High transplant-related mortality associated with haematopoietic stem cell transplantation for paediatric therapy-related acute myeloid leukaemia (t-AML). A study on behalf of the United Kingdom Paediatric Blood and Bone Marrow Transplant Group

Changing causes of death in persons with haematological cancers 1975-2016

Causes of death in persons with haematological cancers include the index cancer, a new cancer or a seemingly unrelated cause such as cardio-vascular disease. These causes are complex and sometimes confounded. We analyzed trends in cause of death in 683,333 persons with an index haematological cancer diagnosed in 1975-2016 reported in the Surveillance, Epidemiology and End Results dataset. Non-cancer deaths were described using standardized mortality ratios. The index cancer was the predominant cause of death amongst persons with plasma cell myeloma, acute lymphoblastic leukaemia and acute myeloid leukaemia. Non-cancer death was the major cause of death in persons with chronic lymphocytic leukaemia, Hodgkin lymphoma and chronic myeloid leukaemia, mostly from cardio-vascular diseases. The greatest relative decrease in index-cancer deaths was amongst persons with Hodgkin lymphoma, chronic myeloid leukaemia and chronic lymphocytic leukaemia, where the proportion of non-cancer deaths increased substantially. Changing distribution of causes of death across haematological cancers reflects substantial progress in some cancers and suggests strategies to improve the survival of persons with haematological cancers in the future.

Outcomes of pediatric patients with therapy-related myeloid neoplasms

Long-term outcomes after allogeneic hematopoietic cell transplantation (HCT) for therapy-related myeloid neoplasms (tMNs) are dismal. There are few multicenter studies defining prognostic factors in pediatric patients with tMNs. We have accumulated the largest cohort of pediatric patients who have undergone HCT for a tMN to perform a multivariate analysis defining factors predictive of long-term survival. Sixty-eight percent of the 401 patients underwent HCT using a myeloablative conditioning (MAC) regimen, but there were no statistically significant differences in the overall survival (OS), event-free survival (EFS), or cumulative incidence of relapse and non-relapse mortality based on the conditioning intensity. Among the recipients of MAC regimens, 38.4% of deaths were from treatment-related causes, especially acute graft versus host disease (GVHD) and end-organ failure, as compared to only 20.9% of deaths in the reduced-intensity conditioning (RIC) cohort. Exposure to total body irradiation (TBI) during conditioning and experiencing grade III/IV acute GVHD was associated with worse OS. In addition, a diagnosis of therapy-related myelodysplastic syndrome and having a structurally complex karyotype at tMN diagnosis were associated with worse EFS. Reduced-toxicity (but not reduced-intensity) regimens might help to decrease relapse while limiting mortality associated with TBI-based HCT conditioning in pediatric patients with tMNs.

Therapy-related acute myeloid leukemia following treatment for cancer in childhood: A population-based registry study

BACKGROUND

Therapy-related acute myeloid leukemia (t-AML) is defined as AML that develops after exposure to cytotoxic chemotherapy and/or radiation therapy. There is a paucity of available literature, particularly in regard to t-AML following childhood cancer. Our aim was to describe the risk of t-AML among children treated for other cancers and their subsequent survival.

PROCEDURE

We utilized data from the population-based Australian Childhood Cancer Registry to examine all childhood patients (<15 years at diagnosis) treated with chemotherapy and/or radiotherapy for cancers other than AML who received a subsequent diagnosis of AML between 1983 and 2014. Standardized incidence ratios (SIRs) were calculated to approximate the relative risk of being diagnosed with AML compared to the general population. Estimates of 5-year observed survival were obtained using the Kaplan-Meier method, with differences determined by the log-rank test.

RESULTS

Fifty-eight of 11,753 patients in the study cohort (0.5%) were diagnosed with t-AML, an almost 50-fold higher risk than expected (SIR = 45.6, 95% confidence interval [CI] = 35.3-59.0). Five-year observed survival from the date of t-AML diagnosis was 31.2% (95% CI = 19.6-43.5%). A significant survival advantage was found for patients who underwent hematopoietic stem cell transplantation (HSCT) following diagnosis of t-AML, with a 5-year survival of 52.4% (29.7-70.9%) compared to 5.7% (0.4-22.6%) for those who did not have HSCT (P < 0.001).

CONCLUSIONS

Although rare, t-AML is an important potential late effect of childhood cancer therapy. Prognosis is generally poor, with HSCT offering some survival benefit.

Secondary acute lymphoblastic leukemia, a retrospective analysis from Washington University and meta-analysis of published data

Secondary acute lymphoblastic leukemia (s-ALL) is rare and poorly defined and data regarding outcomes post-transplant are lacking. Here, we report a detailed analysis of s-ALL at our Institution. Among 211 eligible patients with ALL from 2006 to 2017, 30 (14%) were defined as s-ALL and the remaining as primary ALL (p-ALL). s-ALL patients were older and had higher incidence of adverse risk factors. Overall response (OR) after induction was not different between s-ALL and p-ALL (79% versus 90% respectively, p = 0.106). S-ALL group had a higher risk of relapse (RFS) and death (RFS HR = 1.93, 95% CI 1.2-3.12, p = 0.007. OS HR: =1.95, 95% CI 1.18-3.23, p = 0.01). In multivariate analysis, the adverse effect of s-ALL on RFS and OS was no longer significant, however a pooled meta-analysis of our and published data indicated that s-ALL is an independent risk factor for lower OS (HR: 1.30, 95% CI: 1.11-1.52, p < 0.01). Myeloablative allogeneic transplantation in s-ALL was associated with lower rates of relapse and higher transplant related mortality without improvement in OS. These data indicate that s-ALL status should be considered for risk- stratification of newly diagnosed ALL. The optimal conditioning regimen for s-ALL patients undergoing allogeneic stem cell transplantation needs to be evaluated in a larger study.