A dose-finding study of aspirin for chemoprevention utilizing rectal mucosal prostaglandin E2levels as a biomarker

Dory Sample, Michael Wargovich, Susan M. Fischer, Nikil Inamdar, Peter Schwartz, Xuemei Wang, Kim Anh Do, Frank A. Sinicrope

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


Epidemiological and experimental evidence indicates that aspirin can protect against colorectal cancer. Aspirin inhibits cyclooxygenase enzymes and blocks prostaglandin (PG) biosynthesis. Using rectal PGE2levels as a mucosal biomarker, we sought to determine the optimal aspirin dose that would significantly suppress PGE2levels for chemoprevention trials. We conducted a randomized, double-blinded study in 60 subjects with prior sporadic colorectal adenoma(s) and evaluated three aspirin doses (81, 325, and 650 mg) or placebo taken daily for 4 weeks. PGE2levels in rectal biopsies performed at baseline and week 4 were analyzed by competitive immunoassay. Plasma salicylate levels, pill counts, and subject calendars were used to assess compliance. The 81-mg aspirin dose significantly suppressed PGE2levels relative to placebo (P = 0.005) and did so to an equivalent extent as did higher doses (P > 0.4) in evaluable subjects (n = 55) over a 4-week treatment period. Serum salicylate levels were associated with aspirin dose (P = 0.0002). Pill counts and calendars indicated that >98% of doses were taken by all subjects. No adverse events occurred in this short-term study. The 81-mg daily aspirin dose suppressed PGE2levels to an equivalent extent as did the 650-mg dose and supports the use of this dose for chemoprevention trials.

Original languageEnglish (US)
Pages (from-to)275-279
Number of pages5
JournalCancer Epidemiology Biomarkers and Prevention
Issue number3
StatePublished - 2002

ASJC Scopus subject areas

  • Epidemiology
  • Oncology


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