title: Second cancer after radiotherapy, 1981-2007.
abstract: OBJECTIVE
  Today, there is growing concern about radiotherapy induced secondary malignancies. We analysed the incidence and dose dependence of second cancer.
  
  
  METHODS
  The study includes 12,000 one-year survivors of radiotherapy, treated between 1981 and 2007. For risk estimates a public databank on cancer in Germany served as reference. Contralateral second breast cancer, second oesophageal and colorectal cancer were analysed with retrospective dosimetry. GI-tract data were used for risk modelling.
  
  
  RESULTS
  The incidence rate of second cancers (493 cases) was ~1% per year. Contralateral breast cancer was the most frequent entity (relative risk RR=2.8). The scatter-dose gradient (2-3 Gy) across the contralateral breast did not cause a detectable risk gradient. There was an increased risk for second head and neck cancer (RR=5.1) and for male oesophageal cancer (RR=5.8). For both entities, dose response modelling with case-control data predicted maximum curves with peak induction at 1-5 Gy and positive excess absolute risk values at high doses.
  
  
  CONCLUSIONS
  A survey of second cancer after radiotherapy requires follow-up over decades. Preliminary dose response modelling albeit with low case numbers suggests an increased risk from multiportal techniques. To improve risk assessment, prospective out-of-field dosimetry and long-term multicentre data collection are recommended.
authors: Department of Radiation Oncology, University Hospital Ulm, Germany. detlef.bartkowiak@uniklinik-ulm.de
authors: Detlef
authors: D
authors: Bartkowiak
authors: Nicole
authors: N
authors: Humble
authors: Peter
authors: P
authors: Suhr
authors: Juliane
authors: J
authors: Hagg
authors: Katharina
authors: K
authors: Mair
authors: Bernd
authors: B
authors: Polivka
authors: Uwe
authors: U
authors: Schneider
authors: Dirk
authors: D
authors: Bottke
authors: Thomas
authors: T
authors: Wiegel
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000209:etiology; D004307:Dose-Response Relationship, Radiation; D004938:Esophageal Neoplasms / Q000453:epidemiology / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology / Q000209:etiology*; D016609:Neoplasms, Second Primary / Q000453:epidemiology / Q000209:etiology*; D011878:Radiotherapy / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D013997:Time Factors