Can pretreatment ADC values predict recurrence of bladder cancer after transurethral resection?

The aim of this retrospective study was to investigate the association between the pretreatment apparent diffusion coefficient (ADC) value and recurrence of bladder cancer after transurethral resection.

Patients with superficial bladder cancer were identified. Mean ADC values of the tumors were compared between patients with and without recurrence following trans-urethral resection. A receiver-operator characteristic curve was used for determining the optimal cutoff ADC value. Univariate and multivariate analyses were used to determine the effect of ADC values and other factors.

With a mean follow-up period of 25 months, bladder cancer recurred in 14 of 44 patients (32%). The mean ADC value of tumors in patients with recurrence was lower than in those without recurrence (1.08 mm2/s vs. 1.28×10(-3) mm2/s; p=0.003). The optimal cutoff ADC value for predicting recurrence was determined to be 1.12×10(-3) mm2/s. A modest and significant negative correlation was observed between the ADC values and tumor size (r=-0.436, p=0.008). After adjustment for size and risk groups, an ADC value equal to or less than the optimal cutoff remained a significant predictor of recurrence (odds ratio 6.3, 95% CI 1.23-32.2, p=0.027).

Pretreatment ADC values may be an independent predictor of bladder cancer recurrence.