Conditional Recurrence-Free Survival

Resection of colorectal liver metastases (CLM) remains a curative treatment option. The 5-year overall survival after CLM resection is high, approximately 50%; however, the 5-year recurrence-free survival (RFS) is low, approximately 20%. Survival analysis was traditionally performed at the time of surgery. However, the risk of recurrence after CLM resection changes over time. The group at MD Anderson Cancer Center termed the analyses of RFS after a predefined time without recurrence as “conditional RFS.” In our series, the peak of recurrence risk was approximately 1 year after CLM resection. The recurrence risk decreased from 1 to 3 years, and become steadily after 4 years. At the time of surgery, clinicopathologic factors (T stage, extrahepatic disease, multiple CLMs, largest CLM diameter, and surgical margin) and a genetic factor (RAS/TP53 comutation of CLM) were risk factors for RFS. However, for patients free from recurrence at 2 years after surgery, RAS/TP53 comutation alone was associated with a risk of recurrence. Conditional RFS may be useful to inform changing risks of recurrence with an interval from CLM resection and tailor surveillance frequency and intensity. If patients visit the clinic without recurrence for 2 years after CLM resection, the probability of recurrence is half that present at the time of surgery, and risk factors for recurrence at the time of surgery may no longer be associated with a risk of recurrence.