[Staging of prostate cancer: value of the combined information of endorectal MRI, biopsy Gleason score, and preoperative PSA level].
To evaluate the predictive value of MR imaging criteria, the biopsy Gleason score, and preoperative PSA levels for differentiating between T2 and T3 prostate carcinomas. Endorectal MR images of 81 patients (median age: 65 years, range: 48 to 81 years) who had biopsy-proven prostate cancer and underwent a radical prostatectomy were analyzed retrospectively. The existence of different imaging features were recorded for each patient. A radiological analysis comprising all used imaging criteria was also performed for every patient. Optimal cut-off levels for the biopsy Gleason score and preoperative PSA levels were obtained using ROC analyses. Subsequently, a logistic regression analysis was performed to identify features which make a significant contribution to the prediction of the tumor stage. Histological examination showed that 24 patients (29.6 %) had a T3 tumor and 57 patients (70.4 %) had a T2 tumor. The mean preoperative PSA level was 9.4 ng/ml (+/- 7 ng/ml), and the median Gleason score was 6 with a range of 4 to 8. The radiological judgment comprising all imaging criteria led to a sensitivity of 54.2 % and specificity of 79 % for the detection of a T3 tumor. The obliteration of the rectoprostatic angle (regression coefficient B = 2.30; standard error (se) = 0.80; p = 0.002) and the biopsy Gleason score (B = 1.16; se = 0.3; p = 0.001) were the parameters with the highest independent predictive value for the diagnosis of an extracapsular tumor spread. The other radiological criteria and the preoperative PSA level were not statistically significant. A combination of the parameters "obliteration of the rectoprostatic angle" and "biopsy Gleason score" led to a sensitivity and specificity of 75 % and 79 %, respectively (existence of one parameter sufficient). The optimal cut-off value was a Gleason score of 7 for the differentiation between T2 and T3 prostate carcinomas. In our study, only the criteria "obliteration of the rectoprostatic angle" and "biopsy Gleason score" were of predictive value for the diagnosis of a T3 prostate carcinoma. The other MR imaging criteria and the preoperative PSA levels had no additional benefit.