An aspirin a day may not only keep the cardiologist away, but the oncologist too. Oxford University researchers have found that daily consumption of a small dose of aspirin can lead to a significant reduction in risks of certain types of cancer, cancer metastasis and cancer mortality.
Results from the large study “add to the case for long-term use of aspirin for cancer prevention in middle age in addition to appropriate dietary and lifestyle interventions,” said Peter M. Rothwell, professor at the University of Oxford in England and study co-author.
Among regular aspirin users, the study found:
• 38% reduction in colorectal and gastrointestinal cancers
• 75% reduction in esophageal cancer
• 35 to 40% less cancer metastasis
• 15% decreased cancer mortality
The researchers studied data from 200 randomized case control studies of several million patients. They used a combination of trials and multiple analyses when performing their research.
One analysis showed an increased risk of major bleeding from aspirin, but the risk of bleeding decreased over time. This same analysis demonstrated a reduced risk of vascular events and significantly less fatal brain bleeding among aspirin users.
Another caveat of these studies: two large clinical evaluations of aspirin’s effects on cancer risk were left out of the analyses. The Physician’s Health Study and Women’s Health Initiative involving over 60,000 men and women were omitted from the study because they examined patients who took aspirin every other day rather than every day. Neither of these studies demonstrated an effect on cancer from every other day aspirin use.
“These caveats notwithstanding, Rothwell and colleagues show quite convincingly that aspirin seems to reduce cancer incidence and death across different subgroups and cancer sites, with an apparent delayed effect,” wrote co-authors Nancy R. Cook, ScD and Andrew T. Chan, MD of Harvard and Brigham and Women’s Hospital in Boston. “Thus, for most individuals, the risk benefit calculus of aspirin seems to favor aspirin’s long-term anti-cancer benefit.”
Eric Jacobs, PhD, the strategic director of pharmacoepidemiology for the American Cancer Society, viewed the new analyses as “important new evidence that long-term daily aspirin, even at low doses, may lower the risk of developing cancer.” But he emphasized that the decision to begin a regular aspirin regime should be individualized and occur only after a discussion between patient and doctor.
“Many people may wonder if they should start taking aspirin tomorrow,” noted Jacobs. “It’s important to first discuss aspirin use with your doctor who knows your personal medical history. Decisions about aspirin use should be made by balancing the risks against the benefits.”
“Because these results are new, it will take time for the broader scientific community to evaluate the data in the context of existing knowledge and to consider whether the clinical guidelines should be changed … Clinical guidelines require a systematic analysis of for whom the benefits of aspirin use are likely to outweigh the risks,” explained Jacobs.
Dr. Rothwell agreed, stating that “There is an urgent need for clinical trials of treatment regimens incorporating aspirin.”