Aspirin is already known to reduce the risk of colon cancer, and laboratory studies have indicated that non-steroidal anti-inflammatory drugs (NSAIDs) may inhibit pancreatic cancer. Until now, however, epidemiological data to support this finding has been limited.
Now a prospective study conducted between 1992 and 1999, by members of the Division of Epidemiology at the University of Minnesota in Minneapolis, USA, has shed light on this topic, suggesting that aspirin may indeed prevent cancer of the pancreas.
Dr Kristin E. Anderson and colleagues assessed data on 28,283 women, aged 55 to 69, with the aim of examining the association between self-reported use of aspirin and other NSAIDs and the incidence of pancreatic cancer.
A total of 80 incident cases of pancreatic cancer were identified during 7 years of follow-up.
Following analysis of the data, the risk of pancreatic cancer was found to be 43% lower in women who took aspirin, or aspirin-containing products, compared to those women who did not.
There was a trend of decreasing risk of pancreatic cancer incidence with increasing frequency of aspirin use per week.
Compared with women who never took aspirin, women who took aspirin 2 to 5 times a week had a 53% lower risk of developing the cancer, and women who took it 6 times a week had a 60% lower risk.
Non-aspirin NSAID use was not associated with incident pancreatic cancer.
The researchers suggest that these data indicate that aspirin might be chemoprotective for pancreatic cancer.
While the mechanism by which aspirin could reduce the incidence of pancreatic cancer is not clear, it is thought to involve inhibition of expression of cyclo-oxygenase, but it probably involves other mechanisms as well, say the researchers.
| Risk of pancreatic cancer - 43% lower regular aspirin takers |
| Journal of the National Cancer Institute |
"In the study, other NSAIDs, such as ibuprofen, did not decrease the incidence of pancreatic cancer, perhaps reflecting differences in their mechanism of action", said Dr Anderson.
She cautioned, however, that the researchers did not have enough evidence to rule out that other NSAIDs may also reduce the risk of pancreatic cancer.
She said that the women in the study were asked in 1992 about their use of NSAIDs, when the drugs were not as widely used and some newer types had not yet been introduced.
Writing in the current issue of the British Medical Journal, in a news article, Dr Scott Gottlieb points out that the researchers did not collect data on the dose of aspirin the participants took or on the length of time that they were taking aspirin before enrolling in the study.
He adds that they looked only at current use, which precludes a comparison of short term and long term use, and that the homogeneity of the study population - postmenopausal women, 98% of whom were white - makes it difficult to generalize the results.