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
5037 - CXCR4, CCR2 and CCR5 expression in subsets of tumor cells with stem and/or EMT features
Presenter: Olga Savelieva
Session: Poster Display session 1
Resources:
Abstract
5729 - Expression of mutant p53 affects cancer cell sensitivity to topotecan
Presenter: Rimma Mingaleeva
Session: Poster Display session 1
Resources:
Abstract
5725 - Breast cancer organoids a new tool for the prediction of drugs penetration and patient’outcome
Presenter: Giuseppina Roscigno
Session: Poster Display session 1
Resources:
Abstract
5680 - Aptamer-mediated exosomes detection for early breast cancer identification.
Presenter: Cristina Quintavalle
Session: Poster Display session 1
Resources:
Abstract
2460 - MicroRNA-181c promotes tamoxifen resistance in breast cancer cells via upregulation Akt/mTOR axis
Presenter: Alexander Scherbakov
Session: Poster Display session 1
Resources:
Abstract
3751 - Spatio-temporal separation of tumor infiltrating CD8+ T-cells and HER2/neu+ tumor cells in tumor-immune milieu of infiltrating ductal carcinoma of the breast
Presenter: Sandhya Sreedharan
Session: Poster Display session 1
Resources:
Abstract
4664 - Large genomic rearrangements in BRCA1 and BRCA2 genes in the Portuguese population.
Presenter: Joao Pinto
Session: Poster Display session 1
Resources:
Abstract
4611 - Non-BRCA1/2 hereditary breast and ovarian cancer: findings from a multidisciplinary program
Presenter: Ana Monteiro
Session: Poster Display session 1
Resources:
Abstract
5340 - Quantitative imaging and characterization of collagen patterns in high grade serous ovarian carcinoma (HGSOC)
Presenter: Ruby Huang
Session: Poster Display session 1
Resources:
Abstract
4209 - Semiquantitative assessment of vimentin expression in prostate cancer (PC)
Presenter: Marina Puchinskaya
Session: Poster Display session 1
Resources:
Abstract