If you drink alcohol will you die from breast cancer?

Good news, don’t worry. If you are a middle aged woman you have a tiny 0.3% chance of contracting and then dying from breast cancer over the next decade. And, very importantly, this tiny chance is exactly the same whether or not you drink alcohol.

An analysis of various causes of death of middle aged and elderly Americans (Thun et al 1997) found that, of the 251,420 women in the study, 0.3% of the zero and super-light drinkers died from breast cancer, over the 10 years of study observation. And exactly the same proportion, 0.3%, of the moderate to heavy drinkers (1 to 4+ drinks per day).

In a smaller mortality study (85,000 women, Fuchs et al 1995) the chance of death from breast cancer during the 12 year follow-up period was 0.4%, and again this was identical for zero-to-super-light drinkers as with moderate-to-heavy drinkers.

So why do we hear that women who drink have a (slightly) higher risk of being told they probably have (but not dying from) breast cancer? Because women who drink tend to get screened for breast cancer more often (shown in Mu and Mukamal 2016), probably because they tend to be wealthier and live in cities. More screening means that they get diagnosed with more cancer, as much of 50% of which is over-diagnosis and will be harmless.

A longer explanation is available here.