The Evaluation of More Lymph Nodes in Colon Cancer Is Associated with Improved Survival in Patients of All Ages

Background Improvement in survival of patients with colon cancer is reduced in elderly patients compared to younger patients. The aim of this study was to investigate whether the removal of >= 12 lymph nodes can explain differences in survival rates between elderly and younger patients diagnosed with colon cancer. Methods In a population-based cohort study, all patients (N = 41,074) diagnosed with colon cancer stage I to III from 2003 through 2010 from the Netherlands Cancer Registry were included. Age groups were defined as < 66, 66-75 and > 75 years of age. Main outcome measures were overall and relative survival, the latter as a proxy for disease specific survival. Results Over an eight years time period there was a 41.2% increase in patients with >= 12 lymph nodes removed, whereas the percentage of patients with the presence of lymph node metastases remained stable (35.7% to 37.5%). After adjustment for patient and tumour characteristics and adjuvant chemotherapy, it was found that for patients in which >= 12 lymph nodes were removed compared to patients with < 12 lymph nodes removed, there was a statistically significant higher overall survival (< 66: HR: 0.858 (95% CI, 0.789-0.933); 66-75: HR: 0.763 (95% CI, 0.714-0.814); > 75: HR: 0.734 (95% CI, 0.700-0.771)) and relative survival (< 66: RER: 0.783 (95% CI, 0.708-0.865); 66-75: RER: 0.672 (95% CI, 0.611-0.739); > 75: RER: 0.621 (95% CI, 0.567-0.681)) in all three age groups. Conclusions The removal of >= 12 lymph nodes is associated with an improvement in both overall and relative survival in all patients. This association was stronger in the elderly patient. The biology of this association needs further clarification.