Objective  To investigate the clinical outcomes of colorectal cancer (CRC) patients who received capecitabine-based adjuvant chemotherapy after radical resection and the corresponding pharmacogenomics analysis.

  Methods  In The Third Affiliated Hospital of Henan University of Traditional Chinese Medicine from Jannary 2010 to June 2017. A total of 215 patients with CRC who received capecitabine-based adjuvant chemotherapy were included in this study. Peripheral blood of the CRC patients was collected for DNA extraction and genotyping of polymorphisms for CDD. Additionally, pretreated peripheral blood mononuclear cells (PBMC) of 85 CRC patients were collected for cytidine deaminase (CDD) mRNA expression analysis. Association analysis of CDD mRNA expression and polymorphisms was performed.

  Results  Clinical outcomes of the 215 patients were favorable. In terms of the corresponding pharmacogenomics analysis, of the polymorphisms studied, -451C>A was found to be of clinical significance. The survival analysis of patients with different genotypes revealed that the 3-year disease-free survival (DFS) of patients with the GA/AA genotype and the GG genotype was 81.03% and 62.42%, respectively, indicating a statistically significant difference (P=0.002). In terms of overall survival (OS), the 5- year OS of patients with the two genotypes was 72.41% and 53.50%, respectively, which also indicated a statistically significant difference (P=0.016). Additionally, analysis of mRNA expression in 85 PBMC samples showed that CDD mRNA expression in patients with GA or AA genotypes was significantly higher than in those with the GG genotype (P < 0.001).

  Conclusions  The clinical outcomes of postoperative CRC patients who received capecitabine-based adjuvant chemotherapy were favorable. CDD mRNA expression may be affected by the -451C>A polymorphism, making CRC patients get benefits from capecitabine treatment.