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Does aspirin increase the risk of pancreatic cancer?
Maybe, but probably not.
(July 2004)

Recently, we reviewed a study that concluded that aspirin protected against pancreatic cancer. We felt that it was not a very good study. Now, investigators from the Nurses’ Health Study report exactly the opposite - that aspirin increases the risk of pancreatic cancer. They followed 88,778 women for 18 years; during that time, 161 cases of pancreatic cancer occurred. Those women who regularly used over 14 standard (325 milligram) aspirin tablets a week had an 88 percent and statistically significant increased risk. Those who used for more than 20 years showed a 58 percent increased risk. Looked at another way, women using at least an average of one aspirin per day for at least ten years had a 75 percent increased risk. However, only those women who were overweight or obese were at increased risk.

Commentary: There is nothing wrong with the conduct of the study. But, it does not settle anything. The authors refer to five other studies; one showed increased risk from aspirin use; two showed no effect; and two indicated that aspirin protected against pancreatic cancer. So, adding this study, the available studies show absolutely equal division among those showing increased risk, no effect, and decreased risk. Of note, the extent of increased risk appears very impressive, but, in actuality, it is quite modest for this kind of study.

It is interesting that only overweight women were at risk, but unfortunately no distinction was made between up to 20 percent overweight and over 20 percent overweight (obese). Based on other studies, the likelihood is that the alleged increased risk was pretty much confined to those women who were frankly obese.

It is also interesting that the authors say that aspirin has been shown unequivocally to protect against bowel cancer, BUT, a study showing no protection from aspirin that was touted as the best study came from this same group. Perhaps, they now don’t believe their own study.



Schernhammer, E.S., et al. A prospective study of aspirin use and the risk of pancreatic cancer in women. Journal of the National Cancer Institute. Vol 96 (January) Pgs 22-28. 2004.

One member of our Scientific Advisory Board notes “the aspirin dose implicated here (2/day every day) is more than taken by the vast majority of women”.

Another member notes “we really need a randomized clinical trial for bowel and pancreatic cancers to sort this all out”.

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