This leaves the clinician

with the quandary as to what levels to use for basing their clinical decisions. Certainly a tumour marker whose diagnostic threshold varies would not be optimal, and would lead to a great deal of confusion. Indeed, as a result of the diagnostic overlap, the American Society of Clinical Oncology does not currently advocate its use for screening, evaluation of resectability or BIRB 796 in vitro disease follow-up (2). There are a number of Inhibitors,research,lifescience,medical reasons to account for the variations in the Ca19-9 levels reported in the individual studies. The authors highlight the fact that between 1 in 10 and 1 in 20 patients with pancreatic cancer will not express Ca19-9 at all. There are also racial and gender variations in expression of Ca19-9 with highest levels observed in Caucasians (3). Ca19-9 is well known to be elevated in benign conditions (4), as acknowledged in the review, and these must be taken into consideration in relation to the diagnosis of malignancy. The confusion caused by obstructive Inhibitors,research,lifescience,medical jaundice in interpreting

Ca19-9 levels is also well documented. It is well known that benign pancreato-biliary disease may cause a rise in Ca19-9, usually related to biliary Inhibitors,research,lifescience,medical obstruction. In interpreting Ca19-9 levels in an individual believed to have pancreatic cancer it is important for the clinician to be aware whether a stent

was inserted and if so was the Ca19-9 level taken pre-or post-stenting. Marrelli and colleagues (5) reported that bilirubin levels fall in patients with benign disease following stenting but remain Inhibitors,research,lifescience,medical elevated in those with malignant disease. Furthermore it has been shown that for benign disease the Ca19-9 levels correlate with bilirubin but for malignant disease these to variables are independent of each other (6). A further factor in the confusion is the term that is often interchangeably used for pancreatic cancer. Traditionally, series of pancreatic resections have indicated a predominance of pancreatic Inhibitors,research,lifescience,medical carcinoma but with more accurate pathological evaluation (7) the prevalence of pancreatic adenocarcinoma is first lower and that of distal common bile duct cholangiocarcinoma higher, with similar prevalence for ampullary lesions (8). The Ca19-9 levels of these tumours, when assessed separately are significantly different, and so failure to accurately characterize the nature of the periampullary lesion will certainly affect the assessment of Ca19-9 (6). Likewise, histopathological assessment of the lesions according to the format popularised by Verbeke (7) will radically alter assessment of tumour resection status and of stage that in turn may account for the variation in data in relation Ca19-9 and disease stage.