Imatinib Mesylate for Patients with Recurrent or Metastatic Gastrointestinal Stromal Tumors Expressing KIT: A Decade Experience from Taiwan

Survival of advanced/recurrent gastrointestinal stromal tumors treated with tyrosine kinase inhibitors in Taiwan: a nationwide registry study

BACKGROUND

Most gastrointestinal stromal tumors (GISTs) harbor c-KIT or PDGFRA mutations. Administration of tyrosine kinase inhibitors (TKIs) has significantly improved the survival of patients with GISTs. We aimed to evaluate the clinical outcome of advanced or recurrent GIST patients in Taiwan.

METHODS

Patients diagnosed between 2010 and 2020 were enrolled. The collected data included baseline characteristics, treatment pattern, treatment outcome, genetic aberrations and survival status. Progression-free survival (PFS) and overall survival (OS) were analyzed and plotted with the Kaplan-Meier method. Cox regression analysis was used to analyze the prognostic factors of survival.

RESULTS

A total of 224 patients with advanced or recurrent GISTs treated with TKIs were enrolled. All patients received imatinib treatment. Ninety-three and 42 patients received sunitinib and regorafenib treatment, respectively. The 48-month PFS and OS rates for patients treated with imatinib were 50.5% and 79.5%, respectively. c-KIT exon 9 and PDGFRA mutations were prognostic factors for a poor PFS and PDGFRA mutation was a prognostic factor for a poor OS in patients treated with imatinib in multivariate Cox regression analysis. The median PFS of patients who received sunitinib treatment was 12.76 months (95% confidence interval (CI), 11.01-14.52). Patients with c-KIT exon 9 mutations had a longer PFS than those with other genetic aberrations. The median PFS of patients treated with regorafenib was 7.14 months (95% CI, 3.39-10.89).

CONCLUSIONS

We present real-world clinical outcomes for advanced GIST patients treated with TKIs and identify mutational status as an independent prognostic factor for patient survival.

Survival outcomes and prognostic factors of advanced gastrointestinal stromal tumors: in the era of multiple tyrosine kinase inhibitors

Background

Tyrosine kinase inhibitors (TKIs) have shown great efficacy in the treatment of advanced gastrointestinal stromal tumors (GISTs), significantly prolonging the survival of patients. In the era of imatinib, a few studies reported some prognostic factors for patients with advanced GISTs, such as age, sex, performance status, diameter of the largest lesions, KIT exon mutations, and some hematological examination results. However, with the advent of more TKIs, the prognostic factors for patients with advanced GISTs have not been fully understood in the era of multiple TKIs. In this study, we aimed to identify independent prognostic factors associated with the survival of patients diagnosed with advanced GISTs.

Methods

Data on clinicopathologic characteristics, treatment approaches, and survival were retrospectively collected for patients with primary unresectable or recurrent GISTs treated from January 2010 to July 2023 at the First Affiliated Hospital of Chongqing Medical University, China. Univariable and multivariable Cox proportional hazards regression models were used to identify independent prognostic factors of survival.

Results

A total of 194 patients were included in the analysis. The median follow-up duration was 59.9 months (range, 2.7-141.7 months). The median overall survival (mOS) in this cohort was 76.5 months (95% confidence interval, 63.4 to 89.6 months). All patients received TKI therapy during the follow-up period, and 56.2% received two or more types of TKIs. In multivariable Cox analysis, younger age, a single lesion at enrollment, no previous use of TKIs, smaller tumor burden, good Eastern Cooperative Oncology Group performance status (ECOG PS ≤1), and lesions limited to the liver were independent prognostic factors for better survival.

Conclusions

We found that a single lesion at enrollment, no previous use of TKIs, a smaller tumor burden, and lesions limited to the liver were associated with better survival. Drug resistance is a severe challenge for advanced GISTs, and several factors mentioned above may be correlated with the development of drug resistance, leading to the poor survival of patients.

Predicting the progression-free survival of gastrointestinal stromal tumors after imatinib therapy through multi-sequence magnetic resonance imaging

PURPOSE

Identify radiomics features associated with progression-free survival (PFS) and develop a predictive model for accurate PFS prediction in liver metastatic gastrointestinal stromal tumor patients (GIST).

METHODS

This multi-center retrospective study involved a comprehensive review of clinical and imaging data pertaining to 211 patients with gastrointestinal stromal tumors (GIST) from Center A and B. A total of 147 patients with hepatic metastatic GIST were included, with 102 cases as the training set and 45 cases as the external validation set. Radiomics features were extracted from non-enhanced MR images, specifically T2WI, DWI, and ADC, and relevant features were selected through LASSO-Cox regression. A radiomics nomogram model was then constructed using multivariable Cox regression analysis to effectively predict PFS. The models performance were evaluated with the concordance index (C-index).

RESULTS

The median age of the patients was 53 years, with 82 males and 65 females. A total of 21 radiomics features were selected to generate the radiomics signature. Radiomics signature slightly outperformed the clinical model but without significant difference (P > 0.05). Integrated radiomics signature with clinical features to build a nomogram, which exhibited high predictive performance in both training (C-index 0.757, 95% CI 0.692-0.822) and validation cohorts (C-index 0.718, 95% CI 0.618-0.818). Nomogram significantly outperformed the clinical model (P = 0.002 for training cohort, P < 0.001 for validation cohort). Stable long-term predictions shown by time-dependent ROC analysis (AUC 0.765-0.919 in training, 0.766-0.893 in validation). Multivariable Cox regression confirmed radiomics signature as an independent prognostic factor for preoperative survival prediction in hepatic metastatic GIST patients (HR = 3.973).

CONCLUSION

Radiomics signature is valuable for predicting PFS in metastatic GIST patients. Integrating imaging features and clinical factors into a comprehensive nomogram improves accuracy and effectiveness of survival prognosis, guiding personalized treatment strategies.

Compassionate Use of Ripretinib for Patients With Metastatic Gastrointestinal Stromal Tumors: Taiwan and Hong Kong Experience

Background

Ripretinib was recently approved for the fourth-line targeted therapy for advanced gastrointestinal stromal tumor (GIST) refractory to imatinib, sunitinib, and regorafenib based on the pivotal INVICTUS phase III study. The INVICTUS study demonstrated significantly improved median progression-free survival (PFS) of 6.3 months and an overall survival (OS) insignificant benefit of ripretinib of 15.1 months as compared with placebo in 85 patients with advanced metastatic GIST. However, treatment outcome for the Chinese population, including in Taiwan and Hong Kong, was lacking.

Material and Method

A compassionate study regarding ripretinib use for patients with advanced/metastatic GIST was conducted from March 2020 to March 2021 to assess the treatment efficacy and safety in Taiwan and Hong Kong patients.

Result

Twenty evaluable patients (16 men and 4 women) with heavily pretreated metastatic GIST receiving ripretinib from March 2020 to March 2021 were enrolled to evaluate the treatment outcome. The response and clinical benefit rates to ripretinib were 25% (5/20) and 60% (12/20), respectively. The median PFS and OS in this compassionate cohort receiving ripretinib were 6.1 months and not reachable, respectively. Albumin less than 3.5 and disease progression after ripretinib use were the two independent unfavorable factors for PFS. There were 14 out of 20 (70%) experiencing any grade adverse event (AE). Loss of hair is the most common grade I to II AE with an incidence of 55%. Grade III AEs included diarrhea, skin rash, and anemia with one patient (5%) for each AE.

Conclusions

Late-line ripretinib use in pretreated Taiwan and Hong Kong patients with advanced GIST showed efficacy consistent with the INVICTUS study. Albumin less than 3.5 and disease progression after ripretinib use were the two independent unfavorable factors for PFS. Ripretinib is generally tolerable, with loss of hair being the most common AE.

Multicenter analysis of gastrointestinal stromal tumors in inner Mongolia of China: A study of 804 cases

INTRODUCTION

To analyze the clinicopathological characteristics, immunohistochemistry, genotyping and prognosis of patients in the multicenter GIST data in Inner Mongolia, China.

METHODS

Retrospective analysis was performed on GIST data from January 2013 to January 2018 in Inner Mongolia. Descriptive statistics were used to analyze the clinical characteristics of GIST patients. The Chi-square test was performed on the modified NIH criteria by age distribution, and Kaplan-Merie method was used for survival analysis.

RESULTS

A total of 804 patients were included in the GIST database in Inner Mongolia, with a male to female ratio of 1.1102:1. The most common location was the gastric (465). Mitotic count ≤5/50HPFs was found in 67.3 % patients. There were 276 patients with tumor diameter of 2-5 cm and 354 patients with tumor diameter of 5.1-10 cm.The modified NIH criteria was mainly of intermediate risk (210) and high risk (342). The recurrence and metastasis of patients were related to the tumor location, mitotic index, tumor size, and modified NIH criteria. All patients were followed up for 1-10 years, in which 63.1 % of them were followed up for at least three years. The 3-year survival rates of patients with modified NIH criteria of very low risk, low risk, intermediate risk, and high risk were 100 %, 100 %, 100 %, and 96.3 %, respectively.

CONCLUSIONS

The incidence of GIST in middle-aged and elder people in Inner Mongolia is high, and the long-term prognosis of patients after surgical treatment is good, which can objectively reflect the incidence, diagnosis and treatment of GIST in Inner Mongolia.

A Nomogram Predicting Progression Free Survival in Patients with Gastrointestinal Stromal Tumor Receiving Sunitinib: Incorporating Pre-Treatment and Post-Treatment Parameters

Simple Summary

Sunitinib has been approved as the second-line targeted treatment for gastrointestinal stromal tumor (GIST) after imatinib failure. It is thus necessary to effectively assess prognosis after sunitinib use. However, the current assessment remains insufficient for the contemporary period. We examined prognostic factors influencing progression-free survival. Furthermore, we constructed a prognostic nomogram model using these significant pre-treatment and post-treatment variables.

Abstract

The present study aimed to construct a prognostic nomogram incorporating pre-treatment and post-treatment factors to predict progression-free survival (PFS) after use of sunitinib in patients with metastatic gastrointestinal stromal tumors (GISTs) following imatinib intolerance or failure. From 2007 to 2018, 109 metastatic GIST patients receiving sunitinib at Chang Gung Memorial Hospital, Taiwan, were enrolled. A prognostic nomogram to predict PFS was developed. Sixty-three male and forty-six female metastatic GIST patients, with a median age of 61 years (range: 15–91 years), received sunitinib. The median PFS for 109 patients is 9.93 months. For pre-treatment factors, male gender, body mass index more than 18.5 kg/m², no sarcopenia status, higher lymphocyte count, lower platelet/lymphocyte ratio, good performance status, higher sunitinib dose, and non-liver metastasis were significantly associated with favorable PFS. For post-treatment factors, adverse events with hypertension, hand–foot skin reaction, and diarrhea were significantly associated with favorable PFS. However, only eight clinicopathological independent factors for PFS prediction were selected for prognostic nomogram establishment. The calibration curve for probability of PFS revealed good agreement between the nomogram prediction and actual observation. High risk patients will experience the lowest PFS. A prognostic nomogram integrating eight clinicopathological factors was constructed to assist prognostic prediction for individual patients with advanced GIST after sunitinib use.

Cytoreductive Surgery may be beneficial for highly selected patients with Metastatic Gastrointestinal Stromal Tumors receiving Regorafenib facing Local Progression: A Case Controlled Study

Background: Current evidence have shown surgery may provide progression-free survival (PFS) benefit for selected patients with metastatic gastrointestinal stromal tumor (GIST) who received first line imatinib and second line sunitinib. However, impact of cytoreductive surgery for GIST patients receiving third line regorafenib facing progression is not yet reported.

Methods: Between 2014 and 2019, 41 patients with metastatic GIST received regorafenib and 37 of them facing progression.

Results: 37 of 41 (90.2%) pre-treated GIST patients receiving regorafenib who experienced progression of disease after a median follow-up of 12.42 months after regorafenib use and 15 out of 37 (40.5%) patients with local progression underwent cytoreductive surgery (local progression and operation, LPOP). All the patients facing local progression (LP) were significantly younger with more exon 17 mutation than diffuse progression (DP). The complication rate for cytoreductive surgery was 33.3% (5/15). Cytoreductive surgery provided PFS prolongation of 5.52 months. Patients underwent cytoreductive surgery, compared with control group (local progression and no operation (LPNOP) and DP), may gain a significant PFS (12.91 versus 2.33 versus 5.29 months, p = 0.0001) and overall survival (OS) benefit (32.33 versus 5.26 versus 12.42 months, p = 0.004).

Conclusions: Cytoreductive surgery might be feasible in highly selected patients with pre-treated GIST who are being treated with regorafenib experiencing LP.

Clinical practice and outcomes in advanced gastrointestinal stromal tumor: Experience from an Indian tertiary care center

Background:

Management of advanced Gastrointestinal stromal tumors (GIST) has been revolutionized with the use of Imatinib guided by mutation analysis. Data from India remains scarce.

Materials and Methods:

Patients with metastatic GIST who were treated at Department of Gastro-intestinal & Hepaticopancreaticobiliary Oncology Unit at Tata Memorial Hospital, Mumbai between December, 2004 and December 2015 were included in the analysis. Clinical and radiological data was retrieved from stored medical records and charts.

Results:

A total of 83 patients with metastatic GIST were available for analysis. Median age was 54 years with a 3:1 male predominance. Stomach was the most common site of primary with liver being the most common site of metastasis. c-Kit mutation analysis results were available for 44 patients with exon 11 mutant being the most common mutation. With a median follow up of 33 months, the 10 years estimated progression free and overall survival (OS) was 18% and 51% respectively. Overall response rate to first line imatinib was 37.6% and estimated 3 years OS to first line therapy was significantly better for Exon 11 mutated patients (p=0.016). 34 patients received second line therapy in the form of either sunitinib, pazopanib or increased dose imatinib with a clinical benefit rate of 73.5%. C-Kit mutated patients had a better median OS compared to non mutated patients.

Conclusions:

GIST diagnosed and treated in the Indian subcontinent appears to show improved outcomes. The importance of c-Kit mutation analysis in determining the prognosis and outcomes of patients with advanced GIST is emphasized.

Gastrointestinal Stromal Tumor – An Overview

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

Identification of phenothiazine as an ETV1‑targeting agent in gastrointestinal stromal tumors using the Connectivity Map

Gastrointestinal stromal tumors (GISTs) are gastrointestinal tract sarcomas that commonly contain a mutation in the tyrosine kinases, KIT and platelet‑derived growth factor receptor A (PDGFRA). Imatinib, sunitinib and regorafenib are all effective tyrosine kinase inhibitors; however, acquired resistance is inevitable. The E26 variant 1 (ETV1) pathway has been found to be a key downstream effector of KIT and is therefore a reasonable therapeutic target for this disease. In this study, we explored the potential agents targeting ETV1 in GISTs by uploading an ETV1 knockout gene signature of GIST cell lines to the pattern‑matching software 'Connectivity Map'. The activity and mechanisms of identified agents were examined using an in vitro model. Four drugs were identified: Suberanilohydroxamic acid and trichostatin [two histone deacetylase inhibitors (HDACIs)] and trifluoperazine and thioridazine (two phenothiazine‑class drugs). Western blot analysis demonstrated that all four drugs had ETV1‑downregulating effects. As HDACIs have been previously studied in GISTs, we focused on phenothiazine. Phenothiazine was found to exert cytotoxicity and to induce apoptosis and autophagy in GISTs. Treatment with phenothiazine had little effect on the KIT/AKT/mammalian target of rapamycin (mTOR) pathway, but instead upregulated extracellular‑signal‑regulated kinase (ERK) activity. A combination of phenothiazine and a MEK inhibitor had a synergistic cytotoxic effect on GISTs. Western blot analysis indicated that ELK1 and early growth response 1 (EGR1) were activated/upregulated following phenothiazine treatment, and the MEK inhibitor/phenothiazine combination downregulated the ERK/ELK1/EGR1 pathway, resulting in diminished autophagy, as well as enhanced apoptosis. On the whole, the findings of this study established phenothiazine as a novel class of therapeutic agents in GIST treatment and demonstrate that a combination of phenothiazine and MEK inhibitor has great potential for use in the treatment of GISTs.

Clinical Diagnosis of Gastrointestinal Stromal Tumor (GIST): From the Molecular Genetic Point of View

Gastrointestinal stromal tumors (GISTs) originating from the interstitial cells of Cajal are mesenchymal tumors of the gastrointestinal tract and have been found to harbor c-KIT mutations and KIT (CD117) expression since 1998. Later, PDGFRA mutations, SDH alterations, and other drive mutations were identified in GISTs. In addition, more and more protein markers such as DOG1, PKCθ were found to be expressed in GISTs which might help clinicians diagnose CD117-negative GISTs. Therefore, we plan to comprehensively review the molecular markers and genetics of GISTs and provide clinicians useful information in diagnostic and therapeutic strategies of GISTs. Twenty years after the discovery of KIT in GISTs, the diagnosis of GISTs became much more accurate by using immunohistochemical (IHC) panel (CD117/DOG1) and molecular analysis (KIT/PDGFRA), both of which constitute the gold standard of diagnosis in GISTs. The accurately molecular diagnosis of GISTs guides clinicians to precision medicine and provides optimal treatment for the patients with GISTs. Successful treatment in GISTs prolongs the survival of GIST patients and causes GISTs to become a chronic disease. In the future, the development of effective treatment for GISTs resistant to imatinib/sunitinib/regorafenib and KIT/PDGFRA-WT GISTs will be the challenge for GISTs.

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.

Role of PLK1 signaling pathway genes in gastrointestinal stromal tumors

In previous studies by the authors, aurora kinase A (AURKA) was demonstrated as an independent poor prognostic marker for the recurrence of localized gastrointestinal stromal tumors (GISTs) and for the progression of advanced GISTs. In the present study, the prognostic effect of genes involved in cell cycle regulation in GISTs was further examined. Leading edge analysis in gene set enrichment analysis was used to identify the most common genes in the top 10 enriched gene sets of high-risk patients with GISTs in a Japanese study. The obtained gene list was uploaded to the Pathway Interaction Database to search for critical pathways. Selected genes within the pathway were subsequently verified through immunohistochemistry (IHC) in another cohort of patients. A total of 5 genes in 'PLK1 signaling events,' namely AURKA, polo-like kinase 1 (PLK1), cell division cycle 25C (CDC25C), budding uninhibited by benzimidazoles (BUB1), and targeting protein for Xklp2 (TPX2), were identified for subsequent study. Among the Japanese cohort, all 5 genes, except BUB1, were significant prognostic factors for poor recurrence-free survival (RFS). Among 141 patients enrolled for the IHC study, all 5 genes exhibited variable expression patterns. In the association study, only AURKA exhibited significant overexpression in non-gastric tumors. Although all 5 genes were considered as risk factors for poor RFS based on a univariate analysis, only the mitotic count and expression levels of CDC25C, BUB1, and TPX2 retained prognostic effects in the multivariate analysis. The PLK1 signaling pathway is crucial in the disease progression of GISTs. Genes within this pathway may serve as predictive markers for adjuvant therapy.

A phase II trial of regorafenib in patients with metastatic and/or a unresectable gastrointestinal stromal tumor harboring secondary mutations of exon 17

Background

Gastrointestinal stromal tumors (GISTs) are caused by the constitutive activation of KIT or platelet-derived growth factor receptor alpha (PDGFRA) mutations. Imatinib selectively inhibits KIT and PDGFR, leading to disease control for 80%–90% of patients with metastatic GIST. Imatinib resistance can occur within a median of 2–3 years due to secondary mutations in KIT. According to preclinical studies, both imatinib and sunitinib are ineffective against exon 17 mutations. However, the treatment efficacy of regorafenib for patients with GIST with exon 17 mutations is still unknown.

Patients and Methods

Documented patients with GIST with exon 17 mutations were enrolled in this study. Patients received 160 mg of oral regorafenib daily on days 1–21 of a 28-day cycle. The primary end point of this trial was the clinical benefit rate (CBR; i.e., complete or partial response [PR], as well as stable disease [SD]) at 16 weeks. The secondary end points of this study included progression free survival (PFS), overall survival, and safety.

Results

Between June 2014 to May 2016, 18 patients were enrolled (15 of which were eligible for response evaluation). The CBR at 16 weeks was 93.3% (14 of 15; 6 PR and 8 SD). The median PFS was 22.1 months. The most common grade 3 toxicities were hand-and-foot skin reactions (10 of 18; 55.6%), followed by hypertension (5 of 18; 27.8%).

Conclusion

Regorafenib significantly prolonged PFS in patients with advanced GIST harboring secondary mutations of exon 17. A phase III trial of regorafenib versus placebo is warranted.

Trial registration

This trial is registered atClinicalTrials.gov in November 2015, number NCT02606097.

Key message

This phase II trial was conducted to assess the efficacy and safety of regorafenib in patients with GIST with exon 17 mutations. The results provide strong evidence that regorafenib significantly prolonged PFS in patients with advanced GIST harboring secondary mutations of exon 17.

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

BACKGROUND

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Surgical management of patients with progressing metastatic gastrointestinal stromal tumors receiving sunitinib treatment: A prospective cohort study

BACKGROUND

For selected patients with metastatic gastrointestinal stromal tumor (GIST) who have received first-line imatinib (IM) and are undergoing cytoreductive surgery, response to IM at time of surgery correlates with resection completeness as well as favorable progression-free survival (PFS) and overall survival (OS). However, surgical impact in GIST patients receiving second-line sunitinib (SU) is still not well clarified.

MATERIALS AND METHODS

Between 2001 and 2014, 86 of 311 metastatic GIST patients received SU. Among them, 69 patients eventually experienced progression. Twenty-six patients who experienced local progression (LP) and underwent surgeries were investigated. Each tumor was assessed for genetic alterations before and after surgery.

RESULTS

Twenty-six GIST patients receiving SU who experienced LP underwent surgery after a median of 6.2 months of SU use. Nineteen patients (73.1%) had undergone prior surgery on IM. The complication rate was 15.3%, and no additional operation was required for GIST patients receiving SU and experiencing LP who underwent surgery. The median PFS and OS times after surgery and start of SU were 5.2 and 18.9 months, respectively, and 16.4 and 26.0 months, respectively (median follow-up of 15.2 months). GIST patients receiving SU with LP (N = 26) may gain a significant PFS and OS benefit with surgery when compared with those not undergoing surgery (N = 43) (p = 0.003 and p = 0.02, respectively). Secondary exon 17 mutation occurred commonly and might explain SU resistance (8/23; 34.8%).

CONCLUSION

Surgery is feasible in highly selected patients with metastatic GIST who are receiving SU and experiencing LP. Those patients may also have significantly prolonged PFS and OS after surgery. Secondary exon 17 mutation might explain SU resistance.

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

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

Fractioned dose regimen of sunitinib for patients with gastrointestinal stromal tumor: a pharmacokinetic and treatment efficacy study

AIM: Sunitinib has shown benefit in patients with imatinib (IM)–resistant gastrointestinal stromal tumor (GIST). However, its advantages are somewhat diminished because of associated toxicities. Herein, we clarify the efficacy and safety of fractioned dose regimen of sunitinib by a pharmacokinetic and efficacy study. MATERIALS AND METHODS: Between 2001 and March 2013, a total of 214 patients with metastatic GIST was treated at Chang Gung Memorial Hospital. Among them, 55 (11.6%) patients who received sunitinib were investigated. One group of patients was administered with standard dose of once-daily sunitinib (standard dose group) and the other group was administered with standard total daily dose of sunitinib in fractioned doses (fractioned dose group). RESULTS: Thirty-two male and 23 female patients with a median age of 55 years received sunitinib. The median duration of sunitinib administration was 9.2 months. The clinical benefit was 65.2%. The mean peak blood level of sunitinib in patients with fractioned doses was significantly lower than that in those with once-daily dose (83.4 vs 50.1 ng/ml, P = .01). The rates of adverse effects of hand-foot syndrome, mucositis, and yellow skin were significantly decreased by fractioned doses of sunitinib. However, the progression-free and overall survival did not differ between patients with different treatment regimens. CONCLUSION: The fractioned dose regimen of sunitinib appears to be a safe and effective treatment for patients with IM-resistant/intolerant GISTs. Significantly decreased toxicity of this regimen could be explained by significantly lower peak sunitinib blood level. However, the treatment efficacy is not reduced by this regimen.

Identification of aurora kinase A as an unfavorable prognostic factor and potential treatment target for metastatic gastrointestinal stromal tumors

Although imatinib mesylate (IM) has revolutionized the management of gastrointestinal stromal tumors (GISTs), drug resistance remains a challenge. Previous studies have shown that the expression of aurora kinase A (AURKA) predicts recurrence in patients with primary, surgically resected GISTs. The current study aimed to evaluate the significance of AURKA expression as an unfavorable prognostic marker for advanced GISTs, and provide evidence that AURKA could be a potential therapeutic target in GISTs. The prognostic significance of the expression of AURKA, along with other clinicopathological factors, was analyzed in a cohort of 99 IM-treated patients with advanced GISTs. The potential use of an inhibitor of AURKA as a therapeutic agent against GISTs was also tested in GIST cell lines. Among 99 enrolled patients, poor performance status, large tumor size, drug response, and AURKA overexpression were independent prognostic factors for poor progression-free survival (PFS). For overall survival (OS), only large tumor size and AURKA overexpression were identified as independent unfavorable factors. In an in vitro study, MLN8237, an AURKA inhibitor, inhibited growth of both IM-sensitive and IM-resistant GIST cells in a concentration-dependent manner, and exhibited synergistic cytotoxicity with IM in GIST cells. The inhibitory effect of MLN8237 in GIST cells could be attributed to the induction of G2/M arrest, apoptosis, and senescence. Our study shows that AURKA expression independently predicted poor PFS and OS in patients with advanced GISTs who were treated with IM. An AURKA inhibitor may have potential as a therapeutic agent for both IM-sensitive and IM-resistant GISTs.

What are the current outcomes of advanced gastrointestinal stromal tumors: who are the long-term survivors treated initially with imatinib?

The introduction of imatinib to clinical practice revolutionized therapy of advanced gastrointestinal stromal tumors (GIST), but its long-term results have been only just collected. We have attempted to identify factors related to the long-term survival. We have analyzed the data of 430 inoperable/metastatic/recurrent GIST patients treated with imatinib in reference centers, assessed the factors influencing the long-term overall survival (OS), and compared the outcomes in three periods of initiation of imatinib therapy during one decade (2001–2003, 2004–2006, 2007–2010). During analyzed time periods, we have found decrease in median largest tumor size at the start of imatinib therapy: 90.5 mm (2001–2003) versus 74 mm (2004–2006) versus 58 mm (2007–2010) (p = 0.002). Median progression-free survival (PFS) on 1st line imatinib was 37.5 months, without differences in PFS between three groups. Median OS was 5.8 years, 8-year OS rate was 43 %, and no difference in OS was demonstrated for patients treated in analyzed time periods. Independent good prognostic factors for longer OS were as follows: surgery of residual disease, initial WHO performance status 0/1, normal baseline albumin level, and the presence of exon 11 KIT mutations. Current median OS in advanced GIST reaches 6 years. The long-term survivors were characterized by smaller maximal tumors at imatinib start, better blood tests results, better performance status, and the surgical removal of residual disease. The latter might reduce the impact of tumor size and equalize the long-term results of therapy during last decade from introduction of imatinib. After introduction of subsequent lines of therapy (as sunitinib), the effect of primary mutational status on the long-term OS is also less visible.

Clinical practice guidelines for patients with gastrointestinal stromal tumor in Taiwan

For many years, the understanding of gastrointestinal stromal tumors (GISTs), which are the most common mesenchymal tumors of the gastrointestinal tract, has been very limited. However, it is now possible to provide a more precise definition through the use of pathology classification and molecular techniques. Coupled with the advancement of clinical practice, especially the development of targeted therapy, there is now a much better insight into its treatment. At present, organizations such as the National Comprehensive Cancer Network in the USA and the European Society for Medical Oncology in Europe have established a consensus and drawn up guidelines for the diagnosis, treatment, and follow-up of GISTs.With experts coming from various districts in Taiwan and combining the most recent clinical data and experiences, the Taiwan Surgical Society of Gastroenterology drafted the first national GIST treatment guidelines after a consensus meeting in 2007. Following subsequent advances in GIST diagnosis and treatment, further revisions and modifications have been made to the original guidelines. We present here the updated consensus and recommendations of the Taiwan Surgical Society of Gastroenterology for the diagnosis and treatment of GIST. We hope these guidelines can help enhance the quality of diagnosis, treatment, and care of patients with GIST in Taiwan.