Md who is not an oncologist said to me that there is a blood test, after pancreatic tumor removal, that can show micrometasis. i said there isn't.(?)

Sometimes there is.: There are "tumor marker" tests that may be elevated before treatment. For some pancreas tumors CA-19-9 is high. If surgery works, the test should go to normal. If not, there is concern for residual disease. There are other markers for different tumor types. But, they are not specific or sensitive enough to be good for screening, and don't always track disease state accurately.