Abstract: PB2157
Type: Publication Only
Background
Body mass index (BMI) may influence outcome after allogeneic transplantation. Previous studies have demonstrated that being obese or underweight may have a detrimental effect on survival rates after chemotherapy induction in children with acute leukemia. However, the impact of BMI of transplanted patients on survival is still not clear, with conflicting results being reported on this issue.
Aims
To analyze the effect of BMI on UCBT outcomes in children with acute leukemia
Methods
We retrospectively analyzed 517 patients aged from 2 to 20 years with acute leukemia who underwent umbilical cord blood transplantation (UCBT) from 1990 to 2015. Patients were classified according to BMI as normal (5th-85th percentile), underweight (<5th percentile), overweight (85th-95th percentile) and obese (>95th percentile) by using growth charts for age and gender.
Results
Sixty-one percent (n=314) of patients were in the normal category, 12% (n=63) were underweight, 15% (n=80) overweight and 12% (n=60) obese. All patients received single-unit UCBT after a myeloablative conditioning regimen. Diagnosis was acute lymphoid leukemia in 70% (n=363) and acute myeloid leukemia in 30% (n=154). Median age at UCBT was 7.4 years (range 2-19.6). Cytomegalovirus (CMV) serology was positive in 45% patients; 60% of patients were male. Most patients (92%) were in complete remission at UCBT. Median follow-up was 52 months (range 2-201). Total body irradiation (> 6 Gy) was used in 58% of cases; antithymocyte globulin (ATG) in 68% of cases. Median infused total nucleated cell (TNC) dose was 4.2x107/Kg (0.3-17.8); 56% of patients received a graft with 0-1 HLA mismatch donor. Four-year overall survival (OS), leukemia-free survival (LFS) and graft-versus-host disease-free, relapse-free survival (GRFS) were 45±2%, 43±2% and 35±2%, respectively. Cumulative incidence function (CIF) of neutrophil engraftment was 88.6% (85.9-91.4%). CIF for acute GVHD was 34% (30.1-38.4%) at 100 days.
At 4 years chronic GVHD was 19.1% (15.7-23.3%), relapse incidence was 34.5% (30.1-38.9%) and non-relapse mortality (NRM) was 22.8% (19.2-26.7%). In univariate analysis, no statistically significant difference in OS, LFS, GRFS, neutrophil engraftment, NRM and chronic GVHD between the 4 groups identified according to BMI was identified. Conversely, acute GVHD was 44.3% (33.3-58.8%) for underweight, 36% (31-41.8%) for normal, 26.2% (18.1-38%) for overweight and 23.3% (14.7-37.1%) for obese (p=0.03). Among patients underweight who experienced acute GVHD (n=27), 37.5% had grade III-IV acute GVHD with gut involvement.
In multivariate analysis, infused TNC dose>4.2x107/Kg was associated with higher neutrophil engraftment (HR=1.46, CI 95% 1.18-1.82, p=0.001). Positive CMV serology (HR=1.5, CI 95% 1.04-2.26, p=0.03) and female gender (HR=1.5, CI 95% 1.03-2.23, p=0.03) were associated with higher NRM. ATG use (HR=1.6, CI 95% 1.05-2.31, p=0.03) was associated with higher relapse incidence. Moreover, ATG use and a positive CMV serology were associated with worse OS (HR=1.6, CI 95% 1.15-2.17, p=0.04 and HR=1.3, CI 95% 1.01-1.69, p<0.001, respectively) and LFS (HR=1.6, CI 95% 1.17-2.16, p<0.001 and HR=1.34, CI 95% 1.04-1.72, p=0.02, respectively).
Infused TNC >4.2x107/Kg (HR=1.5, CI 95% 1.07-2.14, p=0.02), lack of ATG in the conditioning (HR=2.72, CI 95% 1.6-3.1, p<0.001) and BMI <5th percentile (HR=1.8, CI 95% 1.19-2.78, p<0.001) were associated with higher incidence of acute grade II-IV GVHD.
Conclusion
In conclusion, we did not find association of obesity with transplant outcomes in this study population. However a BMI < 5th percentile at UCBT was found to be associated with higher risk of acute GVHD, highlighting the importance of nutritional status before UCBT.
Session topic: 22. Stem cell transplantation - Clinical
