Impact of Anatomic Extent of Nodal Metastasis on Adjuvant Chemotherapy Outcomes in Stage III Colon Cancer.

BACKGROUND An oxaliplatin-based chemotherapy regimen improves the survival outcomes of patients with stage III colon cancer. However, its complications are well-known. OBJECTIVE The purpose of this study was to distinguish between the survival outcomes of patients who underwent curative resection for stage III colon cancer with oxaliplatin chemotherapy and those who underwent such resection without oxaliplatin chemotherapy. DESIGN This was a retrospective analytical study based on prospectively collected data. SETTINGS This study used data on patients who underwent surgery at our hospital between January 2010 and December 2014. PATIENTS A cohort of 254 consecutive patients who underwent curative resection for stage III colon cancer was included in this study. The patients were divided into 2 groups: patients with isolated pericolic lymph node metastasis (n = 175) and those with extrapericolic lymph node metastasis (n = 79). MAIN OUTCOME MEASURES Clinicopathologic features and 3-year survival outcomes were analyzed with and without oxaliplatin therapy in the pericolic lymph node group. RESULTS The pericolic lymph node group showed significantly improved overall survival compared with the extrapericolic lymph node group at a median follow-up of 48.5 months (95.8% vs 77.8%; p < 0.001). In contrast, there was no significant difference in overall survival (99.0% vs 92.0%; p = 0.137) and disease-free survival (89.1% vs 88.2%; p = 0.460) between the oxaliplatin and nonoxaliplatin subgroups of the pericolic lymph node group. Multivariate analysis showed that the administration of oxaliplatin chemotherapy to the pericolic lymph node group did not lead to a significant difference in the overall survival (p = 0.594). LIMITATIONS The study was limited by its retrospective design and single institutional data analysis. CONCLUSIONS This study suggests that the anatomic extent of metastatic lymph nodes could affect patient prognosis, and the effect of oxaliplatin-based adjuvant chemotherapy may not be prominent in stage III colon cancer with isolated pericolic lymph node metastasis.