Friday, January 25, 2008

Decision to take a heavy dose of radioactive iodine

So, no cancer--I can leave, right?

Dr. Halkar and I spent some time reviewing the options. The decision was made to go ahead and take a heavy dose of radioactive iodine, even though there was no evidence of cancer.

Here is why?

1. Kill the remaining thyroid tissue in the neck.

There is always some true thyroid gland left after surgery in the neck. Imagine trimming the fat off a good steak. Unless you cut some of the good steak away, there is always some fat left. With that analogy, Dr. Grist the surgeon, left about 4% of my thyroid in my neck. Anything less than 7% is what is expected. We want to kill the remnant thyroid.

A. It could contain cancer.
B. Once you have had cancer in an organ, there is a greater chance that it will become cancerous again in the future. Get rid of the sucker.
C: My future testing to make sure that cancer does not come back can be misleading if there is thyroid remaining. The tests are designed to detect thyroid cells, and the relatively large mass in the neck would cause problems.

2. All the scans and tests in the world can't detect microscopic cancer.

Imagine a relatively small number 100-200 thyroid cancer cells in my lung. The scan would not pick them up. The radioactive iodine should hopefully eliminate them.

3. The massive dose of radioactive iodine allows a more thorough scan to be done in 10 days. The dose I took for the scan was 4mc. The dose to ablate (kill) the remaining thyroid and any cancer is 150mc. Giant. Glowing. On Fire. I am scheduled for another full body scan on February 4.

If there is no cancer found at that time, it is very unlikely there is any that will cause any trouble.
I will have follow up scans every 3-6 months for the first year and then scans every 6-12 months for the rest of my life.

What if they find cancer at this next scan?

Nothing is done. It take months for the radioactivity to kill all cells. Why? It really does not kill the cells. It makes it so that they can clone or reproduce. Cancer is cancer because it multiplies uncontrollably. The irradiated cancer cells can reproduce and will eventually die on their own.

Why about Hurthle Cells?--they don't absorb radioactive iodine well.

This is correct. However, no other thyroid cells were found anywhere in my body. And, it would be almost impossible for the ONLY cells to have cancer to be the Hurthle Cells. Dr. Halkar believes that we wound find some evidence of some other type of thyroid cells in the body--but we didn't. (So far).

Finally, the reason for the follow up scans (every 6-12 months for live) are just to check for cancer that may have are in my body undetectable. If any is found, we treat those cells--surgery, radiation or any other method that may come in the future.

Where we are: We are about 95% sure that I have a good prognosis. There is a 5% chance the scan on February 4, with the higher radiation level, will find cancer. If it does, I go back in 3-4 months for another scan to see if the radiation did its job. If there is no cancer, I wait about 6 months to have my first follow up scan.