Breast cancer: a clear association

As the UK National Case-Control Study Group data clearly showed, the younger women are when they start the Pill, the longer they take it and the more of them develop breast cancer.

Pill starting age % of women taking OCs for over 4 years

Breast cancer cases Controls

up to 18 years 80 70

19 to 21 years 71 61

22 to 24 years 57 48

25 + years 50 29

The RCGP study, the world's largest Pill study, begun in 1968, is now mostly following past users and "never" users.

In spite of breast cancer being exacerbated by pregnancy, all events reported during pregnancy were excluded in this study, as was use of hormones for period problems, fertility drugs or HRT use by takers or controls. Even so, breast cancer increases among Pill ever users compared with their controls are are alarming.

By 1985 Increase

Women aged 30 to 34 who stopped the Pill 8-9 years before 15.8 times

Women with one child stopping the Pill 10 years before 13.19 times

Women aged 30 to 34 when breast cancer diagnosed who

took the Pill for 10 years 10.17 times

All women aged 30 to 34 when diagnosed with breast cancer 3.33 times All women aged 25 to 29 when diagnosed 2.53 times

All women aged 45 to 54 1.77 times

This is what the study showed. But results of the RCGP Pill Study are

standardized rates. Standardization is a form of statistical manipulation which may or may not give a more accurate picture. For example, the actual number of pill ever users diagnosed with breast cancer younger than 35 was 27 compared with six controls, which looks like a 4.5 increased risk. Nevertheless, standardization reduces this to only 2. 38 times risk. Results are manipulated according to social class, which may depend on a husband's job, age at diagnosis, number of children when diagnosed and whether or not the women smoked when they joined the trial. The real figures may be far worse.