Apparent diffusion coefficient as a prognostic biomarker of upper urinary tract cancer: a preliminary report

To investigate the role of apparent diffusion coefficient (ADC) as a biomarker reflecting the aggressiveness of upper urinary tract urothelial cell carcinoma (UUT-UCC). Thirty-four consecutive patients treated with nephroureterectomy for non-metastatic disease were prospectively enrolled in this study. ADC was compared with clinicopathological variables including Ki-67 labelling index (LI) and cancer-specific survival (CSS). The overall 3-year CSS rate was 82 % (median follow-up, 36 months). ADC was significantly lower in grade 3 disease than in grades 1-2 disease (P = 0.011) and significantly and inversely correlated with Ki-67 LI (rho = -0.59, P = 0.0002). Low ADCs (< 1.10 x 10(-3) mm(2)/s) were significantly associated with shorter CSS (P = 0.039). Multivariate analysis of preoperative variables identified ADC and MRI-based clinical T stage as independent indicators of shorter CSS; the patients were stratified into high-risk (8 patients with low ADC and at least clinical T3) and low-risk (26 patients with high ADC or not more than clinical T2) groups with 3-year CSS rates of 43 % and 93 % (P = 0.0003). Our preliminary data suggest the potential role of ADC as a quantitative biomarker reflecting the aggressiveness of UUT-UCC. ADC might be useful for preoperative risk stratification of UUT-UCC patients. aEuro cent Diffusion-weighted MRI offers new information about the aggressiveness of urinary tract cancers. aEuro cent The apparent diffusion coefficient acts as a quantitative biomarker for upper urinary tract cancers. aEuro cent ADC inversely correlates with immunohistochemical and histological grading of UUT-UCC. aEuro cent ADC offers a prognosis for UUT-UCC patients treated with nephroureterectomy.