Preoperative imatinib for patients with primary unresectable or metastatic/recurrent gastrointestinal stromal tumor

A systematic review and meta-analysis of neoadjuvant imatinib use in locally advanced and metastatic gastrointestinal stromal tumors

BACKGROUND

Several doubts remain regarding the optimal use of neoadjuvant imatinib in gastrointestinal stromal tumors (GISTs), such as ideal treatment duration, patient selection, and long-term survival outcomes. This manuscript provides a comprehensive review on neoadjuvant imatinib treatment outcomes and facilitate evidence-based decision-making for the use of imatinib therapy in GISTs.

METHODS

Four databases (PubMed, EMBASE, Scopus, and Cochrane Library) were searched from inception to September 9, 2023. Meta-analyses of proportions were performed for the outcomes of R0 resection, disease responses, and 1-year, 3-year, and 5-year overall survival (OS) as well as 1-year, 3-year, and 5-year disease free survival (DFS). Sensitivity analyses in the form of leave-one-out analyses, meta-regression, and subgroup analyses were performed for outcomes with substantial statistical heterogeneity.

RESULTS

The search yielded 1254 articles, and 36 studies were included in our analysis. Meta-analysis of proportions revealed that 1-year, 3-year, and 5-year OS was 100%, 94%, and 88%, while 1-year, 3-year and 5-year DFS was 99%, 89%, and 79%, respectively. An R0 resection rate of 89% and a disease response rate of 67% was achieved after a mean duration of treatment of 8.41 ± 0.367 months. KIT exon 9 mutation was significantly associated with poorer 5-year DFS.

CONCLUSION

This study quantified key outcomes for neoadjuvant imatinib in locally advanced and metastatic or recurrent GIST. Patients with gastric and rectal tumous stand to benefit from neoadjuvant imatinib with an optimal treatment duration of 8 months. Furthermore, the potential utility of mutational analysis in guiding treatment with neoadjuvant imatinib was demonstrated.

Simultaneous Integrated Boost Intensity-Modulated Radiotherapy for Locally Advanced Drug-Resistant Gastrointestinal Stromal Tumors: A Feasibility Study

Background

As an emerging clinical problem, locally advanced drug-resistant gastrointestinal stromal tumors (LADRGISTs) has relatively few therapeutic schemes. Although radiotherapy is not often considered for GISTs, it could be a valuable contributing modality. The aim of our study is to explore a safe and effective radiation regimen for LADR-GISTs.

Methods

Three patients with LADR-GISTs were treated with simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) plans. In the SIB-IMRT plans, gross target volume (GTV) was divided into GTV-outer, GTV-mid, and GTV-center. And the prescribed dose of planning gross target volume (PGTV) and GTV-outer were both set to 50.4 Gy in 28 fractions. GTV-mid and GTV-center were simultaneously boosted to 60–62 Gy and 62–64 Gy respectively. For comparison purposes, conventional IMRT (Con-IMRT) plans with uniform dose distribution were generated for same optimization objectives without a dose boost to GTV-mid and GTV-center. All plans were optimized to make sure that deliver at least 95% of the prescription dose was delivered to PGTV. Isodose distribution, dose profiles, conformity indexes (CIs), monitor units (MUs), and dose volume histogram (DVH) was evaluated for each individual patient. After the three patients were treated with SIB-IMRT plans, the relative changes in the tumor size and CT values by CT scanning were also tracked.

Results

Compared with Con-IMRT plans, SIB-IMRT plans saw a significant increase from D₉₅ to D₂ of the GTV. With steeper dose gradients in the dose profiles, SIB-IMRT plans had GTV-mid and GTV-center accumulated with higher dose mainly by delivering extra 93 MUs in average. However, there was no significant difference in CIs and organs at risks (OARs) DVH. The relative changes in tumor size and CT values of the three patients in follow up were up to the Choi criteria and the three patients were all assessed as partial response.

Conclusions

The proposed SIB-IMRT may be a potential technique for achieving objective response and prolonging survival of selected GISTs patients.

Open transanal resection of low rectal stromal tumor following neoadjuvant therapy of imatinib mesylate: Report of 11 cases and review of literature

OBJECTIVE

The global burden of rectal gastrointestinal stromal tumor (GIST) is increasing. However, a limited number of reports hinder our ability to reach a definitive conclusion regarding the current treatment and prognosis. In this study, we outline our experience with open transanal resection of rectal GIST following neoadjuvant therapy with imatinib mesylate (IM).

PATIENTS AND METHODS

We retrospectively analyzed 11 patients with rectal GISTs treated with neoadjuvant IM therapy and open transanal resection between April 2011 and April 2017 in Shanghai Changzheng Hospital.

RESULTS

The patients had 400-600 mg/day IM once daily for a median of 7 months (range: 3-9 months). Tumor size, distance from the lower margin of the tumor to the anal verge (AV), mitotic rates and mutation analysis were assessed on pretreatment biopsy. After reassessment, all 11 patients underwent transanal R0 resection. With median follow-up of 28 months (range: 8-80 months), there was no tumor recurrence or metastasis.

CONCLUSION

Open transanal resection of rectal GIST after neoadjuvant treatment with IM has good surgical and survival outcomes.

Preoperative therapy with sunitinib malate in a patient with a gastrointestinal stromal tumor and liver metastases: A case report

RATIONALE

Patients with gastrointestinal stromal tumors (GISTs) are often found to have liver metastases at their 1st presentation. Most patients need preoperative treatment to reduce the size of the liver metastases to increase the possibility of surgical resection. Currently, imatinib mesylate is the drug of 1st choice for preoperative treatment and sunitinib malate (SM) is seldom used. Here we report a case of GIST with liver metastases where SM was used as a preoperative treatment.

PATIENT CONCERNS

A 56-year-old worker presented with intermittent abdominal pain and eating difficulties.

DIAGNOSES

An enhanced computed tomography scan showed a 15 × 15 × 10 cm malignant mass in the upper abdomen, and 2 metastases (15.1 × 13.1 cm and 14.8 × 8.8 cm) in the liver. The postcaval and middle hepatic veins were compressed by the liver metastases, making radical resection very difficult.

INTERVENTIONS

First the primary tumor in the jejunum was resected, and then SM was used as a preoperative treatment to reduce the size of the liver metastases to improve the possibility of surgical resection.

OUTCOMES

Both liver metastases regressed considerably in size and it was then possible to perform a radical resection.

LESSONS

The SM has the potential to be used as preoperative therapy for GIST with large liver metastases. This method provides a new option for the preoperative treatment of GIST with liver metastases.

Excision of a Large Gastrointestinal Stromal Tumour Following 16 Months of Neoadjuvant Therapy with Imatinib (Case Report)

Introduction

Although the standard treatment for stromal tumours is surgery, in locally advanced forms, it is often necessary to achieve tumour downstaging to improve surgical outcomes. Neoadjuvant treatment in gastrointestinal stromal tumours (GISTs) with tyrosine kinase inhibitors, including imatinib, has been shown to be effective in several studies, but the duration of this treatment is still a subject of debate.

Case report

We report a case of a large GIST of the stomach in a 51-year-old patient with atypical presentation that was initially unresectable. Neoadjuvant treatment with imatinib for 16 months resulted in a good response, allowing secondary surgical excision.

Conclusion

Imatinib in neoadjuvant therapy should be continued as long as there is a good response and tolerance to the medication to obtain tumour downsizing compatible with carcinologic excision.

Electronic supplementary material

The online version of this article (10.1007/s40487-019-00101-4) contains supplementary material, which is available to authorized users.

Enormous gastrointestinal stromal tumor arising from the stomach causing weight loss and anemia in an elderly female: Case report

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Gastrointestinal stromal tumors are the most common mesenchymal tumors of gastrointestinal tract.

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Surgical excision with normal safety margins is the main form of treatment.

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Preoperative imatinib therapy is used in unresectable or recurrent tumors.

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Huge tumors may not respond to medical therapy.

Introduction

Gastrointestinal stromal tumors are the most common mesenchymal tumors of gastrointestinal tract originating from the interstitial cell of Cajal. The presentation is variable depending on the size and site. CT scan is the most widely used imaging. The primary treatment is surgical resection. Imatinib may be used in unresectable tumors or preoperatively.

Case presentation

A 65-year-old lady had weight loss and repeated vomiting for one year. Examination showed a non-tender mass in the left hypochonrdium arising below the costal margin extending to 15 cm toward the left iliac fossa. It was firm with smooth surface. CT-scan examination showed a 45 cm × 21 cm mass arising between the spleen and the left kidney and displacing the kidney toward the midline. Gastroscopy and biopsy showed gastrointestinal stromal tumor. During surgery an enormous gastric tumor attached to the spleen. Total gastrectomy en-block with splenectomy and reconstruction done through roux-en-y esophago-jejunostomy and jejunojejunostomy.

Conclusion

GISTs most commonly affect the stomach, most tumors are treated by primary surgical excision with normal safety margins, advanced disease may need imatinib before surgery which helps in decreasing the size of the tumor and makes surgery easier.

Giant gastric stromal tumor mimicking as a posterior mediastinal mass: A case report and literature review

RATIONALE

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Mediastinal GISTs are rare and mostly arise from the esophagus.

PATIENT CONCERNS

A 68-year-old woman with dysphagia who presented with a huge posterior mediastinal mass.

DIAGNOSES

The patient was diagnosed with a GIST through chest computed tomography (CT)-guided core biopsy of the mass.

INTERVENTIONS

Complete excision including the tumor, lower part of the esophagus and fundus of the stomach were performed.

OUTCOMES

On follow-up after 48 months, the patient is currently alive without any evidence of tumor recurrence.

LESSONS

The case highlights GISTs are taken into consideration in the differential diagnosis of posterior mediastinal masses.

Radiotherapy for Gastrointestinal Stromal Tumors

OBJECTIVE

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal tumors of the gastrointestinal tract, which frequently cause intraabdominal metastases. The current standard of care is surgery for localized cases, and adjuvant imatinib is recommended for tumors with a high risk of recurrence. To date, radiotherapy has not been commonly accepted as a part of multimodality treatment approach other than palliation. However, recently published case reports and some small series suggest that radiotherapy is a valuable option for controlling locally progressive, drug-resistant disease. The aim of this review is to provide a viewpoint from a radiation oncologist concerning the management of GISTs, especially rectal GIST, and clarify the role and technical aspects of radiotherapy in the treatment approach.

DATA SOURCES

A comprehensive search in PubMed using the keywords "radiotherapy for rectal GIST" and "rectal GIST" was undertaken. The literature search included the related articles after 1995.

STUDY SELECTION

The main articles including rectal GIST case reports and GIST series containing rectal cases were the primary references.

RESULTS

Surgery is the mainstay of treatment. However, to date, radiotherapy is included in the multidisciplinary treatment strategy of rectal GISTs in some circumstances with palliative, adjuvant, or definitive intent using different treatment doses and fields.

CONCLUSIONS

Recently reported long-term local control rates indicate that GIST is a radiosensitive disease. This makes radiotherapy a valuable alternative in GIST management with curative intent, especially in patients who (1) cannot tolerate or are resistant to chemotherapy agents, (2) have an unresectable disease, (3) have a gross or microscopic residual disease after surgery, and (4) have a recurrent disease.

Imaging therapy response of gastrointestinal stromal tumors (GIST) with FDG PET, CT and MRI: a systematic review

Purpose

Improvement of the therapeutic approaches in gastrointestinal stromal tumors (GIST) by the introduction of targeted therapies requires appropriate diagnostic tools, which allow sufficient assessment of therapeutic response, including differentiation of true progression from pseudoprogression due to myxoid degeneration or intratumoral hemorrhage. In this literature review the impact and limitations of different imaging modalities used in GIST therapy monitoring are discussed.

Methods

PubMed and Cochrane library search were performed using appropriate keywords. Overall, 39 original papers fulfilled the defined criteria and were included in this systematic review.

Results

Morphological imaging modalities like computed tomography (CT) are primarily used for both diagnosis and therapy monitoring. However, therapy with tyrosine kinase inhibitors and other targeted therapies in GIST may lead only to a minor tumor volume reduction even in cases of response. Therefore, the use of Response Evaluation Criteria in Solid Tumors (RECIST) has limitations. To overcome those limitations, modified response criteria have been introduced for the CT-based therapy assessment, like the Choi criteria as well as criteria based on dual energy CT studies. Functional imaging techniques, mostly based on FDG PET-CT are in use, in particular for the assessment of early treatment response.

Conclusions

The impact and the limitations of PET-based therapy monitoring, as well as its comparison with CT, MRI and survival data are discussed in this review. CT is still the standard method for the evaluation of therapy response despite its several limitations. FDG PET-CT is helpful for the assessment of early therapy response; however, more prospective data are needed to define its role as well as the appropriate time intervals for therapy monitoring. A multiparametric evaluation based on changes in both morphological and functional data has to be assessed in further prospective studies.

Preoperative imatinib mesylate (IM) for huge gastrointestinal stromal tumors (GIST)

Background

Preoperative imatinib mesylate (IM) treatment has not yet been standardized. Here, we aim to further explore such therapy on patients with gastrointestinal stromal tumors (GIST) retrospectively.

Methods

Patients experiencing preoperative IM were identified from January 2009 to February 2015.

Results

A total of 28 GIST patients were identified. The patients received preoperative IM treatment for a median length of 13.5 months, ranging from 5 to 37 months. PR and SD were observed in 24 (85.7%) and 4 (15.3%) patients, respectively. The tumor shrinkage occurred predominantly within 6 to 12 months, and slight tumor shrinkage could be observed after 12 months in certain patients. Nineteen patients (67.9%) received surgery, and R0 resection was acquired in 18 (94.7%) patients. The initial mean maximum diameter was 10.5 (5.2 to 19.0) cm and decreased to 5.9 (2.7 to 19.0) cm after preoperative treatment with a median length of 12 (ranging from 5 to 36) months (P < 0.001) in patients receiving operations. Three in 7 cases of rectum GIST underwent abdominoperineal resection, and four others adopted sphincter-sparing resection. Partial gastrectomy was performed in four patients.

Conclusions

IM prior to surgery can effectively prevent tumor rupture and facilitate surgery with low surgical morbidity for GIST patients. Tumor shrinkage following IM occurred predominantly within 6 to 12 months, and slight tumor shrinkage could be observed after 12 months in certain patients. In selected patients, prolonged exposure to IM is seemingly advisable under close radiological surveillance.

Is surgery mandatory in locally advanced gastrointestinal stromal tumors after imatinib? A case report and literature review

Oesophageal gastrointestinal stromal tumors (GISTs) are rare neoplasms (about 2% of all GISTs); radical surgery is the standard treatment of all GISTs but in case of locally advanced and unresectable disease no clear treatment guide lines are available. Studies including neoadjuvant imatinib mesylate (IM) are relatively recent, includes small sample size of heterogeneous patients and do not report a standardized duration of neoadjuvant treatment. The main question still remains whether surgery after neoadjuvant IM gives a survival benefit in locally advanced disease. A 46-year-old man with locally advanced unresectable oesophageal GIST harboring KIT exon 11 mutation was treated in our institution for 12 months with neoadjuvant IM; a reduction of 83% of tumor volume was obtained in 9-month of neoadjuvant IM, but in the last 3 months no further response was seen. After neoadjuvant therapy, patient underwent radical surgery and adjuvant IM, which is still ongoing. Since no definitive data are available about survival benefit of surgery after neoadjuvant IM in locally advanced GISTs, a careful balance between morbidity and mortality derived from surgery should be considered and more studies are needed to better define the utility and the optimal duration of neoadjuvant treatment.

Clinicopathological features and prognosis of small gastrointestinal stromal tumors outside the stomach

The aim of the present study was to assess the clinicopathological features and prognostic factors of primary small gastrointestinal stromal tumors (GISTs) outside the stomach. The clinical data, clinicopathological features and prognostic factors of 20 patients with a pathologically-confirmed diagnosis of non-gastric GIST that were treated at Liaoning Cancer Hospital & Institute between July 2006 and December 2013 were retrospectively analyzed. In total, 15 patients were male and 5 were female, with a median age of 58 years (range, 44–82 years). A change in bowel habits was the original symptom of rectal small GISTs in 6 out of 8 patients, while patients with small GISTs in other locations demonstrated no overt symptoms and the lesions were detected by systematic examinations of other diseases or abdominal surgical procedures performed on other organs. In total, 19 patients out of the total 20 patients underwent surgery, and 1 patient with rectal GIST received continuous oral imatinib mesylate (400 mg once a day) instead of undergoing surgery. The mean diameter of tumors was 1.55±0.54 cm (range, 0.3–2.0 cm) and the median was 1.70 cm. The pathomorphology of the lesions was mainly spindle cell, and immunohistochemistry revealed the expression rate of cluster of differentiation (CD)117, CD34 and discovered on GIST-1 were 85, 80 and 70%. According to the mitosis index, small rectal GISTs were more frequent compared with other positions (P<0.05), while the frequency of small GISTs >1 cm in size was not significantly different from the frequency of small GISTs ≤1 cm in size (P=0.995). All 20 patients were followed up, with a median follow-up duration of 49.5 months (range, 10.5–94.4 months). At the end of the follow-up period, tumor recurrence occurred in 5 patients and 1 patient succumbed following progression. According to the analysis of the tumor sites, the RFS time of patients with small rectal GISTs was significantly different than the RFS time in patients with small GISTs in other positions. The clinical symptoms of non-gastric small GISTs were not evident and were challenging to detect. Small GISTs, regardless of size, possessed malignant potential and once detected, GISTs should be surgically resected. Lesions located in the rectum demonstrated an increased degree of malignancy and were more likely to recur. The tumor size and Ki67 index could not be considered as prognostic factors of non-gastric small GISTs.