Sometimes people with biopsy-proven thyroid cancer are recommended for a partial thyroidectomy. This is not recommended and is a sign that the surgeon may not be that experienced with thyroid removal. The majority of thyroid cancer patients will have a total thyroidectomy and modi? ed neck dissection, which involves removing all the thyroid gland and any nearby lymph nodes that are cancerous.
Partial thyroidectomy is reserved for people with small papillary cancers (under 1 cm in diameter) and can involve a few types of procedures. One procedure, a lobectomy, involves removing one lobe. Another procedure, called a lobectomy and isthmusectomy, involves removing one lobe and the isthmus, which is the bridge of tissue linking the lobes of the thyroid gland together (like the horizontal line in an H). A near-total thyroidectomy or subtotal thyroidectomy removes the tumor from the cancerous side of the gland, as well as the isthmus and most of the other lobe.
Many thyroid cancer experts support that a total thyroidectomy should be performed for most cancers because it is necessary for proper treatment and accurate long-term follow-up.
When you’re considering your treatment plan, you’ll have to weigh that 2 percent risk against the fact that thyroid cancer patients whose papillary tumors are greater than 1 cm and who have a total thyroidectomy followed by radioactive iodine therapy and thyroid suppression have a signi?cantly lower recurrence rate of their cancers. In addition, the less normal thyroid tissue left in your body, the greater the bene?t of radioactive iodine therapy after surgery. RAI therapy is an important way to eradicate the thyroid cells that are frequently left behind after surgery, which are all potentially cancerous tissue. But if there’s half a thyroid gland still left inside you, the radioactive iodine will probably wind up in the intact lobe, causing thyroiditis, which happens about 60 percent of the time. The bottom line is that the more thyroid tissue there is left inside you, the less effective the treatment and follow-up to the cancer may be. Despite potential problems, it may be worth having a total thyroidectomy to absolutely minimize your risk of recurrence and optimize your care.
Repeat thyroid surgery also may involve working through previous scar tissue, which can take longer and may involve more complications. Having another surgery performed in the same site as a previous thyroid surgery makes having problems with damaged parathyroid glands and paralyzed vocal cords far more likely. Thus, you’d never want a surgeon to remove part of a thyroid lobe, putting you at risk for another surgery on that same side. If the risks of complications are 2 percent for experienced thyroid surgeons, these risks are greater for less experienced surgeons.
Vocal Cord Nerve Damage
The vocal cord nerves on both sides pass near (or into) the thyroid gland. If one nerve is damaged during surgery, then the vocal cord it connects to becomes paralyzed, causing a hoarse or weak voice.
Sometimes the tumor itself causes this problem by eating its way into these nerves. If both nerves become damaged, then you may need to have a hole made in the windpipe (a tracheostomy) to permit you to breathe.
The most experienced surgeons are least likely to damage the vocal cords; however, this is a known risk of this surgery and should be carefully explained to you before you consent to the surgery. It’s good practice to ask the surgeon about the frequency with which these problems have occurred in his or her other patients and about his or her own experience and training in this surgery.
Numbness and Nerve Damage
Thyroid surgery frequently involves cutting nerve endings in the neck area, which can leave parts of your neck and shoulder area numb.
Some thyroid cancer survivors have even had numbness around ear lobes or the tongue. It can take years for these nerve endings to grow back. Each person will have different types of numbness that can often be helped through massage or acupuncture.
Sometimes you can still feel itches on the numb regions but lack the ability to scratch them. This can be maddening but may be controlled through creams recommended by a dermatologist.
After surgery, you will be permanently hypothyroid unless you take thyroid hormone. This is considered not as a risk but rather as an outcome of the surgery.
The most common risk of thyroid surgery is damage to the parathyroid glands. These four tiny glands are found near the thyroid gland and can be damaged or mistaken by the surgeon for lymph nodes. They make parathyroid hormone (PTH), which controls the calcium level in your body, telling the kidney to keep calcium from going out in the urine and enhancing the activation of vitamin D to absorb more calcium from the intestines. If all four parathyroid glands are damaged, the resulting loss of PTH, called hypoparathyroidism, causes the kidneys to lose calcium in the urine and decreases their ability to absorb more calcium. The result is that calcium levels plummet. This causes numbness or tingling sensations around the lips, numbness or tingling of the hands or feet, muscle cramps, twitching, and sometimes seizures. If the parathyroid glands are merely bruised from the surgery, the resulting hypocalcemia (low calcium) will be temporary, lasting from days to weeks. If the parathyroid glands have been accidentally removed or their blood supply disrupted during the surgery, the loss of PTH can be permanent. Although severe PTH disturbances can be detected by obtaining a calcium level, an ionized calcium level is the most sensitive test for this.
Treatment of hypoparathyroidism entails taking high doses of activated forms of vitamin D, along with suf?cient calcium pills to maintain the ionized calcium within the low end of the normal range.
Vitamin D analogs (calcitriol, dihydrotachysterol, or vitamin D2) cause the intestines to absorb suf?cient amounts of the calcium pills to offset the calcium losses through the kidney.
Follow-Up Scans and Tests
Thyroid cancer patients will need to go for regular follow-up scans involving radioactive iodine. Preparation for these scans includes being made hypothyroid or taking a drug called Thyrogen, as well as following the low-iodine diet prior to a radioactive iodine scan or treatment.
Thyroglobulin (Tg) is a protein that is made only by thyroid cells or thyroid cancer cells. No other part of the body can make this special protein. Usually, thyroid or thyroid cancer cells release this protein into the blood, making it possible to measure it in a blood sample.
Since there is no other source of thyroglobulin, once the thyroid gland has been completely removed by surgery and its remnants destroyed by radioactive iodine, there should be no measurable thyroglobulin left in the blood. Thus, the presence of measurable thyroglobulin indicates the presence of thyroid cancer. (Note that it’s important not to confuse the thyroglobulin level with the thyroglobulin antibody level or a thyroxine-binding globulin level, both of which are unrelated and often confused by patients and doctors for the thyroglobulin level.) You should have a blood test for thyroglobulin at least every six months. This will only be an accurate indicator of a thyroid cancer recurrence if you’ve had a total thyroidectomy followed by radioactive iodine therapy. The thyroglobulin test (Tg test) is more accurate when your TSH level is not suppressed; the usual method is to perform Tg tests while you are hypothyroid or taking Thyrogen, when appropriate. Some physicians believe that selected patients with low risks of thyroid cancer recurrence may be evaluated with Thyrogen-stimulated Tg testing only after their scans are clean and they’re having regular Tg tests with results that are so low as to be undetectable.
It’s important to account for cancers that may have lost the ability to make thyroglobulin or take up radioactive iodine. This can be assessed with additional imaging tests (such as MRI scans or CT scans without contrast dye), as well as MIBI scans, PET scans, or nuclear scans using radioactive thallium.
Around one-quarter or more of thyroid cancer patients, particularly women, have immune systems that produce antibodies against their own thyroglobulin. The reasons for this are not clearly understood and they do not directly in?uence your health; however, this can make thyroglobulin testing dif?cult or even impossible. This is because these antibodies interfere with the blood test for thyroglobulin performed in the laboratory and prevent the thyroglobulin level in your blood from being accurately measured. Thus, it is standard practice to measure both the thyroglobulin level and the thyroglobulin antibody level each time a thyroglobulin assessment is made. If the thyroglobulin antibody level is undetectable, then the measured thyroglobulin level may be considered reliable. If thyroglobulin antibody level is above the normal values for the laboratory, then you cannot rely upon the thyroglobulin level to con?rm that you are free from persistent thyroid cancer.