July 2013 Journal study linking synthetic T4 with lung cancer in females. Useful ammunition for your doctor or endocrinologist

Here is a neat journalistic summary of a recent Italian study in July's Journal of Reproductive Endocrinology


and here is the article itself


I printed it off and took it to a recent referral to an NHS endocrinologist, to back up my perfectly reasonable refusal of a second go of artificial T4. I've just had a second operation of breast cancer and really don't want any more. He hadn't read it, but took it away. He'd never seen an iodine loading test either. we won't be meeting again.

I hope this is helpful. Good luck.

9 Replies

  • Thanks for posting. x

  • Hope you recover quickly from your operation and thank you for posting. We really are 'between the devil and the deep blue sea' with this horrible illness. Janet.

  • Before frightening everyone who finds T4 works for them, Mary Shomon wrote about this study and is not impressed... 'This was the most simple and bare-bones correlation of total amount of levothyroxine sold in Italy with the total number of women in Italy who have lung cancer. Such gross correlations do not necessarily have anything to do with "cause." The authors implied that the correlation has something to do with levothyroxine somehow causing lung cancer, but this research is far from actually showing it.'


  • I agree. The link could equally be to people who have thyroid disease rather than what they are taking for it, or even something entirely unrelated. Surely taking T4 is better than not treating hypothyroidism if the synthetic T4 is working for the patient. There are far too many health 'studies' that make assumption rather than bothering to eliminate other possibilities. It's like saying "all the people with lung cancer had two ears therefore having two ears causes lung cancer". It's what some people call Fool's Logic!

    I'm all for studies that show t4/t3 combination therapies, T3 treatment or NDT can work better for some people but the fact remains that some people do better on T4 and totally discrediting the medication is nothing more than scaremongering, as you say.

    Something like this was posted a while back and I felt the same way. There may be something in what the author claims but they are far from proving it in this 'research'.

    I should just say that I am someone for whom synthetic T4 does not work. Mind you, T4 in NDT also didn't work for me. I'm all for alternatives being available so, just because I don't agree with this study, it is not because I am pro synthetic T4 being the only treatment. I personally need to take t3 only. I thought I should add that just in case people thought I'm from 'the other side' ;)

    Carolyn x

  • I agree. And while T4 seems to work for me at present, I'm aware that it doesn't suit everyone (and may not suit me in the future) so I also have no wish to protect the monopoly of T4 as the only appropriate treatment for hypothyroidism.

    Liza x

  • Hopefully you will continue to be well :)

  • Thank you Carolyn - so do I, but if I'm not, then I'm better informed, better educated and better prepared thanks to the work and support of Thyroid UK. Happy New Year! :)

  • And to you! Xxx

  • I just found this article too. It does say they are not sure if levothyroxine or just being hypothyroid can cause lung cancer. I've noticed links between thyroid cancer & lung cancer of late, was also in the film The Fault In Our Stars which is based on a true story. I've been struggling to breath lately so am worried.

You may also like...