Autologous Stem Cell Transplantation (HCT) with or Without Total Body Irradiation (TBI) in Newly Diagnosed Mantle Cell Lymphoma (MCL) Patients

ABSTRACT Introduction MCL is considered incurable due to relapsing course and eventual resistance despite initial responses to treatment. The 1st line treatment in advanced disease is immunochemotherapy induction followed by high-dose chemotherapy +/- TBI and HCT in the first complete (CR) or partial remission (PR). The best conditioning regimen is unknown and the TBI role is one of the main issues. Very few retrospective analyses are available. Methods We retrospectively evaluated all MCL patients treated 1st line +/- TBI as a part of myeloablative procedure at the Oncology Institute in Warsaw between 1999-2011 with some patients treated in the European MCL Network trial for younger. We analyzed data for 7 women and 26 men, median age 56 years (39-63). Most (82%) had disease stage III-IV with bone marrow involvement in 64%. Majority received chemotherapy with rituximab for induction (79%). All received doxorubicin and 45% cytarabine. 22 had TBI conditioning (TBI group). Most of the remaining 11 patients received BEAM (non-TBI group). Before conditioning 18 had CR (12 before TBI, 6 before conditioning without TBI) and 15 PR (10 before TBI, 5 before conditioning without TBI). There were no statistically significant differences between groups, including age, sex, disease stage and MIPI. After HCT 27 patients had CR (18 in TBI, 9 in non-TBI), 6 remained in PR (4 in TBI, 2 in non-TBI). Median observation time from the start of therapy was 50.9 months (6.9-144.8) and from HCT 49.5 months (0.85-139.7). Results After HCT the 1, 3 and 5-year overall survival (OS) rates were 96.9%, 89.8%, 75% and the progression free survival (PFS) 93.7%, 73.1% and 67.9% respectively. In bivariate analysis the 1, 3 and 5-year OS rates were similar in TBI vs. non-TBI groups: 95.4% vs. 100%; 90.4% vs. 88.8%; 82.2% vs. 66.7% (p= 0.41). Comparison of 1, 3 and 5-year PFS rates between TBI vs. non-TBI groups: 95.2% vs. 90.9% and 86.6% vs. 47.1% and 78 % vs. 47.1% (p= 0.046) indicated superiority of TBI. In a multivariate analysis TBI was an independent PFS prognostic factor with relative risk 0.24 (95% CI 0.06–1.02) (p = 0.04). Conclusion The results showed PFS advantage of TBI conditioning prior to HCT in newly diagnosed MCL patients and no OS advantage. Disclosure All authors have declared no conflicts of interest.