Det skal bl.a. overvejes, om statistikkerne skal omfatte justering for overlevelse, analyse af kumulative tumorrisici i forhold til overlevelsesvarighed, analyse af tid til tumor og analyse i tilfælde af afslutning af en eller flere grupper før tid.
Issues to consider include whether the statistics should include adjustment for survival, analysis of cumulative tumour risks relative to survival duration, analysis of the time to tumour and analysis in the event of premature termination of one or more groups.