Table 2.
Performance of prediction rules among discovery and validation biopsy cohorts.
| Discovery (n=610) | Validation (n=922) | |||||||
|---|---|---|---|---|---|---|---|---|
| Rule | Specificity1 | Overall | Confirmatory Biopsy | Subsequent Biopsy | ||||
| Sensitivity (95% CI) | Specificity (95% CI) | Sensitivity (95% CI) | Specificity (95% CI) | Sensitivity (95% CI) | Specificity (95% CI) | |||
| R1: clinical only | Biopsy if clinical score (CS)* > 0.083 | 17% | 97% (95–99%) | 15% (11–18%) | 99% (98–100%) | 7% (4–10%) | 93% (88–98%) | 22% (16–26%) |
| R2: clinical then PHI | Biopsy if (CS>0.185) or (CS>0.05 and phi>27.6) | 27% | 90% (86–93%) | 28% (24–33%) | 95% (91–98%) | 23% (19–28%) | 83% (76–90%) | 33% (27–39%) |
| R3: clinical + PHI(linear) | Biopsy if CS + phi score** > 0.092 | 21% | 93% (90–96%) | 21% (17–24%) | 97% (94–99%) | 12% (8–16%) | 88% (81–93%) | 28% (22–33%) |
| R4:clinical or PHI | Biopsy if (CS > 0.12) or (phi>39.0) | 25% | 93% (89–96%) | 22% (18–26%) | 95% (91–98%) | 16% (12–20%) | 90% (83–95%) | 27% (21–33%) |
1
Sensitivity fixed at 95% for performance assessment based on fitted model coefficients for discovery cohort.
*
CS = expit (-1.77 + 0.80*log PSA + 0.19*Initial Biopsy + 0.03*Age + 0.06*BMI + 0.75*Prior Cores ratio ≥ 0.2 – 1.57*Neg Bx ≥ 2 – 1.29*log prostate volume)
**
CS + phi = expit (-4.47 + 0.74*log phi + 0.48*log PSA + 0.18*Initial Biopsy + 0.033*Age + 0.05 * BMI + 0.68 * Prior Cores ratio ≥ 0.2 – 1.42 * Neg Bx ≥ 2 – 1.07 * log prostate volume)