RESUMO
OBJECTIVE: The aims of this study were to evaluate the role of 3 tesla multiparametric magnetic resonance imaging (3TmMRI) without endorectal coil in the detection of radiographic local recurrences (rLRs) in a contemporary cohort of patients with prostate cancer who presented with biochemical recurrence after radical prostatectomy (RP) with low prostate-specific antigen (PSA) levels, and to identify clinical parameters associated with the 3TmMRI findings. MATERIALS AND METHODS: Between 2009 and 2013, 57 patients with biochemical recurrence of prostate cancer after RP who were considered for salvage radiation therapy (SRT) were included. 3TmMRI with T2-weighted imaging, diffusion weighted imaging (DWI) and dynamic contrast-enhanced imaging without endorectal coil was carried out in all patients before treatment. RESULTS: In 14 out of 57 patients (24.56%) local recurrence was detected through 3TmMRI. Median pre-SRT PSA was 0.40 ng/ml (interquartile range 0.30-2.05 ng/ml). The recurrence was perianastomotic in eight out of 14 patients (57.14%) and retrovesical in six out of 14 patients (42.86%). The median size of the local recurrence was 15.2 mm (range 8.0-46.0 mm). The probability of rLR was significantly higher in patients with PSA levels above 0.5 ng/ml [adjusted odds ratio (OR) 6.25, 95% confidence interval (CI) 1.27-30.79, p = 0.02] or PSA doubling time (PSADT) over 14 months (adjusted OR 7.12, 95% CI 1.40-36.25, p = 0.01). CONCLUSIONS: This is the first study to find a significant relationship between the PSADT and the rLR through MRI. Patients with PSADT longer than 14 months or pre-SRT PSA above 0.5 ng/ml benefited most from 3TmMRI. Its routine use could have significant clinical implications for SRT.
