Prediction of patient-specific risk and percentile cohort risk of pathological stage outcome using continuous prostate-specific antigen measurement, clinical stage and biopsy Gleason score

Huang, Y., S. Isharwal, A. Haese, F.K.H. Chun,D.V. Makarov, Z. Feng, M. Han, E. Humphreys, J.I. Epstein, A.W. Partin, and R.W. Veltri
BJU International, Vol. 107, no. 10, pp. 1562-1569. DOI: 10.1111/j.1464-410X.2010.09692.x

Objectives: To develop a ‘2010 Partin Nomogram’ with total prostate-specific antigen (tPSA) as a continuous biomarker, in light of the fact that the current 2007 Partin Tables restrict the application of tPSA as a non-continuous biomarker by creating ‘groups’ for risk stratification with tPSA levels (ng/mL) of 0–2.5, 2.6–4.0, 4.1–6.0, 6.1–10.0 and >10.0. • To use a ‘predictiveness curve’ to calculate the percentile risk of a patient among the cohort.

Patients and Methods: In all, 5730 and 1646 patients were treated with radical prostatectomy (without neoadjuvant therapy) between 2000 and 2005 at the Johns Hopkins Hospital (JHH) and University Clinic Hamburg-Eppendorf (UCHE), respectively. • Multinomial logistic regression analysis was performed to create a model for predicting the risk of the four non-ordered pathological stages, i.e. organ-confined disease (OC), extraprostatic extension (EPE), and seminal vesicle (SV+) and lymph node (LN+) involvement. • Patient-specific risk was modelled as a function of the B-spline basis of tPSA (with knots at the first, second and third quartiles), clinical stage (T1c, T2a, and T2b/T2c) and biopsy Gleason score (5–6, 3 + 4 = 7, 4 + 3 = 7, 8–10).

Results: The ‘2010 Partin Nomogram’ calculates patient-specific absolute risk for all four pathological outcomes (OC, EPE, SV+, LN+) given a patient’s preoperative clinical stage, tPSA and biopsy Gleason score. • While having similar performance in terms of calibration and discriminatory power, this new model provides a more accurate prediction of patients’ pathological stage than the 2007 Partin Tables model. • The use of ‘predictiveness curves’ has also made it possible to obtain the percentile risk of a patient among the cohort and to gauge the impact of risk thresholds for making decisions regarding radical prostatectomy.

Conclusion: The ‘2010 Partin Nomogram’ using tPSA as a continuous biomarker together with the corresponding ‘predictiveness curve’ will help clinicians and patients to make improved treatment decisions.

Wagner Faculty