Systematic review
Acetylsalicylic acid (ASA) in prevention of cancer
Systematic review
|Updated
Acetylsalicylic acid (ASA), also named aspirin, has antipyretic, analgesic and anti-inflammatory properties as well as anti-platelet properties.
Key message
Acetylsalicylic acid (ASA), also named aspirin, has antipyretic, analgesic and anti-inflammatory properties as well as anti-platelet properties. Low doses of ASA are being used for prevention of cardiovascular disease. Based on its pharmaceutical properties, it has been debated for several years whether ASA may have a role in cancer prevention.
The Directorate of Health asked us to examine the potential effect of ASA use on overall mortality, cancer mortality, cancer incidence and possible side effects, in patients without prior history, or increased risk, of cancer. We included 12 systematic reviews. None of the included systematic reviews had examined the effect of ASA in the intended population. All identified studies were originally designed and performed to examine the role of ASA use in primary and secondary prevention of vascular events.
The results:
- indicated a lower overall mortality associated with ASA use
- showed lower cancer mortality associated with ASA use
- showed lower cancer incidence associated with ASA use
- showed a clear increase in bleeding events associated with ASA use
Summary
Background
Acetylsalicylic acid (ASA), also named aspirin, belongs to the non-steroidal anti-inflammatory drugs (NSAIDS). It has the antipyretic, analgesic and anti-inflammatory properties of other NSAIDs, as well as antiplatelet properties. Low doses of ASA are being used for prevention and treatment of cardiovascular disease. It has been reported that higher level of prostaglandins were found in tumors than in normal tissue, and hypothesized that prostaglandins may play a role in cancer. NSAIDs target the cyclooxygenase enzyme that is responsible for forming prostaglandins, and it has been debated for several years whether ASA may have a role in cancer prevention.
Objective
This project was commissioned, as a rapid review, by The Directorate of Health and is aimed at examining the use of ASA as possible primary prevention of cancer in persons without prior history, or increased risk, of cancer. We examined the potential effect of ASA use on overall mortality, cancer mortality, cancer incidence and side effects.
Method
We performed a systematic search for systematic reviews in electronic databases. The most recent publication(s) reporting results according to our objective was selected and results summarized.
Results
In this rapid review, we have systematically reviewed and summarized 12 systematic reviews of ASA use compared with no such treatment or placebo in patients without prior diagnosis of cancer or increased risk of cancer.
Based on studies originally designed and performed to examine the role of ASA use in primary and secondary prevention of vascular events, the results indicated a lower overall mortality associated with ASA use. Results also showed that ASA use resulted in lower cancer mortality and cancer incidence. This benefit, however, came at a cost of a clear increase in bleeding events.
Discussion
This is a rapid review summarizing systematic reviews. Hence, its format is compact and without the level of detail normally found in full systematic reviews of individual studies.
Although the possible role of ASA in cancer prevention has been discussed for several years, none of the included systematic reviews identified any long-term randomized controlled studies designed purposely to investigate ASA use for cancer prevention. The estimates of the association between ASA use and the risk of cancer or cancer mortality resulted from randomized controlled trials which analyzed ASA use in primary or secondary prevention of cardiovascular disease.