I'm. just starting this post due to a previous post raised over this. As a BC survivor with Hypothyroidism diagnosed prior to BC it has caused me concern and worry. My initial research found this:-
In this article they are talking about the links to autoimmune response, link is to HypERthyroidism and states it's not linked to Hypothyroidism.
I was always told by my NHS endocrinologist that so long as my thyroid hormones stay in range I would be fine.
Once I've made contact with my Oncologist and find out about outcomes I will update.
Please remember that Breast Cancer is an umbrella term as there are multiple forms of BC which act in different ways, have different treatments, different long term outcomes/reoccurance rates so it's a very wide field that can't be dealt with in a generic way.
I suggest anyone with BC or a history contacts their own specialist for advice on any research published.
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It seems to me that the pertinent issue is not the original diagnosis per se. (eg hypo / or hyper)... but it is the levels of thyroid hormone.
you would have to look in detail on the studies used to show hypothyroid patient had lower risk of BC ... (eg (27) below )...... is this showing an association with untreated hypo (people with lower thyroid hormone levels) .. or is it an association with anyone who was diagnosed hypo , but has since been treated and now has higher levels of thyroid hormone.
"a prospective cohort study by Søgaard et al. The latter study, involving 61,873 women with hypothyroidism and 80,343 women with hyperthyroidism (27), demonstrated that patients with hypothyroidism had a slightly reduced risk of BC, while patients with hyperthyroidism had an increased risk of BC. In agreement with Søgaard and colleagues, this current meta-analysis demonstrated that patients with hypothyroidism had a reduced risk of BC"
The meta analysis does mention the same concerns discussed in the other post , about higher thyroid hormone levels having a potential effect on promoting cancer cell proliferation.
"Recent studies have suggested that TH may play a positive role in the cause and development of BC at a cellular level (8-11) "
It goes on to say the association of hypothyroidism with lower risk of BC is likely due to lower thyroid hormone levels found in hypothyroidism :
"Additionally, in vitro studies using BC cell lines, showed that triiodothyronine (T3), a TH secreted by the thyroid gland, promoted the proliferation of tumor cells and enhanced the cell proliferation effects of estradiol (E2) (44). Hence, it is possible that TH promotes the occurrence of BC, and patients with hypothyroidism may have a reduced risk of BC due to lower TH levels. "
So .... hypothyroid patients who are using thyroid hormone replacement to raise their thyroid hormone levels ~ now have higher thyroid hormone levels than 'hypothyroid' subjects ... therefore presumably their risks increase along with their thyroid hormone levels ?
Tattybogle BC is incredibly complex so I'm sorry I don't feel qualified to interpret research to my particular diagnosis. There are multiple factors at play here so it would be simplistic to just say it was thyroid hormone levels that did it. I do think there is a danger interpreting these results to mean you must do x or y. My Oncologist was very clear he wanted my Ft3 and ft4 levels high going through treatment. Luckily for me I wasnt aware of what they were during treatment, they rose a bit. Ft4 went over range a bit I was horrified. And I then lowered my dose and told him off for not telling me. His argument was that a year of aggressive treatment requires my body to be able to fight. Lowering thyroid hormones would make it harder for my body to do so. It worked a 10cm tumour was undetectable post chemo after my masectomy..that treatment worked because they picked up the type HER2 positive on top of Estrogen positive and appropriate treatment for that was then implemented.... Without which I would've died. 7yrs on I stopped the Estrogen treatment. It's a long process.
Given 1in2 people will be diagnosed with Cancer I doubt it's down to thyroid hormones but I do believe something fundamental is going on here.....
The science behind all of my treatment was way over my head. I've tried to read papers on this but honestly I just don't have the scientific knowledge. Hypothyroidism is a walk in the park in comparison!! Best I can do is read the reviews of the body of research but even this isn't always easy to understand for a layperson.
My Oncologist is honest and straight as he knows I need to know. I'm very face on.
Beyond a certain point I feel you just have to live, enjoy what your gift of a reprieve ..... none of us knows what's round the next corner, cancer survivors just get the heads up that life is finite. Enjoy it!!
is this showing an association with untreated hypo (people with lower thyroid hormone levels) .. or is it an association with anyone who was diagnosed hypo , but has since been treated and now has higher levels of thyroid hormone.
I suspect that the length of time someone stays untreated could have a bad effect on cancer risk. Personally, I think I've been hypothyroid since birth and wasn't diagnosed or prescribed any thyroid treatment until I was in my early 50s.
And there isn't just the TSH / Free T4 / Free T3 to consider...
What about the gut problems, the cortisol issues, and the reduction in nutrient levels?
i suspect the contribution of thyroid hormone levels to cancer risk is relatively small when compared to ..... living stressful lives, breathing and eating on a polluted planet ...unless you can manage 'Zen' on an unpolluted mountain top .. oh wait, there are no 'unpolluted mountain top' s left ...
The fact that we happen to have some choice in our thyroid hormone levels and that this could potentially be used to lower our cancer risk is a bit academic if we can't realistically lower them without having a naff quality of life anyway.
but i do think it may turn out to be a useful argument for not having endo's just chuck more levo at the problem when a bit less levo and some T3 gives will give us more physiological ratios of T4/T3.
Indeed although there are plenty of people with hypothyroidism out there who might laugh at the idea that they have choice over their level of thyroid hormones!! 🤣😉
As for what is best. Here's a classic story of what happens when you consider only one aspect. Estrogen blockage therapy is considered the gold standard for female patients post bc treatment for estrogen positive tumours. 10years is now the gold standard period, increased from 5years. The difference between 5 years and 10years treatment is survival is 3/100 more women will be alive at 15years as opposed without. So that great you might think..... However the following has recently been discovered:-
After just four years of treatment, High risk of dementia especially linked to Altzeimers, loss of high executive functions of the brain, vaginal prolapse, bowel incontinence, bone degeneration requiring significant interventions or resulting in fractures of the spine and bones, carpel tunnel syndrome, low or no libedo, significant aches/pains, low energy levels, fatigue, faster aging.
So yes at 10years of this treatment you might have on average increased survival of a further 3% at 15years but at what cost to QOL? I quit at 7yrs. In my opinion one year too many due to the damage it caused that they didn't know about at the time they recommended it. They didn't tell me the above.
Such research recommending treatment for specific conditions does not consider the impact on other aspects of the body or mind....because it is targeted research. It has a small scope. There in lies the fatal flaw of most research. Because much of it is funded the scope is restricted to what the funder wants.
This is why research is so misleading and large if not massive pinches of salt are required. Estro gen Blockage therapy has been used for years. Loads of women have complained about it's effects for years but they were dismissed. It only last year this research came out about the true effects validating many women's complaints. The question is why has it taken so long?? I think that one is pretty obvious....
That’s an interesting thought. I think I’ve also had hypothyroidism at least since childhood, so probably from birth. I had breast cancer in my 50s and was diagnosed hypothyroid and very low vit d at age 60. I always wondered if the breast cancer and tamoxifen kicked the thyroid even lower, but maybe it was the other way around, or circular?
That sort of throws out the theory of lower thyroid hormones, especially T4 reduces estrogen positive cancer risk as you were probably heading that way at the time of diagnosis. I didn't need to adjust my thyroid hormone treatment when on Exmastane for 7yrs but then I doubt my thyroid has much if any capacity to produce thyroid hormones.I still felt rubbish on it!! The truth is it's very complex. The endocrine system is not fully understood but when you throw in cancer as well the complexity must be greatly increased.
It will take some time for me to study the review document you link to. I posted about a topic on my website which discusses Thyroxine and Cancer. This includes a page on Liver and Breast Cancer ibshypo.com/index.php/thyro... . The intention of this page is to point out Liver and Breast cancers are exceptions to the discussion that follows. At the time I searched PubMed on the terms 'cancer', 'thyroxine', 'liothyronine' but not 'thyroid'. Hence, I missed this review.
I was careful to exclude studies that assessed TSH, fT3, fT4 within a year of the initial TFT or during the cancer stage - cancer can affect thyroid hormone levels. I don't know if the studies referenced in the review do this.
I came to the conclusion that thyroid hormone may promote breast cancer but the evidence is not conclusive. A casual glance at the above review suggets this may be the case but odds ratios appear to be small (1.12 for hyperthyroidism and 0.95 for hypothyroidism). In which case we should not worry unduly about it. It may be that thyroid hormones have more pronounced effects on specific forms of breast cancer, this is well beyond my ken and I suspect little is known about it.
I have no illusions about my future. I only have to look at Predict and the chart that come up for me is a bit like lemmings falling off a cliff after 10yrs. Except of course such research evidence is retrospective and hasn't yet caught up with the wonder of Herceptin which is changing things massively. It maybe the lemming Cliff will become more a gentle gradient but they'll only know this as us survivors reach those years and beyond.
This recent mini review ncbi.nlm.nih.gov/pmc/articl... discusses the effects of T4 on breast cancers. I've never studied BC so much of the technical details is beyond me. It looks like there are two factors for thyroid hormone and BC namely genomic (T3) and non-genomic (T4) actions. Which has the greater effect I suspect noone knows and it will probably vary between patients and their specific breast cancer.
Thankyou Jim but this is associated specifically with estrogen positive cancer. It doesn't discuss other bc types as far as I can understand. Mine was estrogen positive but also HER2 positive. It doesn't discuss effects on Multifocal. . HER2 positive bc had a very poor outlook but with the treatment of Herceptin this has significantly improved matters. My Onc was probably focused on the latter type due to its aggressive unforgiving nature. Bare in mind that treatment options are discussed by a MDT to explore best ways forward. The treatment was harsh and long. I doubt making me hypothyroid would've assisted me making it through a tough regime of treatment. I ended up in hospital twice as an emergency with Neutropenia. As with most bc papers it's very technical so I find them hard to follow. It doesn't discuss the effects on the body being made hypothyroid and fighting bc so to me it looked like it's discussing the effects of BC estrogen positive cancer cells when deprived of T4? Given 70% 0F BC is estrogen positive then it would be interesting to know the clinical implications. Unless they're hoping to devise a way of blocking access to T4 for estrogen positive cancer cells only.
This technical detail is beyond me. As a general comment this team is looking at how T4 acting on the cell membrane integrin alphaVbeta3 receptor proliferates many cancers (not so much BC).There are thyroid hormone analogues e.g Tetrac, that block this effect with little or no effect on thyroid hormone action. So, they are looking at developing drugs that can be used to fight cancers.
My interest is that levothyroxine monotherapy puts patients in a higher than average fT4 group and so at greater cancer risk. I believe using a little T3 would allow an fT4 in the lower half of its interval and so save many lives, especially when someone gets a cancer diagnosis.
All this shows how complex it gets. I see two separate objectives. 1. Using combination therapy to reduce overall cancer and cardiac risk. 2. If someone receives a cancer diagnosis considering how their thyroid treatment should be adjusted according to their individual case, under the care of the oncologist.
Jim if you find it hard to follow and am guessing you're in the scientific field than really am sure you can see how impossible it is for a layperson. I really appreciate you looking at it and explaining. I doubt they will want to adjust people's thyroid meds unless they are pre cancer because as you know it can be a long process adjusting thyroid meds and time is of the essence with cancer. I do hope however it will put off the Endocrinologists insistence on thyroid mono therapy beyond mild hypothyroidism (though these days they don't treat that!!) Interestingly though my Endo wanted me to stop all T3 and go mono T4 but at a very low dose. I doubt I would've survived.
I'm on Armour which is a combination therapy. Been on it for years.
I still think in the cancer field they will want to look at a targeted agent that blocks cancer cells to accessT4 which sounds as if it may slow it down but not cure it.
No one has been really able to explain why cancer is now so prevalent... 1in 2 in someone's life span is very high. Is it we are living longer or other factors like toxicity in our envirinments/food chain etc...
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