Obesity has become a pandemic, affecting both children and adults. We sought to determine the effect of obesity among 200 children who were prospectively enrolled on a multicenter cord blood transplant (CBT) trial. All patients received myeloablative preparative regimens. Children were classified into groups according to body mass index percentile. Normal weight was defined as body mass index between the 5th and 85th percentile (n=117), overweight between the 85th and 95th percentile (n=35) and obesity above 95th percentile (n=39) for age and gender. A total of 55 patients (27%) had AML, 113 patients (57%) had ALL and 32 patients (16%) had other malignant diseases. There was no evidence for a difference in all major characteristics among the groups. Time to neutrophil and platelet engraftment, TRM, risk of acute GVHD, disease-free survival and OS were not significantly different in overweight or obese patients compared with normal weight patients. There was a trend towards increased risk of chronic GVHD in obese patients (P=0.05) compared with normal weight patients. In conclusion, there is insufficient evidence from this sample that obesity has an effect on multiple outcomes after unrelated CBT in children with malignant diseases.

In the absence of a related donor, unrelated cord blood transplant (CBT) may be a potential option for patients with a primary immune deficiency (PID). Most published experience consists of single-center data using multiple preparative regimens and GVHD prophylaxis. We report the results of a multicenter prospective trial of unrelated CBT for PID. A total of 24 children with PID, with a median age of 1 year (range: 0.23-7.81 years) and a median weight of 10.5 kg (range: 4-24.4 kg) received unrelated CBT between 1999 and 2003. All patients received a fully ablative conditioning regimen with identical GVHD prophylaxis and supportive care. Most patients (79%) received a 1 or 2 HLA Ag-mismatched cord unit with a median nucleated cell infused of 9.3 Â 10 7 /kg (range: 1.0-31.2) and a median CD34 of 2.7 Â 10 5 /kg 2.9 (range: 0.6-84.5). The cumulative incidence of neutrophil engraftment by day 42 was 58% (95% CI: 38-79%) at a median of 19 days. Cumulative incidence estimates of grade III-IV acute GVHD at day 100 and chronic GVHD at 1 year were 29% (95% CI: 10-48%) and 24% (95% CI: 3-44%), respectively. The probability of survival at 180 days and 1 year was 66.7% (95% CI: 44.3-81.7%) and 62.5% (95% CI: 40.3-78.4%), respectively. Unrelated CBT should be considered in children with PID.

Purpose: Dose calculation accuracy for the out‐of‐field dose is important for predicting the dose to the organs‐at‐risk when they are located outside primary beams. The investigations on evaluating the calculation accuracy of treatment planning systems (TPS) on out‐of‐field dose in existing publications have focused on low energy (6MV) photon. This study evaluates out‐of‐field dose calculation accuracy of AAA algorithm for 15MV high energy photon beams. Methods: We used the EGSnrc Monte Carlo (MC) codes to evaluate the AAA algorithm in Varian Eclipse TPS (v.11). The incident beams start with validated Varian phase‐space sources for a TrueBeam linac equipped with Millennium 120 MLC. Dose comparisons between using AAA and MC for CT based realistic patient treatment plans using VMAT techniques for prostate and lung were performed and uncertainties of organ dose predicted by AAA at out‐of‐field location were evaluated. Results: The results show that AAA calculations under‐estimate doses at the dose level of 1% (or less) of prescribed dose for CT based patient treatment plans using VMAT techniques. In regions where dose is only 1% of prescribed dose, although AAA under‐estimates the out‐of‐field dose by 30% relative to the local dose, it is only about 0.3% of prescribed dose. For example, the uncertainties of calculated organ dose to liver or kidney that is located out‐of‐field is <0.3% of prescribed dose. Conclusion: For 15MV high energy photon beams, very good agreements (<1%) in calculating dose distributions were obtained between AAA and MC. The uncertainty of out‐of‐field dose calculations predicted by the AAA algorithm for realistic patient VMAT plans is <0.3% of prescribed dose in regions where the dose relative to the prescribed dose is <1%, although the uncertainties can be much larger relative to local doses. For organs‐at‐risk located at out‐of‐field, the error of dose predicted by Eclipse using AAA is negligible. This work was conducted in part using the resources of Varian research grant VUMC40590‐R.