2.8. Statistical Analysis

Descriptive statistics were applied for clinical and pathological characteristics and presented as frequencies, percentages, and median (range). Time to biopsy was calculated as the interval from patient acceptance of biopsy to the performance of biopsy (days). Progression Free Survival (PFS) was defined as the time from first line treatment initiation to radiologically verified progression. Overall Survival (OS) was defined as the time from first line treatment initiation to death of any cause. PFS and OS were calculated by the Kaplan–Meier method through GraphPad prism v8.4.3. Patients with no progression or death by the cut-off date 30 June 2021 were censored. Only patients with a performed re-biopsy were included for further analyses.