T4N0 colon cancers should be treated like T3N1 disease

Background: Patients with positive lymph nodal involvement in colon cancer have always been deemed to fare worse than those without. However, questions have been increasingly raised on the true prognosis of T4N0 disease. We conducted this study to investigate how T4N0 disease would compare with T3N1 disease. Methods: All patients with colon cancer treated from 2008 to 2014 was collected. Preoperative, intraoperative and histological information was compared between patients with T4N0 and T3N1 disease. Variables which significantly differed were included in multivariate analysis for recurrence and survival. Kaplan-Meier curves and cox regression analysis for time to recurrence and survival were evaluated. Results: Seventy-eight patients had T4N0 colon cancer, while 160 had T3N1 disease. Vascular invasion, lymphatic invasion, total lymph node yield, and the administration of adjuvant chemotherapy were identified as variables for evaluation. Over a median follow-up of 41.4 (range, 21.6-65.0) months for T4N0 patients and 42.4 (range, 21.1-63.8) months for T3N1 patients, there was no statistically significant difference in the association of stage of cancer with survival [overall survival (OS): 0.97 (95% CI, 0.38-2.45), P=0.94]. Kaplan-Meier curves also showed no difference in time to death (P=0.867). There was no statistically significant difference in the time to death [hazard ratio (HR): 0.56 (95% CI, 0.20-1.55), P=0.26]. Conclusions: T4N0 colon cancers have similar outcomes to T3N1 disease and should be considered as stage III disease in future classification. Patients diagnosed with T4N0 disease should receive similar treatment as those with T3N1 disease and counselled accordingly.