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 journalArticle

46 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 - Jan 1 2002

ASJC Scopus subject areas

  • Epidemiology
  • Oncology

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