Initiated through ESGO the decision to develop multidisciplinary guidelines has been made jointly by the ESGO, ESTRO, and ESP. The ESGO has provided administrative support. The ESGO, ESTRO and ESP are nonprofit knowledgeable societies.The development group (including all authors) is collectively responsible for the decision to submit for publication. Nicole Concin (chair), Carien L. Creutzberg (cochair), Xavier Matias-Guiu (co-chair) and François Planchamp (methodologist) have written the first draft of the manuscript. All other contributors have actively given personal input, reviewed the manuscript, and have given final approval before submission.