S has not had breast cancer, but because her mother had it, and at a fairly early age, S has had regular mammograms and was invited to participate in the IBIS study designed to test whether Tamoxifen could have a protective effect against the development of breast cancer in women who might have a genetic pre-disposition towards the disease. (Actually, her mum's cancer was treated before there were tests to determine whether a particular cancer might benefit from Tamoxifen.)
S decided to participate in the trial. She was on HRT at the time, mainly because her mum was thought to be suffering from osteoporosis (though it was later decided that she wasn't). Those running the trial were aware that she was on HRT.
During the five year trial, S started to develop memory problems. She became convinced, before we ever knew anything about a possible connection, that Tamoxifen was the culprit. Shortly before the trial was due to end, she stopped taking the tablets (which might of course have been a placebo as this was a double-blind trial). Somewhere around this time she stopped the HRT also.
As things got worse, I started looking into Tamoxifen and found a surprising number of references to a possible link between Tamoxifen and memory problems. S eventually sought to discover whether she had actually been taking Tamoxifen or a Placebo and it was confirmed that she had been taking Tamoxifen.
We mentioned all this to the Professor at the memory clinic and he certainly didn't dismiss it out-of-hand (as he was quite prepared to do with other ideas).
I tried to find out from IBIS whether they had asked people on the trial if they had noticed problems with their memory (they sent out an annual questionnaire). It turned out that they had not though, interestingly, I understand that they do ask a question about this when surveying participants in the IBIS2 follow-up study testing Anastrozole, an alternative to Tamoxifen.
Eventually we were invited to meet a Professor who was one of those leading these trials. He was a very personable guy who thought S's mum might have been one of his early patients. I raised some of the things that perplexed me about the drug and its possible effects and he, very charmingly, answered them - up to a point though the answer often amounted to 'we don't really know'.
In a follow-up post I will summarise the letter he sent us following our meeting, when I have unearthed it from my increasingly chaotic 'filing system'.
Now I must go and wake S up as, for the second day running, she has slept well past noon.
At least, one way or another, she has so far avoided breast cancer. There's always a bright side if you look hard enough.