Abstract
BACKGROUND: Neoadjuvant chemotherapy is increasingly used to treat locally advanced (T3-4 Nx-2 M0) colon cancer due to its potential advantages over the standard approach of upfront surgery. The primary objective of this systematic review and meta-analysis was to analyse data from comparative studies to assess the impact of neoadjuvant chemotherapy on oncological outcomes. METHODS: A systematic review was conducted by searching the MEDLINE and Scopus databases. The search encompassed RCTs, propensity score-matched studies, and controlled prospective studies published up to 1 April 2023. As a primary objective, overall survival and disease-free survival were compared. As a secondary objective, perioperative morbidity, mortality, and complete resection were compared using the DerSimonian and Laird models. RESULTS: A total of seven studies comprising a total of 2120 patients were included. Neoadjuvant chemotherapy was associated with a reduction in the hazard of recurrence (HR 0.73, 95% c.i. 0.59 to 0.90; P = 0.003) and death (HR 0.67, 95% c.i. 0.54 to 0.83; P < 0.001) compared with upfront surgery. Additionally, neoadjuvant chemotherapy was significantly associated with higher 5-year overall survival (79.9% versus 72.6%; P < 0.001) and disease-free survival (73.1% versus 64.5%; P = 0.028) rates. No significant differences were observed in perioperative mortality (OR 0.97, 95% c.i. 0.28 to 3.33), overall complications (OR 0.95, 95% c.i. 0.77 to 1.16), or anastomotic leakage/intra-abdominal abscess (OR 0.88, 95% c.i. 0.60 to 1.29). However, neoadjuvant chemotherapy was associated with a lower risk of incomplete resection (OR 0.70, 95% c.i. 0.49 to 0.99). CONCLUSION: Neoadjuvant chemotherapy is associated with a reduced hazard of recurrence and death, as well as improved overall survival and disease-free survival rates, compared with upfront surgery in patients with locally advanced colon cancer.