RecruitingPhase 2Radiation therapyRadiotherapy Followed by Tiselizumab Combined With RCHOP in Previously Untreated Bulky Follicular LymphomaThis was a single center, single arm, phase II study. Patients with previously untreated follicular lymphoma were enrolled from the department of lymphoma, Tianjin Medical University Cancer Institute and Hospital. The bulky disease was received radiation (dose:18~24Gy) before RCHOP. Patients began chemoimmunotherapy 1~2 weeks later than radiation. Treatment included Tiselizumab (200 mg iv d1) plus R-CHOP (rituximab 375 mg/m2 intravenous \[IV\] day 2, cyclophosphamide 750 mg/m2 IV day 3, doxorubicin 50 mg/m2 IV day 3, vincristine 1.4 mg/m2 \[maximum 2.0 mg total\] IV day 3, and prednisone 100 mg oral days 3-7, 21~28 days for one cycle ) for six cycles. Rituximab was given every 2 months to patients who were complete metabolic response /partial metabolic response(CMR/PMR)after first-line chemo until 2 years. Response was assessed by PET/CT scan after cycle 4 and cycle 6.