Adjusting CA19-9 values to predict malignancy in obstructive jaundice： Influence of bilirubin and C-reactive protein
摘要
AIM:To find a possible relationship between inflammation and CA19-9 tumor marker by analyzing data from patients with benign jaundice(BJ) and malignant jaundice(MJ).METHODS:All patients admitted for obstructive jaundice,in the period 2005-2009,were prospectively enrolled in the study,obtaining a total of 102 patients.On admission,all patients underwent complete standard blood test examinations including C-reactive protein(CRP),bilirubin,CA19-9.Patients were considered eligible for the study when they presented obstructive jaundice confirmed by instrumental examinations and increased serum bilirubin levels(total bilirubin > 2.0 mg/dL).The standard cut-off level for CA19-9 was 32 U/mL,whereas for CRP this was 1.5 mg/L.The CA19-9 level was adjusted by dividing it by the value of serum bilirubin or by the CRP value.The patients were divided into 2 groups,MJ and BJ,and after the adjustment a comparison between the 2 groups of patients was performed.Sensitivity,specificity and positive predictive values were calculated before and after the adjustment.RESULTS:Of the 102 patients,51 were affected by BJ and 51 by MJ.Pathologic CA19-9 levels were found in 71.7% of the patients.In the group of 51 BJ patients there were 29(56.9%) males and 22(43.1%) females with a median age of 66 years(range 24-96 years),whereas in the MJ group there were 24(47%) males and 27(53%) females,with a mean age of 70 years(range 30-92 years).Pathologic CA19-9 serum level was found in 82.3% of MJ.CRP levels were pathologic in 66.6% of the patients with BJ and in 49% with MJ.Bilirubin and CA19-9 average levels were significantly higher in MJ compared with BJ(P = 0.000 and P = 0.02),while the CRP level was significantly higher in BJ(P = 0.000).Considering a CA19-9 cut-off level of 32 U/mL,82.3% in the MJ group and 54.9% in the BJ group were positive for CA19-9(P = 0.002).A CA19-9 cut-off of 100 U/mL increases the difference between the two groups:35.3% in BJ and 68.6% in MJ(P = 0.0007).Adjusting the CA1