Adding aspirin to cancer treatment regimens can reduce mortality by 20% in patients with colon cancer, according to a meta-analysis published in PLOS One.
Previous studies have linked low-dose aspirin use to a reduced risk of cancer incidence, reduced mortality in patients with colorectal and other cancers, and reduced risk of metastasis. To systematically evaluate the effects of aspirin when it is used as an adjunct treatment in cancer, researchers led by Peter C Elwood, DSc, MD, Cardiff University, United Kingdom, conducted a systematic review and meta-analysis of the available literature. The search identified 373 reports, 42 of which were determined by the researchers to be relevant and to have sufficient data to be included in the meta-analysis.
In colon cancer, the researchers found that aspirin use was associated with a reduction in colorectal deaths of ~25% and a reduction in all-cause mortality of ~20%. For breast cancer and prostate cancer, the reviewed evidence indicated a ~13% reduction and a ~11% reduction, respectively, in cause-specific deaths. Overall, the researchers estimated a reduction in mortality of ~15% for all three cancers.
Aspirin was associated with even greater reductions in mortality in patients with specific biomarkers, including PIK3CA, HLA class I antigen, or COX-2 over-expression. Still, the authors caution that selection of patients for treatment with aspirin on the basis of a mutation or other biomarker is currently unwarranted based on the present evidence.
Additional analysis also revealed evidence that aspirin reduces the spread of cancer.
Although aspirin use has been associated with bleeding risk in short-term vascular trials, the reviewed evidence did not suggest an increase in bleeding risk when aspirin was added to cancer treatment.
Researchers concluded that low-dose aspirin could have a beneficial role as an adjunct treatment for cancer. They suggest that randomized trials be conducted to test this theory more directly. In the meantime, the researchers state that the evidence is sufficient to warrant discussions with patients about the possibility of adding aspirin to cancer treatment regimens.
