Objective: To investigate patterns in the relapse frequency after curative surgical intervention, with the intention of determining the feasibility of a complete holiday from chemotherapy for metastatic colorectal cancer (mCRC) patients.
Methods: Patients with stage IV mCRC who received curative surgical intervention between January 1999 and December 2009 at Changhua Christian Hospital, Changhua, Taiwan were investigated retrospectively. Factors influencing the frequency and pattern of relapse were analyzed by logistic regression. Factors influencing overall survival (OS) were analyzed with Cox proportional hazard ratios. Significant factors were extracted and relationships to OS were evaluated by Kaplan-Meier with Log-Rank test.
Results: One hundred and thirty-two patients were included in the study in which 94 (71.2%) suffered from relapse. The number of relapses peaked between 3 and 6 months. The incidence of relapse and Disease-free survival had a negative influence on OS, with a hazard ratio (HR) of 0.36 (95% CI: 0.01-0.26) and 0.93 (95% CI: 0.90-0.95). The prognosis was significantly worse when the relapse (n=25) occurred within 6 months after metastectomy (p<0.001). Patients exhibited significantly better long-term OS if the relapse does not occur within 28 months after surgery (p<0.001).
Conclusion: Early relapse indicated a worse prognosis. We determined that if mCRC patients remain cancer-free for 28 months after curative surgery, their chance of long-term survival is significantly better.