Neoadjuvant Versus Adjuvant Chemotherapy for Resectable Metastatic Colon Cancer in Non-academic and Academic Programs

Background: Overall survival advantage of chemotherapy before versus after metastasectomy of liver or lung lesion is not clear for colon cancer with synchronous liver or lung metastasis. Materials and Methods: Adults 20 years or older with primary colon cancer and single organ metastatic disease either in the liver or lung at diagnosis were identified between 2010 and 2015 through the National Cancer Database (NCDB). Patients were categorized into 2 cohorts: pre-operative/peri-operative chemotherapy (neoadjuvant -[NAC]) or post-operative chemotherapy (adjuvant [AC]). Survivals and factors associated with were compared between the 2 groups. Results: A total of 3038 patients with colon cancer with liver or lung metastases were identified. The percentage of patients receiving NAC had steadily increased from 12.29% to 28.31%, mostly in academic programs. On multivariate analysis, patients who received NAC had an overall survival advantage in the non-academic setting whereas no advantage is seen in the patients treated in the academic settings. The median overall survival for patients receiving NAC and AC was 47.24 months and 38.08 months, respectively. Factors associated with overall survival advantage in NAC patients treated in non-academic programs included age 20-49 years, CEA value of >30, right-sided colon primary, liver metastasis, and clear resection margins. Conclusions: Metastatic colon cancer with single organ liver or lung lesions benefits from neoadjuvant chemotherapy, especially in non-academic settings. The overall survival advantage in this setting has not been shown before.