Aspirin linked to greater risk of pancreatic cancer
The risk of pancreatic cancer in women is increased with long-term, regular aspirin use, according to US researchers.
Their finding is at odds with evidence that non-steroidal anti-inflammatory
drugs reduce the risk of several cancers and pre-cancerous lesions.
Eva Schernhammer, of the Brigham and Women’s Hospital and Harvard
Medical School in Boston, and her colleagues examined the association
between aspirin use and risk of pancreatic cancer among 88,378 women
participating in the US Nurses’ Health Study. They documented 161
cases of pancreatic cancer over 18 years of follow-up.
Overall, there was no significant difference in risk of pancreatic cancer
between regular aspirin users (those who took two or more 325mg aspirin
tablets per week) and nonusers (defined as those who took less than two
tablets per week). However, when the researchers looked at duration of
aspirin use, they found that women who reported more than 20 years of
regular aspirin use had a 58 per cent increased risk of pancreatic cancer
compared with women who never regularly consumed more than two aspirin
tablets per week (P=0.01).
Furthermore, risk of pancreatic cancer increased with increasing aspirin
dose for women who reported consistent, regular use. Compared with non-users,
women who took 14 or more aspirin tablets per week had an 86 per cent
increased risk of pancreatic cancer (P=0.02).
The researchers point out that the positive association between aspirin
use and the risk of pancreatic cancer could reflect analgesic use for
pain from occult or preclinical malignancies. “However, the increasing
risk of pancreatic cancer with increasing duration of use, particularly
after more than 20 years, makes this explanation unlikely.” Moreover,
the
findings remained largely unchanged after the researchers excluded the
first two years of
follow-up from their analysis.
“Our findings do not support a protective effect of analgesics
use on the risk of pancreatic cancer. Rather, aspirin appears to increase
the
risk of pancreatic cancer after extended periods of use,” the researchers
say. “Risks and benefits associated with the use of aspirin have
to be weighed carefully in any recommendations made by health care providers.”
The study is published in the Journal of the National Cancer Institute (2004;96:22).
The author of an accompanying editorial (ibid, p4) comments: “There
are no easy answers to the question of what aspirin and other non-steroidal
anti-inflammatory drugs do to pancreatic carcinogenesis.
“The findings by Schernhammer et al, are provocative and force
us to think carefully about the actions of aspirin and other NSAIDs and
the mechanisms
underlying pancreatic cancer.” |
