title: Two Metachronous Neoplasms in the Radiotherapy Fields of a Young Man With Familial Adenomatous Polyposis.
abstract: BACKGROUND
  It is recognized that various radiation-induced malignancies often follow childhood radiotherapy. Radiation-induced neoplasms have been shown to occur with increased frequency in syndromes due to mutated tumor suppressor genes. There exist no recommendations for the management of cancer patients with germline APC gene mutations. Preclinical data suggest that APC gene mutations cause enhanced radiosensitivity, but no clinical observations exist that show that patients with this mutation are at higher risk for radiation-induced malignancies.
  
  
  RESULTS
  We report the case of a 32-year-old man with a genetic diagnosis of familial adenomatous polyposis (FAP) who initially presented at age 10 with a medulloblastoma treated with radiotherapy and surgery. Radiation-induced papillary thyroid carcinoma followed 13 years later. Finally, radiation-induced soft tissue osteosarcoma occurred with widespread metastasis 20 years thereafter.
  
  
  CONCLUSIONS
  This is the first report of 2 malignancies in the prior radiotherapy fields of a patient with a genetic diagnosis of FAP. More important, this suggests that APC-defective cells are at an enhanced sensitivity to the carcinogenic effects of radiotherapy compared with APC-proficient cells. This could argue for genetic screening in affected members of these families and for creation of treatment recommendations to more seriously consider the risks of radiation therapy.
authors.affiliation: University of Mississippi Medical Center, Jackson, MS, USA.
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Williams
authors.affiliation: University of Mississippi Medical Center, Jackson, MS, USA.
authors.forename: Feriyl
authors.initials: F
authors.lastname: Bhaijee
authors.affiliation: University of Mississippi Medical Center, Jackson, MS, USA.
authors.forename: Luminita
authors.initials: L
authors.lastname: Rezeanu
authors.affiliation: University of Mississippi Medical Center, Jackson, MS, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Hamilton
authors.affiliation: University of Mississippi Medical Center, Jackson, MS, USA.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Vijayakumar
keywords: APC gene; FAP; radiation-induced neoplasm; tumor suppressor gene