Comparison of clinical features and treatments of extramedullary relapse after haploidentical and matched sibling donor allogeneic hematopoietic stem cell transplantation in acute leukemia patients

Abstract

Objective To compare the clinical features of extramedullary relapse (EMR) of acute leukemia after haploidentical donor (HID) allogeneic hematopoietic stem cell transplantation (HSCT) and matched sibling donor (MSD) HSCT. Methods Medical records of acute leukemia patients treated with HSCT including 48 HID-HSCT patients and 42 MSD patients from January 2001 to December 2015 were analyzed retrospectively. Results The most common site of EMR in HID group was central nervous system (56.2%) and the most common sites of EMR in MSD group were central nervous system (38.1%) and skin/soft tissues (38.1%). The most common sites of EMR after HSCT in group HID and group MSD were central nervous system and skin/soft tissues. Patients in group MSD were more likely to involve multiple extramedullary sites than that in group HID (33.3% vs. 10.4%, χ2=7.064, P=0.010), and patients in group MSD were more likely to involve site of skin/soft tissue. The EMR time of HID group was 241.5(10~2 856) days, which was earlier than that of MSD group [302(35~1 532) days, Z=2.091, P=0.037]. The rates of complete remission (CR) of EMR treatments in the two groups were 56.2% vs. 69% respectively (χ2=1.561, P=0.277). The 2-year progression-related mortality (PRM) were (45.4±8.2)% and (37±8.1)% respectively (χ2=1.002, P=0.317). The 2-year treatment-related mortality (TRM) after EMR were (15±5.8)% vs. (10.3±5.0)% respectively (χ2=0.098, P=0.754). The 2-year overall survival (OS) after EMR were (39.6±8.0)% vs. (52.7±8.2)%, respectively (χ2=1.527, P=0.217). There were no differences in PRM, TRM and OS between the two groups. The 2-year OS after EMR in the combination treatment group was higher than that in the monotherapy group [(53±6.7)% vs. (31.9±11.2)%, χ2=7.966, P=0.005], especially for patients receiving MSD-HSCT [(63±8.9)% vs. (14.6±13.3)%, χ2=6.542, P=0.011]. Conclusions The most common sites of EMR after allo-HSCT were central nervous system and skin/soft tissues. The skin/soft tissues involvement was more common in MSD-HSCT recipients. The patients in MSD group were more likely to involve multiple systems after allo-HSCT, and this group of patients might be more likely to benefit from the combination treatment. For patients with EMR after HID transplant, further studies will be needed to improve prognosis. Key words: Acute leukemia; Extramedullary relapse; Allogeneic hematopoietic stem cell transplantation; Haploidentical