## 3 Results
### The PCO Classifier Application  
We calculated the PCO classifier score based on the nomogram depicted in Figure 1 and the data shown in Table 3. The total PCO classifier score was calculated as the sum of the values for each variable. The total scores ranged from 0 to 156. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Category** & **N** & **Percent** \\ \hline  & Under 59 & 60 & 7.4 \\ Age at diagnosis & 60–69 & 313 & 38.7 \\ (Mean, Range) & 70–79 & 354 & 43.8 \\ Over 80 & 82 & 10.1 \\  & 70.04 (44–100) & & \\ \hline  & T1 (T1b, T1c) & 537 & 66.4 \\ T-stage & T2a & 135 & 16.7 \\ T2b & 97 & 12.0 \\  & T2c + T3 & 40 & 4.9 \\ \hline  & Low (3 + 3 or less) & 302 & 37.3 \\ Gleason score & Favorable intermediate (7 = 3 + 4) & 292 & 36.1 \\ Unfavorable intermediate (7 = 4 + 3) & 146 & 18.0 \\  & High (4 + 4 or greater) & 69 & 8.5 \\ \hline  & \(\leq\)10.0 ng/mL & 598 & 73.9 \\ Pretreatment PSA & \(>\)10.0 and \(\leq\)20.0 ng/mL & 170 & 21.0 \\  & \(>\)20.0 ng/mL & 41 & 5.1 \\ \hline  & Gleason score \(\leq\) 6 and PSA \(\leq\) 10 ng/mL & 222 & 27.4 \\ Modified risk level & Gleason score \(\leq\) 6 and PSA \(>\) 10 and PSA \(\leq\) 20 & 67 & 8.3 \\  & Gleason score = 7 (3 + 4) & 281 & 34.7 \\  & Gleason score = 7 (4 + 3) & 142 & 17.6 \\  & Gleason Score \(\geq\) 8 or PSA \(>\) 20 & 97 & 12.0 \\ \hline  & No BCR & 791 & 97.8 \\ BCR & BCR & 18 & 2.2 \\ \hline  & Median & \multicolumn{2}{c}{574 days} \\ Follow-up periods & Mean & \multicolumn{2}{c}{758 days} \\  & Maximum & \multicolumn{2}{c}{2227 days} \\ \hline  & Total & 809 & 100 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Demographics of 809 patients. BCR: biochemical recurrence; PSA: prostate specific antigen. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Variables** & **HR** & **95.0\% CI** & \(p\) \\ \hline Age at diagnosis & 2.62 & 1.326–5.166 & 0.006 ** \\ T-stage & 1.03 & 0.643–1.641 & 0.910 \\ Modified risk level & 1.47 & 0.997–2.154 & 0.052 \\ \hline  & \multicolumn{2}{c}{** \(p<0.01\).} \\ \end{tabular}
\end{table} 
Table 2: Cox multivariable regression analysis on BCR. The patients were classified using a total score range that was based on the BCR-free survival rate at 4 years: 99%, 90%, and 80%. The total scores ranged from 0 to 156. The PCO classifier application categorized prostate cancer patients into three risk-groups based on the BCR-free survival rate at 4 years: 137 patients were low risk (16.9%); 570 patients were intermediate risk (70.5%); and 102 patients were high risk (12.6%). We defined scores of 0-34 as a low-risk group, scores of 35-115 as an intermediate-risk group, and scores of 116-156 as a high-risk group. The classifier calibration was assessed by grouping patients by their PCO classifier score (Figure 2). The calibration of the PCO classifier application illustrates how its predictions compare with the actual outcomes for the 809 patients. The performance of the PCO classifier application was within 10% of the actual outcomes and more accurate at 90% predicted probability. The \(x\)-axis is the predicted value \begin{table}
\begin{tabular}{c c c} \hline  & **Variables** & **Score** \\ \hline \multirow{4}{*}{Age at diagnosis} & Under 59 & 0 \\  & 60–69 & 33 \\  & 70–79 & 67 \\  & Over 80 & 100 \\ \hline \multirow{4}{*}{T-stage} & T1 (T1b, T1c) & 0 \\  & T2a & 1 \\  & T2b & 2 \\  & T2c-T3 & 3 \\ \hline \multirow{4}{*}{Modified risk level} & [PERSON] score \(\leq 6\) and PSA \(\leq 10\) ng/mL & 0 \\  & [PERSON] score \(\leq 6\) and PSA \(>10\) and PSA \(\leq 20\) & 13 \\ \cline{1-1}  & [PERSON] score = 7 (3 + 4) & 26 \\ \cline{1-1}  & [PERSON] score = 7 (4 + 3) & 40 \\ \cline{1-1}  & [PERSON] score \(\geq 8\) or PSA \(>20\) & 53 \\ \hline \end{tabular} PSA: pretreatment PSA.  
\end{table} 
Table 3: Prostate Clinical Outlook (PCO) classifier application score. Figure 1: PCO nomogram.