Women who take aspirin daily may reduce their risk of ovarian cancer by 20 percent, report a team of medical scientists who reviewed reams of data pooled from 12 large studies.
The research, reported in the current issue of the Journal of the National Cancer Institute, was conducted by institute scientists and adds credence to a provocative notion: The old medicine cabinet standby may possess potent anti-cancer properties.
"Our study suggests that aspirin regimens -- proven to protect against heart attack -- may reduce the risk of ovarian cancer as well," said Dr. Britton Trabert of the NCI's cancer epidemiology and genetics division.
Dr. Vincent Yang, chairman of medicine at Stony Brook University Hospital, said aspirin and cancer prevention have a long and storied past.
"Aspirin is an anti-inflammatory agent. So by suppressing inflammation, you can reduce the risk," said Yang, who was not involved in the NCI analysis.
He added that while intriguing, the research is not strong enough to recommend aspirin as a preventive. Aspirin can cause side effects, especially gastrointestinal bleeding, Yang said.
Trabert and NCI colleague Dr. Nicolas Wentzensen conducted the type of study known as a meta-analysis. They re-examined previously published data.
From the 12 large studies they reviewed -- nine from the United States -- 8,000 women were involved.
Each participant took one of three types of medications: aspirin; other nonsteroidal anti-inflammatory drugs -- NSAIDs -- such as ibuprofen; or, acetaminophen, a pain reliever that doesn't reduce inflammation.
Aspirin takers had the highest risk reduction. For those who took non-aspirin NSAIDs, the outcome was less clear.
The scientists found only a 10 percent risk reduction among women who took an NSAID at least once per week. Acetaminophen, they said, was not associated with reduced ovarian cancer risk.
Dr. Michael Pearl, director of Stony Brook University Hospital's division of gynecological oncology, said as tantalizing as the study's results seem, he will not recommend aspirin as a preventive.
"When would you start recommending aspirin usage? Age 16 or when a woman is in her forties?" Pearl asked.
"This wasn't a prospective trial," Pearl said, referring to a randomized, placebo-controlled study, in which participants would take specific aspirin doses and results are compared with placebo takers.
Pearl defines ovarian cancer as the most lethal among gynecologic malignancies, its vague symptoms usually translating into late detection.
Trabert noted the study wasn't designed to influence clinical recommendations.
"Dosages [were] not uniform across participants," Trabert said of women who consumed varying aspirin doses. "We saw that participants who used aspirin daily . . . had a 20 percent lower risk of ovarian cancer compared to participants who did not use aspirin regularly."
Trabert's research, however, hails from a deepening well of scientific scholarship, which demonstrates that the pennies-per-dose drug has a powerful impact on cancer prevention.
Two weeks ago, scientists in Boston noted the risk of multiple myeloma -- a cancer involving blood-forming cells in the bone marrow -- also appears lower among aspirin takers.
Malignant melanoma, colorectal and breast cancers also may be lower among aspirin users, studies show.