Optimal timing of adjuvant chemotherapy initiation in colon cancer patients: real-world clinical practice data

Aim. To determine the optimal timing of adjuvant chemotherapy (ACT) initiation based on real-world clinical practice data and to assess factors influencing timely ACT initiation in patients with colon cancer (CC).

Materials and methods. This study is a single-center retrospective cohort analysis. Patients with CC who received ACT between 2015 and 2023 were included. Uni- and multivariate analyses of factors affecting ACT initiation timing were performed. The threshold value for ACT initiation timing in relation to overall survival (OS) and recurrence-free survival (RFS) was evaluated using area under the curve (AUC) analysis. The frequency of completing more than 3 months of ACT depending on the surgical approach was also analyzed.

Results. During the study period, 871 patients received ACT. A 6-week period was established as the threshold for CC progression risk. Five-year OS was 66.4 % in the group of patients who started ACT more than 6 weeks after surgery, and 81.5 % in the group who started treatment within 6 weeks of surgery. The differences in OS were significant (hazard ratio (HR) 0.532; 95 % confidence interval (CI) 0.360–0.787; p = 0.002). Significant differences were also found in 5-year RFS (HR 0.637; 95 % CI 0.447–0.908; p = 0.013): 61.8 % in the group starting ACT more than 6 weeks after surgery and 72.4 % with earlier initiation. Multivariate analysis showed that only the absence of postoperative complications influenced the likelihood of starting ACT within 6 weeks (HR 0.365; 95 % CI 0.140–0.955; p = 0.040).

Conclusion. Optimal ACT initiation timing may be shorter than 8 weeks in real-world clinical practice. Minimally invasive surgery may improve patient adherence to the ACT regimen.