<qa>  What is the specific research question if there are changes of the CTC count in the postThis prospective, randomized study will be conducted over a 36-month period to investigate whether commonly used anesthetics volatile versus intravenous have an effect on the changes or occurrence of CTC in patients suffering from primary pancreatic cancer undergoing curative surgery. The specific research question is if there are changes of the CTC count in the postoperative phase in the desflurane group intervention compared to the propofol one control. A secondary question is if these changes can be correlated to tumor outcome. 