Timing of Radiation Therapy in Pediatric Wilms Tumor – A Report from the National Cancer Database
Menée à partir des données du registre national américain portant sur 1 488 patients âgés de 25 ans ou moins et atteints d'une tumeur de Wilms diagnostiquée entre 2004 et 2013, cette étude évalue, en fonction de la présence de métastases, l'effet du délai entre le traitement chirurgical et la radiothérapie sur la survie des patients
Purpose : Many patients with Wilms tumor (WT) will require adjuvant radiotherapy in addition to surgery and chemotherapy. National Wilms Tumor Studies (NWTS) 1 and 2 found delayed radiation correlated with relapse; however, subsequent analyses have not confirmed this finding. We used the National Cancer Database (NCDB) to determine the impact of the surgery-to-radiotherapy interval (SRI) on survival in contemporary patients with WT. Methods : The NCDB was queried for patients aged ≤25 years diagnosed from 2004-2013 with unilateral WT who underwent definitive surgery and radiotherapy. The SRI was calculated for each patient. A stratified analysis was performed based on presence of metastasis using logistic regression to calculate risk factors for prolonged SRI, with a focus on the recommended SRI according to recent Children’s Oncology Group trials (by day 14) and NWTS-5 (by day 9). Cox regression was performed to assess the association of SRI with overall survival. Results : A total of 1,488 patients were included; 32.1% had metastasis at diagnosis. Among both metastatic and non-metastatic groups, older patients were more likely to have prolonged SRI. For those without metastasis, SRI >14 days was associated with increased risk of mortality (HR 2.13, p=0.013). Analyzing SRI as a continuous variable also demonstrated an increased risk of death with longer SRI (HR 1.04 per day, p=0.006) in this group. In contrast, among patients with metastasis, no significant association between SRI and mortality was found. Conclusion : Early initiation of radiotherapy remains a critical component of multimodal treatment for patients with non-metastatic WT. For non-metastatic patients, SRI ≤14 days correlates with improved overall survival. However, no such association was noted for patients with metastases. These results may inform the development of future WT trials.