Abstract 1214
Background
GISTs are rare tumours with an incidence of around 1/100000/year. The principle treatment in localised disease remains resection. If an R0 resection is not expected, Imatinib can be used in the NA setting to shrink tumours and improve chances of a complete resection. Current guidelines suggest Imatinib should be used for 6-12 months in the NA setting.
Methods
Data were collected for patients treated for GISTs with Imatinib in either the NA or palliative (PA) setting in two UK tertiary centres to assess response in the primary tumour volume (PTV). This study aimed to find the time to maximum reduction of PTV in NA and PA settings.
Results
29 patients were treated with Imatinib over a 3 year period; 13 in the PA setting and 16 in the NA setting. In the NA setting, 10 patients proceeded to surgery, 2 patients declined surgery and 4 patients remained inoperable. All patients deemed operable at baseline underwent surgery after NA Imatinib. The median time to surgery was 7.2mths (Range (R) 1.6 – 28.9mths). Overall, 10 patients died (none in the NA setting), 5 on treatment and 5 post-treatment. At baseline, the median PTV was 199.3cm3 (R 4.0 – 10472.0cm3). The median time to best response was 7.6mths (R 1.4 – 46.2mths) for all patients, 4.7mths (R 1.4 – 21.6mths) in NA patients and 14.1mths (R 3.3 – 46.2mths) in PA patients. As the majority of NA patients did not have progressive disease (PD) prior to surgery, the maximum response may not have been reached and therefore the results in PA patients may better reflect the time to best response. 9 patients had PD, 2 in NA setting with 1 patient proceeding to surgery. The median time to PD for all patients was 19.6mths (R 1 – 51.4mts). The overall response rate to Imatinib was 85.2%. The median reduction in PTV was 65.3% (R -182.7 – 93.4%). In NA patients the median reduction in PTV was 62.7% (R -182.7 – 93.4%) and in PA patients the median reduction in PTV was 57.6% (R 20 – 82.4%).
Conclusions
Imatinib has high response rates in both the NA and PA settings. This study suggests the maximum reduction in PTV can be achieved after greater than 12mths of treatment. For patients responding to NA Imatinib who have ongoing concerns regarding resectability, a more prolonged course of treatment may further reduce PTV to facilitate an R0 resection.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Sharath Gangadhara.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
1357 - Upfront atezolizumab chemoimmunotherapy-associated Immune-related adverse events in patients with advanced non-small cell lung cancer
Presenter: Francis Mogollon-Duffo
Session: Poster Display session 1
Resources:
Abstract
1851 - Nivolumab-induced and radiation recall pneumonitis in patients with non-small cell lung cancer: a multicenter real world analysis of 669 patients
Presenter: Nobuaki Mamesaya
Session: Poster Display session 1
Resources:
Abstract
851 - Retrospective analysis of immunotherapy prognostic scores in advanced NSCLC at Nottingham University Hospitals (UK)
Presenter: Cristina Lopez Escola
Session: Poster Display session 1
Resources:
Abstract
3639 - Applicability of lung immune prognostic index (LIPI) to predict efficacy of first-line pembrolizumab in advanced non-small-cell lung cancer (NSCLC)
Presenter: Xabier Mielgo Rubio
Session: Poster Display session 1
Resources:
Abstract
2950 - Delayed Onset Immune Related Adverse Effects (IRAEs) of Pembrolizumab in Non-Small Cell Lung Cancer
Presenter: Haixi Yan
Session: Poster Display session 1
Resources:
Abstract
3659 - Clinical implication of multiplex IHC and serologic biomarkers on Hyperprogression in NSCLC patients receiving Immune checkpoint blockers in real world.
Presenter: Joori Kim
Session: Poster Display session 1
Resources:
Abstract
4882 - Local ablative treatment and treatment beyond progression for oligo-progression in stage IV non-small cell lung cancer after tumor response to anti-PD1 treatment
Presenter: Florian Guisier
Session: Poster Display session 1
Resources:
Abstract
1358 - Atezolizumab in combination with chemotherapy for first-line treatment of advanced non-small cell lung cancer: A systematic review and meta-analysis of randomized controlled trials (RCTs)
Presenter: Francis Mogollon-Duffo
Session: Poster Display session 1
Resources:
Abstract
2170 - Prognostic Impact of Metastatic Sites for Pembrolizumab Efficacy as First-line therapy in Patients with PD-L1 tumor proportion score (TPS) ≥ 50% Advanced Non–Small Cell Lung Cancer: A Retrospective Multicenter Study
Presenter: Hayato Kawachi
Session: Poster Display session 1
Resources:
Abstract
3051 - Impact of visceral fat area as independent predictive factor in patients with advanced non-small cell lung cancer treated with nivolumab
Presenter: Yuki Sato
Session: Poster Display session 1
Resources:
Abstract