Should the therapeutic approach to prostate cancer with seminal vesicle invasion be reviewed: Improving functional results without diminishing oncological outcome?

Seminal vesicle invasion in prostate cancer: evaluation by using multiparametric endorectal MR imaging

PURPOSE

To retrospectively evaluate the diagnostic performance of multiparametric endorectal magnetic resonance (MR) imaging, including T2-weighted, diffusion-weighted (DW), and dynamic contrast material-enhanced (DCE) MR techniques, for the diagnosis of seminal vesicle invasion (SVI) and to determine the incremental value of DW MR and DCE MR images.

MATERIALS AND METHODS

This retrospective HIPAA-compliant study was approved by the institutional review board, with a waiver of informed consent. The study included 131 patients (mean age, 68 years; range, 43-75 years) who underwent endorectal MR imaging before radical prostatectomy between January 2007 and April 2010. Two radiologists (A: experienced, B: less experienced) estimated the likelihood of SVI by using a five-point ordinal scale in three image-viewing settings: T2-weighted images alone; T2-weighted and DW MR images; and T2-weighted, DW MR, and DCE MR images. Sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve (AUC) were calculated. Confidence intervals estimated with bootstrapping and the McNemar test or Fisher exact test were used to compare sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

Of the 131 patients, 23 (17.6%) had SVI identified after surgery. Review of T2-weighted MR images alone resulted in high specificity (93.1% and 93.6%, for radiologists A and B, respectively) and high negative predictive value (94.8% and 94.0%) but moderate sensitivity (59% and 52%) and positive predictive value (52% and 50%). Review of T2-weighted and DW MR images significantly improved specificity (96.6% [P = .02] and 98.3% [P = .003]) and positive predictive value (70% [P < .05] and 79% [P < .05]) without significantly improving AUC. Additional review of DCE MR images did not yield further incremental improvement.

CONCLUSION

Additional review of DW MR images improves specificity and positive predictive value in SVI detection compared with reviewing T2-weighted images alone. Addition of DCE MR images to this combination, however, does not provide incremental value for diagnosis of SVI.

Prediction of Seminal Vesicle Invasion in Prostate Cancer: Incremental Value of Adding Endorectal MR Imaging to the Kattan Nomogram

PURPOSE

To retrospectively determine whether endorectal magnetic resonance (MR) imaging findings contribute incremental value to the Kattan nomogram for predicting seminal vesicle invasion (SVI) in patients with prostate cancer.

MATERIALS AND METHODS

The institutional review board issued a waiver of authorization, which included a waiver of informed consent, for this HIPAA-compliant study. From October 2000 through January 2005, 573 patients (mean age, 58.3 years; age range, 36-86 years) underwent endorectal MR imaging before prostate cancer surgery. The endorectal MR imaging results had been prospectively interpreted by seven radiologists, and the likelihood of SVI was retrospectively scored on the basis of radiologists' written reports. MR imaging findings, individual clinical variables (serum prostate-specific antigen [PSA] level, Gleason grade, clinical stage, greatest percentage of cancer in all biopsy cores, percentage of positive cores in all biopsy cores, and perineural invasion), and the Kattan nomogram were evaluated with respect to SVI prediction; surgical pathologic analysis was used as the reference standard. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed.

RESULTS

At pathologic analysis, 28 (4.9%) of 573 patients had SVI. At univariate analysis, endorectal MR imaging results and all clinical variables except the percentage of positive biopsy cores were significantly associated with SVI (P<.02); endorectal MR imaging (0.76) had a larger area under the ROC curve (AUC) than any clinical variable (0.62-0.73). At multivariate analysis, endorectal MR imaging results, Gleason grade, PSA level, and the percentage of cancer in all biopsy cores were significantly associated with SVI (P<or=.02). The Kattan nomogram plus endorectal MR imaging (0.87) had a significantly larger (P<.05) AUC than either endorectal MR imaging alone (0.76) or the Kattan nomogram alone (0.80).

CONCLUSION

The addition of endorectal MR imaging contributes significant incremental value to the Kattan nomogram for predicting SVI.