Chemotherapy consisted of eight 21-day cycles of nab-paclitaxel plus gemcitabine (nab-paclitaxel 125 mg/m² by intravenous infusion for approximately 30-45 mins, followed by gemcitabine 1000mg/m² intravenous infusion for approximately 30 mins on days 1 and 8). Anti-PD-1 antibody (camrelizumab, Hengrui Medicine Co., Ltd) 200 mg was administered intravenously for 30 mins every three weeks. During the chemotherapy-treated period, camrelizumab was administered on day 1 of each 21-day cycle before the infusion of chemotherapy. Radiotherapy started after two cycles of chemotherapy. A total radiation dose greater than 50 Gy without damaging organ function was the essential requirement.

Chemotherapy consisted of eight 21-day cycles of nab-paclitaxel plus gemcitabine (nab-paclitaxel 125 mg/m² by intravenous infusion for approximately 30-45 mins, followed by gemcitabine 1000mg/m² intravenous infusion for approximately 30 mins on days 1 and 8).

Radiotherapy started after two cycles of chemotherapy. External beam radiation therapy was performed using an intensity modulated radiation therapy technique. The gross target volume included the gross primary tumor and positive regional lymph nodes as defined by the multiphasic imaging. A total radiation dose greater than 50 Gy without damaging organ function was the essential requirement.

defined as the time from randomization until disease progression or death from any cause, whichever happens first. Patients who withdraw or who are lost to follow-up will be censored at the date last known to be alive and progression free. Patients not having an event will be censored at the date last seen alive.

defined as the time from randomization until death from any cause. Patients who withdraw or who are lost to follow-up will be censored at the date last known to be alive. Patients remaining alive throughout the duration of the study will have their survival time censored on the date last seen alive.

adverse events during the treatment period using Common Terminology Criteria for Adverse Events (CTCAE) (version 5.0).

measured according to the Response Evaluation Criteria in Solid Tumors (RECIST) criteria 1.1 by means of computed tomography (CT) or magnetic resonance imaging (MRI) at each follow-up.