Hello everyone,
I've read this whole thread and there's a lot of misinformation and inaccuracies. I won't go on about them. Just want to say that 95% of all cancer types are multifactorial, which means that a lot of factors are at play. Only 5% are inherited and purely genetic. The risk factors for cancer are different depending on the specific type of cancer.
Regarding breast cancer, some risks have already been quoted above, but they're not the only ones. There are risk factors you cannot change: genetic mutations, getting older, early menarche (first period) and late menopause, dense breasts, atypical breast hyperplasia and lobular carcinoma in situ (benign), family history, previous radiation therapy before age 30, DES (diethylstillbestrol), a drug used between 1940 to 1971 to prevent miscarriages, both users and offspring conceived during use are at risk.
The risk factors you can change are: not being physically active, being overweight or obese after menopause, reproductive history (having the first pregnancy after age 30, not breastfeeding and never having a full-term pregnancy), alcohol and taking hormones.
Some forms of hormone replacement therapy (those that include both estrogen and progesterone) taken during menopause can raise risk for breast cancer when taken for more than five years. Certain oral contraceptives (birth control pills) also have been found to raise breast cancer risk.
Research suggests that other factors such as smoking, being exposed to chemicals that can cause cancer, and changes in other hormones due to night shift working also may increase breast cancer risk."
Source: CDC/US
I won't quote the previous posts but will add some info and my own opinion on the matter:
Birth control pills are taken by young women. One of the main key factors for cancer development is time. It takes a long time for a cell and its progeny to acquire the sort and number of mutations necessary to cause an irreversible state of deregulated multiplication. So time is an important factor for older menopausal women who are on HRT or not. The relative risk for women on HRT is slightly increased and that's what this meta-analysis study is about. The analysis has also produced other interesting results ('relative risks were attenuated by starting MHT after age 60 years or by adiposity, with little risk from oestrogen-only MHT in women who were obese).
There are no randomised controlled studies on HRT spanning 26 years, so that's why this meta-analysis is so important. Time of exposure is of the utmost importance for accessing cancer relative risks.
I sincerely doubt that the pharmaceutical companies will dispute the study. On the contrary, they will probably update the leaflets in no time. HRT is not their priority, health and money wise.
The fact that this study has come out during the HRT shortages is purely coincidental, studies take a long time to be drawn up, accepted and published. There's another possibility that could also be inferred from the timing of this report. Maybe some pharmaceutical companies knew about this study prior to its publication and decided to stop manufacturing hormones until further developments? It's highly unlikely, but also possible.
Newspaper headlines and reports can't usually be taken as scientific or accurate. It's often useful to read scientific or specialised reports instead of general media reports. The authors of this study are prominent scientists in the fields of Epidemiology and Statistics and they are doing an excellent job helping women getting informed about the relative risks of taking hormones. Newspapers editors are another story.
Medical doctors (private or NHS, or both) have their own opinion on the matter, but that's what it is, their opinion. I wouldn't take their word as gospel, when many are on the hormone business.
I could go on an on, but this is not important. The important thing is: Know thyself, knowledge is power. Don't let panic, anxiety, fear, anger or misinformation take control.
Overall, this is good news for all of us, on hormone therapy or not, the more we know about this subject, the more we know about ourselves.
BeaR.