s ingediend voor het Amsterdam Kindersymposium 2013 67 Existing radiotherapy dose quantification methods in published late effects studies: a review of the literature Judith L. Kok MSc (1,12), Wil V. Dolsma MD PhD (2,12), Flora E. van Leeuwen PhD (3,12), Marry M. van den Heuvel-Eibrink MD PhD (4,12), Wim J.E. Tissing MD PhD (5,12), Eline van Dulmen-den Broeder PhD (6,12), Jacqueline Loonen MD PhD (7,12), Dorine Bresters MD PhD (8,12), Birgitta A. Versluys MD (9,12), Irma W.E.M. van Dijk MSc (10), Berthe M.P. Aleman MD PhD (11), Huib N. Caron MD PhD (1,12), Arjen van der Schaaf PhD (2), Leontien C.M. Kremer MD PhD (1,12) and Cecile M. Ronckers PhD (1,12), for the Dutch Childhood Oncology Group (DCOG) LATER Dosimetry Research Group (1) Dept. of Pediatric Oncology, Emma Children’s Hospital/Academic Medical Center, Amsterdam, the Netherlands (2) Dept. of Radiation Oncology, University Medical Center Groningen, Groningen, the Netherlands (3) Dept. of Psychosocial Research and Epidemiology, the Netherlands Cancer Institute, Amsterdam, the Netherlands (4) Dept. of Pediatric Oncology, Sophia Children’s Hospital/Erasmus Medical Center, Rotterdam, the Netherlands (5) Dept. of Pediatric Oncology and Hematology, University Medical Center Groningen, Groningen, the Netherlands (6) Dept. of Pediatric Oncology, Free university Medical Center, Amsterdam, the Netherlands (7) Dept. of Pediatric Oncology and Hematology, Radboud University Medical Center, Nijmegen, the Netherlands (8) Willem Alexander Children’s Hospital, Leiden University Medical Center, Leiden, the Netherlands (9) Dept. of Pediatric Oncology and Hematology, University Medical Center Utrecht, Utrecht, the Netherlands (10) Dept. of Radiation Oncology, Academic Medical Center, Amsterdam, the Netherlands (11) Dept. of Radiotherapy, the Netherlands Cancer Institute, Amsterdam, the Netherlands (12) Dutch Childhood Oncology Group Late Eff ects after Childhood Cancer (DCOG-LATER) Consortium INTRODUCTION Radiotherapy (RT) is widely used in childhood cancer (CC) therapy. Combined therapies, including RT, greatly increased survival, but also cause adverse health eff ects because healthy organs (organs at risk: OAR) absorb varying levels of the prescribed tumour dose. Risk estimation for late eff ects in retrospective studies requires appropriate dose estimation. We aim to provide a review of various RT dose quantifi cation methods used in late eff ects studies, including advantages and drawbacks. METHODS A Pubmed search was performed to identify eligible studies, i.e. late eff ects studies published between 2002 and 2012, describing methods that quantify RT dose and including at least 100 long-term CC survivors. Titles and abstracts were screened by two independent reviewers (JK, CR). RESULTS The search resulted in 1782 studies; of which 70 fulfi lled the inclusion criteria. We categorized RT dose quantifi cation methods into three main groups (Table 1). Retrospective dose reconstruction (1) provides information about absorbed dose at OAR. Eff ects of various Table 1. Categorization of RT dose quantifi cation methods Category Explanation Advantages Drawbacks 1. Retrospective dose reconstruction Dose calculation by mathematical phantom Absorbed dose at OAR Volume and fraction size typically not reported 2. Radiobiological dose metrics Recalculation of total dose and dose per fraction according to biological eff ectiveness Uniform comparison of various fractionation schedules Prescribed tumour dose as surrogate of absorbed dose 3. Prospective RT registration Documentation of absorbed dose to OAR as calculated by modern RT planning systems Dose and volume at OAR available Requires high-quality long-term prospective, clinical follow-up