Just about every Angeleno has a bottle of aspirin in his or her medicine chest. Many take it for pain or fever relief and some take it to reduce the risk of a heart attack. However, two new studies have reported that aspirin may reduce the risk of cancer. One study reported that it reduced the risk of colorectal cancer and the other reported that it reduced the risk of cervical cancer.
A study published in the February 2012 issue of Cancer Prevention Research reported that daily aspirin treatment was associated with a significant reduction in colorectal cancer mortality. The researchers reviewed follow-up data of nearly 14,000 patients from four randomized, cardiovascular disease prevention trials; they found that showed that daily aspirin treatment for about five years was associated with a 34% reduction in 20-year colorectal cancer mortality. A separate meta-analysis of nearly 3,000 patients with a history of colorectal adenoma (a cancer precursor) or colorectal cancer in four randomized adenoma prevention trials found that aspirin reduced the occurrence of advanced adenomas by 28% and any adenoma by 17%. The researchers noted that aspirin had also been shown to be beneficial in a clinical trial of patients with Lynch syndrome, a hereditary type of colorectal cancer; individuals treated with aspirin for at least two years, experienced a 50% or more reduction in the risk of cancer commencing five years after the study and after aspirin had been discontinued. In addition, the study authors noted that a few observational studies have shown an increase in survival among patients with colorectal cancer who use aspirin.
They noted that taken together, these findings strengthen the case for consideration of long-term aspirin use in colorectal cancer prevention. They added, however, that despite these convincing data, a lack of consensus remains about the balance of risks and benefits associated with long-term aspirin use, particularly in low-risk populations. They also noted that the optimal dose to use for cancer prevention and the precise mechanism underlying aspirin's anticancer effect require further investigation.
According to a study published in the January 2102 issue of the same journal, Cancer Prevention Research, aspirin should be evaluated for its potential to prevent cervical cancer in women infected with HIV. The study found that the virus that causes AIDS also increases production of a prostaglandin known as PGE2 in cervical tissue. PGE2 is associated with inflammation and the development of tumors. The authors noted that aspirin is a potent blocker of a chemical known as COX-2, which allows prostaglandins to be formed. Because of this property, the authors suggested that a large study should be conducted to determine if low-dose aspirin could prevent cervical cancer in high-risk women. Cervical cancer is caused by the human papillomavirus (HPV), and some researchers believe women co-infected with HIV are up to five times more likely to have HPV lesions on their cervix progress to cancer. The authors noted that, currently, cervical cancer is not responsible many deaths for women who reside in affluent nations; however, it is a major cause of death in poor ones where Pap smears are too expensive and HPV vaccines are not yet available.
A limitation of the study was its size: it compared tissue samples from 48 women, some of whom had only HIV, some of whom had both HIV and HPV infections, and some of whom had neither. However, the researchers, from NewYork-Presbyterian/Weill Cornell Medical Center as well as institutions in Haiti and Qatar, found levels of PGE2 high enough to suggest that a larger study is indicated to test whether giving low-dose aspirin to thousands of women would reduce cervical cancer fatalities.
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