Children who undergo allogeneic blood or marrow transplantation (BMT) remain at an elevated risk of premature death even 25 years after the procedure, results of large, retrospective cohort study suggest.
Despite a significant decrease over several decades, the risk of all-cause mortality remained elevated, compared with the general population, according to this study of individuals who had BMT performed in childhood between 1974 and 2010.
“These findings emphasize the need for lifelong follow-up care after allogeneic BMT performed in childhood,” reported Anna Sällfors Holmqvist, MD, PhD, of the department of clinical sciences at Skåne University Hospital, Lund University, Sweden, and her associates.
, Dr. Holmqvist and her colleagues reported in .
Their retrospective analysis included 1,388 individuals who lived at least 2 years after allogeneic BMT performed in childhood at one of three centers: the University of Alabama at Birmingham; the University of Minnesota, Minneapolis; and City of Hope, Duarte, Calif.
There were 295 deaths over a median of 14.9 years of follow-up, for an overall survival rate of 79.3% at 20 years after BMT, reported Dr. Holmqvist and her associates. The three leading causes of death were infection or chronic graft-versus-host disease in 49.6% of cases, primary disease in 24.6%, and later malignancies in 18.4%.
Relative to the general population, the cohort had a 14.4-fold increased risk of premature death (95% confidence interval, 12.8-16.1), compared with the general population. Relative mortality was highest 2-5 years after BMT and dropped substantially after that but remained elevated – even 25 years or more after the procedure, the investigators noted.
Mortality decreased significantly over the 3 decades evaluated in this study. The rate of all-cause, 10-year cumulative mortality was 18.9% before 1990, 12.9% from 1990 to 1999, and 11.0% from 2000 to 2010 (P = .002).
That decrease in cumulative mortality over time could not be explained by changes in transplant practice over those three time periods, according to results of a mediation analysis performed by Dr. Holmqvist and her associates.
That finding suggests that unmeasured variables might underlie the decrease in late mortality, the investigators said.
Those unmeasured variables might include supportive care strategies, management of chronic graft-versus-host disease, or improved patient selection, they noted.
Dr. Holmqvist and her associates cited as one limitation their reliance on death certificates for causes of death. In addition, the causes of death for 51 of the 295 deceased patients were lacking.
The study was supported in part by grants from the National Cancer Institute, the Leukemia Lymphoma Society, and the Swedish Childhood Cancer Foundation. Dr. Holmqvist and her associates reported no conflicts of interest.
SOURCE: Holmqvist AS et al. JAMA Oncol. 2018 Jul 26. doi: 10.1001/jamaoncol.2018.2453.