How aspirin lowers cancer risk is unknown

NEW YORK, Oct. 14 (UPI) -- Aspirin may reduce the recurrence of colorectal polyps but how that happens is still a mystery, U.S. researchers say.

The study, reported in the Journal of the National Cancer Institute, tested the hypothesis aspirin affects cancer by affecting inflammation markers.

Researchers at Albert Einstein College of Medicine in New York, led by Gloria Ho, found changes of five inflammation markers -- C-reactive protein, interleukin 6, tumor necrosis factor, soluble TNF receptor type II and IL-1 receptor antagonist -- are not associated with adenoma recurrence. Adenomas are benign tumors that over time may progress to become malignant.

Inflammation markers do not appear to be involved with aspirin's preventative effect on colorectal adenomas, the researchers say.

The researchers looked at inflammation marker changes in 884 subjects divided into three aspirin groups -- including an aspirin placebo group and two folic acid groups including a folic acid placebo group. Dietary folic acid -- a B vitamin -- has also been linked with less colorectal cancers.

"Our data suggest that low-dose aspirin has modest effects on stabilizing C-reactive protein, which may be abrogated by a high level of folate," the study authors say in a statement. "However, such beneficial effects do not appear to confer protection against colorectal neoplasia. Inflammation markers do not mediate the previously observed effects of aspirin and folic acid on colorectal adenomas."