NICE guidance - HRT and breast cancer risk
Last reviewed 10/2020
Breast cancer risk and HRT
- the baseline risk of breast cancer for women around menopausal age varies
from one woman to another according to the presence of underlying risk factors
- HRT with oestrogen alone is associated with little or no change in the
risk of breast cancer
- HRT with oestrogen and progestogen can be associated with an increase in
the risk of breast cancer
- any increase in the risk of breast cancer is related to treatment duration and reduces after stopping HRT
Absolute rates of breast cancer for different types of HRT compared with no HRT (or placebo), different durations of HRT use and time since stopping HRT for menopausal women
- difference in breast cancer incidence per 1000 menopausal women over 7.5 years (95% confifidence interval) (baseline population risk in the UK over 7.5 years: 22.48 per 1000)
| Current HRT users | Treatment duration <5 years | Treatment duration 5-10 years | >5 years since stopping treatment | ||
| Women on oestrogen alone | RCT estimate | 4 fewer (-11 to 8) | No available data | No available data | 5 fewer (-11 to 2) |
| Women on oestrogen alone | Observational estimate | 6 more (1 to 12 | 4 more (1 to 9) | 5 more (-1 to 14) | 5 fewer (-9 to -1) |
| Women on oestrogen + progestogen | RCT estimate | 5 more (-4 to 36) | No available data | No available data | 8 more (1 to 17) |
| Women on oestrogen + progestogen | Observational estimate | 17 more (14 to 20) | 12 more (6 to 19) | 21 more (9 to 37) | 9 fewer (-16 to 13 |
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