B54: Dynamic contrast-enhanced MRI to predict treatment response to neoadjuvant chemotherapy in muscle invasive bladder cancer: MARBLE study

Rachel Pearson1,2,Emily Fitzgerald3,Pete Thelwall4,Jim Snell2,Jill McKenna2,Piotr Pieniazek5,Rhona McMenemin2,Ashraf Azzabi2,Ian Pedley2,Rakesh Heer1,Ross Maxwell1,Ruth Plummer1,2,Herbie Newell1,John Frew2

1Northern Institute for Cancer Research, Newcastle upon Tyne, UK,2Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK,3Newcastle University Medical School, Newcastle upon Tyne, UK,4Newcastle MR Centre, Campus of Ageing and Vitality, Newcastle upon Tyne, UK,5Department of Radiology, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK

Presenting date: Tuesday 3 November

Background

 

Functional magnetic resonance imaging (MRI) is emerging as a promising tool to detect early treatment responses. MARBLE is a prospective feasibility study of patients with muscle invasive bladder cancer who are planned to receive neoadjuvant chemotherapy. The aims of the study are to develop a scanning protocol which can determine if semi-quantitative and quantitative MRI parameters differ between treatment responders and non-responders, and if these parameters could be used with Ki67 score as a surrogate response biomarker. To our knowledge there is little reported on bladder cancer imaging biomarkers. Image acquisition is variable and there is no standard method of data analysis.  Preliminary dynamic contrast-enhanced MRI data will be presented.

Method

 

Serial diffusion weighted and dynamic contrast-enhanced (DCE) scans were acquired pre-treatment, and after one and two cycles of chemotherapy.  Initial analysis comprised fitting the Tofts extended model to whole tumour region of interests to obtain estimates of Ktrans, Vp and Ve. Arterial input function was obtained from a population-based AIF due to considerable variation in results obtained from the external iliac artery.

Results

 

Of the seven patients who attended for pre-treatment DCE scans, 5/7 were female and mean age 57 years (range 37-68). All patients had T3 or T4 disease and 2/7 were node positive.  Mean Ktrans 0.37 (range 0.18-0.65), Kep 0.94 (range 0.44-1.85), Ve 0.45 (range 0.16-0.8). 4/7 patients have attended for one or both response scans and this data will be presented at the conference.

Conclusion

 

DCE-MRI data in bladder cancer patients has been acquired and analysed to obtain kinetic parameters. These may have prognostic, predictive and surrogate response biomarker potential. The study will recruit a further four patients for DCE response assessment at which point definitive statistical analysis will be performed.