Early localization of recurrent prostate cancer after prostatectomy by endorectal coil magnetic resonance imaging

Introduction: To evaluate the ability of endorectal coil (e-coil) magnetic resonance imaging (MRI) to identify early prostatic fossa recurrence after radical prostatectomy. Materials and methods: We identified 187 patients from 2005-2011 who underwent e-coil MRI with dynamic gadolinium-contrast enhancement followed by transrectal ultrasound (TRUS) guided prostatic fossa biopsy for possible local prostate cancer recurrence. For analysis, local recurrence was defined as a negative evaluation for distant metastatic disease with a positive prostatic fossa biopsy, decreased prostate-specific antigen (PSA) following salvage radiation therapy, or increased lesion size on serial imaging. Results: Local recurrence was identified in 132 patients, with 124 (94%) detected on e-coil MRI. The median PSA was 0.59 ng/mL (range < 0.1-13.1), and median lesion size on MRI was 1 cm. The sensitivity of MRI was 91%, with a specificity of 45%. The positive predictive value was 85%, with a negative predictive value of 60%. For patients with a PSA < 0.4 ng/mL the sensitivity of e-coil MRI was 86%. When a lesion was identified on MRI, the positive biopsy rate was 65% and lesion size was a significant predictor of positive biopsies. The positive biopsy rates were 51%, 74%, and 88% when the lesion was < 1 cm, 1 cm-2 cm, or > 2 cm, respectively (p = 0.0006). Conclusions: E-coil MRI has a high level of sensitivity in identifying local recurrence of prostate cancer following radical prostatectomy, even at low PSA levels. E-coil MRI should be considered as the first imaging evaluation for biochemical recurrence for identifying patients suitable for localized salvage therapy.