“Empiric Radioactive Iodine Dosing Regimens Frequently Exceed Maximum Tolerated Activity Levels in Elderly Patients with Thyroid Cancer,” Journal of Nuclear Medicine Vol. 47 No. 10 1587-1591
“The Evolving Role of 131I for the Treatment of Differentiated Thyroid Carcinoma”, Journal of Nuclear Medicine Vol. 46 No. 1 (Suppl) 28S-37S
The 1940's was when the art of RAI was introduced and began its roll in thyroid carcinoma treatment. The studies on the role of RAI and its effects are quite extensive and start as far back as the 1950's. Several groups in the United States and Europe began to formally evaluate the safety and efficacy of RAI at this time. Early investigation showed that the best iodine uptake occurred when the serum thyroid-stimulating hormone (TSH) was elevated. Not a mile stone assumption there.. the researchers determined that the best was to accomplish this effect and optimal RAI treatment was to withdraw patients from thyroid hormone and wait for the TSH to raise and balance out. What FUN! And they still do this to this day. Side Effects and Risks of RAI:
1) The most common and clinically documented side effects of 131I treatment are usually considered minimal and transient in the form of nausea and gastric pain. The typical duration is in the 2 weeks after treatment with a duration of a few days, but note typical is not an absolute. Some have it occur for longer and periodic periods. It all depends on your body and how well it will handle the RAI.
2) Sialadenitis (FANCY almost impossible to pronounce term that means swollen spit glands) is common in the first few days after therapy. This is associated with pain and enlargement of salivary glands (spit glands.. drool pits.. you get the piture.. expect a soar dry mouth
) but rarely progressing to chronic xerostomia (Another medical term that means permanent dry mouth due to diminished or dead salivary glands). The treatment most Mds recommend normally takes the form of drink lots of fluids (spit stimulating fluids – lemon juice) and chew gum. There is no medical evidence that this is going to fix things.. but constant steady drinking should help with dry mouth.
3) The subsequent obstruction of salivary gland ducts may occur weeks to years later. In some cases patients experience periodic and sudden swelling, tenderness, and rarely infected salivary glands, most commonly the parotid gland. Ugh! This just sounds bad IMO.
4) Loss of taste (aka to Mds as dysgeusia) is a regular feature of post RAI treatment. Most commonly it only lasts a few days, but there are cases where the loss of taste is does not return completely. It would suck for chocolate to taste like dirty socks or something for the rest of your life.. I think it would give me serious depression to lose the taste of chocolate.
5) Ocular dryness (DRY EYES) and nasolacrimal drainage system obstruction (STUFFY NOSE AND BLOCKED SINUSES) have recently been reported in thyroid cancer patients treated with 131I .
6) In cases of large thyroid remnants neck edemas can manifest. Studies show edemas may be prevented by short-term corticosteroid therapy.
7) It is noteworthy that no respiratory sequelae (lung scar tissue) were observed after 131I treatments of diffuse lung metastases. The older you are the slower it is for you to purge that RAI. Patients over the age of 70 show the least tolerance to RAI exposure. These studies show that in older patients pulmonary complications do arise as a result of pooled or retained high RAI doses in lung metastases.
8) In males, repeated RAI administration is associated with an impairment of spermatogenesis (low sperm production = low sperm count = increased infertility), increased FSH levels, and decreased inhibin B levels. Testosterone levels seem to remain unchanged.
9) In females, RAI is shown to result in a transient ovarian failure, mainly in older pre-menopausal women, and an earlier onset of menopause. In addition there is an excess risk of breast cancer reported in females treated for a thyroid carcinoma by RAI.
10) The prevalence of these issues did not increase or change in cases of multiple exposure. One RAI is enough to increase your risk of the above issues. Now in females who desire to get pregnant, stidues have been extensive. There is no conclusive data showing that having an RAI before pregnancy effects the fetus AS LONG AS sufficient time is given to purge the RAI from your system. Issues arise when you conceive a child with in a year of having an RAI. Complications and issues with fetal development are maximized in females that did not wait a year post RAI to get pregnant. So it is well documented and recommended that females wait at least a year or longer after an RAI to attempt conception. It is also stressed that it can take a year or more post RAI until control of thyroid hormonal status has been achieved. So the Mds recommend that thyroid hormonal status should be carefully monitored (before conception and during pregnancy) post RAI to avoid hypothyroidism complications.
11) The results of many different studies of large groups of thyroid cancer survivors treated with RAI are also being monitored for an increased risk of solid tumors or leukemias. However given the study sets and parameter variations in the RAIs.. there is no definitive trend here and thus one must say it is inconclusive.
12) A large European study found an increased risk of all solid tumors in RAI thyroid cancer patients, and a site-by-site analysis found a relationship between RAI exposure and the occurrence of bone and soft tissue, colorectal, and salivary gland cancers. Studies are still on going to determine what sort of increased risk is caused by an RAI.
13) Since the introduction of RAI as a treatment of metastatic thyroid cancer in the early 1940s, repeated dosing is clearly documented to cause bone marrow depression.
14) Parathyroids have been known to take in RAI and die as a result of exposure as well.