Mantle cell lymphoma: initial report from the North American Mantle Cell Lymphoma Consortium.

Abstract

8035 Background: The goal of the North American Mantle Cell Lymphoma (MCL) Project is to evaluate the clinical, biological, and genomic markers that affect the outcome of patients with MCL. Methods: We have retrospectively studied the clinical and pathological features of 307/421 patients diagnosed with MCL between January 2000 to December 2012 from 23 institutions across North American. Results: The male to female ratio of MCL patients was 3.5:1, with a median age of 66 years (range: 24-106 years). Approximately 29% of patients (78/269) presented with B symptoms and 257 (257/307, 83.7%) patients had extranodal involvement at diagnosis. Median follow-up was 7.1 years (range, 0.03 to 16.6 years) with the five-year PFS and OS at 27.8%, and 54.4%, respectively. Univariate analysis revealed that the following factors were significantly associated with both inferior OS and PFS ( p< 0.05): older age (≥60 years), presence of B symptoms, advanced Ann Arbor stage, elevated LDH, low platelets (≤100K/ml), blastoid/pleomorphic cytology, Ki67 proliferation ≥30%, circulating tumor cells, no transplantation (vs. transplantation), and allogeneic (vs. autologous) stem cell transplantation. In addition, large tumor size (maximal diameter > 3cm), high WBC ( > 10×103/ml), CD5 or CD23 positivity, and a complex karyotype were associated with inferior OS ( p< 0.05). Multivariate Cox regression analysis showed age (≥ 60y; p= 0.0028, HR = 2.44, 95% CI: 1.36-4.38) and high LDH ( p= 0.0062, HR = 2.19, 95% CI: 1.25-3.84) were the two factors predicting the clinical outcome. MIPI-c, a commonly used prognostic scoring system which includes Ki67, stratified the 100 MCL cases into four group with distinct clinical outcomes ( p< 0.001). Using readily-available clinical and pathological variables, we developed a simple and robust scoring system, MIPI-P (pathology), which consisted of age (≥60 years), LDH (high), Ki67 index (≥30%), Ann Arbor stage (III/IV), and cytological type (blastoid/pleomorphic), each contributing one point. The MIPI-P system stratified 104 MCL cases into three distinct groups ( p< 0.001). Median survival for the different groups were: low grade (0-1 points): 11.8 years; intermediate grade (2-3 points): 4.9 years; and high grade (4-5 points): 1.6 years. We further validated this system in an independent cohort of 33 MCL cases and confirmed that the modified MIPI-P provided robust prognostic predication ( p= 0.014). Conclusions: The clinical and biologic characteristics of MCL can provide information assisting with the prognosis of patients with MCL.