(this is a link to the latest talks so will go out of date)
I think this will be a very useful talk as we need to improve how we sort out endocrinologists and the NHS! In particular, given the latest nonsense about liothyronine from the BTA/BTF we are no better off than we were 20 years ago.
I will not be able to tune in to this talk. Professor Sikora is a cancer expert so I have submitted the following question in advance:
"The thyroid secretes thyroxine (T4) and a smaller amount of the active hormone triiodothyronine (T3). The body converts some T4 to T3. In the UK hypothyroid patients are only prescribed levothyroxine (LT4), because liothyronine (LT3) is more expensive. Higher T4 levels are needed to achieve normal T3 levels.
Research over the past decade has shown that T4 (not T3) acting on the integrin αvβ3 receptor promotes cancer. People with higher free T4 have increased cancer risk and mortality. Hence, hypothyroid patients are assigned a higher cancer risk. Combination therapy using a little liothyronine allows lower and safer T4 levels.
How can we get endocrinologists to prescribe safer therapy?
The levothyroxine Patient Information Leaflet (PIL) could include a warning: ‘speak to your doctor if you receive a cancer diagnosis’. How do we get the PIL changed?"
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jimh111
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I've already registered for the above and just hope it is more interesting than the previous one and do you want to put odds on your question being openly discussed ?
I'm unable to attend the meeting o it will be a few weeks before the video recording appears. Anyone can register to watch the presentation and take part.
Personally I would not take advice from this ‘doctor’.
An update. I don't know why Prof Sikora didn't go into the details of my question, perhaps he thought it was confidential.
Here is a summary of his reply. The risk of getting a cancer is increased by slightly too much thyroid hormone but there is no conclusive evidence that a mix of T3 and T4 would reduce cancer risk - it would be extremely difficult to get the data. The integrin link is interesting but there are many more powerful cancer risks with other hormones such as corticosteroids, oestrogens and androgens. He felt that from the current data no conclusion could be drawn re the risk balance between T3 and T4. He also suplied a copy of this review frontiersin.org/articles/10... , a very detailed and complex paper that I had read / skimmed.
I should first point out that this is the first response I've got on this issue, a couple of previous questions, including one to a BTF meeting on thyroid cancer had been lost. I'm not sure if cancer or questioning the safety record of levothyroxine are taboo subjects. I'm suggesting that all patients that are happy and doing reasonably well on levothyroxine monotherapy should be switched to combination therapy - this upsets the apple cart.
I disagree with Prof Sikora's reply, not easy to do because he is the expert and cancer is such a difficult subject, especially for those of us (me) that know next to nothing about it. I think we can overcomplicate matters, the issue of whether monotherapy increases cancer risk. As far as we know thyroid hormone proliferates cancer by two mechanisms: (1) having too little or too much hormone and (2) by T4 action on the integrin αvβ3 receptor. So, we don't need to consider all the complex in vitro, in vivo actions of T3 and T4 acting as thyroid hormones - both monotherapy and combination therapy target the same end point, euthyroidism. There will be similar levels of thyroid hormone activity.
As regards T4 acting on the integrin αvβ3 receptor we would logically expect levothyroxine monotherapy to be more harmful, because it involves higher T4 levels. This hypothesis is reasonable but we need evidence from studies to back it up, I give futher details in my previous post healthunlocked.com/thyroidu... . Studies of patients on levothyroxine monotherapy do show higher all cause mortality and cancer mortality.
I feel we should switch to combination therapy. For example, someone on 125 mcg levothyroxine might switch to 100 mcg levothyroxine plus 5 mcg liothyronine twice daily. This would bring fT4 down from a high normal to a low normal level. An additional benefit would be that we quickly get large scale data on the effects of combination therapy so that optimal safety levels can be found.
When levothyroxine monotherapy was introduced they should have set up a process to monitor its effectiveness (in terms of symptoms) and above all its safety. Adopting natural fT3 / fT4 levels should be the default starting point for thyroid therapy. There are cases, such as mine, where abnormal hormone balance is necessary. These cases likely carry additional risk, we need to be aware of this and doctors need to put more effort into finding the underlying causes.
Other hormones affect cancer risk but hypothyroidism is so common. About 3% of the population receive levothyroxine prescritions rising to around 10% of women over 60 and of course cancer is common in old age.
In summary I feel we should switch to combination therapy, levothyroxine monotherapy should not be routinely used.
There should also be a warning on the levothyroxine patient information leaflet to 'speak to your doctor if you are diagnosed with cancer'. This would allow the oncologist to adjust thyroid therapy in view of the latest knowledge of how thyroid hormone affects the specific type of cancer.
I'm not in a position to question the science but just considering the ' fall out ' should the guidelines be torn up and we are treated, as a matter of course, with both T3 and T4 :
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Crazy Underactive Thyroid, Maxed out on Meds
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