It appears you have not yet Signed Up with our community. To Sign Up for free, please click here....

Cancer: Thyroid Message Board

Synthyroid and thyroid cancer

Post New Thread   Closed Thread
LinkBack Thread Tools Search this Thread
Old 03-25-2006, 01:09 PM   #1
Senior Veteran
Join Date: Feb 2005
Location: East Texas
Posts: 873
Synthyroid and thyroid cancer

Why do doctors always prescribe synthroid when one has thyroid cancer. Is it not good to take t3 or does it stimulate the cancer cells?

Sponsors Lightbulb
Old 03-25-2006, 01:27 PM   #2
Senior Veteran
Join Date: Feb 2005
Location: East Texas
Posts: 873
Re: Synthyroid and thyroid cancer

And I have been wondering ............if only a very small % of nodules are cancerous, why are we reading so much about it on this board????

Old 03-26-2006, 04:26 AM   #3
Senior Member
Join Date: Nov 2005
Location: Ontario Canada
Posts: 143
kathy590 HB User
Re: Synthyroid and thyroid cancer

I agree with that, thats all i heard about nodules before my surgery, how rare the cancerous ones are. They are not rare, but they are very cureable and noninvasive, thats for sure.

Old 03-26-2006, 04:58 PM   #4
Senior Veteran
Join Date: Jun 2003
Location: Nashville, TN
Posts: 526
Divermon HB User
Re: Synthyroid and thyroid cancer

About 50% of the general population have thyroid nodules. So I'm not sure nodules are automatically cause for concern.

There are two issues with thyroid nodules:

1. "Hot Nodules" - these are nodules what secrete excess amounts of thyroid hormone. That doesn't sound too bad, except that they are not constant, and can cause large enough variation to make you swing from hypo to hyper.

2. "Cold Nodules" - there are the type, especially when the boundaries are well formed, that are under suspicion of cancer. In this case, a Fine Needle Aspiration Biopsy (FNAB) can be performed to determine if they are cancerous or not.

It isn't always necessary, but not a bad idea to have an ultrasound to have a better look at nodules. A somewhat definitive method is the uptake scan. However, that requires that you are off meds for a while, which isn't pleasant. There is controversy whether or not the uptake scan gives enough more useful information, over an ultrasound. It's been a while since I did my research, but I remember I determined that I would not have the uptake scan.

But to your question about T3. I haven't researched this directly, and maybe someone can answer more definitively. I would be pretty sure that T3 would only be supportive to the same goal as to why Doctors prescribe Synthroid for thyroid cancer. This is my logic:

Doctors prescribe Snythroid (and other synthetic T4-only medications, such as Levoxyl and Unithroid) to slow down your thyroid gland, or de-stimulate it. The thought is to keep the whole gland, including the cancerous part of it, as inactive as possible.

The mechanism that achieves this is as follows:
1. T4 med enters the digestive tracts
2. T4 med is absorbed through the intestine, into the blood stream as Total T4 (TT4)
3. Most of this T4 (99%+) is then bound to protein in the blood. What is left over is Free T4 (FT4).
4. Organs in the body (mostly the liver), then convert FT4 into Total T3 (TT3).
5. Most of this T3 (99%+) is then bound to protein in the blood. What is left over is Free T3 (FT3).
6. The Hypothalamus gland constantly monitors the blood for FT3. Upon finding more than enough FT3 in your blood, the Hypothalamus secretes Thyrotropin Releasing Hormone (TRH), telling the Pituitary to release more Thyroid Stimulating Hormone (TSH), telling the Thyroid gland to slow down.

So, you see, it is essentially FT3 that controls TSH, more-so than FT4 anyway. It is only logical that taking a medication with T3 in it, does support the same goal, of de-stimulating the Thyroid gland.

However, if all your mechanisms are working correctly... that is, your body readily converts FT4 into T3 ok, etc.... and you still have your Thyroid gland... then I think there is less risk in taking a T4-only medication. T4 meds raise your hormone levels slower than T3 meds. Also, Doctors are typically more familiar with T4-only meds.

Note, this completely disregards what med would be best to take for health reasons outside of Thyroid cancer, and to generally alleviate symptoms.
My opinions only, not medical advice. Always follow advice of your Doctor, not what I say here.

Old 03-26-2006, 05:21 PM   #5
Senior Veteran
Join Date: May 2005
Location: NY
Posts: 3,804
Reece HB UserReece HB UserReece HB UserReece HB UserReece HB UserReece HB UserReece HB UserReece HB UserReece HB UserReece HB UserReece HB User
Re: Synthyroid and thyroid cancer

The objective with thyroid cancer patients is to keep TSH suppressed to prevent a recurrence. Mine is something like .02. This often means you are a little bit "hyper" and if you are a little bit "hyper"---even just on T4, you should not really need T3.

I started on synthroid, then my doctor added cytomel because I still wasn't feeling great---now fortunately I don't really use the cytomel, because I've adjusted and I'm fine on just synthroid for thyroid cancer for now. So that's not true that they wouldn't give you cytomel, just that it might not be necessary if your TSH is kept supressed.

Thyroid cancer is rare, is on the rise, but probably more obvious on this board, because there aren't many boards to go to when you have questions about nodules---which is why I found this board.

Closed Thread

Similar Threads
Thread Thread Starter Board Replies Last Post
need help with armour dosing/switched from synthyroid tired47 Thyroid Disorders 1 01-15-2009 07:23 PM
How long for Synthyroid to help symptoms? Dawn80 Thyroid Disorders 6 11-10-2008 08:23 AM
anyone been on armour went back to synthyroid? Glitterygrl Thyroid Disorders 11 07-29-2008 09:27 PM
can anyone help me with synthyroid problem? joules123 Thyroid Disorders 8 06-11-2008 09:17 AM
Cytomel Anju20 Thyroid Disorders 12 02-10-2006 12:20 PM
Possible Hypothyroidism??? Need help! MikeysWifey0316 Thyroid Disorders 13 06-10-2005 01:53 PM
Radioactive Iodine & Levoxyl vs. Synthyroid Waimea Thyroid Disorders 7 05-23-2005 11:02 AM
Synthyroid problem or is it just me, sigh... Renee' Thyroid Disorders 15 04-12-2004 02:54 PM
Synthyroid for enlarged thyroid???? Ladybug1241973 Thyroid Disorders 9 02-15-2004 12:42 PM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Sign Up Today!

Ask our community of thousands of members your health questions, and learn from others experiences. Join the conversation!

I want my free account

All times are GMT -7. The time now is 11:10 PM.

Site owned and operated by HealthBoards.comô
© 1998-2018 HealthBoards.comô All rights reserved.
Do not copy or redistribute in any form!