Neoadjuvant chemotherapy for colon cancer: A systematic review and meta-analysis of randomized controlled trials

Neoadjuvant chemotherapy (NAC) treatment has appeared as a promising alternative to upfront surgery to improve efficacy outcomes in non-metastatic colon cancer, but the findings are still controversial. Considering this ongoing debate, we conducted a systematic review and meta-analysis of randomized controlled trials to assess the benefit of NAC in high-risk stage II and stage III colon cancer.

We searched PubMed, Embase, and Cochrane for clinical trials evaluating NAC in non-metastatic colon cancer. Random and fixed effects models were employed for statistical analyses in Review Manager software version 5.4. Moreover, to evaluate the heterogeneity, I² statistics were used.

A total of 1248 patients from 4 clinical trials were included. The NAC group demonstrated a 38 % reduction in the risk of death. (HR 0.62; 95 % CI 0.41-0.92; I² = 0 %), and a 21 % reduction in the risk of disease recurrence (HR 0.79; 95 % CI 0.65-0.96; I² = 0 %). Additionally, the NAC group had higher R0 resection, with an increase of 80 % in the odds compared to upfront surgery (OR 1.80; 95 % CI 1.24-2.61; I² = 0 %). Pathological complete response and major pathologic response (PCR) were achieved in 5.9.% % and 36.2 %, respectively. Patients with proficient mismatch repair achieved a higher PCR rate and a consistent reduction in the risk of recurrence compared to the overall population, with proportions of 6.3 % and 32 %, respectively. Also, there was no significant addition to the toxicity profile in the NAC arm.

Our systematic review and meta-analysis support the feasibility and survival benefits of neoadjuvant chemotherapy for high-risk stage II and III colon cancer.