Despite advances in transplantation procedures and significant prolongation in survival, relapse following allogeneic hematopoietic stem cell transplantation (SCT) for myelofibrosis (MF) remains a significant issue. Most relapse occurs during the early period of allogeneic SCT. We aimed to analyze the clinical characteristics of the patients with late relapse following allogeneic SCT.
In this cross-sectional study we retrospectively evaluated the ?les of 259 patients with myelofibrosis transplanted between 1994 and 2015 for late relapses. Late relapse was defined as the relapses later than first five years of stem cell transplantation (SCT). Study patients were grouped according to their relapse status under follow-up after five years. Group A consisted of patients with a late relapse. Patients under long term follow-up after five years with no relapse consisted Group B. Clinical and laboratory parameters of late relapse were investigated.
A total of 94 patients (M/F=55/39, 58.5 vs. 41.4%, respectively) out of 259 MF transplant patients were identified with a median follow-up of 9.15 years (range, 5.12-19.61). Median age at transplantation of the whole study population was 56 (range;29-75). Sixty two patients (66%) had primary MF (PMF), 18 (19.1%) had post polycythemia vera (PV) and 14 (%14.9) had post essential thrombocythemia (ET) myelofibrosis. Thirteen patients (M/F=7/6) experienced (12%) late molecular (n=6) or hematological (n=6) relapses at a median of 7.1 years (range , 5.02-10.20). Eighty- one patients (M/F=48/33) with a median follow-up of 8.76 years (5.02-19.61) did not experienced relapse. Median age at transplant was similar in both groups (Group A vs Group B: 55 (36-73) vs. 57 (29-75)). Although, numerically smaller, median time from diagnosis to transplantation, 20 months (3-100) in Group A and 13 months (1-353) in Group B, had no effect on relapses. Other clinical and laboratory parameters analyzed were not associated with a significantly higher risk of late relapse. Relapse patients received either DLI (n=9) and/or second transplantation (n=4). Of those 61.5 % achieved again full donor cell chimerism and/or molecular remission. After a median follow up of 105 months (range,4-236) of the relapsed patients the 2 years PFS and overall survival is 92.3% and 84.6%, respectively.
In this large MF group we observed late molecular or hematological relapses. DLI and second SCT are effective to induce remission. Early detection of minimal residual disease (MRD) and therapy adjustment resulted in full chimerism and negative MRD status. Our results implicate the importance of close monitoring of MF patients even after 5 years post allograft.
Nothing to declare