Gemcitabine plus nub-paclitaxel (GA) regimen was recently presented at an international oncology meeting and represents a new standard regimen in the treatment of metastatic pancreatic cancer. Therefore, it was decided to consider the balance of safety and efficacy on survival time as a preoperative chemotherapy, the investigators use the NAC-GA regimen includes only two cycles (three times weekly and one week rest) of GA regimen.