Treatment outcomes in children with Acute lymphoblastic leukemia with versus without coexisting Down's syndrome: A systematic review and meta-analysis

BACKGROUND: Down syndrome (DS) also known as Trisomy 21, is a chromosomal disorder affecting approximately 1 in 732newborns annually in the United States. Children with DS are more likely to develop acute lymphoblastic leukemia (ALL). For the management of pediatric ALL, different treatment protocols have been set up since years. However, ALL children with coexisting DS have shown to have increased therapy-related toxicities compared to those without DS. Therefore, in this study, we aimed to systematically analyze the treatment outcomes in acute ALL children with versus without coexisting DS. METHODS: Electronic databases including the Web of Science, EMBASE, Cochrane Central, MEDLINE, http://www.ClinicalTrials.gov, and Google scholar were searched for publications reporting treatment related outcomes in ALL children with versus without co-existing DS. Several treatment protocols were used accordingly. This study had a long-term follow-up time period ranging from 5 to 10 years. The RevMan 5.3 software was used to carry out this analysis. Odds ratios (OR) with 95% confidence intervals (CI) were used to represent the results post analysis. RESULTS: A total number of 31,476 children with ALL enrolled between the years 1981 and 2011 were included. Among the total number of children with ALL, 1303 had coexisting DS. Our results showed that event-free survival was similar in ALL children with versus without DS (odds ratio [OR]: 1.34, 95% confidence interval [CI]: 0.51–3.50; P = .55). Overall mortality (OR: 1.63, 95% CI: 0.86–3.10; P = .13) and participants who achieved clinical remission (OR: 1.04, 95% CI: 0.12–9.29; P = .97) were also similarly manifested. However, treatment-related mortality (OR: 4.29, 95% CI: 2.90–6.36; P = .00001) and induction failure (OR: 2.77, 95% CI: 1.08–7.07; P = .03) were significantly higher in the DS group. Also, total (OR: 1.38, 95% CI: 1.02–1.88; P = .04) and bone marrow relapses (OR: 1.29, 95% CI: 1.00–1.67; P = .05) were significantly higher in ALL children with DS. Nevertheless, central nervous system relapse (OR: 1.15, 95% CI: 0.60–2.20; P = .67), testicular relapse (OR: 0.84, 95% CI: 0.38–1.85; P = .87), and other relapses (OR: 1.12, 95% CI: 0.27–4.62; P = .88) were not significantly different when these outcomes were separately analyzed. CONCLUSION: Based on this analysis of the treatment outcomes in ALL children with versus without DS, event-free survival, overall mortality, and patients who achieved clinical remission were similar during this long-term follow-up time period. However, due to the significantly higher treatment-related mortality, induction failure, and certain relapses in ALL children with DS, new guidelines might have to focus on reconsidering or modifying treatment regimens for ALL children with DS.