Prediction of seminal vesicle invasion in prostate cancer: incremental value of adding endorectal MR imaging to the Kattan nomogram.
OBJECTIVE
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.


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).


CONCLUSIONS
The addition of endorectal MR imaging contributes significant incremental value to the Kattan nomogram for predicting SVI.
Wang
Liang
L
Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10021, USA. wang6@mskcc.org
Hricak
Hedvig
H
Kattan
Michael W
MW
Chen
Hui Ni
HN
Kuroiwa
Kentaro
K
Eisenberg
Halley F
HF
Scardino
Peter T
PT
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006305:Health Status Indicators; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging / Q000379:methods*; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000473:pathology*; D012007:Rectum / Q000473:pathology; D015203:Reproducibility of Results; D012669:Seminal Vesicles / Q000473:pathology*; D012680:Sensitivity and Specificity