age, pre-treatment PSA, clinical-radiologic stage, bGS and %PC are highly significant predictors of biochemical relapse in both univariate and multivariate Cox models: all Ps are lower than 0.001 except for age, whose values are P = 0.001 and P = 0.019 in univariate and multivariate analyses, respectively (Table 2 ).
comparing patients treated up to 2004 (569 cases) versus 2005 onwards (1924 patients), there is an almost significant time trend concerning total biopsic Gleason Score with bGS means increasing from 6.5 to 6.7, respectively (both medians are equal to 7, P = 0.06 at Wilcoxon-Mann–Whitney test).
The 360-cells-table combining all the possible combinations of the stratified parameters clearly shows a strong trend, going from very-low risk (in blue) on the upper-left corner to very-high-risk (in red) in the lower-right corner; in between can be noticed low-risk (in green), intermediate-risk (in yellow) and high-risk (in orange, see Table 3 and Additional file 1 : Table S2).