Few breast cancers prevented by tamoxifen
The percentage of breast cancers that might be prevented with tamoxifen prophylaxis is likely to be small, according to a new estimate.
Recent evidence suggests that prophylaxis with tamoxifen can reduce the
risk of breast cancer in women at high risk of the disease. However,
the British National Formulary says that the drug’s adverse effects
preclude its routine use in most women.
US researchers have now estimated that only a small proportion of breast
cancers would be prevented using this approach.
The researchers, from North Carolina, studied questionnaires completed
by 605 women in general practitioners’ waiting rooms.
Among white women, 9 per cent in their 40s, 24 per cent in their 50s
and 53 per cent in their 60s were judged to be at increased risk of breast
cancer. The figures for black women were 3 per cent in their 40s, 7 per
cent in their 50s and 13 per cent in their 60s.
When the possible side effects of tamoxifen were considered in white
women, 10 per cent or fewer in all age groups were potentially
eligible for chemoprevention. Existing conditions such as high blood
pressure and diabetes would have ruled out use of the drug for most women.
The researchers calculate that the maximum proportion of breast cancers
that might have been prevented by chemoprevention was only 6 to 8.3 per
cent (Archives of Internal Medicine 2004;164:1897-1903). |
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