Search

Background: A cohort of 201 patients with small bowel gastrointestinal stromal tumors (GIST) treated between January 1st, 2009 and December 31st, 2016 in five GIST expertise centers in the Netherlands was analyzed. Goal of this study was to describe the clinical, surgical and pathological characteristics of this rare subpopulation of GIST patients, registered in the Dutch GIST registry., Methods: Clinical outcomes and risk factors of patients with small bowel GIST who underwent surgery or treated with systemic therapy were analyzed. A classification was made based on disease status at diagnosis (localized vs. metastasized)., Results: 201 patients with small bowel GIST were registered of which 138 patients (69%) were diagnosed with localized disease and 63 patients (31%) with metastatic disease. Approximately 19% of the patients had emergency surgery, and in 22% GIST was an accidental finding. In patients with high risk localized disease, recurrence occurred less often in patients who received adjuvant treatment (4/32) compared to patients who did not (20/31, p < 0.01). Disease progression during palliative imatinib treatment occurred in 23 patients (28%) after a median of 20.7 (range 1.8-47.1) months. Ongoing response was established in 52/82 patients on first line palliative treatment with imatinib after a median treatment time of 30.6 (range 2.5-155.3) months., Conclusion: Patients with small-bowel GIST more frequently present with metastatic disease when compared to patients with gastric GIST in literature. We advocate for Prospective registration of these patients and investigate the use of surgery in patients with limited metastatic disease., (Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Purpose: Patients, platelet-derived growth factor receptor alpha (PDGFRA) D842V-mutated gastrointestinal stromal tumours (GISTs) are known for their insensitivity to imatinib. However, in clinical practice responses have been observed in some patients. We describe the natural history and treatment outcomes in a cohort of PDGFRA exon 18 mutated GIST patients., Patients and Methods: A retrospective cohort study was conducted in PDGFRA exon 18 mutation GIST patients treated in six expert centres in the Netherlands and the United States. Two independent radiologists assessed radiological response to imatinib according to Choi's criteria in all patients with measurable disease treated with imatinib in neo-adjuvant or palliative intent., Results: Seventy-one patients with PDGFRA exon 18 mutation were identified of whom 48 patients (69%) had a D842V mutation. Twenty-two (45.8%) D842V-mutated GIST patients received imatinib treatment, 16 had measurable disease. Fourteen out of the 23 (60.9%) patients with non-D842V mutations received imatinib treatment, eight had measurable disease. Two out of 16 (12.5%) D842V-mutated GIST patients had partial response, 3 patients (18.8%) had stable disease and 9 patients (56.3%) had progressive disease as best response. Two patients did not have follow-up computed tomography scans to assess response. Six out of 8 (75%) patients with non-D842V exon 18 mutations had partial response and two (25%) had stable disease as best response., Conclusion: Patients with D842V-mutated GISTs can occasionally respond to imatinib. In the absence of better therapeutic options, imatinib should therefore not be universally withheld in patients with this mutation., (Copyright © 2017 Elsevier Ltd. All rights reserved.)