803 Risk stratification model for lymphovascular invasion, pathological T stage, lymph node involvement, and c-reactive protein predicts high-risk patients - who are candidate for adjuvant chemotherapy in upper urinary tract urothelial cancer

effect of the ADC on CSS fitted a linear model, and there was no abrupt increase in the hazard ratio for CSS. With the cut-off ADC determined at 1.10 x 10 mm/sec, 40 (62.5%) and 24 patients (37.5%) were classified into the low and high ADC1 groups, respectively, and 38 (59.4%) and 26 patients (40.6%) were classified into the low and high ADC2 groups, respectively. Interobserver agreement between the readers was good (k 1⁄4 0.71) for this ADC stratification. Low ADCs were significantly associated with shorter CSS regardless of the ADC reader (5-y CSS rate: ADC1 low vs. high, 70% vs. 90%; P 1⁄4 0.024, ADC2 low vs. high, 70% vs. 89%; P 1⁄4 0.036). Multivariate analysis revealed that ADC can serve as an independent pre-operative indicator of shorter CSS among age, gender, tumor location, clinical T stage, and ADC. CONCLUSIONS: ADC value reflects the clinical aggressiveness of UTUC and predicts survival after the operation, regardless of the ADC reader. ADC value might be a useful imaging biomarker for a preoperative prognostic stratification.