title: External beam radiotherapy for colon cancer: patterns of care.
abstract: OBJECTIVE
  Despite its common and well characterized use in other gastrointestinal malignancies, little is known about radiotherapy (RT) use in nonmetastatic colon cancer in the United States. To address the paucity of data regarding RT use in colon cancer management, we examined the RT patterns of care in this patient population.
  
  
  METHODS
  Patients with nonmetastatic colon cancer, diagnosed between 1988 and 2005, were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate methods were used to identify factors associated with RT use.
  
  
  RESULTS
  On univariate analysis, tumor location, age, sex, race, T stage, N stage, and geographic location were each associated with differences in RT use (all p < 0.01). In general, younger patients, male patients, and patients with more advanced disease were more likely to receive RT. On multivariate analysis, tumor location, age, gender, T and N stage, time of diagnosis and geographic location were significantly associated with RT use (all p < 0.001). Race, however, was not associated with RT use. On multivariate analysis, patients diagnosed in 1988 were 2.5 times more likely to receive RT than those diagnosed in 2005 (p = 0.001). Temporal changes in RT use reflect a responsiveness to evolving evidence related to the therapeutic benefits of adjuvant RT.
  
  
  CONCLUSIONS
  External beam RT is infrequently used for colon cancer, and its use varies according to patient and tumor characteristics. RT use has declined markedly since the late 1980s; however, it continues to be used for nonmetastatic disease in a highly individualized manner.
authors.affiliation: Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA. dunn@humonc.wisc.edu
authors.forename: Emily F
authors.initials: EF
authors.lastname: Dunn
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Kozak
authors.forename: John S
authors.initials: JS
authors.lastname: Moody
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D003110:Colonic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D018714:Radiotherapy, Adjuvant / Q000706:statistics & numerical data; D018426:SEER Program; D012737:Sex Factors; D055815:Young Adult