Published in:
01-03-2015
Mass-like peripheral zone enhancement on CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer
Published in: Abdominal Radiology | Issue 3/2015
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Purpose
To determine whether focal peripheral zone enhancement on routine venous-phase CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.
Materials and methods
IRB approval was obtained and informed consent waived for this HIPAA-compliant retrospective study. Forty-three patients with higher-grade prostate cancer (≥Gleason 4 + 3) and 96 with histology-confirmed lower-grade (≤Gleason 3 + 4 [n = 47]) or absent (n = 49) prostate cancer imaged with venous-phase CT comprised the study population. CT images were reviewed by ten blinded radiologists (5 attendings, 5 residents) who scored peripheral zone enhancement on a scale of 1 (benign) to 5 (malignant). Mass-like peripheral zone enhancement was considered malignant. Likelihood ratios (LR) and specificities were calculated. Multivariate conditional logistic regression analyses were conducted.
Results
Scores of “5” were strongly predictive of higher-grade prostate cancer (pooled LR+ 9.6 [95% CI 5.8–15.8]) with rare false positives (pooled specificity: 0.98 [942/960, 95% CI 0.98–0.99]; all 10 readers had specificity ≥95%). Attending scores of “5” were more predictive than resident scores of “5” (LR+: 14.7 [95% CI 5.8–37.2] vs. 7.6 [95% CI 4.2–13.7]) with similar specificity (0.99 [475/480, 95% CI 0.98–1.00] vs. 0.97 [467/480, 95% CI 0.96–0.99]). Significant predictors of an assigned score of “5” included presence of a peripheral zone mass (p < 0.0001), larger size (p < 0.0001), and less reader experience (p = 0.0008). Significant predictors of higher-grade prostate cancer included presence of a peripheral zone mass (p = 0.0002) and larger size (p < 0.0001).
Conclusion
Focal mass-like peripheral zone enhancement on routine venous-phase CT is specific and predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.