title: Frequency distribution of second solid cancer locations in relation to the irradiated volume among 115 patients treated for childhood cancer.
abstract: OBJECTIVE
  To provide better estimates of the frequency distribution of second malignant neoplasm (SMN) sites in relation to previous irradiated volumes, and better estimates of the doses delivered to these sites during radiotherapy (RT) of the first malignant neoplasm (FMN).
  
  
  METHODS
  The study focused on 115 patients who developed a solid SMN among a cohort of 4581 individuals. The homemade software package Dos_EG was used to estimate the radiation doses delivered to SMN sites during RT of the FMN. Three-dimensional geometry was used to evaluate the distances between the irradiated volume, for RT delivered to each FMN, and the site of the subsequent SMN.
  
  
  RESULTS
  The spatial distribution of SMN relative to the irradiated volumes in our cohort was as follows: 12% in the central area of the irradiated volume, which corresponds to the planning target volume (PTV), 66% in the beam-bordering region (i.e., the area surrounding the PTV), and 22% in regions located more than 5 cm from the irradiated volume. At the SMN site, all dose levels ranging from almost zero to >75 Gy were represented. A peak SMN frequency of approximately 31% was identified in volumes that received <2.5 Gy.
  
  
  CONCLUSIONS
  A greater volume of tissues receives low or intermediate doses in regions bordering the irradiated volume with modern multiple-beam RT arrangements. These results should be considered for risk-benefit evaluations of RT.
authors.affiliation: U605 Institut National de la Santé et de la Recherche Médicale, Villejuif, France. ibrahim.diallo@igr.fr
authors.forename: Ibrahima
authors.initials: I
authors.lastname: Diallo
authors.forename: Nadia
authors.initials: N
authors.lastname: Haddy
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Adjadj
authors.forename: Akhtar
authors.initials: A
authors.lastname: Samand
authors.forename: Eric
authors.initials: E
authors.lastname: Quiniou
authors.forename: Jean
authors.initials: J
authors.lastname: Chavaudra
authors.forename: Iannis
authors.initials: I
authors.lastname: Alziar
authors.forename: Nathalie
authors.initials: N
authors.lastname: Perret
authors.forename: Sylvie
authors.initials: S
authors.lastname: Guérin
authors.forename: Dimitri
authors.initials: D
authors.lastname: Lefkopoulos
authors.forename: Florent
authors.initials: F
authors.lastname: de Vathaire
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009369:Neoplasms / Q000532:radiotherapy*; D009381:Neoplasms, Radiation-Induced / Q000473:pathology*; D016609:Neoplasms, Second Primary / Q000473:pathology*; D011879:Radiotherapy Dosage; D017741:Survivors