OBJECTIVEThe purpose of this study was to investigate the association between single nucleotide polymorphism (SNP) of CCND1 A870G and acute adverse events (AEs) in postoperative rectal cancer patients who received capecitabine-based postoperative chemoradiotherapy (CRT).

METHODSFour hundred patients with stage II and III rectal cancer received postoperative CRT of capecitabine with or without oxaliplatin were accumulated and prostectively studied in this study. The patients were randomly divided into two groups. Two hundred and twenty-eight patients were treated with concurrent capecitabine and radiotherapy (Cap-CRT), and 172 patients were treated with capecitabine and oxaliplatin plus radiotherapy (Cap-Oxa-CRT). Adverse events were graded according to the Common Terminology Criteria for Adverse Events, v. 3.0 (CTCAE v3.0). The genotype of CCND1 A870G in the patients was detected by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) analysis. The associations between the SNP and acute AEs were indicated by odds ratios (ORs) and 95% confidence intervals (CIs), which were computed with logistic regression model.

RESULTSA total of 136 patients presented severe AEs. Among them the frequencies of the three genotypes GG, GA and AA were 16.9%, 50.7% and 32.4%, compared with 24.6%, 48.1% and 27.3%, respectively, among the patients without severe AEs. Diarrhea was the most common AE, and severe diarrhea occurred in 109 patients. The frequencies of the three genotypes GG, GA and AA were 15.6%, 47.7% and 36.7% among these patients, compared with 24.4%, 49.5% and 26.1%, respectively, among patients without severe diarrhea. Multivariate logistic regression analysis showed a 1.66-fold increased risk for severe diarrhea in patients with AA genotype (95%CI 1.03 - 2.67, P = 0.038) compared with the cases with GG or GA genotypes. Stratified analysis showed that in the Cap-Oxa-CRT group, patients with AA genotype showed a 2.34-fold increased risk for severe diarrhea (95%CI 1.16 - 4.76, P = 0.018) compared with those with GG or GA genotypes, but in the Cap-CRT group, the SNP was not associated with the risk of severe diarrhea.

CONCLUSIONSThe genetic polymorphism of CCND1 A870G might be a potential biomarker for predicting acute AEs in postoperative stage II and III rectal cancer patients treated with adjuvant concurrent chemoradiotherapy of capecitabine and oxaliplatin.