Value of diffusion-weighted imaging for assessing site-specific response of advanced ovarian cancer to neoadjuvant chemotherapy: Correlation of apparent diffusion coefficients with epithelial and stromal densities on histology
Issue title: Metastasis Imaging: Current Concepts and Future Challenges
Guest editors: Christina Messiou and Nandita M. de Souza
Affiliations: [a] CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK | [b] Experimental Pathology Laboratory, London Research Institute, Cancer Research UK, London, UK | [c] Gynaecological Oncology, Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK | Cancer Research UK Clinical Magnetic Resonance Research Group, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT, UK
Correspondence:
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Corresponding author: Dr. Nandita M. deSouza, CR-UK and EPSRC Cancer Imaging Centre, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Downs Road, Surrey SM2 5PT, United Kingdom. Tel.: +44 (0)20 8661 3289; Fax: +44 (0)20 8661 0846; E-mail: nandita.desouza@icr.ac.uk.
Abstract: This study correlates apparent diffusion coefficients (ADCs) from Diffusion-weighted Imaging (DWI) in primary ovarian tumours and their omental metastases following neoadjuvant chemotherapy with epithelial and stromal densities in order to relate them to histological composition. Eight patients underwent DWI at 1.5 T with four b-values (0, 600, 900, and 1,050 s/mm2) at baseline and after one and three cycles of platinum-based chemotherapy. Mean ADCs were calculated at each timepoint from solid tumour at ovarian and omental sites. Specimens from 15 corresponding lesions (8 ovarian, 7 omental), obtained at interval debulking surgery, were stained immunohistochemically to quantify epithelial and stromal components. End-of-treatment ADC was correlated with epithelial and stromal densities. Longitudinal changes in ADC with treatment were compared between primary and metastatic lesions using parametric tests. No baseline differences in ADC between primary and metastatic sites were seen. Mean ADC increased significantly from baseline after both first and third cycle (P < 0.001) in both ovarian and omental lesions. ADC and total epithelial plus stromal density (lesion cellularity) were negatively correlated in ovarian lesions (r= −0.79, P=0.02) but not in omental metastases or when both sites were considered together. However, ADC and epithelial density were negatively correlated in ovarian (r=− 0.78, P=0.02) and omental lesions (r=−0.75, P=0.04) and when both sites were considered together (r=−0.77, P< 0.001). There was no significant correlation between ADC and stromal density. Thus ADC reflects mainly epithelial content in advanced ovarian cancer and is not solely a function of lesion cellularity.
