Prognostic significance of serum beta-2 microglobulin in patients with diffuse large B-cell lymphoma in the rituximab era

// Seyoung Seo 1, * , Jung Yong Hong 1, * , Shinkyo Yoon 1, 7 , Changhoon Yoo 1 , Ji Hyun Park 1 , Jung Bok Lee 2 , Chan-sik Park 3 , Jooryung Huh 4 , Yoonse Lee 4 , Kyung Won Kim 5 , Jin-Sook Ryu 6 , Seok Jin Kim 8 , Won Seog Kim 8 , Dok Hyun Yoon 1 , Cheolwon Suh 1 1 Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 2 Department of Medical Statistics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 3 Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 4 Department of Otorhinolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 5 Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 6 Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 7 Department of Hemato-oncology, Bundang Jesaeng Hospital, Gyeonggi-do, Korea 8 Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea * These authors contributed equally to this work Correspondence to: Cheolwon Suh, email: csuh@amc.seoul.kr Dok Hyun Yoon, email: dhyoon@amc.seoul.kr Keywords: beta 2-microglobulin, diffuse large B-cell lymphoma, rituximab, prognosis, non-Hodgkin lymphoma Received: July 22, 2016      Accepted: October 12, 2016      Published: October 18, 2016 ABSTRACT The prognostic value of serum beta-2 microglobulin for diffuse large B-cell lymphoma (DLBCL) is not well known in the rituximab era. A retrospective registry data analysis of 833 patients with de novo DLBCL treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) was conducted to establish the prognostic significance of serum beta-2 microglobulin at a ≥2.5 mg/L cutoff. Five-year progression-free survival (PFS, 76.1% vs. 41.0%; p < 0.001) and overall survival (OS, 83.8% vs. 49.2%; p < 0.001) were significantly worse in patients with elevated serum beta-2 microglobulin ( n = 290, 34.8%). Furthermore, the five parameters of the International Prognostic Index, accompanying B symptoms, bone marrow involvement and impaired renal function were associated with worse PFS and OS. In multivariate analysis, elevated beta-2 microglobulin was a significant poor prognostic factor for PFS (hazard ratio [HR], 1.70; 95% confidence interval [CI], 1.29–2.24; p < 0.001) and OS (HR, 2.0; 95% CI, 1.47–2.75; p < 0.001). In an independent validation cohort of 258 R-CHOP treated patients with de novo DLBCL, elevated beta-2 microglobulin levels remained a significant poor prognostic factor for PFS (HR, 2.03; 95% CI, 1.23–3.32; p = 0.005) and exhibited a strong trend of association with worse OS (HR, 1.64; 95% CI, 0.98–2.75; p = 0.062). The significance of serum beta-2 microglobulin levels as an independent prognostic factor for patients with DLBCL receiving R-CHOP is confirmed.