- Normally recurrence-free-survival  refers to local or regional relapses of the tumor, while the disease-free-period includes also the development of distant metastases.    (ref: https://www.researchgate.net/post/Are_the_disease-free_survival_and_recurrence-free_survival_the_same_definitions_in_oncology_studies)
- Overall survival: still the gold standard: why overall survival remains the definitive end point in cancer clinical trials.
- It's a chaos about the survival end point definition.
https://www.researchgate.net/post/Are_there_differences_between_progression-free_survival_relapse-free_survival_and_recurrence-free_survival2
survival analysis sample size?
r - What is the minimum sample size for kaplan meier - Cross Validated
SSiz Survival Pgm
sample-size-753-2008.pdf