Local staging of prostatic carcinoma: comparison of transrectal sonography and endorectal MR imaging.

OBJECTIVE: We compared the results of transrectal sonography and endorectal MR imaging in the local staging of prostatic carcinoma. SUBJECTS AND METHODS: 56 patients (mean age, 61.1 +/- 7.3 years) with the diagnosis of prostate cancer who by transrectal sonography had no evidence of gross extracapsular extension underwent endorectal coil MR imaging prior to radical prostatectomy. Imaging findings prospectively evaluated in each patient were cancer laterality, extracapsular extension, and seminal vesicle invasion. Twenty-one of 56 (38%) patients had extracapsular extension on final pathology. A total of 100 sides and five seminal vesicles were involved with cancer, and 27 sides (21 patients, six with bilateral extracapsular extension) demonstrated extracapsular extension. Imaging results were correlated with step-sectioned, radical prostatectomy pathologic data, and statistical analysis was expressed at a p = .05 level of significance. Retrospective readings of the images were used to construct receiver operating characteristic curves for the detection of extracapsular extension. RESULTS: For tumor laterality, transrectal sonography was compared with endorectal coil MR imaging for sensitivity (70% versus 97%; p < .001), specificity (58% versus 58%), positive predictive value (93% versus 95%) and negative predictive value (18% versus 70%). For extracapsular extension, transrectal sonography was compared with endorectal coil MR imaging for the entire prostate and individually for each side of the prostate. The respective results for sensitivity (48% versus 91%, p < .01 and 37% versus 78%, p < .005), specificity (71% versus 49% and 87% versus 73%), positive predictive value (50% versus 51% and 48% versus 48%), and negative predictive value (69% versus 90% and 81% versus 91%). The receiver operating characteristic analysis of retrospective data demonstrated endorectal coil MR imaging to be superior to transrectal sonography in the detection of extracapsular extension. The small number of seminal vesicles involved by cancer (n = 5) precluded meaningful comparisons between the imaging techniques. CONCLUSIONS: Endorectal coil MR imaging is more sensitive but less specific than transrectal sonography for detecting extracapsular extension of carcinoma of the prostate. Both procedures have low positive predictive values yet similarly high negative predictive values when each side of the prostate is assessed independently for extracapsular extension.

Preoperative urodynamic evaluation: does it predict the degree of urinary continence after radical retropubic prostatectomy?

Preoperative evaluation of voiding patterns and detailed urodynamic evaluation before radical retropubic prostatectomy was carried out in an attempt to identify patients at higher risk of developing urinary incontinence postoperatively. Ninety-two men, mean age 64 years (range 54-72), who completed 1 year of follow-up after radical retropubic prostatectomy for clinically localized adenocarcinoma of the prostate were included in the study. According to the preoperative urodynamic findings, patients were divided into two main groups: group 1 (n = 64) patients with normal urodynamic findings, and group 2 (n = 28) patients with abnormal urodynamic findings. The latter group was further subdivided according to the abnormality: detrusor instability (n = 12), weak sphincter mechanism (n = 9), and detrusor and sphincter instability (n = 7). The degree and incidence of urinary incontinence were evaluated in both groups at the 1-year follow-up visit. There was a substantial difference in the incidence of urinary incontinence between the two main groups with only 2 patients with incontinence in group 1 (3%) versus 11 patients in group 2 (39%). In addition, the incidence of incontinence in group 2 differed depending on the type of abnormality: the lower incidence occurred in patients with detrusor instability (17%) and the higher incidence in patients with both detrusor and sphincter instability (71%). Identification of sphincteric and bladder dysfunction preoperatively may indicate a high risk of urinary incontinence after radical prostatectomy.

Pathophysiology of urinary incontinence after radical prostatectomy.

To define the origin of urinary incontinence after radical prostatectomy urodynamic studies in 24 incontinent patients were compared to those of 13 continent patients. A statistically significant difference between incontinent and continent patients was found for the mean functional profile length (2.1 versus 3.6 cm., respectively, p less than 0.001), maximal urethral closure pressure (39 versus 74 cm. water, respectively, p less than 0.001) and maximal urethral closure pressure during voluntary contraction of the external sphincter (107 versus 172 cm. water, respectively, p less than 0.002). The differences among maximal detrusor pressure, initial bladder volume at which a detrusor contraction occurs, maximal cystometric capacity and residual urine were not statistically significant between the 2 groups. Urethral instability was present in 1 of the 24 incontinent patients (4.2%) and in none of the 13 continent patients, while detrusor instability was present in 6 (25%) and 3 (23.1%), respectively. Urethral and detrusor instability correlated poorly with incontinence (correlation coefficients 0.123 and 0.021, respectively). The appearance of the bladder outlet on voiding cystourethrography was correlated with urodynamic parameters and the presence or absence of continence. Tubularization above the level of the external sphincter was present in continent but absent in incontinent patients. Continence after radical prostatectomy is dependent upon sphincteric efficiency, which may be influenced by the anatomical configuration of the reconstructed bladder outlet and the integrity of the distal urethral sphincteric mechanism.