2.3.1. Stratification by Age

Using the median age of 71 years as a cut-off to define the two age groups (≤71 vs. >71 years), age itself was not associated with RFS (Table 4). In the univariate Cox's regression analysis in the younger age group, low *CXCL9* (RR = 6.21; *p* = < 0.001) was associated with an increased risk of recurrence (Table 5). This finding is in accordance with the above mentioned results for all patients, but it indicates the greater relevance of *CXCL9* mRNA in younger patients. Low *PD1* mRNA was only associated with a risk of shorter RFS in the younger patient group (RR = 4.93; *p* = 0.035). Altogether, the higher risks of recurrence for *CXCL9* and low *PD1* levels were only relevant to the younger age group (Table 5).



Significant values are in bold face.
