title: Racial and ethnic disparities in outcomes with radiation therapy for rectal adenocarcinoma.
abstract: BACKGROUND
  Race/ethnicity may modify cancer outcomes and manifest as survival disparities for patients with rectal cancer. Our objective was to determine whether disparate rectal cancer outcomes result from variable efficacy of radiation therapy for major racial/ethnic groups.
  
  
  METHODS
  The Los Angeles County Cancer Surveillance Program (CSP) identified patients with rectal adenocarcinoma between the years 1988 and 2006. Patients who underwent curative-intent surgery were grouped by race/ethnicity and by receipt (yes vs. no) and timing (neoadjuvant vs. adjuvant) of radiation therapy. The impact of receipt and timing of radiation therapy on overall survival was then assessed.
  
  
  RESULTS
  Of 4,961 patients in CSP, 2,229 (45%) received radiation therapy. Overall, there was no difference in survival among patients according to receipt of radiation therapy. We then examined the radiation cohort, wherein 919 (41%) and 1,310 (59%) patients received neoadjuvant or adjuvant radiation, respectively. Overall, patients who received neoadjuvant compared to adjuvant radiation had improved survival (median survival (MS), 9.4 vs. 6.8 years, respectively; p < 0.001). Among those patients who received neoadjuvant radiation, whites, Hispanics, and Asians had significantly longer survival than blacks (MS, 10.4, 10.4, and 10.4 vs. 4.4 years, respectively; p = 0.003). On multivariate analysis, race/ethnicity was an independent predictor of survival (p = 0.001).
  
  
  CONCLUSIONS
  To our knowledge, this is the first study examining the efficacy of radiation therapy for racial/ethnic groups with rectal cancer. Disparate outcomes were observed for the administration of radiation therapy for select racial/ethnic groups. The reasons for these disparities in outcomes should be investigated to better optimize radiation therapy for patients with rectal cancer.
authors.affiliation: Department of Surgery, City of Hope Comprehensive Cancer Center, 1500 East Duarte Road, Duarte, CA 91010, USA.
authors.forename: Wendy
authors.initials: W
authors.lastname: Lee
authors.forename: Rebecca
authors.initials: R
authors.lastname: Nelson
authors.forename: Yasir
authors.initials: Y
authors.lastname: Akmal
authors.forename: Brian
authors.initials: B
authors.lastname: Mailey
authors.forename: Shaun
authors.initials: S
authors.lastname: McKenzie
authors.forename: Avo
authors.initials: A
authors.lastname: Artinyan
authors.forename: Kimlin Tam
authors.initials: KT
authors.lastname: Ashing-Giwa
authors.forename: Yi-Jen
authors.initials: YJ
authors.lastname: Chen
authors.forename: Julio
authors.initials: J
authors.lastname: Garcia-Aguilar
authors.forename: Joseph
authors.initials: J
authors.lastname: Kim
mesh_terms: D000230:Adenocarcinoma / Q000208:ethnology* / Q000532:radiotherapy*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005006:Ethnicity; D005260:Female; D054625:Healthcare Disparities; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy; D044469:Racial Groups; D012004:Rectal Neoplasms / Q000208:ethnology* / Q000532:radiotherapy*; D012959:Socioeconomic Factors; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult