Overall survival analysis
Median follow-up time was 34 months with 50% of global survival rate at
3 years of follow up. The Lasso penalized Cox regression analysis
identified as potential predictors of OS: standard deviation
(p =0.0082) at medium scale (SSF = 4), mean gray-level
(p =0.0010) at medium scale (SSF = 0), mean gray-level
(p =0.0312) at medium scale (SSF = 5) and age at diagnosis
(p =0.0436). In multivariate Cox regression analysis, mean
gray-level at medium scale (SSF = 5) and age at diagnosis were
significantly associated with overall survival (HR = 1.07 [1.02;
1.12], p =0.003 and HR = 1.08 [1.03; 1.13], p =0.001,
respectively) (Table 2A).
When dichotomized at the optimal threshold identified using ROC curve,
mean gray-level greater than 5.89 at medium scale (SSF = 5) was
significantly associated with lower survival time (HR = 3.7 [1.4;
10.2], p =0.01) (Figure 2A).