Page 334 - Haematologica Vol. 109 - July 2024

LETTER TO THE EDITOR
P=0.22). Second CNS relapse after the first was detected in 15 (22.7%) of these patients: 5 in AML (13.9%) and 10 (33.3%) in ALL patients.
The OS for the 66 patients was 24% at two years and 12% at five years (Figure 2B). There was no difference in OS between AML and ALL patients (AML: 28.8% and 8.2% at 2 and 5 years; ALL: 19.4% and 15.6% at 2 and 5 years, P=0.66) (Figure 3A). The 2-year OS was better in isolated CNS re- lapse versus CNS and concomitant BM relapse (37.5% vs. 6.7%, P=0.004) (Figure 3B).
This study is the largest multicenter study on CNS relapse in leukemia after allo-HSCT to date. We demonstrate that CNS relapse after allo-HSCT is a rare event (1.1%), but is more frequent in ALL than in AML; the prognosis, however, is dismal. Around half the patients could achieve CR, but the OS remains low (8.2% in AML, 15.5% in ALL at 5 years). OS was better in isolated CNS (37.5% vs. 6.7% at 2 years). Only 7 of the 91 patients were alive five years after CNS relapse, 6 patients were censored alive before five years, so only 13 of 91 patients were alive at their last follow-up
AB
Figure 2. Central nervous system relapse by year and overall survival after relapse. (A) Central nervous system (CNS) relapse by year. (B) Overall survival (OS) after relapse for the entire population. HSCT: hematopoietic stem cell transplantation.
AB
Figure 3. Overall survival by diagnosis and central nervous system isolated versus combined with bone marrow. (A) Overall sur- vival (OS) after relapse year of diagnosis. (B) OS after isolated central nervous system (CNS) relapse versus bone marrow (BM) and CNS relapse. HSCT: hematopoietic stem cell transplantation.
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