Table 3.
The ability of various combinations of preoperative parameters of interest to predict BCR and metastatic recurrence, in a multivariable analysisa
| Variable | SHR (95% CI) | p value | AIC | C-index (95% CI) | ||
|---|---|---|---|---|---|---|
| BCR | Model 1 | %GP4/5 | <0.0001 | 1512 | 0.77 (0.72–0.82) | |
| 0–20 | 1.00 (Ref.) | – | ||||
| 30–75 | 5.03 (3.31–7.63) | <0.0001 | ||||
| 100 | 7.11 (4.08–12.37) | <0.0001 | ||||
| Diameter (mm) | 1.03 (1.01–1.05) | 0.003 | ||||
| Model 2 | %GP4/5 | <0.0001 | 1505 | 0.78 (0.73–0.82) | ||
| 0–20 | 1.00 (Ref.) | – | ||||
| 30–75 | 4.66 (3.05–7.10) | <0.0001 | ||||
| 100 | 6.02 (3.34–10.85) | <0.0001 | ||||
| Diameter (mm) | 1.02 (1.00–1.05) | 0.031 | ||||
| PSA density (ng/ml/ml) log | 1.45 (1.11–1.89) | 0.006 | ||||
| Model 3 | %GP4/5 | <0.0001 | 1500 | 0.77 (0.73–0.82) | ||
| 0–20 | 1.00 (Ref.) | – | ||||
| 30–75 | 4.39 (2.88–6.69) | <0.0001 | ||||
| 100 | 7.01 (4.87–11.79) | <0.0001 | ||||
| MCCL (mm) | 1.14 (1.08–1.20) | <0.0001 | ||||
| Model 4 | %GP4/5 | <0.0001 | 1493 | 0.78 (0.74–0.83) | ||
| 0–20 | 1.00 (Ref.) | – | ||||
| 30–75 | 4.05 (2.64–6.19) | <0.0001 | ||||
| 100 | 5.83 (3.34–10.18) | <0.0001 | ||||
| MCCL (mm) | 1.12 (1.06–1.19) | <0.0001 | ||||
| PSA density (ng/ml/ml) log | 1.46 (1.12–1.89) | 0.004 | ||||
| Metastatic recurrence | Model 5 | %GP4/5 | <0.0001 | 512 | 0.86 (0.79–0.91) | |
| 0–30 | 1.00 (Ref.) | – | ||||
| 40–75 | 11.10 (4.64–26.56) | <0.0001 | ||||
| 100 | 12.20 (4.16–35.72) | <0.0001 | ||||
| Diameter (mm) | 1.05 (1.02–1.08) | <0.0001 | ||||
| Model 6 | %GP4/5 | <0.0001 | 513 | 0.86 (0.80–0.92) | ||
| 0–30 | 1.00 (Ref.) | – | ||||
| 40–75 | 10.68 (4.44–25.62) | <0.0001 | ||||
| 100 | 11.42 (3.80–34.32) | <0.0001 | ||||
| Diameter (mm) | 1.05 (1.02–1.08) | 0.0004 | ||||
| PSA density (ng/ml/ml) log | 1.18 (0.81–1.71) | 0.37 | ||||
| Model 7 | %GP4/5 | <0.0001 | 511 | 0.85 (0.78–0.91) | ||
| 0–30 | 1.00 (Ref.) | – | ||||
| 40–75 | 9.70 (4.08–23.06) | <0.0001 | ||||
| 100 | 14.02 (5.22–37.63) | <0.0001 | ||||
| MCCL (mm) | 1.20 (1.10–1.30) | <0.0001 | ||||
| Model 8 | %GP4/5 | <0.0001 | 512 | 0.85 (0.79–0.92) | ||
| 0–30 | 1.00 (Ref.) | – | ||||
| 40–75 | 9.06 (3.78–21.66) | <0.0001 | ||||
| 100 | 12.63 (4.59–34.74) | <0.0001 | ||||
| MCCL (mm) | 1.19 (1.09–1.29) | <0.0001 | ||||
| PSA density (ng/ml/ml) log | 1.29 (0.92–1.80) | 0.13 |
AIC = Akaike information criterion; BCR = biochemical recurrence; CI = confidence interval; %GP4/5 = percentage of Gleason pattern 4 or 5; MCCL = maximum cancer core length; PSAD = prostate-specific antigen density; Ref. = reference; SHR = subhazard ratio.
Several multivariable models were tested, including PSAD (as a continuous variable, after log transformation), a tumor size variable (either diameter or, after log transformation, the MCCL), and/or %GP4/5 (using the best threshold value from the univariate analysis). The AIC and Harrell's C-index are reported as a guide to the models’ respective performances: the lower the AIC and the higher the C-index, the better the prediction.