purine and pyrimidine pool may ensure higher imatinib efficacy or re-sensitise imatinib-resistant tumours.

Descriptive epidemiology of soft tissue sarcomas and gastrointestinal stromal tumors in Thailand

This study aimed to analyze burden of STS and GIST in population and survival rate which represented the current situation of treatment in Thailand. The data was collected from five population-based cancer registries around the country for the period 2001 through 2015. The Segi world standard population was used to calculated age-standardized incidence rates (ASR). Standardized rate ratios (SRR) were used to compare populations. Joinpoint Trend Analysis was used to assess changes in incidence. STATA was used to examine patient survival rates. During the study period, 4080 cases of STS and 457 cases of GIST were reported. The ASR of STS and GIST was 2.14/100,000 person-years and 0.22/100,000 person-years, respectively. The most common histological types of STS were unspecified sarcoma (24.8%), leiomyosarcoma (19.0%) and liposarcoma (11.4%). The overall ASR of STS in Thailand was relatively low compared to Western countries. The five-year survival rate was 62.6% for STS and 63.4% for GIST, which was comparable to the rates reported in other countries. This is the first report of STS and GIST from PBCRs in Thailand. Based on current healthcare service, an overall survival rates of STS and GIST are comparable to those reported from others.

Prognostic Factors After Neoadjuvant Imatinib for Newly Diagnosed Primary Gastrointestinal Stromal Tumor

INTRODUCTION

Neoadjuvant imatinib (Neo-IM) therapy may facilitate R0 resection in primary gastrointestinal stromal tumors (GISTs) that are large or in difficult anatomic locations. While response to preoperative tyrosine kinase inhibitors is associated with better outcome in metastatic GIST, little is known about prognostic factors after Neo-IM in primary GIST.

STUDY DESIGN

Patients with primary GIST with or without synchronous metastases who underwent Neo-IM were retrospectively analyzed from a prospective maintained institutional database for Response Evaluation Criteria in Solid Tumors (RECIST), tumor viability, and mitotic rate. Overall survival (OS) was estimated by Kaplan-Meier and compared by log-rank test. Cox proportionate hazard models were used for univariate and multivariate analysis.

RESULTS

One hundred and fifty patients were treated for a median of 7.1 months (range 0.2-160). By RECIST, partial response, stable disease, and progressive disease were seen in 40%, 51%, and 9%, respectively. By pathologic analysis, ≤ 50% of the tumor was viable in 72%, and the mitotic rate was ≤ 5/50HPF in 74%. On multivariate analysis, RECIST response and tumor viability were not associated with OS, while post-treatment high mitotic rate (hazard ratio (HR) for death 5.3, CI 2.3-12.4), R2 margins (HR 6.0, CI 2.3-15.5), and adjuvant imatinib (HR 0.4, CI 0.2-0.9) were (p < 0.05). Five-year OS was 81 vs. 38% for low vs. high mitotic rate; 81, 59, and 39% for R0, R1, and R2 margins; and 75 vs 61% for adjuvant vs. no adjuvant imatinib therapy (p < 0.05).

CONCLUSIONS

In primary GIST undergoing Neo-IM therapy, progression was uncommon, but substantial down-sizing occurred in the minority. High tumor mitotic rate and incomplete resection following Neo-IM were associated with poor outcome, while adjuvant imatinib was associated with prolonged survival.

Incidence of gastrointestinal stromal tumor in Chinese urban population: A national population-based study

BACKGROUND

Information on incidence of gastrointestinal stromal tumor (GIST), the most common type of mesenchymal tumor in gastrointestinal tract, was limited in China. This study aimed to estimate the incidence of GIST in urban population from mainland China in 2016.

METHODS

Urban Employee Basic Medical Insurance (UEBMI) and Urban Residence Basic Medical Insurance (URBMI) in China were used. The denominator of incidence was the total person-years of insured individuals in 2016 in the database, covering approximately 0.43 billion individuals. The numerator was the number of incident GIST cases in 2016.

RESULTS

The crude incidence in 2016 was 0.40 per 100,000 person-years (95% CI, 0.06-1.03). Male incidence was higher than female incidence (0.44 vs. 0.36, rate ratio: 1.22, p < 0.001). The mean age at diagnosis was 55.20 years (SD = 14.26) and the incidence among those aged 50 years or older was 2.63 times (0.84 vs. 0.32, p < 0.001) higher than those aged under 50. The highest incidence was observed in East China (2.29, 95% CI: 0.46-5.54).

CONCLUSIONS

The incidence of GIST in mainland China was lower than Europe, North America and Korea. The mean age at diagnosis of GIST in China was younger than that of Europe and Canada. This study provides useful information to further research, policy formulating and management of GIST.

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

Background

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

Methods

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

Results

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

Conclusion

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

Population-based incidence of gastrointestinal stromal tumors in Puglia

INTRODUCTION

This study presents the incidence of gastrointestinal stromal tumors (GISTs) in an Italian region of over 4 million inhabitants monitored for 10 years and is the largest incidence study of this type of cancer conducted so far in Italy.

METHODS

In order to ensure the registration of all GISTs, including those with nonmalignant behavior, a cancer list was integrated with the cases found through an ad hoc data mining process that covered all the pathologic reports of Puglia. Case distributions by sex, age groups, site, and prognostic groups according to Miettinem and Lasota classification and crude and age-standardized incidence rates were produced.

RESULTS

In the 10-year period 2006 to 2015, 708 cases of GIST were recorded in Puglia. The average crude incidence rate was 1.7 per 100,000 person-years and the age-standardized incidence rate, using 2013 European standard population, was 1.8 per 100,000 person-years (95% confidence interval [CI], 1.6-1.9). Incidence was higher in men than in women: crude incidence rate was 2.0 per 100,000 person-years and age-standardized incidence rate 2.2 per 100,000 person-years (95% CI, 2.0-2.4) in men and 1.5 per 100,000 person-years and 1.4 per 100,000 person-years (95% CI, 1.2-1.6) in women.

DISCUSSION

Our incidence rates are comparable with those of other international studies and they are located in the medium to high end of the range. The comparisons are affected by a different capacity of the cancer registries to intercept and record GISTs with nonmalignant behavior. Distribution of cases for sex, age groups, sites, and prognostic risk groups are consistent with previous results.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Optimal thresholds of risk parameters for gastrointestinal stromal tumors

BACKGROUND

Gastrointestinal stromal tumors (GIST) are the most frequent mesenchymal neoplasms of the gastrointestinal tract with highly variable potential for relapse. Tumor size and mitotic index (MI) are major risk factors that predict the outcome of GIST patients. Recent risk stratification schemes include some or all of the empirical size thresholds of 2 cm, 5 cm, and 10 cm and MI thresholds of 5 per 50 high-power fields (hpf) and 10 per 50 hpf. However, data that verify these numbers are sparse.

METHODS

By exhaustive regression tree analysis, maximally selected rank statistics and survival difference analysis with bootstrap sampling on a naive GIST population of 161 patients with a mean follow-up of 44 months, current stratification schemes using tumor size and MI were analyzed herein.

RESULTS

/Conclusions: Thresholds that optimally stratify the risk of recurrence are observed at tumor sizes of 4-5 cm and 10-11 cm and at mitotic indices of about 5 per 50 hpf and 10 per 50 hpf, respectively. While these data validate the canonical thresholds for size and MI used in risk stratification of GIST, transition regions as well as differences in the implementation of these thresholds between the different classification schemes proposed in the recent years should be considered when classifying GIST.

EPIGIST: An observational real-life study on patients with metastatic gastrointestinal stromal tumors receiving imatinib

Background

Gastrointestinal stromal tumors (GISTs) are rare, but represent the most common mesenchymal neoplasms of the gastrointestinal tract. EPIdemiology GIST, is an observational multicenter longitudinal follow-up cohort study reporting the prescribing patterns of imatinib in patients with GIST and the impact of the treatment in a real-world (standard clinical) setting.

Methods

Eligible patients had a confirmed diagnosis of unresectable or metastatic KIT-positive GIST and started treatment with imatinib for the first time between May 24, 2002, and June 30, 2010. During routine visits, annual collection of clinical characteristics was requested, i.e., age, GIST stage at diagnosis, history, imatinib treatment duration and dosage, adherence, and concomitant medications. Survival outcomes were estimated using the Kaplan-Meier method. Other data were analyzed using descriptive statistics.

Results

Of 151 patients enrolled, imatinib was initiated for 126 patients before enrollment and for 25 patients on the day of enrollment or soon after. The patient characteristics were similar to those in published prospective trials. The estimated 1-, 2-, 3-, and 4-year overall survival rates were 90.4% (95% confidence interval [CI; 84.8%-94.0%]), 84.7% (95% CI [78.1%-89.4%]), 73.0% (95% CI [65.0%-79.4%]), and 60.7% (95% CI [51.4%-68.8%]), respectively. The most common adverse events (AEs) were diarrhea (39%), asthenia (39%), eyelid or periorbital edema (32%), abdominal pain (23%), and anemia (21%). Eight of 126 serious AEs were possibly related to the treatment as assessed by investigators.

Conclusions

Study results showed that patients in real-life populations are generally treated in accordance with national and international clinical recommendations and have outcomes comparable to those of patients in clinical trials.

Clinicopathological and Molecular Characterization of Metastatic Gastrointestinal Stromal Tumors with Prolonged Benefit to Frontline Imatinib

BACKGROUND

Oncogenic KIT/PDGFRA signaling inhibition with imatinib achieves disease control in most patients with advanced/metastatic gastrointestinal stromal tumor (GIST), but resistance eventually develops after 20-24 months. Notably, a small subset of these patients obtain durable benefit from imatinib therapy.

METHODS

We analyzed clinical, pathological, and molecular characteristics and long-term outcomes in patients with metastatic GIST treated with continuous daily dosing of frontline imatinib in a cohort of patients benefiting for ≥5 years. A control group was obtained from the national Spanish Group for Sarcoma Research database and used as comparator.

RESULTS

Sixty-four imatinib long-term responders (LTRs) and 70 control cases were identified. Compared with controls, LTRs at baseline had better performance status (PS) 0-1 (100% vs. 81%), lower mitotic count (median, 8 vs. 15), and tumor burden (number of metastases, 3 vs. 7). KIT exon 11 was the only region found mutated in LTRs. LTRs achieved 34% complete responses and a median progression-free survival of 11 years, compared with 4% and 2 years, respectively, in the control cohort. Prognostic factors that independently predicted long-term benefit with imatinib were PS, number of metastases prior to imatinib, and response to imatinib. Fifteen LTR patients developed new side effects attributable to imatinib after ≥5 years of continuous treatment. No resistance mutations were found in metastatic samples from three patients progressing on imatinib.

CONCLUSION

GISTs in LTRs are a distinctive entity with less aggressive behavior and marked sensitivity to KIT inhibition. Patients reaching 5 or more years on imatinib have a higher chance of remaining progression free over time.

IMPLICATIONS FOR PRACTICE

This work demonstrates that clinical and inherent tumor characteristics define a subset of patients with gastrointestinal stromal tumor (GIST) with increased likelihood to achieve durable response to first-line imatinib therapy. Patients reaching ≥5 years on imatinib have a greater chance of remaining progression free over time, although the disease is unlikely to be cured. Imatinib is well tolerated for >5 years, and emergent toxicities are overall manageable. Resistance to imatinib emerging in patients with GISTs after long-term imatinib treatment does not involve polyclonal expansion of KIT secondary mutations.

Gene expression analyses determine two different subpopulations in KIT-negative GIST-like (KNGL) patients

Introduction

There are limited findings available on KIT-negative GIST-like (KNGL) population. Also, KIT expression may be post-transcriptionally regulated by miRNA221 and miRNA222. Hence, the aim of this study is to characterize KNGL population, by differential gene expression, and to analyze miRNA221/222 expression and their prognostic value in KNGL patients.

Methods

KIT, PDGFRA, DOG1, IGF1R, MIR221 and MIR222 expression levels were determined by qRT-PCR. We also analyzed KIT and PDGFRA mutations, DOG1 expression, by immunohistochemistry, along with clinical and pathological data. Disease-free survival (DFS) and overall survival (OS) differences were calculated using Log-rank test.

Results

Hierarchical cluster analyses from gene expression data identified two groups: group I had KIT, DOG1 and PDGFRA overexpression and IGF1R underexpression and group II had overexpression of IGF1R and low expression of KIT, DOG1 and PDGFRA. Group II had a significant worse OS (p = 0.013) in all the series, and showed a tendency for worse OS (p = 0.11), when analyzed only the localized cases. MiRNA222 expression was significantly lower in a control subset of KIT-positive GIST (p < 0.001). OS was significantly worse in KNGL cases with higher expression of MIR221 (p = 0.028) or MIR222 (p = 0.014).

Conclusions

We identified two distinct KNGL subsets, with a different prognostic value. Increased levels of miRNA221/222, which are associated with worse OS, could explain the absence of KIT protein expression of most KNGL tumors.

Gastrointestinal stromal tumors: 16 years' experience within a university hospital

AIM

the aim was to convey our 16-year experience regarding gastrointestinal stromal tumors within in a high volume university hospital. Factors that may impact on patient survival were evaluated.

MATERIAL AND METHODS

all patients diagnosed with gastrointestinal stromal tumors in our clinic over a 16-year period were retrospectively evaluated. All patients included in the study had their tumors surgically resected. Survival analyses were performed using the Kaplan-Meier method. Survival time comparisons between groups were performed using the log-rank test. The effect of continuous variables on survival times were evaluated via a Cox-regression analysis with a backward conditional method.

RESULTS

one hundred and thirty-five patients (76 males and 59 females) were included into the study and the mean age was 62.8 ± 13.3 years. Overall survival time was 121.3 ± 7.0 months and the 5-year survival rate was 66.6 ± 4.2%. Patients with colorectal tumors had significantly lower survival times than patients with tumors located in the stomach (p = 0.001) and small intestine (p = 0.033). Patients with moderate risk scores had a significantly longer survival compared to patients with high risk scores (p = 0.003) and patients with tumor recurrence had a significantly shorter survival (p < 0.001). There was no significant relationship between survival and factors such as gender and tumor size (p > 0.05). However, age, Ki-67 and the mitotic index were poor prognostic factors and C-kit was considered as a good prognostic factor.

CONCLUSION

some of the findings in this study are consistent with published data. However, our data significantly differs from previous studies such as the common finding of the effect of gender and tumor size on survival.

Clinical and pathological features of "small" GIST (≤2 cm). What is their prognostic value?

INTRODUCTION

Small GIST (<2 cm) are tumors whose biological behavior is benign and frequently involutes. Despite their increasing incidence, few studies have addressed the characteristics of these GIST. The aim of this work is to clarify the management of this entity.

PATIENTS AND METHOD

The characteristics of ≤2 cm GIST were initially described, and then compared with those >2 cm. This series comprises 104 patients and they were divided according to tumor size in 4 groups: tumors which are ≤2 cm (group 1, G1), >2 and ≤ 5 cm (G2), >5 and ≤ 10 cm (G3) and >10 cm (G4).

RESULTS AND DISCUSSION

Most of small GIST were asymptomatic and incidental, and were located in the stomach. There is an association between patients with associated tumors and asymptomatic GIST. A high overall mortality rate of up to 40% is observed being disease-specific mortality 4.5%. The disease-specific mortality increases proportionally with size. The overall survival (OS) at 5 years are lower for both <2 cm (61%) and >10 cm (53%) than the rest (85-91%). When analyzing the impact of tumor association on <2 cm GIST, we observed that the OS of patients with non-associated tumors was much higher than in the associated ones (90% vs 32% at 5 years, respectively), while no differences were observed in the disease specific survival.

CONCLUSIONS

Small GIST are tumors that are very often incidentally discovered in the course of complementary examinations. Its prognosis is very good, but it depends on the associated tumor.

Data quality in rare cancers registration: the report of the RARECARE data quality study

PURPOSE

Rare cancers represent 22% of all tumors in Europe; however, the quality of the data of rare cancers may not be as good as the quality of data for common cancer. The project surveillance of rare cancers in Europe (RARECARE) had, among others, the objective of assessing rare cancer data quality in population-based cancer registries (CRs). Eight rare cancers were considered: mesothelioma, liver angiosarcoma, sarcomas, tumors of oral cavity, CNS tumors, germ cell tumors, leukemia, and malignant digestive endocrine tumors.

METHODS

We selected data on 18,000 diagnoses and revised, on the basis of the pathologic and clinical reports (but not on pathologic specimens), unspecified morphology and topography codes originally attributed by CR officers and checked the quality of follow-up of long-term survivors of poor prognosis cancers.

RESULTS

A total of 38 CRs contributed from 13 European countries. The majority of unspecified morphology and topography cases were confirmed as unspecified. The few unspecified cases that, after the review, changed to a more specific diagnosis increased the incidence of the common cancer histotypes. For example, 11% of the oral cavity epithelial cancers were reclassified from unspecified to more specific diagnoses: 8% were reclassified as squamous cell carcinoma (commoner) and only 1% as adenocarcinoma (rarer). The revision confirmed the majority of long-term survivors revealing a relative high proportion of mesothelioma long-term survivors. The majority of appendix carcinoids changed behavior from malignant to borderline lesions.

CONCLUSIONS

Our study suggests that the problem of poorly specified morphology and topography cases is mainly one of difficulty in reaching a precise diagnosis. The awareness of the importance of data quality for rare cancers should increase among registrars, pathologists, and clinicians.

Gastrointestinal stromal tumors (GISTs): SEAP-SEOM consensus on pathologic and molecular diagnosis

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the digestive tract, with an incidence of 1.1 cases/100,000 inhabitants/year. A group of experts from the Spanish Society of Pathology and the Spanish Society of Oncology met to discuss a brief update on GISTs and agree on aspects relating to the pathological and molecular diagnosis of these tumors. GISTs are generally solitary, well-circumscribed lesions of variable size (<10 mm-35 cm) that may present with intra- or extra-luminal parietal growth or a mixed-type (hourglass) growth pattern. Histologically, they are unencapsulated neoplasms displaying expansive growth and spindle-shaped (70%), epithelioid (20%), or mixed cellularity (10%). Mitotic activity is generally moderate or low and should be evaluated only in areas with high cellularity or higher mitotic frequency. The great majority of GISTs harbour mutually exclusive activating mutations in genes coding for the type III receptor tyrosine kinases KIT and PDGFRA; less commonly, GISTs have also been reported to display mutations elsewhere, including BRAF and NF1 and SDH-complex genes. The method most widely used to detect KIT and PDGFRA mutations is amplification of the exons involved by polymerase chain reaction followed by direct sequencing (Sanger method) of these amplification products. Molecular analyses should always specify the type of analysis performed, the region or mutations evaluated, and the sensitivity of the detection method employed.

Clinico-pathological characteristics and prognostic factors of gastrointestinal stromal tumors among a Chinese population

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms in the gastrointestinal tract, exhibiting wide variability in their biological behavior. The aim of the present study was to investigate the clinicopathological characteristics and prognostic factors of GISTs in Chinese patients. All GIST cases (n=182) retrieved from the pathology database and the archived files in Shanghai Changzheng Hospital between January 2011 and December 2014 were reviewed. The clinical symptoms, preoperative investigations, treatments, pathological characteristics and follow-up data of these patients were reviewed, and univariate and multivariate survival analyses were performed. A total of 73.1% of the GISTs were located in the stomach, and the most common three symptoms included abdominal pain (30.2%), dyspepsia (23.1%) and gastrointestinal bleeding (21.4%). Univariate analysis revealed that larger tumor size (P<0.001), higher mitotic rate (P<0.001), aggressive behavior (P<0.001), negative smooth muscle actin expression (P=0.009) and palliative resection (P<0.001) contributed toward poor overall survival (OS). In addition, non-gastric disease location (P<0.001), larger tumor size (P<0.001), higher mitotic rate (P=0.004), aggressive behavior (P<0.001) and palliative resection (P<0.001) were associated with poor relapse-free survival (RFS). Multivariate analysis indicated that mitotic rate [hazard ratio (HR=3.761, P=0.015)] and aggressive behavior (HR=3.916, P=0.010) were independent risk factors for OS, while non-gastric location (HR=4.740, P=0.002) and aggressive behavior (HR=4.009, P=0.004) were independent risk factors for RFS. The present study provided information on the clinicopathological characteristics and epidemiology of GISTs in the Chinese population. Non-gastric disease location, higher mitotic rate and tumor metastasis or local invasion prior to treatment were identified as predictors of a poor prognosis.

Global epidemiology of gastrointestinal stromal tumours (GIST): A systematic review of population-based cohort studies

BACKGROUND

Gastrointestinal stromal tumours (GISTs) are rare, yet the most common mesenchymal tumour within the digestive tract. Lack of diagnostic criteria and no specific code in the ICD system has prevented epidemiological evaluation except from overt malignant cases in the past. A global estimate of incidence and disease patterns has thus not been available.

METHODS

A systematic literature search of all available population-based studies on GIST published between January 2000 and December 2014 were reviewed. Descriptive epidemiological data are presented.

RESULTS

The search found 29 studies of more than 13,550 patients from 19 countries that reported sufficient data for regional or national population-based statistics. Age at diagnosis ranged from 10 to 100 years, with median age being mid 60s across most studies. Gender distribution was equal across studies. On average, 18% of patients had an incidental diagnosis (range from 5% to 40%). Anatomical location of primary tumour in 9747 GISTs demonstrated gastric location as the most frequent (55.6%) followed by small bowel (31.8%), colorectal (6.0%), other/various location (5.5%) and oesophagus (0.7%). Most studies reported incidence at 10-15 per million per year. Notably, lowest incidence was in China (Shanxi province) with 4.3 per million per year. Highest incidence rates were reported also from China (Hong Kong and Shanghai areas), and in Taiwan and Norway (Northern part), with up to 19-22 per million per year.

CONCLUSIONS

Epidemiology of GIST demonstrates some consistent features across geographical regions. Whether the reported extreme differences in incidence reflect real variation in population risk warrants further investigation.

Incidental finding of GIST during obesity surgery

BACKGROUND

The purpose of this study was to review the incidence of incidental gastrointestinal stromal tumors (GISTs) in a cohort of morbidly obese patients undergoing laparoscopic sleeve gastrectomy (LSG) or Roux-en-Y gastric bypass (RYGB), analyzing surgery indication, morbidity, and follow-up data.

METHODS

All cases with incidental GISTs found were reviewed.

RESULTS

Two thousand six hundred three patients underwent obesity surgery founding a gastric GIST in eight patients (incidence 0.31 %). Mean tumor size was 7.65 mm (range 2.5-13 mm) with the majority of the lesions located in the fundus of the stomach. All lesions had negative resection margins. At a mean follow-up of 30 months, all patients were disease-free.

CONCLUSION

The long-term disease-free survival of 100 % in our study establishes laparoscopic wedge resection during RYGB and LSG as safe and effective in treating incidental gastric GISTs <2 cm.

The GOLD ReGISTry: a Global, Prospective, Observational Registry Collecting Longitudinal Data on Patients with Advanced and Localised Gastrointestinal Stromal Tumours

BACKGROUND

Gastrointestinal stromal tumours (GISTs) are the most common gastrointestinal sarcomas. This global, prospective registry followed patients with advanced or localised GIST (2007-2011).

METHODS

Current and evolving diagnostics, treatments and outcome measures in patients with GIST were assessed. Eligible patients were diagnosed with advanced or localised GIST within 15months of registry entry. No treatment plan was prescribed, and no visit schedule was mandated. Treating physicians recorded patient information, including tumour response, diagnostic methods, medications, surgeries performed, mutation status and adverse events leading to dose/medication changes. Survival outcomes were estimated using the Kaplan-Meier method. Other data were analysed using descriptive statistics.

RESULTS

The registry included 1663 patients (advanced GIST, n=1095; localised GIST, n=537). Medications (e.g. tyrosine kinase inhibitor use and dosing), disease progression or recurrence and physician assessment of response to treatment in registry patients were consistent with controlled trials and prevailing clinical recommendations. In advanced GIST, estimated 30-month progression-free survival (PFS) (59.8%) and overall survival (OS) (82.7%) were higher than results from previously reported trials (≈40% and ≈70%, respectively). Consistent with treatment guidelines, the most common initial treatments were imatinib for advanced GIST, and complete surgical resection for localised GIST. Computed tomography scans were the most common imaging technique used at diagnosis and follow-up. Mutation analysis was performed at diagnosis in only 15.3% and 14.5% of patients with advanced and localised GIST, respectively.

CONCLUSIONS

In this real-world GIST registry, patients with advanced GIST were treated with imatinib and patients with localised GIST received surgical resection, in accordance with prevailing clinical recommendations.

Population-based SEER trend analysis of overall and cancer-specific survival in 5138 patients with gastrointestinal stromal tumor

BACKGROUND

The objective of the present population-based analysis was to assess survival patterns in patients with resected and metastatic GIST.

METHODS

Patients with histologically proven GIST were extracted from the Surveillance, Epidemiology and End Results (SEER) database from 1998 through 2011. Survival was determined applying Kaplan-Meier-estimates and multivariable Cox-regression analyses. The impact of size and mitotic count on survival was assessed with a generalized receiver-operating characteristic-analysis.

RESULTS

Overall, 5138 patients were included. Median age was 62 years (range: 18-101 years), 47.3% were female, 68.8% Caucasians. GIST location was in the stomach in 58.7% and small bowel in 31.2%. Lymph node and distant metastases were found in 5.1 and 18.0%, respectively. For non-metastatic GIST, three-year overall survival increased from 68.5% (95 % CI: 58.8-79.8%) in 1998 to 88.6% (95 % CI: 85.3-92.0%) in 2008, cancer-specific survival from 75.3% (95 % CI: 66.1-85.9%) in 1998 to 92.2% (95 % CI: 89.4-95.1%) in 2008. For metastatic GIST, three-year overall survival increased from 15.0% (95 % CI: 5.3-42.6%) in 1998 to 54.7% (95 % CI: 44.4-67.3%) in 2008, cancer-specific survival from 15.0% (95 % CI: 5.3-42.6%) in 1998 to 61.9% (95 % CI: 51.4-74.5%) in 2008 (all PTrend < 0.05).

CONCLUSIONS

This is the first SEER trend analysis assessing outcomes in a large cohort of GIST patients over a 11-year time period. The analysis provides compelling evidence of a statistically significant and clinically relevant increase in overall and cancer-specific survival from 1998 to 2008, both for resected as well as metastatic GIST.

SLITRK3 expression correlation to gastrointestinal stromal tumor risk rating and prognosis

AIM: To assess the influence of SLIT and NTRK-like family member 3 (SLITRK3) on the prognosis of gastrointestinal stromal tumor (GIST) and determine whether SLITRK3 can help improve current risk stratification systems.

METHODS: We hypothesized that SLITRK3 could be used as a prognostic molecular biomarker for GIST. 35 fresh tumor samples and 417 paraffin-embedded specimens from GIST patients were utilized. SLITRK3 mRNA expression in GIST tumor tissue was detected by real-time polymerase chain reaction, and SLITRK3 protein levels were estimated by immunohistochemistry. The correlation of SLITRK3 expression with various tumor clinicopathological characteristics and follow-up data were analyzed.

RESULTS: GIST tumors had high expression of SLITRK3 compared with adjacent normal tissues and the expression level gradually increased with risk grade. SLITRK3 protein expression was closely associated with gastrointestinal bleeding, tumor site, tumor size, mitotic index, and National Institutes of Health (NIH) classification. Survival analysis showed that SLITRK3 expression was closely correlated with overall survival and disease-free survival of GIST patients. Multivariate analysis also identified SLITRK3 expression, mitotic index, and NIH stage as significant risk factors of GIST recurrence.

CONCLUSION: SLITRK3 expression is a highly significant predictor of GIST recurrence and metastasis. Combinations of SLITRK3 and NIH stage have strong predictive and prognostic value, and are feasible markers for clinical practice in gastrointestinal stromal tumor.

Correlation between mutational status and survival and second cancer risk assessment in patients with gastrointestinal stromal tumors: a population-based study

BACKGROUND

Gastrointestinal stromal tumors are sarcomas of the digestive tract characterized by mutations mainly located in the c-KIT or in the platelet-derived growth factor receptor (PDGFR)-alpha genes. Mutations in the BRAF gene have also been described. Our purpose is to define the distribution of c-KIT, PDGFR and BRAF mutations in a population-based cohort of gastrointestinal stromal tumors (GIST) patients and correlate them with anatomical site, risk classification and survival. In addition, as most of the GIST patients have a long survival, second cancers are frequently diagnosed in them. We performed a second primary cancer risk assessment.

METHODS

Our analysis was based on data from Tarragona and Girona Cancer Registries. We identified all GIST diagnosed from 1996 to 2006 and performed a mutational analysis of those in which paraffin-embedded tissue was obtained. Observed (OS) and relative survival (RS) were calculated according to risk classifications and mutational status. Multivariate analysis of variables for observed survival and was also done.

RESULTS

A total of 132 GIST cases were found and we analyzed mutations in 108 cases. We obtained 53.7% of mutations in exon 11 and 7.4% in exon 9 of c-KIT gene; 12% in exon 18 and 1.9% in exon 12 of PDGFR gene and 25% of cases were wild type GIST. Patients with mutations in exon 11 of the c-KIT gene had a 5-year OS and RS of 59.6% and 66.3%, respectively. Patients with mutations in exon 18 of the PDGFR gene had a 5-year OS and RS of 84.6% and 89.7%. In multivariate analysis, only age and risk group achieved statistical significance for observed survival. GIST patients had an increased risk of second cancer with a hazard ratio of 2.47.

CONCLUSIONS

This population-based study shows a spectrum of mutations in the c-KIT and PDGFR genes in GIST patients similar to that previously published. The OS and RS of GIST with the exon 18 PDGFR gene mutation could indicate that this subgroup of patients may be less aggressive and have a good prognosis, although less sensitive to treatment at recurrence. In our study, GIST patients have an increased risk of developing a second neoplasm.

Prevalence of gastrointestinal stromal tumour (GIST) in the United Kingdom at different therapeutic lines: an epidemiologic model

BACKGROUND

The prevalence of patients with gastrointestinal stromal tumourgst (GIST) who fail currently available treatments imatinib and sunitinib (third-line treatment-eligible GIST) is unknown, but is expected to be below an ultra-orphan disease threshold of 2/100,000 population used in England and Wales. Our study was designed to estimate the prevalence and absolute number of UK patients with unresectable/metastatic GIST at first-, second- and eventually third-line treatment.

METHODS

Our open population model estimates the probability that the prevalence of UK third-line treatment-eligible GIST patients will remain under the ultra-orphan disease threshold. Model parameters for incidence, proportion of unresectable/metastatic disease and survival estimates for GIST patients were obtained from a targeted literature review and a UK cancer register. The robustness of the results was checked through differing scenarios taking extreme values of the input parameters.

RESULTS

The base-case scenario estimated a prevalence of third-line treatment-eligible GIST of 1/100,000 and a prevalence count of 598 with a 99.9% likelihood of being below the ultra-orphan disease threshold. The extreme scenarios, one-way and probabilistic sensitivity analyses and threshold analysis confirmed the robustness of these results.

CONCLUSIONS

The prevalence of third-line treatment-eligible GIST is very low and highly likely below the ultra-orphan disease threshold.

Incidence and survival analysis of gastrointestinal stromal tumors in shanghai: a population-based study from 2001 to 2010

Objectives. A population-based study was undertaken to investigate the epidemiological features of gastrointestinal stromal tumors (GISTs) in Shanghai, especially the incidence and the preliminary exploration of survival. Methods. A total of 1923 patients with GISTs diagnosed from 2001 to 2010 in Shanghai were reviewed. The annual incidence and overall survival of GISTs were calculated; Cox proportional hazards' regression was used to analyze several prognostic factors. Results. The average crude incidence of GISTs was 2.11 per 100,000 between 2004 and 2008, and the age-standardized incidence was 1.28 per 100,000. The incidence increased gradually from 2004 to 2008. In addition, 57% of cases had GIST in the stomach and 33% in the intestine. The 5-year overall survival of GISTs was 86.98%. The Cox regression analysis showed older age (≥65 yr versus <40 yr, HR = 5.085; (40, 65) yr versus <40 yr, HR = 1.975), male gender (HR = 1.474), and tumor locations (intestinal versus stomach, HR = 1.609) were predictors of its mortality. Conclusion. GISTs, mainly occurring in the stomach, are more common in elderly population, with an increasing incidence from 2004 to 2008. Older age, male gender, and tumor locations are risk factors for its mortality.

The epidemiology of gastrointestinal stromal tumors in Taiwan, 1998-2008: a nation-wide cancer registry-based study

Background

To investigate the incidence of gastrointestinal stromal tumors (GISTs) in Taiwan and the impact of imatinib on the overall survival (OS) of GIST patients.

Methods

GISTs were identified from the Taiwan Cancer Registry (TCR) from 1998 to 2008. The age-adjusted incidence rates and the observed OS rates were calculated. Cox proportional hazards models were applied to examine the mortality risk in three time periods (1998–2001, 2002–2004, 2005–2008) according to the application and availability of imatinib.

Results

From 1998 to 2008, 2,986 GISTs were diagnosed in Taiwan. The incidence increased from 1.13 per 100,000 in 1998 to 1.97 per 100,000 in 2008. The most common sites were stomach (47-59%), small intestine (31-38%), and colon/rectum (6-9%). The 5-year observed OS was 66.5% (60.3% for men, 74.2% for women, P < .0001). GISTs in the stomach had a better 5-year observed OS (69.4%) than those in the small intestine (65.1%) (P < .0001). The outcome of GIST improved significantly after the more widespread use of imatinib; the 5-year observed OS increased from 58.9% during 1998–2001 to 70.2% during 2005–2008 (P < .0001). Younger age, female sex, stomach location, and later diagnostic years were independent predictors of a better survival.

Conclusions

The incidence of GIST has been increasing in Taiwan, partially due to the advancement of diagnostic technology/method and the increased awareness by physicians. The outcome of GIST has improved significantly with the availability and the wider use of imatinib.

Submucosal tumors: comprehensive guide for the diagnosis and therapy of gastrointestinal submucosal tumors

Small submucosal tumors (SMT) without symptoms are frequently found by endoscopic and radiological examinations. To find proper diagnostic measures and therapeutic indications for histologically undiagnosed SMT, we reviewed published articles in PubMed between 1990 and March 2013 using the key words 'submucosal tumor' and the name of a specific disease. SMT is observed in a wide range of gastrointestinal (GI) diseases and conditions, including compression by extra-GI organs and lesions, congenital tumors, inflammation, and benign as well as malignant neoplastic lesions. In the diagnosis of diseases and decision-making for therapy, endoscopic ultrasonography (EUS) and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) may play a key role. Symptomatic SMT and SMT histologically diagnosed as malignant or potentially malignant tumors such as gastrointestinal stromal tumor (GIST) should be treated by surgery. SMT >5 cm, SMT increasing in size and those with'high-risk features' including irregular border, heterogeneous internal echo such as anechoic area, and heterogeneous enhancement by contrast media may also be removed by surgery. Laparoscopic approach is feasible for gastric GIST <5 cm and this is considered less invasive than the open approach. Emerging techniques using flexible endoscopes appear less invasive, but require further evidence and are still under clinical study. Correct diagnosis of SMT is challenging; however, EUS and EUS-FNA are useful in the histological diagnosis and clinical decision-making. In the future, minimally invasive approaches may be a mainstream of surgical treatment for small SMT.

Descriptive epidemiology of sarcomas in Europe: report from the RARECARE project

Sarcomas are a heterogeneous group of malignant neoplasms arising from mesenchymal cells which encompass dozens of histological types and can occur in virtually any anatomic site. They form one of the principal groups of rare cancers in Europe as defined in the RARECARE project. We analysed 45,568 incident cases diagnosed during 1995-2002 and registered by 76 population-based cancer registries. Total crude incidence was 5.6 per 100,000 per year with an estimated 27,908 new cases per year in the EU27 countries, of which 84% were soft tissue sarcomas and 14% were bone sarcomas. Gastrointestinal stromal tumours (GIST) were only widely recognised as an entity in the late 1990s and consequently were under-registered. Their true incidence is believed to be about 1.5 per 100,000. Age-standardised incidence of soft tissue sarcomas ranged from 3.3 per 100,000 in Eastern Europe to 4.7 per 100,000 in Northern Europe. About 280,000 persons were estimated to be alive at the beginning of 2003 with a past diagnosis of sarcoma, of which 83% were soft tissue sarcomas and 16% were bone sarcomas. Five-year relative survival for 2000-2002 by the period was 58% for soft tissue sarcomas and 62% for bone sarcomas. The diversity and rarity of sarcomas combined with the quite large number of people affected by them mean that they provide a classic example of the importance of networking in diagnosis, therapy and research for rare cancers.

Small intestine gastrointestinal stromal tumors

PURPOSE OF REVIEW

To review the contemporary management of gastrointestinal stromal tumor (GIST), including endoscopy, surgery, and systemic therapy, highlighting the aspects unique to small intestinal tumors.

RECENT FINDINGS

Tumor size, mitotic count, and site of origin are the three key prognostic factors, with mitotic count being the single strongest predictor of recurrence. Tumors arising in the small bowel have worse prognosis than those of comparable size and mitotic count arising in other organs. Endoscopy and endoscopic ultrasound-guided, fine-needle aspiration are key components in the diagnosis of GIST. The role of endoscopy in surveillance and resection remain investigational. Surgery, either open or laparoscopic, remains the only curative option, but recurrence rates are high. Adjuvant therapy with imatinib mesylate improves recurrence-free survival rates and may improve overall survival (OS) with longer duration of treatment. Neoadjuvant imatinib may play an important role in the management of patients with locally advanced disease. For patients with advanced disease, first-line imatinib and second-line sunitinib malate have improved progression-free and OS rates. Systemic treatment should be continued life-long or until treatment failure.

SUMMARY

Advances in the last decade have dramatically changed the management and prognosis of patients with primary and advanced GIST.

Adjuvant and neoadjuvant imatinib therapy: current role in the management of gastrointestinal stromal tumors

Although surgery remains the mainstay for the treatment of primary gastrointestinal stromal tumors (GIST), a significant number of patients experience disease recurrence within 5 years of surgery. The emergence of imatinib therapy for the treatment of patients with advanced GIST has offered unprecedented improvements in clinical outcomes for these patients. Prospective clinical trials have supported the efficacy and safety of imatinib before and after surgical resection of GIST. The American College of Surgeons Oncology Group Z9001 pivotal trial revealed that 1 year of adjuvant imatinib therapy provides significantly superior recurrence-free survival in patients with GIST after surgical resection, when compared to placebo. Additional trials and case studies have also begun to define the potential clinical benefit of imatinib in the neoadjuvant setting. Optimized risk stratification paradigms will be required to ensure the appropriate selection of patients to undergo treatment with imatinib in these settings. Risk stratification schemes are evolving that potentially will include mutation status and tumor rupture, and predictive nomograms have recently been proposed. The recent European Society of Medical Oncology and National Comprehensive Cancer Network guidelines mention use of adjuvant imatinib for ≥ 1 year in patients with KIT(+) , resectable GIST at high risk of recurrence. Moreover, the guidelines support the use of neoadjuvant imatinib in cases of limited disease if it would facilitate less extensive surgery and organ sparing. This article reviews pivotal efficacy and safety data for adjuvant imatinib and explores the potential clinical benefit of neoadjuvant imatinib in patients with GIST.

Surgical treatment of gastric and small bowel gastrointestinal stromal tumours

AIM

This study aimed to evaluate a set of gastrointestinal stromal tumours (GIST) of the stomach and the small bowel managed with a laparoscopic technique.

MATERIAL AND METHODS

The study covers a period from January 1, 2007 until June 1, 2010 during which 13 patients underwent the laparoscopic removal of stomach tumours and 2 patients underwent the removal of a small bowel GIST in the General Hospital in Pardubice. In all cases tumours were removed in a laparoscopic way, including the healthy border of the stomach tissue.

RESULTS

No death was observed in our study. Two patients suffered from wound infection (secondary healing), one of them requiring repeat surgery owing to the excessive narrowing of the distal part of the stomach. Dehiscence of laparoscopic sutures or other intra-abdominal complications were not observed. During monitoring all patients were free of signs of local recurrence, but tumour progression into the liver was observed in 1 patient. Gastrointestinal stromal tumours are very rare tumours but their incidence is increasing. At this time the consensus about the necessity of preoperative unambiguous differentiation between malignant or less malignant variants is not available. Strict differentiation is very difficult and the decision whether to choose a more radical surgical approach for more malignant variants is not clear-cut.

CONCLUSIONS

In cases of gastric and small bowel GISTs the local removal of a tumour with the healthy border of the stomach tissue may be chosen as an adequate approach. Our results support this local surgical approach.

Gastrointestinal stromal tumours treated before and after the advent of c-kit immunostaining

BACKGROUND

Recently developed immunohistochemical markers have revolutionised the classification of gastrointestinal stromal tumours (GISTs) whilst tyrosine kinase inhibitors (imatinib) have had a significant impact on the treatment of advanced tumours. We review the clinicopathological features of previously resected mesenchymal tumours of the gastrointestinal tract in our institution to 1) reclassify the histological diagnosis of those stained prior to c-kit availability; 2) perform survival analysis to identify prognostic factors, and 3) to consider the implications for patients.

METHODS

Clinicopathological records of patients with a diagnosis of mesenchymal tumours treated between May 1992 and April 2007 were reviewed.

RESULTS

82 patients were reviewed. 26 (32%) were reclassified as GISTs following c-kit immunostaining and a further 14 patients were treated for GIST up to April 2007 (Total: 40 patients; 21 males and 19 females, mean age 67, range 30-92 years). 36 (90%) underwent complete resection. 5-year survival of patients with GIST alone was 80%. Females had a better median survival (M: F 43 months: 73 months).

CONCLUSIONS

The availability of c-kit staining allowed 32% of previously diagnosed mesenchymal tumours to be reclassified as GISTs. This may have implications for the follow-up of patients diagnosed prior to the availability of this method.

A rare cause of intestinal obstruction: neonatal gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GISTs) are rare in the childhood period. The authors reported a case who was admitted to the neonatal intensive care unit (NICU) on a suspicion of intestinal obstruction. She was operated and a mass in a size of 6 x 4.5 x 4 cm was resected from the ileum. Histologic and immunohistochemical studies showed a GIST. CD34, small muscle actin (SMA), and desmin were positive. The baby was discharged on the 13th day after operation.

Added value of molecular targeted agents in oncology

The treatment of certain cancers has been revolutionised in recent years by the introduction of novel drugs designed to target specific molecular factors implicated in tumour growth. Notable examples include trastuzumab, a humanized monoclonal antibody (mAb) against human epidermal growth factor receptor (HER)-2 in women with HER2-positive breast cancer; rituximab, an anti-CD20 mAb in patients with non-Hodgkin's lymphoma; imatinib, a tyrosine kinase inhibitor in KIT-positive gastrointestinal stromal tumours and sunitinib, another tyrosine kinase inhibitor, in metastatic renal cell carcinoma. For regulatory reasons, new molecular targeted agents are first evaluated in advanced and metastatic disease, wherein they prolong survival. However, their most profound impact has been observed in the adjuvant setting, where they may contribute to curative therapy rather than mere palliation. Expansion in the use of molecular targeted therapies will have important cost implications for health care systems. Although expensive, on a monthly basis, molecular targeted therapies may not be more costly than treatments for other major chronic diseases, especially considering the contribution of cancer to the global disease burden, the associated socioeconomic costs and the long-term benefits of therapy. Nevertheless, the use of these agents must be optimised, in part using molecular biomarkers associated with drug response.

Imatinib mesylate for the treatment of gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GISTs) are rare neoplasms of mesenchymal origin arising in the GI tract. These tumors are characterized by activating mutations of either receptor tyrosine kinase KIT or PDGFRA, which are found in 85% of cases. The introduction of imatinib mesylate (IM), which targets the kinases presenting with these molecular alterations, has dramatically changed the management of these rare tumors, which were resistant to conventional cytotoxic chemotherapy, both in advanced and localized phases. IM is orally available, has a favorable safety profile and induces partial responses and disease stabilization in up to 80% of patients with advanced GIST. Recently, IM was approved for the postoperative treatment of patients with completely resected localized GIST.

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.

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.

Advances in imaging diagnosis of extra-gastrointestinal stromal tumors

Since Mazur and Clark first proposed the term gastrointestinal stromal tumors (GIST) in 1983, GIST have become a hot topic of pathological and clinical research. Stromal tumors that occur outside the gastrointestinal tract (EGIST) are relatively rare. Imaging technology plays an important role in the diagnosis of EGIST. In this article, we will review the advances in imaging diagnosis of EGIST.

Cost effectiveness of tyrosine kinase inhibitor therapy in metastatic gastrointestinal stromal tumors

BACKGROUND

Tyrosine kinase inhibitors (TKIs) such as imatinib mesylate have revolutionized the treatment of primary unresectable and/or metastatic gastrointestinal stromal tumors (GISTs), providing durable disease control and extended survival. Although most patients eventually progress on therapy, dose escalation has been shown to benefit some patients. Sunitinib, a multitargeted kinase inhibitor is effective against imatinib-resistant or intolerant GIST patients. Although the cost of TKI therapy in GIST is high, no other effective systemic treatment options exist.

OBJECTIVE

Review pharmacoeconomic studies to determine the cost effectiveness (CE) of 1st- and 2nd-line TKI therapies in GIST.

METHODS

A literature review using Medline and PubMed databases was conducted to identify published economic analyses of TKI therapy in GIST. Key results from these studies were analyzed.

RESULTS

Six pharmacoeconomic studies were identified, including three analyses of 1st-line imatinib and three analyses of 2nd-line sunitinib. These studies employed various time horizons and discount rates and modeled CE from a number of different perspectives. Most of the pharmacoeconomic studies reviewed used survival as their efficacy endpoint, projecting outcomes beyond available data to model CE. Analyses of 2nd-line sunitinib using survival additionally faced the challenge of adjusting for the effect of placebo crossover to active treatment in the pivotal phase III study. Most studies used Markov techniques with a range of transition probabilities.

CONCLUSIONS

Published pharmacoeconomic studies of 1st- and 2nd-line TKI therapy for advanced GIST employ various time horizons, discount rates, and different CE models. Consequently, these differences make comparisons between studies difficult. Studies of 1st-line imatinib concluded that imatinib was cost effective in advanced, metastatic GIST. Likewise, based on data reviewed here, 2nd-line sunitinib appears to be cost effective in patients with advanced GIST who are intolerant/resistant to imatinib. Key limitations of this review included inconsistency among the studies evaluated with regard to methodologies, countries of origination (currency and healthcare systems), and patient demographics.

Gastrointestinal stromal tumors (GIST) in children and adolescents: A comprehensive review of the current literature

Standards for the management of gastrointestinal stromal tumors (GIST) in children do presently not exist. Thus a systematic review and summary of the current literature was conducted serving as a basis for the further development of optimal management strategies for childhood GIST within a cooperative network. Presently 21 cases with familial GIST, and more than 100 pediatric cases each with Carney triad or sporadic GIST have been published so far. An international prospective registration based on national registries has recently started to acquire more clinical and molecular data and to develop appropriate management strategies for children and adolescents with GIST.

Nilotinib in the treatment of advanced gastrointestinal stromal tumours resistant to both imatinib and sunitinib

Patients diagnosed with advanced gastrointestinal stromal tumours (GISTs) who are resistant or intolerant to both imatinib and second-line sunitinib have a poor prognosis and few therapeutic options. We evaluated the efficacy of nilotinib, a novel tyrosine kinase inhibitor (TKI) in patients pretreated with imatinib and sunitinib. Fifty-two consecutive patients treated with oral nilotinib, 400mg twice daily, within the nilotinib compassionate use programme in 12 European cancer centres, were included in this retrospective analysis. Median age was 59 years (range 24-80), and all patients had WHO performance score better than 3. All patients had failed both imatinib and sunitinib pretreatment, either due to progressing GIST (96%) or intolerance (4%). Five patients (10%; 95% confidence interval (CI) 2-18) responded to nilotinib and 19 patients (37%; 95% CI 24-50) achieved a disease stabilisation. Nilotinib was generally well tolerated, but six patients (12%) discontinued treatment due to intolerance. Median progression-free survival of nilotinib treatment was 12 weeks (95% CI 9-15; range 0-104) and median overall survival was 34 weeks (95% CI 3-65; range 2-135). Nilotinib is active in GIST resistant to both imatinib and sunitinib. These results warrant further investigation of nilotinib in GIST.

Inherited predisposition to gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract and are a relatively recently identified category of mesenchymal tumors. Germline mutations in a number of different genes predispose to GIST. This article discusses familial GIST syndrome, Carney triad, Carney-Stratakis syndrome, and neurofibromatosis type 1, and addresses the recognition of an inherited predisposition in GIST patients.