Abstract: Objective To explore the clinical characteristics, efficacy evaluation, risk factors for disease progression and survival prognosis of patients with primary mediastinal large B-cell lymphoma (PMBCL). Method The clinical data of 16 patients with PMBCL from March 2015 to February 2022 in First Affiliated Hospital of USTC (Anhui Provincial Hospital) were retrospectively analyzed. The clinical characteristics and prognosis of the patients were statistically analyzed. Results The median overall survival (OS) time of 16 patients with PMBCL was not reached, and the 5-years OS rate was 92.3%. And the median progression-free survival (PFS) time was 7 (95%CI: 6.5~15.5) months, and the 5-years PFS was 43.3%. As of the follow-up date, the median follow-up time was 25 (4~70) months. One (1/16, 6.3%) patients was lost to follow-up, 14 (93.3%) patients was alive, in which 8 patients reached complete remission (CR) and 5 patients reached partial remission (PR), and the overall response rate (ORR) was 86.67%. The ORR was 75% in patients with refractory relapse PMBCL after using PD-1 inhibitor. Univariate analysis showed that Ann Arbor stage, group B symptoms, LDH level, whether there was a huge mass, aa-IPI score, whether SUV Max and mum-1 were positive in PET-CT lesions, and different Ki-67 levels were not risk factors for PMBCL disease progression. Conclusion The OS in the patients with PMBCL, who received induction chemotherapy treatment containing rituximab, has been improved. However, the PFS has not been improved well and the new regimen is needed to achieve the goal of cure in patients. The regimen containing PD-1 inhibitor can be considered for patients with relapsed and refractor PMBCL.

Key words: Primary mediastinal large B-cell Lymphoma, PD-1 inhibitor, Prognosis, Clinical characteristics