Daily Aspirin to Prevent and Treat Cancer?

Cancer incidence and metastasis reduced with daily aspirin therapy

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Aspirin has long been the go-to drug to relieve common aches and pains. Its utility is reaching new heights these days as a potential drug to prevent and possibly treat cancer. Exciting stuff!

Three published papers have added to the growing evidence of aspirin's ability to keep cancer at bay.

"Ask your doctor if aspirin therapy is right for you. "

Professor Peter M. Rothwell of University of Oxford and John Radcliffe Hospital, and colleagues authored the papers, two of which appeared March 20, 2012 in The Lancet and one of which was published the same day in The Lancet Oncology.

Past research by this team has shown that taking an aspirin a day reduces the long-term risk of dying from cancer. The short-term effects, especially in women, have not been studied nor has the risk/benefit profile of aspirin over time.

The first study examined patient data from 51 randomized trials testing daily aspirin verses none to learn if the regimen prevented heart attacks and other vascular events. Researchers found in addition to reducing the risks of major cardiovascular events, daily low-dose aspirin:

  • Reduced the incidence of cancer by about one quarter - 23 percent in men and 25 percent in women - for those on the regimen three years and longer.
  • Reduced the risk of cancer death by 37 percent among those who took daily aspirin for five years or longer.

The side effect of major bleeding that was seen in daily aspirin use waned with extended use.

The authors write, "Alongside the previously reported reduction by aspirin of the long-term risk of cancer death, the short-term reductions in cancer incidence and mortality and the decrease in risk of major extracranial bleeds with extended use, and their low case-fatality, add to the case for daily aspirin in prevention of cancer."

The second study looked at the impact of aspirin on the spread - metastasis - of cancer. Researchers examined data regarding the metastasis of cancers that were diagnosed  during five randomized trials of daily aspirin (75 mg or more) verses control. These studies were also looking at the prevention of cardiovascular events.

After 6.5 years, researchers found the people taking aspirin experienced:

  • A 36 percent reduced risk of cancer with distant metastasis
  • A 46 percent reduction in common solid tumors (adenocarcinoma) of the colon, lung and prostate
  • An 18 percent reduced risk of bladder and kidney cancers
  • A nearly 50 percent reduction in the risk of dying from adenocarcinoma

"These findings provide the first proof in man that aspirin prevents distant cancer metastasis," said the authors.

"That aspirin prevents metastasis at least partly accounts for the reduced cancer mortality recently reported in trials of aspirin versus control in prevention of vascular events and suggests that aspirin will also be effective in treatment of some cancers," the conclude.

The third study analyzed the effect of aspirin on metastasis. They conducted a systematic review of observational rather than randomized trials.

Researchers found aspirin resulted in a 38 percent reduced risk of developing colorectal cancer. These matched findings of randomized trials. Similar risk reductions were seen for esophageal, gastric, breast and stomach cancers.

The authors conclude: "Observational studies show that regular use of aspirin reduces the long-term risk of several cancers and the risk of distant metastasis."

Results of methodologically rigorous studies are consistent with those obtained from randomized controlled trials, but sensitivity is particularly dependent on appropriately detailed recording and analysis of aspirin use."

In an associated comment, Drs. Andrew T. Chan and Nancy R Cook of Brigham and Women's Hospital, Harvard Medical School, write, "Rothwell and colleagues' impressive collection of data moves us another step closer to broadening recommendations for aspirin use. Moreover, future evidence-based guidelines for aspirin prophylaxis can no longer consider the use of aspirin for the prevention of vascular disease in isolation from cancer prevention."

dailyRx Contributing Expert Adam Brufsky, M.D., professor of medicine at the University of Pittsburgh, said, "This is really fascinating data that suggests that aspirin can not only prevent cancer occurrence, but also distant spread of disease. We now need to understand more about the mechanisms behind both of these findings, so we can perhaps figure out who will benefit from this intervention, and who will not."

Reviewed by: 
Review Date: 
March 20, 2012
Last Updated:
October 21, 2012