BackgroundWhile the effectiveness of tyrosine kinase inhibitors (TKIs) seems similar in older patients with gastrointestinal stromal tumors (GIST) compared with younger patients, toxicities in... Show moreBackgroundWhile the effectiveness of tyrosine kinase inhibitors (TKIs) seems similar in older patients with gastrointestinal stromal tumors (GIST) compared with younger patients, toxicities in older patients treated with TKIs more often lead to discontinuation of treatment.ObjectiveTo better understand the age-related pharmacology and pharmacodynamic differences in patients with GIST treated with TKIs, the primary aim of this study was to evaluate TKI dosing patterns in older patients with GIST, while the secondary aims were to evaluate differences in imatinib trough plasma concentrations between age groups and to compare the overall survival (OS) in patients with and without dose reductions in all treatment lines in a palliative setting.MethodsPatients (18 years of age or older) with histologically proven GIST diagnosed between January 2009 and June 2021 and treated with one or more lines of TKIs were selected from the Dutch GIST Registry (DGR) database. Age groups were divided into younger patients (age <70 years) and older patients (age ≥70 years). All imatinib trough plasma concentrations of blood withdrawals taken from initiation of imatinib until a maximum of 1 year of treatment with imatinib were collected. Reasons for first adjustment of treatment were classified as adverse event, dose modification, progressive disease and other reasons. The next treatment steps after first adjustment of treatment were defined as dose escalation, dose reduction, dose interruption, or end of treatment. The association of dose reduction and OS was analyzed using the landmark approach.ResultsOverall, 871 patients were included in this study, including 577 younger patients and 294 older patients. Older patients more often had an adverse event as the reason for first adjustment of treatment with both imatinib (45.6%; p < 0.001) and sunitinib (58.6%; p = 0.224) compared with younger patients (19.5% and 42.7%, respectively). Adjustment of imatinib and sunitinib after starting on a standard dose because of an adverse event most often resulted in dose reduction in both age groups. Median trough plasma concentrations of all samples taken within the first year after initiation of imatinib were higher in older patients (1228 ng/mL, interquartile range [IQR] 959–1687) compared with younger patients (1035 ng/mL [IQR 773–1377]; p < 0.001). No significant differences were seen between OS in patients with or without dose reduction in all treatment lines (imatinib: p = 0.270; sunitinib: p = 0.547; and regorafenib: p = 0.784).ConclusionOlder patients showed higher imatinib trough plasma concentrations compared with younger patients and also had earlier and more often adverse events as the reason for first adjustment of treatment with imatinib followed by dose reduction. However, in a landmark analysis, patients with imatinib dose reductions had no poorer outcomes compared with patients not requiring a dose reduction. Show less
Brink, P.; Kalisvaart, G.M.; Schrage, Y.M.; Mohammadi, M.; Ijzerman, N.S.; Bleckman, R.F.; ... ; Hage, J.A. van der 2023
BackgroundThe added value of local treatment in selected metastatic GIST patients is unclear. This study aims to provide insight into the usefulness of local treatment in metastatic GIST by use of... Show moreBackgroundThe added value of local treatment in selected metastatic GIST patients is unclear. This study aims to provide insight into the usefulness of local treatment in metastatic GIST by use of a survey study and retrospective analyses in a clinical database.MethodsA survey study was conducted among clinical specialists to select most relevant characteristics of metastatic GIST patients considered for local treatment, defined as elective surgery or ablation. Patients were selected from the Dutch GIST Registry. A multivariate Cox-regression model for overall survival since time of diagnosis of metastatic disease was estimated with local treatment as a time-dependent variable. An additional model was estimated to assess prognostic factors since local treatment.ResultsThe survey's response rate was 14/16. Performance status, response to TKIs, location of active disease, number of lesions, mutation status, and time between primary diagnosis and metastases, were regarded the 6 most important characteristics. Of 457 included patients, 123 underwent local treatment, which was associated with better survival after diagnosis of metastases (HR = 0.558, 95%CI = 0.336–0.928). Progressive disease during systemic treatment (HR = 3.885, 95%CI = 1.195–12.627) and disease confined to the liver (HR = 0.269, 95%CI = 0.082–0.880) were associated with worse and better survival after local treatment, respectively.ConclusionLocal treatment is associated with better survival in selected patients with metastatic GIST. Locally treated patients with response to TKIs and disease confined to the liver have good clinical outcome. These results might be considered for tailoring treatment, but should be interpreted with care because only specific patients are provided with local treatment in this retrospective study. Show less
Mohammadi, M.; IJzerman, N.S.; Hollander, D. den; Bleckman, R.F.; Oosten, A.W.; Desar, I.M.E.; ... ; Gelderblom, H. 2023
BackgroundPatients with unresectable and metastasized gastrointestinal stromal tumor (GIST) experienced a remarkable improvement of progression-free survival (PFS) and overall survival (OS) after... Show moreBackgroundPatients with unresectable and metastasized gastrointestinal stromal tumor (GIST) experienced a remarkable improvement of progression-free survival (PFS) and overall survival (OS) after the introduction of imatinib. Our hypothesis is that the outcomes of treatment with imatinib are even better nowadays compared with the registration trials that were performed two decades ago. To study this, we used real-life data from a contemporary registry.MethodsA multicenter, retrospective study was performed by exploring clinical data from a prospective real-life clinical database, the Dutch GIST Registry (DGR). Patients with advanced GIST treated with first-line imatinib were included and PFS (primary outcome) and OS (secondary outcome) were analyzed. Results of our study were compared with published results of the European Organisation for Research and Treatment of Cancer (EORTC) 62005 trial, which marked the first era of imatinib in the treatment of GIST.ResultsOverall, 420 of the 435 patients treated with imatinib in the DGR had recorded response evaluation and were included in the analysis. During a median follow-up of 35.0 months (range 2.0–136.0), progression of GIST was eventually observed in 217 patients (51.2%). The DGR cohort showed a longer median PFS (33.0 months, 95% confidence interval [CI] 28.4–37.6) compared with the EORTC 62005 trial (an estimated PFS of 19.5 months). Additionally, the median OS of 68.0 months (95% CI 56.1–80.0) was longer than the exposed median OS (46.8 months) published in the long-term follow-up results of the EORTC 62005 trial (median follow-up duration 10.9 years).ConclusionThis study provides an update on outcomes of imatinib in the treatment of advanced GIST patients and demonstrates improved clinical outcomes since the first randomized studies of imatinib 2 decades ago. Furthermore, these results represent outcomes in real-world clinical practice and can serve as a reference when evaluating effectiveness of imatinib in patients with advanced GIST. Show less
Bleckman, R.F.; Roets, E.; IJzerman, N.S.; Mohammadi, M.; Bonenkamp, H.J.J.; Gelderblom, H.; ... ; Etten, B. van 2023
Background and objectivesPrevious literature showed a high risk of recurrence following surgical treatment in patients with gastrointestinal stromal tumours (GISTs). However, little is known about... Show moreBackground and objectivesPrevious literature showed a high risk of recurrence following surgical treatment in patients with gastrointestinal stromal tumours (GISTs). However, little is known about the patient- and treatment characteristics of local recurrences (LRs) in GIST patients. Therefore, this study aimed to better understand patterns of LR in surgically treated localised GIST and to describe treatment options based on our Dutch GIST Registry (DGR).MethodsData of primary surgically treated localised GIST between January 2009 until July 2021 were retrospectively retrieved from the DGR.ResultsOf 1452 patients registered in the DGR, 912 patients were included in this study. Only 3.8% (35/912) of patients developed LR, including 20 patients with LR only and 15 patients with simultaneous LR and distant metastases (DM). Median time to LR was 30 (interquartile range 8–53) months from date of surgery. Eleven percent (100/912) of patients developed only DM. A total of 2.3% (6/259) of patients treated with adjuvant treatment developed an LR during adjuvant therapy. Seventy percent of patients with LR only (14/20) were treated with surgery (85.7% R0), which was mostly combined with systemic treatment.ConclusionsPatients with primary surgically treated localised GIST have a limited risk of developing recurrence. Fifteen percent developed recurrence, of which one quarter developed an LR. Therefore, less intensified follow-up schedules could be considered, especially during treatment with adjuvant imatinib. In patients with LR only, potentially curative treatment strategies, including surgical (re-)resection, are often possible as treatment for LR. Show less
Praag, V.M. van; Fiocco, M.; Bleckman, R.F.; Houdt, W.J. van; Haas, R.L.M.; Verhoef, C.; ... ; Sande, M.A.J. van de 2023
Introduction: Patients with locally extensive high-grade extremity soft tissue sarcomas (eSTS) are often presented in multidisciplinary teams to decide between ablative surgery (amputation) or limb... Show moreIntroduction: Patients with locally extensive high-grade extremity soft tissue sarcomas (eSTS) are often presented in multidisciplinary teams to decide between ablative surgery (amputation) or limb-salvage surgery supplemented with either neo-adjuvant radiotherapy (RT) or induction isolated limb perfu-sion (ILP).In The Netherlands, ILP typically aims to reduce the size of tumors that would otherwise be considered irresectable, whereas neo-adjuvant RT aims mainly at improving local control and reducing morbidity of required marginal margins. This study presents a 15-year nationwide cohort to describe the oncological outcomes of both pre-operative treatment strategies.Methods: All consecutive patients with locally extensive primary high-grade eSTS surgically treated between 2000 and 2015 at five tertiary sarcoma centers that received neo-adjuvant ILP or RT were included. 169 patients met the inclusion criteria (89 ILP, 80 RT). Median follow-up was 7.3 years. Results: Limb salvage was achieved in 84% of cases in the ILP group (80% for patients with amputation indication) and 96% of cases in the RT group. 5-Year overall survival was 47% in the ILP group, 69% in the RT group. 5-Year local recurrence rate was 14% in the ILP group, 10% in the RT group. Distant metastasis rate was 55% in the ILP group, 36% in the RT group.Conclusion: We find oncological outcomes and limb salvage rates in line with existing literature for both treatment modalities. Whether the tumor was locally advanced with an indication for induction therapy to prevent amputation or morbid surgery appeared to be the main determinant in choosing between neo-adjuvant ILP or RT.(c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Show less
IJzerman, N.S.; Werkhoven, E. van; Mohammadi, M.; Hollander, D. den; Bleckman, R.F.; Reyners, A.K.L.; ... ; Graaf, W.T.A. van der 2022
Background: Sex differences in cancer have gained attention in recent years. The role of sex as a prognostic factor in gastrointestinal stromal tumours (GIST) has not been well established. The aim... Show moreBackground: Sex differences in cancer have gained attention in recent years. The role of sex as a prognostic factor in gastrointestinal stromal tumours (GIST) has not been well established. The aim of this research was to elucidate potential sex differences in GIST patients and the influence of sex on disease-specific survival (DSS). Methods: A review of the literature was carried out to obtain an overview of all literature with sex as a covariate on GIST survival analyses. Furthermore, in the Dutch GIST Registry, GIST characteristics between males and females were compared and the influence of sex on DSS was analysed. Results: A total of 118 articles from the review of the literature met our selection criteria; 58% of the articles found no sex difference in survival and 42% did find a sex difference. All differences favoured female patients, although there was substantial overlap of individual patients in the various reported groups. The Dutch GIST Registry cohort consisted of 1425 patients (46% female). Compared with female patients, male patients had larger tumours (mean 9.0 cm versus 7.9 cm) and higher mitotic rates (34.4% versus 28.0% > 5 mitoses/5 mm(2)). GIST in males was more often metastasized at diagnosis (21.3% versus 13.7%) and incurable (38.5% versus 31.0%). Male patients less often received surgery of the primary tumour (71.7% versus 78.9%), but did experience more tumour ruptures (18.2% versus 13.3%). Male patients had a worse DSS than females. This was not statistically significant when corrected for differences in GIST characteristics. Conclusions: In case of sex differences in GIST in the literature, male patients have a worse outcome. In our Dutch GIST cohort a similar finding was made, but sex was shown not to be an independent factor. Male patients more often had aggressive GISTs, with larger tumours, higher mitotic rates, more tumour ruptures, and metastases, which could explain the sex differences in DSS. Show less
Mohammadi, M.; Jansen-Werkhoven, T.M.; Ijzerman, N.S.; Hollander, D. den; Bleckman, R.F.; Oosten, A.W.; ... ; Gelderblom, H. 2022
Background: The prognosis of patients with advanced gastrointestinal stromal tumor (GIST) has improved greatly after the introduction of imatinib. However, primary or secondary resistance to... Show moreBackground: The prognosis of patients with advanced gastrointestinal stromal tumor (GIST) has improved greatly after the introduction of imatinib. However, primary or secondary resistance to imatinib occurs in the majority of patients. Sunitinib is the standard second line treatment in exon-9 mutated GIST. Objective: We compared the clinical outcomes of sunitinib with imatinib dose escalation in patients with progressive advanced non-KIT exon 9 mutated GIST after failure of first line imatinib. Patients and Methods: A retrospective study was performed, retrieving data from a real-life database (Dutch GIST Registry) including patients with GIST treated with sunitinib or imatinib dose escalation after failure on first line imatinib 400 mg daily. Primary outcome measures were progression free survival (PFS) and overall survival (OS). Results: In total, 110 patients were included, 72 (65.5%) patients were treated with sunitinib (group A) and 38 (34.5%) received an imatinib dose escalation (group B). Important prognostic features at baseline, such as tumor size, stage at diagnosis, mitotic count and localization were equally distributed in both groups. No significant difference (p = 0.88) between median PFS in group A [8.7 months (95% CI 5.6-11.3)] and group B [5.6 months, (95% CI 2.6-8.7)] was observed. Moreover, the OS was similar between group A and group B; 63.2 months and 63.4 months, respectively. Conclusion: This study represents a proper sample size cohort containing detailed data on mutational status of patients with advanced GIST. We illustrated that imatinib dose escalation could serve as a good alternative for sunitinib as second-line treatment in patients with a non-KIT exon 9 mutation. Show less
Introduction: This subgroup analysis of undifferentiated pleomorphic soft tissue sarcoma of the extremity (eUPS) from the PERSARC collaborative group aimed to achieve a more personalized... Show moreIntroduction: This subgroup analysis of undifferentiated pleomorphic soft tissue sarcoma of the extremity (eUPS) from the PERSARC collaborative group aimed to achieve a more personalized multimodality treatment approach for primary eUPS in elderly patients. Material and methods: A multicenter retrospective study including primary high-grade eUPS surgically treated with curative intent between 2000 and 2016. Overall survival (OS), local recurrence (LR) and distant metastasis (DM) curves were calculated by Kaplan Meier analysis. Cox proportional hazard models were used to determine the effect of radiotherapy. Results: From a total of 2511 patients with extremity soft tissue sarcoma (eSTS) of the PERSARC study collaborative; 703 patients with eUPS were included in this study. In elderly patients with eUPS 5-year OS, LR and DM were 35.4 (95%CI 29.3-42.8), 17.7 (95%CI 12.7-22.6) and 24.6 (95%CI 19.1-30.1). eUPS was significantly less treated with radiotherapy compared with other eSTS, especially in elderly patients. Patients with R1-R2 margins treated with radiotherapy had about half the risk of developing LR compared with patients treated without radiotherapy (HR = 0.454, p = 0.033). Conclusion: Elderly patients with eUPS were less often treated with radiotherapy and showed higher LR. Nowadays, given an increasing life expectancy in elderly patients, multimodality treatment should be considered. (C) 2021 The Authors. Published by Elsevier Ltd. Show less
