Differential impacts of clinical variables and 5-fluorouracil-based adjuvant chemotherapy on 5-year disease-free survival of patients with stage IIa and IIb colon cancer

Background: The aim of this study was to evaluate practicable predictors of 5-year disease-free survival (DFS) and impact of 5-fluorouracil (5-FU)-based adjuvant chemotherapy in stage IIa and IIb colon cancer. Materials and Methods: A total of 1474 patients with stage II colon cancer were enrolled in study. The independent predictors of 5-year DFS and the benefits of adjuvant chemotherapy were analyzed for patients with stage IIa (n = 771) and IIb (n = 703). Results: The incidences of pretreatment anemia, hypoalbuminemia, emergent surgery, and lymphovascular invasion (LVI) corresponded significantly to an advanced T-stage in patients with stage II colon cancer. Although the incidence of surgical morbidity was not different between stage IIa and IIb, stage II patients with hypoalbuminemia had a higher incidence of surgical morbidity than did those with normal serum albumin (17.2% vs. 9.6%, P < 0.001). The co-independent survival predictors in patients with stage IIa and IIb colon cancer were carcinoembryonic antigen (CEA < 5 ng/mL, P = 0.007 and 0.043), serum albumin (≥3.5 g/dL, P < 0.001 and P = 0.025), and nonsurgical morbidity (P < 0.001, both). Suboptimal lymph node harvest (<12 examined nodes, P < 0.001) and no adjuvant chemotherapy (P = 0.008) were poor prognostic factors only in stage IIb colon cancer. LVI showed a trend to worse DFS (P = 0.059). A survival benefit from adjuvant chemotherapy analyzed in four subgroups stratified by stage IIa and IIb, with or without the present prognostic factors, was only observed in patients with stage IIb colon cancer with hypoalbuminemia, abnormal CEA, suboptimal lymph node harvest, and postoperative morbidity. Conclusion: Different predictors of DFS were observed in stage IIa and IIb colon cancer; adjuvant chemotherapy could provide a survival benefit for patients with stage IIb colon cancer who have one of the four factors that were studied in our hospital-based analysis