ESTRO 2022 - Abstract Book

S1220

Abstract book

ESTRO 2022

Materials and Methods Seventy-six patients who received adjuvant nodal RT after excision of node field recurrence following a previous node dissection between 1990 and 2011 were identified from the Melanoma Institute Australia database. The RT fractionation schedule (conventional fractionation or hypofractionation) was at the discretion of the treating radiation oncologist. Results Dissected lymph node fields were axilla (49%), groin (26%) and neck (25%). The median time to diagnosis of node field recurrence after initial nodal dissection was eight months (range 23 days-17 years). Salvage surgery varied from local excision of the recurrence to a “re-do” lymph node dissection, as considered appropriate for the individual patient. Involved surgical margins were reported in 19 patients (25%), and lymph nodes with extra-nodal spread in 18 (24%). Adjuvant RT with conventional fractionation (median dose 48 Gy in 20 fractions) was given to 43 patients (57%) and hypofractionated RT (median dose 33 Gy in 6 fractions) to 33 patients (43%). The median follow-up duration was 19 months (range 1-246 months). The five-year node field control rate was 70% (95% CI 59-84%) (figure), five-year RFS 17% (95% CI 10-29%), five- year MSS 26% (95% CI 18-39%) and five-year OS 25% (95% CI 17-38%).

Conclusion Despite the recurrence and the presence of high-risk features such as a positive margin in 25% of patients and extranodal spread in 24% of patients, node field control was achieved in 70% of patients. Therefore melanoma patients with resected isolated melanoma node field recurrence after a previous dissection may benefit from adjuvant RT. However, disease progression at distant sites was common and survival outcomes were poor. Unfortunately, comparing our node field control rate after salvage surgery and adjuvant RT with a cohort treated with salvage surgery without RT was not feasible due to very low number of patients. Prospective data to assess the role of adjuvant RT in the setting of systemic therapy with checkpoint inhibitors or targeted therapy is required to guide treatment decisions in this subgroup of patients at high risk of nodal as well as distant recurrence.

Poster (digital): Paediatric tumours

PO-1439 Renal toxicity in paediatric patients with high-risk neuroblastoma treated with radiotherapy

E. Gomis Selles 1 , A.M. Burgueño Caballero 1 , O. Muñoz Muñoz 1 , B.D. Delgado Leon 1 , P. Cabrera Roldan 1

1 Virgen del Rocio University Hospital, Radiation Oncology, Seville, Spain

Purpose or Objective 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. Materials and Methods 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.

Results