What causes TSH to shoot up to 8.94 in 3 months

[iris986]

I had thyroid cancer last year, micro papillary cancer 0.5cm. It has now been 18 months months since surgery. Every time I have had my thyroid levels checked in 2010 they are low at 0.64 to 1.65. On June 4, 2010 I had my TSH level checked and it was 0.64 and today I get a call from my Docs office telling me my TSH level has suddenly jumped to 8.94    

Does this mean that the knot on my neck could be cancerous? I know don't jump to conclusions.

I have no symptoms of being at 8.94. I made an appt with an Endocrinology Clinic in Houston, Tx on the 29th of this month.

[iris986]

Total thyroidectomy and one enlarged parathyroid was taken out along with nodules and cancer.

My Gastro had the TSH run but didn't run any of the other test.

It just worries me because I have always been low since they got me leveled off and now the sudden jump.

[iris986]

Total thyroidectomy and one enlarged parathyroid was taken out along with nodules and cancer.

My Gastro had the TSH run but didn't run any of the other test.

It just worries me because I have always been low since they got me leveled off and now the sudden jump.

[Barb135]

Is TSH the only thing you are being tested for, or is your doctor testing FT3 and FT4 levels also?  

What type of surgery did you have, 18  months ago?  

Sorry to ask so many more questions, but it's impossible to say too much, based only on TSH levels.