Omer Jalil, Abstract Co-Author: Nothing to Disclose

Balaji Ganeshan PhD, Presenter: Scientific Director, TexRAD Limited

Asim Afaq FRCR, Abstract Co-Author: Nothing to Disclose

Tan Arulampalam, Abstract Co-Author: Nothing to Disclose

Darren Boone MRCS, FRCR, Abstract Co-Author: Nothing to Disclose

Ashley McAllister Groves MBBS, Abstract Co-Author: Investigator, GlaxoSmithKline plc Investigator, General Electric Company Investigator, Siemens AG

To assess the prognostic significance of heterogeneity of rectal tumours on MRI, quantified by texture analysis in patients treated with neoadjuvant chemoradiation.

Retrospective analysis of 29 consecutive patients with rectal cancer with 1.5T rectal MRI pretreatment and 6 weeks post neoadjuvant chemoradiation Tumor heterogeneity was quantified on the T2 axial small field of view image with the largest tumour diameter, using TexRAD, a commercially available software. This used filtration-histogram based texture analysis technique to extract pixel size based (fine, medium, coarse) features and quantified histogram parameters including Kurtosis (K), skewness (S) and normalized standard-deviation (SDn). Kaplan-Meier analysis compared texture parameters with overall (OS) and disease-free survival (DFS). Mean follow-up was 39.4 months.  

4 patients showed complete pathological response. Median OS and DFS was 52.3 (95% CI: 40.5-64.0) and 37.3 (95% CI: 15.3-59.2) months respectively. On pre-treatment MR, lower SDn and higher K/S were significantly associated with reduced OS for different texture scales (medium scale: SDn <0.52, p=0.0007; K>1.58, p=0.017; S>0.9, p=0.018) and lower SDn and K were significantly associated with reduced DFS for different texture scales (medium texture scale: SDn <0.52, p=0.0068; K<-0.27, p=0.0195). At 6 weeks post treatment, an increase in SDn and decrease in K/S were associated with poor prognosis (medium texture scale: SDn >8.1%, p=0.0431; K<-50.8%, p=0.018; S<-0.12, p=0.041). Pathological response, tumor stage, nodal stage and circumferential resection margin status) were not significant predictors of OS and DFS.                

Pre-treatment and 6 weeks post chemoradiation rectal tumor MRI texture parameters were associated with reduced OS and DFS. Changes in biological parameters such as tissue hypoxia may be reflected by changes in tumour heterogeneity

Tumour heterogeneity on pretreatment and 6 weeks post chemoradiation rectal MRI may be useful in predicting poorer clinical outcome and provide opportunity to target those patients suited for intensive management.

Jalil, O, Ganeshan, B, Afaq, A, Arulampalam, T, Boone, D, Groves, A, MRI Tumor Heterogeneity as a Potential Prognostic Imaging Biomarker in Patients with Rectal Cancer Treated with Neoadjuvant Chemoradiotherapy.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14009712.html