797P - Prognostic relevance of imaging bone metastases by whole body diffusion-weighted magnetic resonance imaging (WBDWI) in metastatic castration-resist...

Date 27 September 2014
Event ESMO 2014
Session Poster Display session
Topics Prostate Cancer
Staging Procedures (clinical staging)
Basic Principles in the Management and Treatment (of cancer)
Imaging
Presenter Raquel Perez Lopez
Citation Annals of Oncology (2014) 25 (suppl_4): iv255-iv279. 10.1093/annonc/mdu336
Authors R. Perez Lopez1, D. Lorente1, J. Mateo1, M.D. Blackledge2, S. Sideris1, Z. Zafeiriou1, A. Smith1, R. Ferraldeschi1, P. Rescigno1, M. Rata2, U. Naumann1, D.J. Collins2, G. Attard1, M.O. Leach2, D. Koh2, J.S. De Bono1, N. Tunariu1
  • 1Drug Development Unit, The Institute of Cancer Research & The Royal Marsden NHS Trust, SM2 5PT - Sutton/GB
  • 2Radiotherapy And Imaging, The Institute of Cancer Research & The Royal Marsden NHS Trust, SM2 5PT - Sutton/GB

Abstract

Aim

Standard CT and bone scans provide inadequate assessment of the extent of bone disease in mCRPC. WBDWI is a magnetic resonance technique with high sensitivity and specificity for detecting bone metastases, allowing quantification of disease volume and assessment of tumor cellularity by assessing apparent diffusion coefficients (ADC). We hypothesized that volume of bony disease, quantified by DWI assessment, is a prognostic biomarker of overall survival in mCRPC.

Methods

mCRPC patients with bone metastases and WBDWI performed on a 1.5-T Siemens scanner between Jun-2010 and Jan-2013, prior to starting a new anticancer therapy, were selected. WBDWI and ADC maps were used to delineate volume of bone metastases (VBM) and represent ADC values on histograms. Clinical data were collected and correlated with VBM and ADC histogram variables. Survival (OS) analysis was performed with Kaplan-Meier analysis and Cox regression (SPSS). Correlations were calculated with Spearman ?s rho coefficient (r).

Results

43 patients were included in the study. Median OS was 12.9 months (m) (95%CI 8.7 – 16.1m). Median VBM was 503.1 mL (range: 5.6 to 2242 mL). Baseline CTC counts and bone scan index (BSI) were available for 21 (65.6%), and 32 (74.4%) patients respectively. VBM as a continuous variable was inversely associated with OS (p = 0.032). VBM with ADC > 775 µm2/s showed a significant inverse correlation with OS (p = 0.037), whereas VBM with ADC < 775 µm2/s, which overlaps with normal bone marrow, did not correlate with OS. VBM significantly correlated with other established prognostic factors: hemoglobin (r = -0.521, p < 0.001); PSA (r = 0.431, p = 0.004); LDH (r = 0.466, p = 0.002), alkaline phosphatase (r = 0.518, p < 0.001), CTC count (r = 0.596, p = 0.004) and BSI (r = 0.565, p = 0.001).

Conclusions

Volume of bone metastases estimated by WBDWI associates with OS in mCRPC. Studies of ADC value distribution provide valuable functional information on mCRPC.

Disclosure

All authors have declared no conflicts of interest.