Adequate lymph node evaluation in the elderly is associated with improved survival in patients with stage I-III colon cancer: A validation study using the National Cancer Data Base

Background: Lymph node involvement (LNI) is an important prognostic factor in colon cancer. But, variations in LNI among different age groups are less known. Adequate lymph node evaluation (LNE) requires assessment of >= 12 nodes. In our previous study, using Surveillance, Epidemiology and End Results (SEER) data, we demonstrated that older patients are less likely to have LNI (Khan et al. 2014). Our current study validates those findings using National Cancer Data Base (NCDB). Methods: NCDB was queried for patients diagnosed with stages I-III colon adenocarcinoma from 2004 to 2008 who underwent surgical resections. Pearson Chi-square test and Cox proportional hazards regression model were utilized for statistical analysis. Results: A cohort of 97,831 patients was identified for analysis. Among patients belonging to 18-64, 65-74 and >75 years age groups, frequency of adequate LNE was 73.6%, 69% and 67.4% respectively, with pathologically confirmed LNI rates being 44.7%, 37.8% and 29.3% respectively (p < 0.0001). Adequate LNE was associated with improved 5-year overall survival (OS) regardless of age, gender, race, comorbidity index, insurance, income, year of diagnosis, pathologic tumor status, stage, grade, type of colectomy, adjuvant chemotherapy or academic level of facility. Rates of adequate LNE increased from 2004 to 2008, with a corresponding increase in survival outcomes (p < 0.0001). Conclusion: Adequate LNE is very crucial for appropriate staging of colon cancer, and carries a high prognostic value. This study validates our previous findings of lower rates of LNI in elderly and reiterates the importance of adequate LNE, which is associated with improved survival. Also identified were increasing rates of adequate LNE over the years, with corresponding improvement in OS. (C) 2017 Elsevier Ltd, BASO - The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.