Preoperative Imatinib Mesylate Combined With Rectal-sparing Surgery in Patients With c-KIT Gene-mutant Rectal GIST

Study Overview
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Brief Summary
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Prior to the implementation of preoperative imatinib mesylate therapy, a considerable percentage (ranging from 34.5% to 67.5%) of individuals diagnosed with rectal gastrointestinal stromal tumors (GIST) underwent abdominoperineal resection (APR), a surgical procedure that involved the removal of the anus and necessitated a permanent colostomy. This study aims to investigate the safety and viability of an organ-preserving approach involving preoperative imatinib mesylate treatment in conjunction with local resection for rectal GIST, specifically targeting patients with c-KIT gene mutations.

Detailed Description
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Prior to the implementation of preoperative imatinib mesylate therapy, a considerable percentage (ranging from 34.5% to 67.5%) of individuals diagnosed with rectal gastrointestinal stromal tumors (GIST) underwent abdominoperineal resection (APR), a surgical procedure that involved the removal of the anus and necessitated a permanent colostomy. Previous studies have established that preoperative administration of imatinib mesylate effectively diminishes the size of rectal gastrointestinal stromal tumors (GIST) and enhances the likelihood of sphincter preservation. After initiating preoperative imatinib mesylate treatment, the sphincter preservation rate has notably escalated from 4.2% to 33.0%-94.9%. In theory, lymph node resection is not required for Gastrointestinal Stromal Tumors (GIST); the local excision of rectal GIST enables sphincter preservation and yields satisfactory anal function and quality of life (QoL). Various surgical techniques are utilized for local excision, including traditional transanal (TA) and transanal minimally invasive surgery (TAMIS) approaches. This study aims to explore the safety and feasibility of an organ-preservation strategy of preoperative imatinib mesylate combined with local resection in rectal gastrointestinal stromal tumor (GIST), specifically for patients with c-KIT gene mutations.

Official Title
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Preoperative Imatinib Mesylate Combined With Rectal-sparing Surgery in Patients With c-KIT Gene-mutant Rectal GIST: an Open-label, Single-arm, Phase III Trial（PIRKER）

Conditions
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Gastrointestinal Stromal Tumor of Rectum

Intervention / Treatment
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* Drug: Imatinib Mesylate
* Procedure: Local resection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Over the age of 18. Newly pathology-diagnosed rectal GIST Tumor > 2cm; local resection of R0 is not possible in the initial evaluation. The lower margin of the tumor is ≤ 5cm from the anal verge. C-KIT gene mutation. Male or non-pregnant female. ECOG score 0-2. Did not receive targeted therapy before the start of the clinical trial. Sufficient organ functions are defined as follows: Total bilirubin < 1.5×ULN (upper limit of normal, ULN), serum AST (SGOT) and ALT (SGPT) < 2. 5 × ULN, creatinine < 1.5×ULN, neutrophil count > 1. 5 ×109 / L, platelet > 100 × 109 / L. The patient's informed consent has been obtained. Exclusion Criteria: Pathology is non-rectal GIST. Under the age of 18. Patients with distant metastasis. The patient is not permitted to have additional primary malignant tumors within five years unless those tumors are currently deemed clinically insignificant and do not necessitate active intervention, such as basal cell skin cancer or cervical cancer in situ. The presence of any other malignant diseases is strictly prohibited. Individuals diagnosed with stage III or IV cardiac conditions, specifically congestive heart failure and myocardial infarction occurring within six months prior to the commencement of the study. The patient presents with severe and/or uncontrolled medical ailments, such as unmanaged diabetes, advanced chronic kidney disease, or active uncontrolled infection. Co-administration of imatinib with warfarin or acetaminophen is contraindicated, necessitating the substitution of alternative medications (e.g., low molecular weight heparin in place of warfarin). Subjects undergoing radiotherapy, chemotherapy, and/or targeted therapy. Pregnant or lactating female patients. Cognitive or psychiatric disorders. Profound cardiac, hepatic, and renal dysfunction. Non-adherence by the patient or the researchers' assessment of the patient's inability to complete the entire trial.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Preoperative Imatinib + local excision<br>Following the attainment of the maximum treatment response through imatinib mesylate administration, typically occurring within 6-12 months, as evidenced by two consecutive imaging evaluations, the tumor exhibited no further reduction in size, thus necessitating the selection of surgical intervention. According to the characteristics of the location of the tumor, the surgeon decides the surgical approach based on the existing literature and the availability of surgical equipment, including: Local transanal resection (TA) Local resection transsacralapproach Local resection via perineal approach Local resection transvaginal approach | Drug: Imatinib Mesylate<br>* For patients with c-KIT exon 11 mutation, imatinib mesylate, 400mg, qd. For patients with c-KIT exon 9 mutation, imatinib mesylate, 600mg or 800mg, qd.<br>* Other names: Gleevec;Procedure: Local resection<br>* According to the characteristics of the location of the tumor, the surgeon decides the surgical approach based on the existing literature and the availability of surgical equipment, including: Local transanal resection (TA) Local resection transsacralapproach Local resection via perineal approach Local resection transvaginal approach<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Organ preservation | Rectum intact, owing to no total mesorectal excision (TME), no locoregional regrowth unless amenable to limited, curative (R0) salvage surgery by local excision (LE) and no permanent stoma (including a never reversed protective stoma, or a stoma owing to toxicities and/or poor functional outcomes) | 18 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 3-year disease-free survival | The proportion of participants who remain disease-free at 3 years after surgery | 36 months | 
| Local recurrence rate | The local recurrence rate is defined as the incidence detection of a tumor involving the bowel wall only that occurs after LE or TME | 36 months | 
| Overall survival | The proportion of participants who remain survival at 3 years after surgery | 36 months | 
| R0 resection rate | The R0 resection rate is defined as the rate of R0 resection | 18 months | 
| Quality of life based on EORTC-QLQs-C30 and EORTC-QLQs-CR29 | Quality of life accessed by EORTC-QLQs-C30 and EORTC-QLQs-CR29 questionnaire | Baseline, 3 months, 12 months, 24 months, and 36 months after surgery | 
| Anorectal function | Anorectal function based on LARS score | Baseline, 3 months, 12 months, 24 months, and 36 months after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gastrointestinal Stromal Tumor, Rectum, Imatinib mesylate, c-KIT gene, Local resection