title: The role of chemoprevention by selective cyclooxygenase-2 inhibitors in colorectal cancer patients - a population-based study.
abstract: BACKGROUND
  There are limited population-based studies focusing on the chemopreventive effects of selective cyclooxygenase-2 (COX-2) inhibitors against colorectal cancer. The purpose of this study is to assess the trends and dose-response effects of various medication possession ratios (MPR) of selective COX-2 inhibitor used for chemoprevention of colorectal cancer.
  
  
  METHODS
  A population-based case-control study was conducted using the Taiwan Health Insurance Research Database (NHIRD). The study comprised 21,460 colorectal cancer patients and 79,331 controls. The conditional logistic regression was applied to estimate the odds ratios (ORs) for COX-2 inhibitors used for several durations (5 years, 3 years, 1 year, 6 months and 3 months) prior to the index date.
  
  
  RESULTS
  In patients receiving selective COX-2 inhibitors, the OR was 0.51 (95% CI=0.29~0.90, p=0.021) for an estimated 5-year period in developing colorectal cancer. ORs showing significant protection effects were found in 10% of MPRs for 5-year, 3-year, and 1-year usage. Risk reduction against colorectal cancer by selective COX-2 inhibitors was observed as early as 6 months after usage.
  
  
  CONCLUSIONS
  Our results indicate that selective COX-2 inhibitors may reduce the development of colorectal cancer by at least 10% based on the MPRs evaluated. Given the limited number of clinical reports from general populations, our results add to the knowledge of chemopreventive effects of selective COX-2 inhibitors against cancer in individuals at no increased risk of colorectal cancer.
authors.affiliation: School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Yi-Hsin
authors.initials: YH
authors.lastname: Yang
authors.forename: Yea-Huei Kao
authors.initials: YH
authors.lastname: Yang
authors.forename: Ching-Lan
authors.initials: CL
authors.lastname: Cheng
authors.forename: Pei-Shan
authors.initials: PS
authors.lastname: Ho
authors.forename: Ying-Chin
authors.initials: YC
authors.lastname: Ko
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D018890:Chemoprevention / Q000379:methods; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000453:epidemiology* / Q000517:prevention & control*; D052246:Cyclooxygenase 2 Inhibitors / Q000008:administration & dosage*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012306:Risk; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
chemical_list: D052246:Cyclooxygenase 2 Inhibitors