No Chage, in reality
values can not be reproduced exactly.
So there is some flucctuation which is normal. There is no real difference unless CEA were to increase by 50% or more. Yours did not change, so I would say the tumor is not changing...or it would be called Stable. Therefore, the same treatment can continue unless there is clear cut progression( CEA value of >15-20 ng , in your case)