Receiver Operating Characteristic for Time Gradient of Total PSA Concentrations after Coakley et al.

ROC constructed for PSA time gradient as test parameter and MRI/MRSI as reference standard
Figure ROC7: Receiver Operating Characteristic for total PSA time gradient (tPSA time gradient, tPSA gradient, also called "PSA velocity", unit ng/L per year) as test variable and MRI/MRSI as reference standard. Area under the receiver operating characteristic AUC = 0.67. A PSA time gradient of >0.75 ng/mL/year (arrow) identifies those men with radiologically progressive disease with a true-positive fraction of 0.71 and a false-positive fraction of 0.39.

Patient characteristics:
69 men with biopsy-proven prostate cancer being managed by watchful waiting, who underwent serial endorectal MRI/MRSI and who had contemporaneous serial PSA measurements. The mean (range) follow-up was 392 (294 ... 571) days. A panel of 3 experienced readers reviewed the initial and follow-up MRI/MRSI studies, and classified findings of prostate cancer as stable or progressive. Another reader assessed BPH [Benign Prostate Hyperplasia] by calculating total gland and central gland volumes on all studies.

Source: Coakley FV, Chen I, Qayyum A, Westphalen AC, Carroll PR, Hricak H, Chen MH, Kurhanewicz J. Validity of prostate-specific antigen as a tumour marker in men with prostate cancer managed by watchful-waiting: correlation with findings at serial endorectal magnetic resonance imaging and spectroscopic imaging. BJU Int. 2007 Jan;99(1):41-5.

Note: This paper emphasizes the value of serial MRI/MRSI. Baseline MRI/MRSI (i.e. taken once as opposed to at a series of times) appear to be not correlated with serial PSA values as has been pointed out by Cabrera et al., 2008 [Cabrera AR, Coakley FV, Westphalen AC, Lu Y, Zhao S, Shinohara K, Carroll PR, Kurhanewicz J. Prostate cancer: is inapparent tumor at endorectal MR and MR spectroscopic imaging a favorable prognostic finding in patients who select active surveillance? Radiology. 2008 May;247(2):444-50].

The MRI and MRSI ROCs of Fig. ROC4 are shown here for comparison. Note that -unlike for the tPSA time gradient model- the reference standard for the MRI/MRSI models are whole-mount step-section pathology maps.

back to Figure ROC4.
Version: July 31, 2008
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Joachim Gruber