Although these results are preliminary, this could signal yet another usage for the miracle drug that was invented more than a century ago and already has been shown to have a beneficial effect on colon cancer and heart disease.
More studies needed to verify results
"I was very excited about the findings because leukaemia is one of those cancers that has a high fatality rate," says Julie Ross, senior author of a paper appearing in the June 13 edition of Cancer Epidemiology, Biomarkers and Prevention. "If this were to hold up in other studies, we're seeing a real reduction in risk."
"It certainly is a teaser in the sense that there seems to be a 50 percent reduction in the incidence of leukaemia," says Alan Kinniburgh, vice president of research at the Leukaemia and Lymphoma Society. He nevertheless adds, "More studies are needed to see if this holds true."
Little is known about the causes of adult leukaemia, which accounts for about five percent of all newly diagnosed malignancies in the United States. Without information on causes, little can be done in the way of prevention. "With blood cancers, we don't really have programmes to give to patients to try to avoid these diseases," Kinniburgh says. "The origin of most leukaemias is unknown."
How the research was conducted
The authors analysed information on 28 244 women who participated in the Iowa Women's Health Study, which looked at overall health, lifestyle, behaviours and incidence of cancer.
The women were sent a mail survey in 1992 asking them, among other things, how often they took aspirin, other NSAIDs (non-steroidal anti-inflammatory drugs) or arthritis medicine. All of the women were cancer-free (except possibly for skin cancer) at the beginning of the study.
The study authors then cross-referenced these same women with the American National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Programme, which tracks cancer diagnoses in certain areas in the US. Between 1993 and 2000, 81 women in the group had developed leukaemia.
50% lower risk of developing leukaemia
Women who reported using aspirin at least two times a week had a more than 50 percent lower risk of developing leukaemia compared to women who reported no aspirin use. There were other small effects depending on what drugs the respondents used, but they were not statistically significant and "the protective effect appears to be with aspirin," says Ross, an associate professor of paediatrics and a member of the University of Minnesota Cancer Center in Minneapolis.
The study has several advantages. It is the first prospective study to look at aspirin use in relation to adult leukaemia, meaning it looked forward rather than backward. It also compared use of aspirin to other NSAIDs.
Limitations of the study
Nevertheless, there are some limitations. For one thing, the researchers didn't know exactly how much aspirin the women were taking, or for how long.
No one knows why aspirin might have a protective effect against this or any other type of cancer. "I have no idea what the mechanism might be," Ross says. "It might come down to something such as platelet aggregation. When platelets clot, growth factors are released locally. Just by reducing that activity, are you reducing overall risk?"
Kinniburgh adds aspirin may have an effect on certain inflammatory processes taking place in leukaemia.
Ross has just submitted a grant proposal to the American National Institutes of Health to conduct a large case-control study of adult leukaemia and aspirin regimens. – (HealthDayNews)