PS1259 LONG-TERM FOLLOW-UP OF JCOG0406 STUDY: INTENSIVE IMMUNOCHEMOTHERAPY (R-HIGH CHOP/CHASER) FOLLOWED BY HIGH-DOSE CHEMOTHERAPY (LEED) WITH AUTO-PBSCT IN UNTREATED MANTLE CELL LYMPHOMA
Authors: M. Ogura, K. Yamamoto, Y. Morishima, M. Wakabayashi, K. Tobinai, K. Ando, N. Uike, M. Kurosawa, H. Gomyo, M. Taniwaki, K. Nosaka, N. Tsukamoto, T. Shimoyama, N. Fukuhara, Y. Yakushijin, K. Ohnishi, K. Miyazaki, K. Sawada, N. Takayama, I. Hanamura, H. Kobayashi, K. Usuki, N. Kobayashi, K. Ohyashiki, T. Utsumi, K. Kumagai, D. Maruyama, K. Ohmachi, Y. Matsuno, S. Nakamura, T. Hotta, K. Tsukasaki, H. Nagai
Journal: HemaSphere (2019)

Background: CLL-like MBL is divided into low and high count, with significant clinical and biological differences. No studies have been conducted so far in CBL-MZ. Aims: In accordance to the proposed grouping of CLL-like MBL, we aimed to investigate the clinical significance of such distinction in MZL-like MBL. Methods: 95 consecutive CBL-MZ cases were analyzed, with any number of circulating CD5- CBL, no B-symptoms, organomegaly, lymphadenopathy, cytopenias or any other features indicating a known lymphoproliferative disorder. Patients were grouped in 3 categories: A. low count (CBL≤500/μL), B. high count (CBL > 500/μL and ≤5000/μL) and C. frank lymphocytosis (CBL>5000/μL). Using this subdivision a comparison of several laboratory and disease evolution parameters was performed. Results: 3/95 patients belonged to group A, 59 to group B and 33 to group C. The characteristics and outcome of the three groups are shown in table. Apart from WBC, ALC and CBL that differed significantly by definition, the only parameters that were statistically different between the three groups, were absolute neutrophil counts, CD11c expression, BM infiltration, and the frequency of evolution to SMZL. More specifically, the frequency of CD11c expression was highest in group C (68%) compared to group B (33%) and A (0%). Surprisingly, ANC were significantly higher with rising ALC. The percentage of BM infiltration differed significantly between the three groups and was highest in the lymphocytosis group (C); however, this difference was mainly due to the difference between group B and C. Notably, the three patients with low-count MBL had BM infiltration between 30–40%, which was similar to the group C. There was a trend for a higher frequency for SMZL evolution in group C. Four out of 5 patients who evolved to SMZL belonged to the group C, whereas the remaining one patient had a low-count MBL. At a median follow-up time of 42 months, need of therapy, time to progression (TTP), time to treatment (TTT) and overall survival (OS) did not differ significantly between the three groups. Not CBL counts, but elevated LDH and BM infiltration≥50% were the only significant factors for TTT by multivariate analysis. Treatment due to cytopenias was more frequent in group B.Summary/Conclusion: CBL-MZ patients have an excellent prognosis. The cut-off of 5x109//L CBL does not seem to be the optimal threshold to distinguish prognostically different subgroups, with the exception of SMZL development. BM infiltration≥50% and elevated LDH are associated with shorter TTT.