Session Item

The endpoint of this research is to evaluate renal toxicity in paediatric patients with high-risk neuroblastoma who have received radiotherapy (RT) as part of their multimodal treatment.

Renal function was analyzed through creatinine clearance (CrCl) calculated according to Shull's formula in pediatric patients diagnosed with high-risk neuroblastoma. These received radiotherapy as part of the definitive treatment between January 2004 and May 2020 in a single institution.

A comparison of blood urea nitrogen (BUN), creatinine and creatinine clearance (CrCl, according to Shull's formula) was evaluated between the last laboratory analysis before treatment, one month after treatment (median = 31 days) and the last one in follow-up. Only routine tests were selected.

All CT (computed tomography) and MRI (magnetic resonance imaging) images performed after treatment were reviewed for the presence of renal atrophy.

We performed subgroup analyzes based on age in treatment, presence of nephrectomy, follow-up period, abdominal radiotherapy, evidence of kidney damage in imaging tests and using of more than one chemotherapy regimen.

Data were analyzed using a paired Student's t-test, Wilcoxon test and a post-hoc intergroup analysis through an ANOVA test for repeated measures adjusted by Bonferroni. We considered a significant result if p value < 0.05. The Saphiro-Wilk test was used to study normality.

31 children with median age of 38 month at diagnosis were treated with RT as a radical aim. All patients received 21 Gy in 14 sessions with IMRT (intensity-modulated radiotherapy).

In the analysis by subgroups, we only found a significant decrease (p value = 0.034) in CrCl in patients below four years old treated with RT (n = 16), however, the values ​​remained within the non-pathological physiological range (Table 1).

A post-hoc intergroup analysis compared the means of the three laboratory determinations (before treatment, one month after treatment and at the end of follow-up) without finding significant differences (Table 2).

The main side effects in the imaging tests were renal atrophy (32.3%), increased vertebral uptake (16.1%) and scoliosis (3.2%).

Moreover, two patients (6.4%) developed arterial hypertension that required treatment. No patient developed significant renal dysfunction.

Table 1

Table 2

Our cohort presented an excellent renal outcome after radiotherapy. A significant decrease in creatinine clearance has been observed in patients under four years of age when treated with radiotherapy. Nevertheless, the renal function always remained within the non-pathological physiological range, therefore this finding is not clinically relevant.

Pathological values ​​that suggest renal failure have not been obtained in any determination. No patient developed chronic renal dysfunction.