Differentiated thyroid cancer (covered mainly in other sets) Flashcards

Question

When is whole body iodine scanning used ?

Answer 1

After sub-total or total thyroidectomys and also after Thyroid remnant ablation

Answer 2

When the thyroid gland has been removed and radioactive iodine given to destroy any remaining cancer cells, thyroglobulin should no longer be produced unless there are still cancer cells left in your body. This makes the thyroglobulin blood test a useful way of detecting any remaining papillary or follicular cancer cells. The blood test is often repeated every 6–12 months. You may also have radioactive iodine scans from time to time, to check whether there are any thyroid cancer cells in your body. Before a radioactive iodine scan you’ll need to stop taking thyroid hormone replacement tablets. If you are taking Page 2 of 3 Questions about cancer? Ask Macmillan 0808 808 00 00 www.macmillan.org.uk After treatment for thyroid cancer thyroxine (T4), you’ll need to stop taking it 4–6 weeks before the scan. Triiodothyronine (T3) tablets will need to be stopped 1–2 weeks before. This is done so that the body will produce enough thyroid-stimulating hormone (TSH) to make the tests as accurate as possible. TSH makes any thyroid cells, or thyroid cancer cells that may be left in your body, produce thyroglobulin and absorb radioactive iodine. Stopping the hormone replacement tablets will mean that your levels of thyroid hormones will get lower. As a result, you’ll begin to develop the symptoms of hypothyroidism, such as depression, weight gain, forgetfulness, decreased concentration and tiredness. This may affect your ability to drive or operate machinery. You can start taking your tablets again once the tests are finished. The symptoms should begin to reduce as the levels of thyroid hormones in your bloodstream increase. Recombinant human thyroid stimulating hormone (rhTSH) It may be possible to be treated with recombinant human TSH (or rhTSH) to overcome the problems of stopping your hormone replacement treatment. This man-made drug (also known as thyrotropin alfa or Thyrogen®) is similar to the TSH produced in your body. If you are given rhTSH you don’t need to stop taking your thyroid hormone replacement tablets, and won’t develop the symptoms of hypothyroidism. The drug rhTSH is given as an injection, usually into the muscle in your buttock. You’ll be given two injections, 24 hours apart. You can be given the radioactive iodine the next day if you are having a scan. The scan will then be done 48–72 hours later. The thyroglobulin blood test is done 72 hours after your second injection of rhTSH.

Answer 3

Basically where the patient is pre-treated with rhTSH the given 2 or3 GBq capsule of I-131 to destroy any cancer cells

Answer 4

Not common - Sialadenitis (swelling of salivary gland) and sore throat most noticeable ones

Answer 5

* Repeat whole body scan performed to ensure uptake in thyroid bed is now \<0.1% * Usually patients maintained on T4 * Aim is to suppress TSH to \<0.1mU/l and have FT4 below 25

Answer 6

A tumour marker

Answer 7

Doubles risk of leukaemia from 1 in 25000 to 1 in 13000 if they don’t have it and rely on surgery alone then 10 year survival about 75% rather than 95% with the gold standard of surgery TRA and follow up

Answer 8

By rising Tg, or by imaging such as whole body iodine scan