Neoadjuvant Chemotherapy Improves Survival in Patients with Clinical T4b Colon Cancer

In 2016, the National Comprehensive Cancer Network included neoadjuvant chemotherapy as a treatment option for patients with clinical T4b colon cancer. However, there is little published data on the survival impact of neoadjuvant chemotherapy for locally advanced colon cancer. Adult patients with non-metastatic clinically staged T3 or T4 colon cancer who underwent surgical resection were identified from the National Cancer Data Base between 2006 and 2014. Treatment was categorized as neoadjuvant chemotherapy followed by surgery and surgery followed by adjuvant chemotherapy. Overall survival was compared between the two groups using propensity score matching. Of 27,575 patients that met inclusion criteria, 26,654 (97%) were treated with surgery followed by adjuvant chemotherapy and 921 (3%) received neoadjuvant chemotherapy followed by surgery. After propensity score matching, patients with T4b colon cancer treated with neoadjuvant chemotherapy had a 23% lower risk of death at 3 years compared to patients that had adjuvant chemotherapy (HR 0.77, 95% CI 0.60-0.98; p = 0.04). However, neoadjuvant chemotherapy did not demonstrate a similar significant benefit for patients with T3 and T4a disease. Patients with clinical T4b colon cancer treated with neoadjuvant chemotherapy may have an improved survival compared to those who receive adjuvant chemotherapy. Further prospective investigation is warranted.