TABLE V.
SENSITIVITY ANALYSIS TO DETERMINE WHETHER THE CHOICE OF CUT-OFF VALUE FOR LOW TPSA MIGHT INFLUENCE OUR FINDINGS
| PSA cut-off ng/ml | No. Patients | No. BCR | Risk (%) | Base model | Base model 1 fPSA and hK2 | Increment |
|---|---|---|---|---|---|---|
| 8 | 226 | 18 | 8 | 0.771 | 0.840 | 0.069 |
| 9 | 261 | 21 | 8 | 0.760 | 0.836 | 0.076 |
| 10 | 294 | 28 | 10 | 0.764 | 0.815 | 0.051 |
| 11 | 325 | 36 | 11 | 0.777 | 0.828 | 0.051 |
| 12 | 339 | 39 | 12 | 0.782 | 0.829 | 0.047 |
| 13 | 356 | 44 | 12 | 0.785 | 0.817 | 0.032 |
| 14 | 371 | 48 | 13 | 0.790 | 0.804 | 0.014 |
| 15 | 388 | 51 | 13 | 0.778 | 0.771 | −0.007 |
| 20 | 426 | 65 | 15 | 0.776 | 0.780 | 0.004 |
| All pt. | 461 | 90 | 20 | 0.806 | 0.802 | −0.004 |
The tPSA cut-off was varied (8–20 ng/ml) and corresponding concordance indices computed. The nomogram probability of BCR was used as the covariate.
BCR, biochemical recurrence; fPSA, free prostate-specific antigen; hK2, human glandular kallikrein 2.