Elevated CA 19.9

My sister who is 68 years old, had stomach cancer and operated in 2004. After chemo and radiotherapy, she has been cancer-free ever since. However, this year the CA 19.9 indicator has been progressively elevating: In March 2011 was 137, in June 2011 jumped to 803. This year,she had several thoratic, stomach and abdominal CT Scans, but they found  nothing related to any metastasis. She also had an endoscopy and colonoscopy without any sign of tumors. The question is, what could possibly cause this sudden elevation given that that the CT scan did not show anything? Also what else can she do to determine the cause of the abnormal CA 19.9?
Thank you,
Mike

[S. Kaul, MD]

Hey Mike!

CA 19-9 may be elevated in cancers of the stomach, colon or pancreas and rarely in a few benign conditions. Since there is a previous history of GI cancer one would have to be very meticulous with the investigation. Since a CT has been negative further testing including MRI, ERCP, other tumour markers etc may be done. I would suggest discussing the investigational plan in detail with her treating doctor.
Hope this is useful.

Take care!