AIM: To examine the predictive effects of baseline serum bilirubin levels and UDP-glucuronosyltransferase(UGT) 1A1*28 polymorphism on response of colorectal cancer to irinotecan-based chemotherapy.METHODS: The present study was based on a prospective multicenter longitudinal trial of Chinese metastatic colorectal cancer(m CRC) patients treated with irinotecan-based chemotherapy(NCT01282658). Baseline serum bilirubin levels, including total bilirubin(TBil) and unconjugated bilirubin(UBil), were measured,and genotyping of UGT1A1*28 polymorphism was performed. Receiver operating characteristic curve(ROC) analysis was used to determine cutoff values of TBil and UBil. The TBil values were categorized into > 13.0 or ≤ 13.0 groups; the UBil values were categorized into > 4.1 or ≤ 4.1 groups. Combining the cutoff values of TBil and UBil, which was recorded as Co Bil, patients were classified into three groups. The classifier’s performance of UGT1A1*28 and Co Bil for predicting treatment response was evaluated by ROC analysis. Associations between response and Co Bil or UGT1A1*28 polymorphism were estimated using simple and multiple logistic regression models. RESULTS: Among the 120 m CRC patients, the serum bilirubin level was significantly different between the UGT1A1*28 wild-type and mutant genotypes. Patients with the mutant genotype had an increased likelihood of a higher TBil(P = 0.018) and a higher UBil(P = 0.014) level compared with the wild-type genotype. Patients were stratified into three groups based on Co Bil. Group 1 was patients with TBil > 13.0 and UBil > 4.1; Group 2 was patients with TBil ≤ 13.0 and UBil > 4.1; and Group 3 was patients with TBil ≤ 13.0 and UBil ≤ 4.1. Patients in Group 3 had more than a 10-fold higher likelihood of having a response in the simple(OR = 11.250; 95%CI: 2.286-55.367; P = 0.003) and multiple(OR = 16.001; 95%CI: 2.802-91.371; P = 0.002) analyses compared with the Group 1 individuals. Patients carrying the UGT1A1*28(TA)7 allele were 4-fold less likely to present wit
AIM: To examine the predictive effects of baseline serum bilirubin levels and UDP-glucuronosyltransferase (UGT) 1A1*28 polymorphism on response of colorectal cancer to irinotecan-based chemotherapy.METHODS: The present study was based on a prospective multicenter longitudinal trial of Chinese metastatic colorectal cancer (mCRC) patients treated with irinotecan-based chemotherapy (NCT01282658). Baseline serum bilirubin levels, including total bilirubin (TBil) and unconjugated bilirubin (UBil), were measured, and genotyping of UGT1A1*28 polymorphism was performed. Receiver operating characteristic curve (ROC) analysis was used to determine cutoff values of TBil and UBil. The TBil values were categorized into > 13.0 or ≤ 13.0 groups; the UBil values were categorized into > 4.1 or ≤ 4.1 groups. Combining the cutoff values of TBil and UBil, which was recorded as CoBil, patients were classified into three groups. The classifier’s performance of UGT1A1*28 and CoBil for predicting treatment response was evaluated by ROC analysis. Associations between response and CoBil or UGT1A1*28 polymorphism were estimated using simple and multiple logistic regression models.RESULTS: Among the 120 mCRC patients, the serum bilirubin level was significantly different between the UGT1A1*28 wild-type and mutant genotypes. Patients with the mutant genotype had an increased likelihood of a higher TBil (P = 0.018) and a higher UBil (P = 0.014) level compared with the wild-type genotype. Patients were stratified into three groups based on CoBil. Group 1 was patients with TBil > 13.0 and UBil > 4.1; Group 2 was patients with TBil ≤ 13.0 and UBil > 4.1; and Group 3 was patients with TBil ≤ 13.0 and UBil ≤ 4.1. Patients in Group 3 had more than a 10-fold higher likelihood of having a response in the simple (OR = 11.250; 95%CI: 2.286-55.367; P = 0.003) and multiple (OR = 16.001; 95%CI: 2.802 -91.371; P = 0.002) analyses compared with the Group 1 individuals. P