Clinical Evidence for the Benefits of Neoadjuvant Chemotherapy and Immunotherapy in Colon Cancer: A Concise Review

Neoadjuvant chemotherapy (NAC) has long been considered technically difficult in locally advanced colon cancer (LACC). However, the introduction of oxaliplatin-based regimens led to a growing interest in NAC for patients with LACC. Several cohort studies showed that NAC was safe and reduced the rate of incomplete resection in patients with LACC. This was followed by the pivotal phase III FOxTROT trials, which showed significant benefits of NAC in this population. However, in patients with deficient mismatch repair (dMMR), the response to a neoadjuvant fluoropyrimidine regimen may be poor, limiting the benefit of NAC in this subset of patients. Neoadjuvant immunotherapy is a potential alternative for NAC in LACC patients with dMMR. In this concise review, we present the published clinical evidence evaluating the efficacy and safety of NAC and/or neoadjuvant immunotherapy in patients with LACC. Overall, the evidence suggests that NAC can be associated with significant downstaging and tumor regression, which facilitate surgical resection. However, the impact of NAC on long-term survival is still under investigation. Despite the promising results of NAC in LACC, several concerns still exist that necessitate further evidence. On the other hand, LACC patients with dMMR can benefit from neoadjuvant immunotherapy; however, further trials are still needed to confirm its effectiveness, as well as biomarkers that can predict response.