Menopausal hormones: definitive evidence for breast cancer
Menée à une échelle internationale à partir de données publiées ou non (données épidemiologiques, essais randomisés, sources informelles, ...) sur la période 1992-2018 et portant sur un total de 108 647 patientes atteintes d'un cancer du sein (âge moyen au diagnostic : 65 ans), cette étude analyse l'association entre un traitement hormonal substitutif de la ménopause et le risque de développer la maladie, en fonction de l'âge au début du traitement hormonal et de son type
For some women, menopause is an easy life transition, but for others, it means sleepless nights, hot flushes, and often a decline in wellbeing. For decades, women have been prescribed synthetic versions of the hormones that are lost with ovarian functional decline, in pill form or in other formulations (eg, patches, gels, or injections), either as oestrogen alone (usually for women who have had a hysterectomy) or as an oestrogen and progesterone combination (usually for those with an intact uterus) to help mitigate some of the symptoms. Prescribing fell after the publicity stemming from the Women's Health Initiative (WHI) trial reports in 2002 and 2004,which showed an increase in the risk of breast cancer with the use of combination therapy (oestrogen and progesterone). Oestrogen alone had no observed effect. The decline in menopausal hormone therapy (MHT) use was followed by a decline in the incidence of breast cancer (fear of breast cancer likely had the greatest effect on the use of hormone replacement therapy [HRT], but to my knowledge this has not been formally established). Perhaps breast cancer worry has deprived millions of women of an effective remedy for some of the symptoms of menopause. It is important to know the cancer risks with accuracy if women are suffering the consequences of avoiding MHT, and possibly, raising the risk of osteoporosis and other conditions, such as cardiovascular health or cognitive decline. The WHI published two randomised trials; elsewhere data come from observational studies. In The Lancet, the Collaborative Group on Hormonal Factors in Breast Cancer reports their study in which they combined data from 58 studies, including 24 prospective cohort studies, using a nested case-control study design to focus on the long-term effects of MHT while taking into account age at first use, duration of use, and time elapsed since last use. They compared oestrogen alone versus never use and combination therapy versus never use. The meta-analysis included 108 647 incident invasive breast-cancer cases within the cohorts (mean age at diagnosis was 65 years) who were matched to up to four controls by age, year of birth, and geographical location.(...)
The Lancet 2019