A break between treatment (chemo or radiation) and surgery is the norm, I believe. I did chemo, then 28 days radiation + weekly gemcitabine infusion, then another round of chemo, then a 4 week break before surgery. I have read anywhere from 4 to 8 weeks break recommended. After my break, I had dead tumor on PET and clear CT. Had surgery in July and all clear so far. Good luck!!