Prognostic Variables of Progression Free Survival in Mantle Cell Lymphoma after Autologous Stem Cell Transplantation

Background Autologous stem cell transplant (ASCT) is frequently used as a consolidative therapy option after induction treatment in fit patients with mantle cell lymphoma (MCL) with the goal of prolonging the initial response duration.  Despite recent advances there remains a subset of patients who experience early disease relapse after ASCT. We examined predictors of shortened progression-free survival (PFS) and post-relapse overall survival (OS) in a cohort of patients completing ASCT in first remission. Methods We evaluated MCL patients treated at 10 US academic medical centers. Eligible patients were treated from 2000 through 2017, and we collected information on demographic, clinical, and treatment-related variables of interest. Patients were then categorized into three post-ASCT PFS groups: 0-2 years, 2-5 years, and > 5 years, with PFS determined from the date of ASCT until progression or death from any cause.  Patients followed for at least 5 years post-ASCT who were relapse free were included in the > 5 sub group. Associations were examined between groups and collected characteristics using chi-squared tests for categorical patient characteristics and ANOVA for numeric patient characteristics. The Kaplan-Meier method was used to estimate overall survival (OS) for each group, using time of relapse after ASCT as the starting point. Results Of 968 total MCL patients, 242 patients completed ASCT in first remission and either had a PFS event or were relapse-free for at least 5 years post-ASCT. Patients were 80% male, and the median age was 59 (Range: 29-83). The patients were divided into groups of post-ASCT PFS 0-2 years (n=74), 2-5 years (n=75), and more than 5 years (n=93).  Post-ASCT PFS was shorter in patients with stage 4 disease (p=0.022), splenomegaly at baseline (p=0.005), and a lymph node size > 5 centimeters at baseline (p=0.043). Other variables were not significantly associated with PFS, including time to transplant and use of intensive therapy. Patients with 0-2 year PFS had a shorter median OS (22.1 months, 95% CI: 13.1- 38.1 months) in comparison to 2-5 year PFS (132 months, 95% CI: 36-132 months) and 5+ year PFS not reached (95% CI: 41.2 – N.A; Figure). Conclusion Patients with higher tumor burden at baseline have a shorter post-ASCT PFS and are more likely to relapse within 2 years.  As has been seen in other lymphoma subtypes, early relapse is associated with shorter OS.  This represents a patient group requiring improved therapies and perhaps are the best candidates for post-ASCT maintenance or consolidation approaches.  Further studies integrating minimal residual disease and molecular risk-stratification may better identify patients at high risk for early progression.