Conditional survival of younger patients with mantle cell lymphoma: Results from a randomized phase III trial of the European MCL Network.

During a fatal disease, patients often request updated information on their prognosis. After patients have already survived a certain time, conditional survival captures their future survival probability. We investigated conditional overall and failure-free survival in 473 younger mantle cell lymphoma (MCL) patients from a randomized phase III trial comparing immunochemotherapies R-CHOP and alternating R-CHOP/R-DHAP before autologous transplantation. Using conditional Kaplan-Meier method and Cox regression, we estimated subsequent survival of patients who had survived 1-8 years, considering MIPI, Ki-67, and treatment failure status. Starting at a lower level, R-CHOP patients only showed increasing subsequent survival as they survived longer (5-year conditional survival: 72% and 81% after surviving 1 and 7 years), while R-CHOP/R-DHAP patients had stable future survival over time (77% and 78%). The prognostic value of MIPI diminished after 3 years in R-CHOP patients but remained unchanged after R-CHOP/R-DHAP. Patients with treatment failure had markedly inferior survival compared with those in ongoing remission, regardless of the time survived. The longer patients remained in remission, the longer they would stay free of treatment failures. Our results enable personalized counselling for younger MCL patients by offering dynamic prognosis and underscore the importance of highly effective first-line treatment to improve survival.