IMAGING

Endorectal and dynamic contrast-enhanced MRI for detection of local recurrence after radical prostatectomy
Casciani E, Polettini E, Carmenini E, Floriani I, Masselli G, Bertini L, Gualdi GF
Department of Radiology, University of Rome “La Sapienza,” U.O.C. Osservazione Medica, Ospedale M. G. Vannini of Rome and Istituto di Ricerche Farmacologiche “Mario Negri” of Milan, Italy
AJR, Am J Roentgenol 2008; 190:1187-1192

• Objective: The objective of our study was to evaluate the sensitivity and specificity of endorectal MRI combined with dynamic contrast-enhanced MRI to detect local recurrence after radical prostatectomy.
• Materials and Methods: A total of 51 patients who had undergone radical prostatectomy for prostatic adenocarcinoma 10 months to 6 years before underwent a combined endorectal coil MRI and dynamic gadolinium-enhanced MRI before endorectal sonographically guided biopsy of the prostatic fossa. The MRI combined with MR dynamic imaging results were correlated with the presence of recurrence defined as a positive biopsy result or reduction in prostate-specific antigen level after radiation therapy.
• Results: Overall data of 46 (25 recurred, 21 nonrecurred) out of 51 evaluated patients were analyzed. All recurrences showed signal enhancement after gadolinium administration and, in particular, 22 of 24 patients (91%) showed rapid and early signal enhancement. The overall sensitivity and specificity of MR dynamic imaging was higher compared with MRI alone (88%, [95% CI] 69–98% and 100%, 84–100% compared with 48%, 28–69% and 52%, 30–74%). MRI combined with dynamic imaging allowed better identification of recurrences compared with MRI alone (McNemar test: chi-square1 = 16.67; p = < 0.0001).
• Conclusion: MRI combined with dynamic contrast-enhanced MRI showed a higher sensitivity and specificity compared with MRI alone in detecting local recurrences after radical prostatectomy.
  
  
• Editorial Comment
  The authors of this manuscript confirms previous publications that has been shown that endorectal magnetic resonance imaging studies are of value for adequate characterization of local recurrence of prostate cancer after radical prostatectomy . Recurrent prostate cancer appears on dynamic contrast magnetic resonance imaging as an abnormal soft tissue mass with faster and stronger contrast enhancement and contrast washout. As we know the management of the patient with PSA recurrence after radical prostatectomy is debatable. In our daily practice, urologists and radiotherapists only sporadically require imaging in patients suspected of prostate cancer recurrence. Unless patient presents with positive digital rectal examination, they usually rely on PSA kinetics. Even when anastomotic biopsies document only benign tissue, the study of PSA doubling time is usually characteristic of the coexistence of residual cancerous cells. Local recurrence of prostate cancer is usually clinically suspected based on PSA kinetics and is usually characterized by a prolonged doubling time (>10 months) in a patient with a Gleason score of 2–7, a positive surgical margin, and absence of seminal vesicles or lymph nodes involvement. Currently these patients may be treated by means of radiation therapy. In our experience both color Doppler transrectal ultrasound and dynamic contrast enhanced MR, followed by TRUS-guided biopsies are useful modalities for early detection and confirmation of local recurrence of prostate cancer. These modalities however, should be used only when confirmation of local recurrence of prostate cancer is mandatory or in other words will modify the patient’s clinical management.

Dr. Adilson Prando
Chief, Department of Radiology and
Diagnostic Imaging
Vera Cruz Hospital
Campinas, São Paulo, Brazil
E-mail: aprando@mpc.com.br