Purpose: Adjuvant chemotherapy use in stage II colorectal cancer (CRC) is debated. We evaluated the prognostic significance of clinicopathological features recommended by most guidelines for identifying high-risk stage II CRC and adjuvant chemotherapeutic response.
Methods: We enrolled 1,039 stage II CRC patients who underwent curative surgery at Taipei Veterans General Hospital from January 2005 to December 2010. Seventy-seven patients who received radiotherapy were excluded. The endpoint was disease-free survival.
Results: Of 962 patients, 37 had stage T4 tumors; 50, lymphovascular invasion; 39, poor differentiation; 249, preoperative carcinoembryonic antigen (CEA) levels >5 ng/mL; and 53 underwent emergent operations. One hundred ninety-four patients received 5-fluorouracil-based adjuvant chemotherapy. During a median follow-up period of 60.2 months, recurrence developed in 110 patients (11.4 %). The 5-year disease-free survival (DFS) was 87.6 %. In multivariate analysis, preoperative CEA >5 ng/ml (p = 0.001), emergent operation for obstruction/perforation (p = 0.008), lymphovascular invasion (p = 0.014), and T4 disease (p = 0.030) were significantly associated with poor DFS. High-risk stage II patients (n = 484) benefited from adjuvant chemotherapy (5-year DFS with and without adjuvant chemotherapy, 87.3 vs. 78.9 %; p = 0.028).
Conclusions: Adjuvant chemotherapy improved DFS in high-risk stage II CRC patients, but not in low-risk patients.