http://gallbladdercancer.wordpress.com/2009/09/16/ca-19-9/

Today I learnt something new about CA 19-9 the Cancer antigen. I have a 70 year old lady who had a markedly raised CA 19-9. We investigate very thoroughly to look for a malignancy,

I read the website above and found this:

CA 19-9 is elevated in most patients with advanced pancreatic cancer, but it may also be elevated in other cancers, conditions, and diseases such as colorectal cancer, lung cancer, gall bladder cancer, gall stones, pancreatitis, cystic fibrosis, and liver disease. Other causes of bile duct obstruction may also cause very high CA 19-9 levels, which fall when the blockage is cleared. It is often a good idea, if the bile ducts are blocked, to wait a week or two after the blockage is removed or treated to check CA 19-9 levels

CT scan did not reveal any pancreatic cancer in this case but she had multiple gallstones and thickened gall bladder wall.  One of the stones must have dropped into the bile duct and temporarily caused a rise in CA 19-9.

The lady agreed to have neeldescopic cholecystectomy.