Chemotherapy Efficacy in Patients With Colorectal Cancer Experiencing Early Recurrence During or After Adjuvant Chemotherapy

Background/Aim: Colorectal cancer (CRC) is the third most diagnosed malignancy worldwide. The efficacy of first-line chemotherapy for metastatic CRC with early recurrence after adjuvant therapy remains unclear; therefore, this study investigated its impact.

Patients and Methods: A retrospective evaluation was conducted on patients with early recurrence after adjuvant chemotherapy from three institutions between 2016 and 2021. Early recurrence was defined as recurrence during or within 1 year of completing adjuvant chemotherapy. Progression-free and overall survival, as well as the overall response rate, were endpoints, with analysis stratified by a recurrence-free interval (RFI) of 6 months.

Results: Data from 455 patients treated with adjuvant therapy were reviewed, identifying 32 eligible patients. Twenty-eight patients (88%) received oxaliplatin-containing regimens, and four (12%) received fluoropyrimidine monotherapy. For palliative chemotherapy, oxaliplatin-based, irinotecan-based, or other regimens were administered to 13 (41%), 13 (41%), and 6 (18%) patients, respectively. Median progression-free and overall survival were 10.4 and 43.0 months, respectively. The overall response rate was 34.4%, and the disease control rate was 75.0%. Patients with RFI <6 months had a lower response rate (26% vs. 56%), shorter progression-free survival (10.4 vs. 17.8 months), and shorter overall survival (31.3 vs. 43.0 months); however, these differences were not statistically significant. Multivariate analysis suggested worse overall survival for patients with RFI <6 months than for those with RFI ≥6 months (hazard ratio=1.78, 95% confidence interval=0.35-8.98; p=0.49).

Conclusion: Patients with CRC and RFI <6 months after adjuvant chemotherapy showed a trend toward poorer outcomes than those with RFI ≥6 months, suggesting a need for more intensive treatment strategies.