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
1735 - mTOR inhibition in the treatment of resistant breast cancer
Presenter: María Rodriguez
Session: Poster Display session 1
Resources:
Abstract
6068 - Study of Photodynamic therapy in vitro
Presenter: Irene Jiménez Munguía
Session: Poster Display session 1
Resources:
Abstract
3011 - The potential of neratinib plus dasatinib in overcoming and preventing neratinib resistance in HER2-positive breast cancer models
Presenter: Neil Conlon
Session: Poster Display session 1
Resources:
Abstract
2644 - Novel HDACi, MHY446, induces apoptosis via regulation of mitochondria-endoplasmic reticulum interaction in HCT116 human colorectal cancer cells
Presenter: Nam Deuk Kim
Session: Poster Display session 1
Resources:
Abstract
3085 - Dual inhibition of TGF-β and AXL as a novel treatment for colorectal cancer
Presenter: Davide Ciardiello
Session: Poster Display session 1
Resources:
Abstract
1314 - PARP inhibition enhances cisplatin sensitivity in cervical cancer by modulating β-catenin signaling
Presenter: Minakshi Mann
Session: Poster Display session 1
Resources:
Abstract
2417 - Synergistic effect of DSF combined treatment with cisplatin in atypical teratoid/rhabdoid tumors (AT/RT)
Presenter: Seung Ah Choi
Session: Poster Display session 1
Resources:
Abstract
1149 - Reactive oxygen species induced by OSU-A9 inhibit the growth of duodenal cancer and gastric cancer cells through dephosphorylating intranuclear pyruvate kinase muscle isozyme M2
Presenter: Li-Yuan Bai
Session: Poster Display session 1
Resources:
Abstract
1862 - New therapy for intrahepatic cholangiocarcinoma targeted to cancer associated fibroblasts
Presenter: Takahiro Yamanaka
Session: Poster Display session 1
Resources:
Abstract
782 - Macrophage-cancer cell fusion is mediated by Phosphatidylserine-CD36 receptor interaction and induced by ionizing radiation
Presenter: Ivan Shabo
Session: Poster Display session 1
Resources:
Abstract