Less HRT Less breast cancer Re: HRT: doctors demand talks with government to tackle “chaos” of shortages
Less HRT means less breast cancer
Merethe Kumle commented that after the early terminations of the WHI HRT studies in 2002 and 2004, falls in HRT use were followed by falls in breast cancer incidences. She listed reports from Norway in 2005, New Zealand in 2006, USA and Canada in 2007, Germany, France and Norway in 2008. 
Bakken et al found that in Norwegian women aged 50-64 years, current HRT use doubled the risk of breast cancer whether or not they had been screened (RR 2.4 with mammography and RR 2.2 without mammography). 
In the UK the large percentage increases and smaller decreases in breast cancer registrations matched the increases and decreases in hormone use since 1961.  Graphs are in my website lectures (harmfromhormones.co.uk)
The Collaborative Group reported in 2019 that HRT use fell from 36 million to 12 million women in western countries in the past two decades. The Group found that of 108 647 postmenopausal women with breast cancer, both combined and oestrogen only HRT causally increased the risk of breast cancer and the risks increased with longer use. 
1 Kumle M. Declining breast cancer incidence and decreased HRT use. Lancet 2008;372:608-610.
2 Bakken K, Lund E, Eggen AE. The impact of hormone replacement therapy on the incidence of breast cancer in Norway. J Clin Oncol. 2005 May 20;23(15):3636-7.
3 Grant ECG. Reduction in mortality from breast cancer: fall in use of hormones could have reduced breast cancer mortality. BMJ 2005; 330:1024.
4 Collaborative Group on Hormonal Factors in Breast Cancer. Type and Timing of menopausal therapy and breast cancer risk individual participant meta-analysis of the worldwide epidemiological evidence. Lancet 2019;394 1159-68. :10.1016/S0140-6736(19)31474332.
Competing interests: No competing interests