Both aspirin and vitamin E fail to reduce cancer risk
Aspirin does not protect over 10 years |
Taking low-dose aspirin every other day does not reduce the risk of a healthy woman developing cancer, newly analysed data suggest.
As part of the Women’s Health Study, conducted in the US from 1992
to 2004, 39,876 women aged 45 years or older who had no history of cancer
were randomised to receive 100mg aspirin or placebo every other day.
After 10 years, aspirin was not seen to have had any effect on the risk
of total cancers (relative risk 1.01, 95 per cent confidence interval
0.94–1.08; P=0.87). No effect was seen on the risk of breast cancer,
colorectal cancer or several other site specific cancers, although there
was a trend towards lower lung cancer risk (0.78, 0.59–1.03; P=0.08).
Compliance (defined as taking at least two thirds of the study tablets)
averaged 73 per cent, and was slightly lower in the aspirin group.
The researchers conclude that despite a growing body of evidence supporting
a protective effect of non-steroidal anti-inflammatory drugs, their data
suggest there is no such effect for most cancers. They add that direct
randomised trial data would be needed to determine whether higher doses
of aspirin taken daily would provide adequate chemoprotection (JAMA 2005;294:47).
Further results from the WHS reported this week show that vitamin E does
not provide protection against cardiovascular disease or cancer. The
same group of women received vitamin E 600IU or placebo on alternate
days. After 10 years, no overall benefit was seen in terms of major cardiovascular
events or development of cancer and taking the vitamin did not affect
total mortality. However, there was a reduction in the proportion of
cardiovascular deaths, and in the proportion of major cardiovascular
events in women aged at least 65 years, data which the researchers say
should be further explored (ibid, p56). (See also PJ, 12 March, p291.) |
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