Acknowledgements
We would like acknowledge colleagues Thomas Carlslund, Bob Smulders, Nora Forbes, and Deborah Anne Schut at the Department of Clinical Oncology, Section of Radiotherapy, Copenhagen University Hospital, for their help to extract the data. Also, an acknowledgement to Heidi Rønde and Camilla Kronborg from the Danish Centre for Particle therapy, for helping with dose summation.
Data availability statement
Data not available due to ethical/legal restrictions.
Disclosure statement
The authors report there are no competing interests to declare.