S340 Neoadjuvant Chemotherapy Versus Upfront Surgery for Locally Advanced Colon Cancer: A Systematic Review and Meta Analysis

Introduction: Currently, the standard of care for locally advanced colon cancer (LACC) is upfront surgery followed by adjuvant chemotherapy if required. In recent years, there has been an increase in evidence regarding the use of neoadjuvant chemotherapy (NACT). Despite good operative outcomes, data regarding survival and disease free survival remains obscure. This study aims to evaluate the effectiveness of neoadjuvant chemotherapy for LACC. Methods: The review conducted follows the PRISMA guidelines and major medical databases, which include PUBMED, Google Scholar and Science Direct, were extensively searched using a comprehensive search term to identify and retrieve available articles. Randomized clinical trials and propensity matched cohort studies that included the assessment of overall survival (OS) and progress/disease free survival (PFS/DFS) following neoadjuvant chemotherapy and upfront surgery were included in the meta analysis. The odds ratio (OR) of OS and PFS between the 2 groups for 1, 3, and 5 years was assessed in the meta-analysis. The data was analyzed using the Meta, Metadata and the Metafor packages of R Studio. The Mantel Haenszel method (common effect model) and the inverse variance method (random effects model) were utilized to analyze the odds ratio. The I2 test was used to assess the heterogeneity of the studies. Results: The study conducted involves a total of 6 studies with 1,591 subjects receiving NACT and 1,290 patients undergoing upfront surgery for LACC. The OS over 1, 3, and 5 years did not significantly vary between the 2 groups: OR 1Y = 1.01 (0.99; 1.03) 95% confidence interval (CI), P = 0.67, I2 = 0%; OR 3Y = 1.03 (1.00; 1.07) 95% CI, P = 0.66, I2 = 0%); OR 5Y = 1.05 (1.00; 1.098) 95% CI, P = 0.72. The 1-year PFS/DFS did not significantly differ between the groups. The 3-year and 5-year PFS were marginally higher in the NACT group: PFS 3Y = 1.09 (1.04;1.13) 95% CI, P = 0.96, I2 = 0%); PFS 5Y = 1.08 (1.02; 1.15) 95% CI, P = 0.90 I2 = 0%). Conclusion: NACT proves to be effective in progressive free survival among LACC in comparison to Upfront surgery. The overall survival was similar in both groups, indicating similar therapeutic efficacy. NACT doesn’t provide a significant benefit in terms of OS and PFS, but studies indicate better histopathological response; further trials have to be conducted to conclude the same.