COX-2 is upregulated in most colorectal cancers. Most of the COX-2 tumor–inducing effects are believed to be mediated through overproduction of prostaglandin E2 (PGE2), which can be measured using a urinary metabolite of PGE2, PGE-M. Urinary PGE-M was assessed in a case–control study of colorectal adenoma. Included in the analysis were 224 cases with at least one advanced adenoma, 152 cases with multiple small tubular adenomas, 300 cases with only a single small tubular adenoma, and 364 polyp-free controls. There were no statistical differences in PGE-M levels between controls and cases with a single small tubular adenoma. However, cases with either an advanced adenoma or multiple small tubular adenomas had more than 25% higher levels of PGE-M than controls. Participants with the highest quartile level of PGE-M were approximately 2.5-fold more likely to have advanced or multiple small tubular adenoma in comparison with those with the lowest level of PGE-M [OR = 2.53; 95% confidence interval (CI), 1.54–4.14; Ptrend < 0.001]. The association was strongest among women. PGE-M level was associated with increased risk for multiple or advanced adenoma but not single small adenoma. Our study suggests that PGE-M may be a useful risk marker for assessing the risk of harboring clinically more important versus less important colorectal neoplasia. Cancer Prev Res; 5(2); 336–42. ©2011 AACR.
- Received September 9, 2011.
- Revision received November 30, 2011.
- Accepted December 1, 2011.
- ©2011 American Association for Cancer Research.