Adaptive radiotherapy in paediatric patients: a SIOP Europe ROWG survey on practice patterns across Europe

Adaptive radiotherapy (ART) is increasingly recognized for its potential to optimize treatment accuracy by adjusting to anatomical changes during therapy. In children, who are particularly sensitive to radiation-induced toxicities and experience rapid anatomical changes, ART could be especially beneficial. We conducted an online survey to assess the current state of ART in children across Europe.

A 21-question survey regarding ART implementation, techniques, indications, and technical infrastructure was distributed online to SIOP-Europe affiliated centres.

Sixty responses from 18 European countries were received. ART was available for children in 68% of centres. Most frequent sites for implementation were pelvis, abdomen, and head-and-neck, with an average of 20% of respondents using ART for >75% of these cases. Higher-volume centres were more likely to implement ART (r = 0.34, P = .048). Fifteen percent performed daily adaptation, while 75% applied it only for major anatomical changes. Half of the centres used offline and 24% online ART. Specific infrastructure included Ethos (21%), MR-LINAC (5%), and Tomotherapy (13%). Automatic contouring was mostly used for OARs (57%). Barriers to implementation included a need for more evidence (50%), specialized equipment (52%) and guidelines (39%).

ART use in paediatric patients is highly variable and remains limited. Only a subset of centres reported routine use of ART, with notable variation in frequency and criteria for adaptation.

This is the first Europe-wide survey to comprehensively map ART practices in paediatric oncology, revealing substantial heterogeneity and identifying key barriers to wider adoption, representing a base to guide standardization and future clinical validation.