Usually with studies like this there is a comment from the British Menopause Society or Menopause Matters but I see they have not commented yet but the press release itself from the BMJ is easy to understand:
https://www.bmj.com/company/newsroom/study-provides-new-estimates-of-breast-cancer-risks-associated-with-hrt/Like it says in the article this is an observational study rather than a trial and as such has limitations. As always unqualified statements such as reported in the press do not give the whole picture. As the report describes - the risk is different for long term vs short term use, current vs recent or past use, and with different regimes as well as different routes of administration ( transdermal vs oral).
The main limitation I see is that the study includes data from 1997-2018 and HRT use has changed dramatically in that time so on quick glance through I could not see any information about transdermal oestrogen and micronised progesterone so it's very much lumping a lot of data together from what I could make out. To me it would be more instructive to look at recent data and there are observational and trial data about the types of HRT more in use today ( can't lay my hands on them right now!).
The other most important point is that the press picks up on figures like "80% increased risk" which sounds alarming - but this is RELATIVE risk. You could say this means the risk is nearly twice as much (which would be 100%). However if the ABSOLUTE risk is low - to give an extreme example, say, an increase of 1 in a million to 2 in a million - then it is still negligible.
From what I can see this study does not alter the broad findings and understanding that there is an increaed risk with long term HRT use (but the absolute risk is still quite small) which depends amongst other things on type and route of HRT, type of progestogen and most importantly other lifestyle factors such as BMI, alcohol use etc. However I only had a quick look at it.
Hurdity x
