Table 1.

Recommended minimum standard timepoints for perioperative sample collection

Timepoint	Timeframe	Potential correlative outcomes
Treatment naive	Prior to treatment, concurrent with initial clinical staging	Pathological response to neoadjuvant therapy, long-term survival and disease status
Post-neoadjuvant therapy and/or restaging	≥4 weeks after completing neoadjuvant therapy; ≤2 weeks of concurrent clinical assessment or restaging and/or resection	Pathological response to neoadjuvant therapy, neoadjuvant rectal score
Post-resection	4–8 weeks after surgical resection with a curative intent	Long-term survival and disease status, including overall survival, disease-free survival and recurrence-free survival
After adjuvant therapy or completion of all potentially curative therapy; minimal residual disease	2–8 weeks after completion of all curative-intent therapy
Disease relapse or recurrence	≤2 weeks, concurrent with clinical assessment and/or restaging showing evidence of disease relapse and/or recurrence