Unfortunately, it may spread to bones, brain, neck lymph nodes, etc --it is very important in your case to be followed by a thyroid cancer specialist - perhaps even university based to be certain it is contained and treated.
Amanda7980 is right on the money - make sure you are getting regular body scans and thyroglobulin tests. Also ask your endo about a PET scan.
How many courses of RAI did you go through?
I'm asking because my family has a *HUGE* incidence of papillary carcinoma and I've been through RAI once (but will need to go through again next fall) and my sister with Stage II has been through three doses of RAI. Two other sisters with Stage I have not been through it yet.
Papillary or follicular, RAI is the best way to "seek and destroy" the thyroid tissue/cancer.
At age *FIVE*???!! Wow.
What type of thyroid cancer was it and how old are you now?
Why are you worried it has spread further?
Also, did you have I-131 treatment (also known as RAI) after the surgery?
Thyroid cancer can metastasize, even after a thyroidectomy. I hope that you have a good endocrinologist and are having regular uptake scans. If not, please get a good endocrinologist (who specializes in thyroids - many only deal with diabetes), take in your history, and ask for a scan ASAP.
http://www.cumc.columbia.edu/dept/thyroid/
http://www.endocrineweb.com/thyroid.html
Please let us know.
Have you had regular follow ups, such as thyrogobulin levels and body scans? If not, I would find a good endo and have it done for your peace of mind. If you have all this done, you should be ok. I had follicular thyroid cancer in 2001 and got the five year "all clear", but will still be followed for the rest of my life.
Age 5.. I know it is rare. It has been 18 years and I have had many treatments. I am just curious if it can still spread to other places, mostly bone.