Wannhoff A, et al. - In patients with primary sclerosing cholangitis, researchers performed a longitudinal analysis of carbohydrate antigen 19-9 (CA19-9). For this investigation, they carried out a retrospective analysis of CA19-9 values in 247 patients with and without biliary malignancy who had primary sclerosing cholangitis. Data revealed that median CA19-9 in cancer-free patients was 15.6 U/mL. According to findings, CA19-9 is highly individual in patients with primary sclerosing cholangitis, and the reference change value should be favored over the reference interval. Investigators found that CA19-9 stayed stable in cancer-free patients but increased early in patients who developed biliary tract cancer. They suggested that regular measurement of CA19-9 could improve early detection of these malignancies.