Is magnetic resonance imaging necessary in the staging of prostate cancer?

Objective: To evaluate the necessity of using magnetic resonance imaging (MRI) in the staging of patients with clinically localized prostate cancer. Methods: Sixty-one patients with prostate cancer were evaluated with MRI for preoperative staging with a conventional body-coil (Siemens Magnetom, 1.0 Tesla superconducting system). Twenty-nine patients underwent radical prostatectomy for presumed clinically localized disease. Of those, 17 were staged both with MRI and computerized tomography (CT). The remaining patients were staged with CT alone. MRI and CT findings, and the final pathologic staging of patients are reviewed. Results: On pathological examination of the surgical specimens, the tumor was found to extend beyond the prostate in 7 patients (41%). Among the 17 patients who were operated, extraprostatic extension (EPE) was detected accurately in 3 patients with MRI (sensitivity 20%, specificity 92%, accuracy 70.5%). No metastatic lymph nodes were detected on the basis of MRI (sensitivity 0%, specificity 93%, accuracy 88.2%). In 1 patient EPE was correctly identified by CT (sensitivity 14%, specificity 100%, accuracy 64.7%). Conclusion: Neither MRI with conventional body-coild nor CT are sufficient to indicate local extension of disease in clinically localized prostate cancer.