Shifting Paradigm: Utilization and Outcomes with Neoadjuvant Chemotherapy for cT4 and cN2 Colon Cancers

Area of Science:

• Oncology
• Surgical Oncology
• Chemotherapy

Background:

• Upfront surgical resection (USR) is standard for resectable colon cancer.
• Locally advanced (cT4) and high nodal burden (cN2) disease present treatment challenges.
• Neoadjuvant chemotherapy (NAC) is being investigated as an alternative or adjunct to USR.

Purpose of the Study:

• To compare overall survival (OS) between NAC followed by surgery and USR followed by adjuvant chemotherapy (AC).
• To evaluate the impact of NAC on margin positivity and lymph node ratio (LNR) in cT4 and cN2 colon cancer.
• To identify factors associated with NAC receipt and patient outcomes.

Main Methods:

• Analysis of the National Cancer Database for nonmetastatic, microsatellite stable cT4 or cN2 colon cancer.
• Comparison of USR + AC versus NAC + surgery groups.
• Propensity score matching (PSM) for OS analysis.
• Logistic regression for covariate analysis.

Main Results:

• NAC was associated with reduced margin positivity (cT4: 12.5% vs 20.5%; cN2: 7.8% vs 12.5%) and lower LNR (cT4: 8.7% vs 18.7%; cN2: 17.3% vs 39%).
• NAC significantly improved OS for both cT4 (p=0.003) and cN2 disease (p<0.001).
• Younger, healthier patients treated at academic centers were more likely to receive NAC.

Conclusions:

• NAC is associated with improved pathological outcomes and OS in cT4 and cN2 colon cancers.
• Findings support further investigation of NAC for these advanced colon cancer stages.
• NAC may offer a survival benefit over traditional upfront surgery for select colon cancer patients.