In patients witih locally advanced pancreatic cancer, how long would you wait after 1st line induction chemotherapy with FOLFIRINOX before you image for assessment of response and deciding about 2nd-line therapy?

We image with Ca-19-9 every 3 months and consolidate with ablative chemoradiation after a minimum of 4 months of FOLFIRINOX. We do not give second line chemotherapy for locally advanced pancreatic cancer unless patients do not tolerate FOLFIRINOX in spite of dose reductions, or experience progressio...