Tumour marker CA 50 levels compared to signs and symptoms in the diagnosis of pancreatic cancer.

The diagnostic merits of CA 50 and of symptoms indicating pancreatic cancer (pain, jaundice, weight loss, malabsorption) were compared prospectively in 512 consecutive patients. Among the final diagnoses were: exocrine pancreatic cancer, 175; periampullary cancer, 44; other gastrointestinal cancer, 45; and chronic pancreatitis, 64 cases. The suspected diagnoses based on symptoms and signs were correct in 80% of the patients with exocrine pancreatic cancer, in 78% with periampullary, in 76% with other gastrointestinal cancer and in 90% with chronic pancreatitis. CA 50 was pathological in 96% of the cases with exocrine pancreatic cancer, in 70% with periampullary, in 78% with other gastrointestinal malignancies and in 36% with chronic pancreatitis. The sensitivity was 96%, specificity 48%, positive prediction 49% and negative prediction 96%, depending on cut-off level. The single CA 50 value was comparable to symptoms and signs regarding sensitivity and negative prediction. In 28 of 42 cases incorrectly clinically classified, CA 50 alone indicated a benign or malignant diagnosis. If both the modalities 'signs and symptoms' and CA 50 were combined, the sensitivity was 91%, the specificity 92%, the positive prediction 86% and the negative prediction 95%. The initial CA 50 value can help to indicate in which patients a pancreatic malignancy should be suspected.