<s>[INST] I am having chemotherapy as my CEA was 65 and Petscan indicted that some liver cysts that have been there for 2 years, may have become cancerous. After 4 sessions of chemo the CEA is down to 10 but my gamma GT is up from 33 to 65. Could this be due to the chemo? I had a 5th session today (Wed) and after the 6th in 2 weeks I will have another Petscan to see if surgery is necessary. Should I be worried about the gamma GT as I drink wine most days but below the recommended maximum levels. [/INST] Thanks for your question on Chat Doctor. In my opinion you should not worry much about this much rise in GGT.GGT is the enzyme raised when there is obstruction in the billiard tract. But in this rise of GGT is many folds. So GGT of 65 is nothing to worry about. It has nothing ti do with chemotherapy.  This may be a laboratory variation. So get your chemotherapy as per schedule and get done follow-up PET scan to see for improvement. </s>