Tg is still 1,6

Hi, Job01. Sorry you need to be here.

While I haven't experienced what you are going through, I perhaps can help with some links and information to help you make a decision about 'next steps' for your treatment.

On a personal basis, in your situation, I would definitely not adopt a 'wait and see' stance with a detectable thyroglobulin level when suppressed.

Based on you having had 3 radioactive Iodine treatments already, I have to assume that you are between 2 years and 3 years or so after initial diagnosis (with a standard of 6 months to a year minimum recommended between each RAI treatment).

During the very first year, after the first RAI treatment, we will sometimes see the thyroglobulin levels decline following RAI, as your internist suggested, to an undetectable point - but that is usually caused by the 'death' of alot of remnant (benign) thyroid tissue.

At this stage in your treatment, which is a situation of persistent or even recurrent disease, not newly treated remnants, you are in another ballpark altogether.

When there is persistent thyroglobulin levels long after all 'normal' remnant tissue has been destroyed, this means there is still cancer.
Period. And unfortunately, that cancer may have the ability to mutate into a much more serious situation, depending on our own genetics - they don't know why this happens, but it can be very serious.

For example, anaplastic thyroid cancer is sometimes 'thyroglobulin negative' - so you wouldn't necessarily see a thyroglobulin count with this, but that is because the tissues have mutated to a much, much more aggressive form. (Thyroglobulin indicates that the malignancy still has some traits of thyroid tissues - which is a good thing for us, treatment wise).

It was/is certainly reasonable to use surgical removal on anything that is in the 1cm range, such as the node found in your chest ... radioactive iodine is often unable to penetrate tissues or tumors that are more than a few millimeters deep, so when we have any malignancy 1cm or above, it does need to be surgically removed.

At the same time, with a persisting thyroglobulin level, even when deeply suppressed, many experienced thyroid cancer doctors would NOT choose to 'leave this', unless the thyroglobulin level was undetectable when you were suppressed, and less than 2 when hypothyroid.

Is there a particular reason why you aren't being seen by an Endocrinologist, rather than an internist? These are the first line specialists in treating thyroid cancer - you do need to locate one with experience in thyroid cancer, though (some specialize more in other endocrine disorders, like diabetes, or growth hormone issues). This link may help a bit, if you are in the US:
http://www.thyroid-cancer.net/resources/findaspec.php3

MD Anderson, John Hopkins, and the University of Kentucky all have well renowned thyroid cancer specialists, with extensive experience in treating persistent or recurrent disease. If any of these are not an option for you, you may want to see if you can locate a doctor though one of these support groups:
In the US: Thyca.org - you can contact the facilitator of the support group nearest you, or attend a meeting to ask other survivors for recommendations, or post a note on the Thyca support website, asking for suggestions
http://www.thyca.org/support.htm
http://health.groups.yahoo.com/group/Thyca/

If you are located in Canada, please consider posting a note to Thry'vors.org:
http://www.thryvors.org/ (main website)
http://health.groups.yahoo.com/group/thryvors/ (this is the support group 'arm' website)

Another option, while it does not provide individual advice, is to ask a 'generic' question about your situation on this website:
http://health.groups.yahoo.com/group/thyroidcancerhelp/

The website is overseen, and provided volunteer information by Dr. Kenneth Ain - here are his credentials (click on download CV):
http://www.thyroidcancerdoctor.com/index.html

You may find information on this exact topic just by reviewing the archives at the thyroidcancerhelp website.

All of the above websites and their support groups are free to join - and you really do need a second opinion from a specialist in the field. Thyca and Thry'vors members would likely be able to give you the name of an excellent specialist in your region/state or province.

Finally, you may want to examine the procedures and protocols/recommended treatment flow charts in both of the following two documents:
http://www.nccn.org/professionals/physician_gls/PDF/thyroid.pdf

http://www.liebertonline.com/doi/pdf/10.1089/thy.2006.16.ft-1

We need to be aware that persistent thyroid cancer has the ability to mutate into much more serious cell types as time passes, in some of us.

No one knows exactly why these mutations occur, but it is now known that untreated or poorly treated, even well differentiated thyroid cancers, left for long periods of time, can mutate to less treatable/poorly differentiated or even undifferentiated/deadly cell types:
http://www3.interscience.wiley.com/cgi-bin/abstract/104085527/ABSTRACT
http://cat.inist.fr/?aModele=afficheN&cpsidt=14462037

Please - get a second opinion. You need to have your files reviewed by someone with lots of expertise in the field, to ensure your long term well being. All the best to you, Job01, and I hope some of this is helpful.