Phased array magnetic resonance imaging for staging clinically localized prostate cancer

Objective. Patients suffering from intra-capsular prostate cancer (T1 - 2, N0, M0) are potential candidates for curative treatment by radical prostatectomy or radiation therapy. Curative intended therapy is frequently associated with substantial side effects, which makes accuracy of preoperative staging important. However, up to 40% of the patients with clinically localized disease turn out to be under-staged and should not have been subjected to curative surgery. The aim of this study was to assess the value of preoperative phased array MRI staging in patients who are candidates for radical prostatectomy. Material and methods. Ninety-five potential candidates for radical prostatectomy suspected of suffering from clinical prostate cancer underwent pre-diagnostic and pre-operative staging by magnetic resonance imaging ( MRI). The results were compared with the postoperative pathological findings including evidence of extra-capsular extension (ECE) of the tumor. The MRI results were not taken into consideration when staging the patients preoperatively or offering treatment. Radical prostatectomy was performed within a few weeks after MRI. Results. In 48 patients the diagnostic biopsy did not detect carcinoma but benign hyperplasia of the prostate (BPH), while 9 patients had T3 disease. Thirty-eight patients had clinically localized prostate cancer and underwent radical prostatectomy. In 16 cases (42%) ECE was postoperatively proven by the pathologist, while only 22 (58%) of the patients suffered from true localized prostate cancer. The sensitivity and specificity of MRI detecting ECE were 24% and 86% respectively, while the positive and negative predictive value of MRI with regard to ECE were only 57% and 61% respectively. Conclusions. Phased array MRI did not in its present form provide the necessary accuracy in preoperative staging in clinically localized prostate cancer patients.