Post‐operative flank irradiation using conformal versus highly conformal radiotherapy techniques for paediatric renal tumours: Results from the French registry PediaRT

Abstract

AbstractPurposeThree‐dimensional conformal RT (3D‐RT) techniques are gold standard for post‐operative flank radiotherapy (RT) in paediatric renal tumours. Recently, highly conformal RT (HC‐RT) techniques have been implemented without comparative clinical data. The main objective of this multicentre study was to compare locoregional control (LRC) in children treated either with HC‐RT or 3D‐RT techniques.MethodsPatients treated with post‐operative flank RT for renal tumour registered in the national cohort PediaRT between March 2013 and September 2019 were included. Treatment and follow‐up data, including toxicities and outcomes, were retrieved from the database. LRC was calculated, and dose reconstruction was performed in case of an event.ResultsSeventy‐nine patients were included. Forty patients were treated with HC‐RT and 39 with 3D‐RT. Median follow‐up was 4.5 years. Three patients had locoregional failure (LRF; 4%). HC‐RT was not associated with a higher risk of LRF. Three‐year LRC were 97.4% and 94.7% in the HC‐RT and 3D‐RT groups, respectively. The proportion of planning target volumes receiving 95% or more of the prescribed dose did not significantly differ between both groups (HC‐RT 88%; 3D‐RT 69%; p = .05). HC‐RT was better achieving dose constraints, and a significant mean dose reduction was observed in the peritoneal cavity and pancreas associated with lower incidence of acute gastrointestinal toxicity.ConclusionLRF after post‐operative flank RT for renal tumours was rare and did not increase using HC‐RT versus 3D‐RT techniques. Dose to the pancreas and the peritoneal cavity, as well as acute toxicity, were reduced with HC‐RT compared to 3D‐RT.