Prognostic Value of Preoperative Carcinoembryonic Antigen and Carbohydrate Antigen 19-9 Levels for Adjuvant Chemotherapy in Stage II Colorectal Cancer: A Nationwide Multicenter Retrospective Study

Objectives: Adjuvant chemotherapy for stage II colorectal cancer patients with high-risk factors for recurrence can be useful; however, its advantage in prognosis remains to be controversial. Thus, in this study, we aimed to assess whether a combination of preoperative serum carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) levels can predict the prognosis and advantage of adjuvant chemotherapy. Methods: Using a Japanese nationwide database, in total, 3,688 patients with curative resected stage II colorectal cancer were registered retrospectively between 2008 and 2012 in 24 referral institutions. Patients were classified into three groups as follows: Group A (both non-high levels of CEA and CA19-9), Group B (either high levels of CEA or CA19-9), and Group C (both high levels of CEA and CA19-9). Results: Multivariable Cox regression analysis, adjusting the depth of tumor invasion, number of dissected lymph nodes, tumor differentiation, lymphatic and venous invasion, and other covariates, showed that the 5year disease-free survival and overall survival were shorter in Group C than in Groups A and B. Furthermore, in Group C, the 5-year disease-free survival rate was improved in the surgery-plus-AC group compared to the surgery-alone group. Conclusions: As with existing high-risk factors for recurrence, the combination assessment of preoperative serum CEA and CA19-9 can predict the prognosis for colorectal cancer. Adjuvant chemotherapy may provide a prolonged disease-free survival advantage in stage II colorectal cancer patients with high levels of both tumor markers.