Thyroid surgery typically involves removal of one or both lobes of the thyroid gland, known as a partial or total thyroidectomy. The most common indications for removal are a nodule or nodules that are suspicious for cancer, an enlarged gland that is compressing your throat, causing a choking sensation, or a thyroid that is over-active (hyperthyroidism). Refer to the prior post, Thyroid Nodules: Evaluation and Workup for details on evaluation of the thyroid and checking for abnormalities.
Since this discussion is all about surgery, it’s important to know a little anatomy. For a primer on the exciting world of thyroid anatomy and its reasons-for-being in your body, check out the “wonderful” post (imagine me patting myself on the back) titled The Thyroid Gland: Where is it and What is it?
When a nodule is involved, patients often ask why not remove the nodule only, leaving the remainder of the gland behind. As the picture above shows, the thyroid is very vascular. Think of a blood-saturated sponge and you’ll get a rough idea. Cutting into the gland and digging into its substance is a bloody mess. Nodules are typically deep within and due to the squishy and vascular nature of the gland it’s nearly impossible to localize and remove a nodule or mass. The bleeding also could not be well-controlled, necessitating removal of the gland anyway.
Let’s talk about thyroid cancer. When we say “cancer,” we are talking about the malignant form of a tumor (unnatural growth, lump or mass). By far, the most common cancers in the thyroid are papillary and follicular carcinomas (carcinoma is a type of cancer arising from epithelial cells, found in numerous sites in the body). Papillary and follicular carcinomas are also referred as well-differentiated thyroid carcinomas, given they behave less aggressively than most other cancer types. Whereas statistics describing prognosis (a prediction of future outcomes) often refer to 5-year survival rates (the percentage of patients still alive 5 years after treatment) for most other cancers, patients with well-differentiated tumors tend to have a near-100% 5-year survival. Survival rates are then determined at 10, 15, and 20 years out, the majority still alive and doing well many years down the line. So though these are cancers, they are considered indolent or more “well-behaved.”
The size of the tumor, whether it extends out of the gland and the presence of spread to lymph nodes are criteria to determine whether only the lobe containing the tumor or the entire gland (right and left lobes and the intervening tissue connecting the two called the isthmus) is removed. Papillary carcinomas tend to have multiple sites or satellite lesions, meaning additional nodules of tumor can be found in the lobe with the major tumor or in the opposite lobe. Interestingly though, these multiple foci do not tend to worsen prognosis (i.e, do not worsen survival rates). Even spread to lymph nodes in the neck for most patients also does not tend to reduce survival. Follicular carcinomas tend not to be multifocal and are less likely to spread to lymph nodes, but can spread through the blood stream and to sites outside of the neck, though this is uncommon.
The other two types of thyroid cancer are far less common. Medullary thyroid carcinoma has a worse prognosis, often needing more aggressive surgery and radiation therapy afterward. It can be associated with other endocrine (glandular functions of other organ systems) making treatment a bit different since these other issues need to be addressed. The other type is anaplastic carcinoma, which is even more rare, is extremely aggressive where patients don’t tend to survive beyond one year. Given these are rather rare and a different breed of cancer altogether, we’ll focus on the more common well-differentiated cancers.
RADIOACTIVE IODINE (RAI) TREATMENT
Now once the gland is removed, there is additional treatment that can be offered. This is typically radioiodine therapy which is administration of a radioactive isotope of iodine. Iodine is naturally found in the body, and as mentioned in an earlier post, iodine is required for the synthesis (creation) of thyroid hormone. In this case, radioactive iodine (abbreviated RAI) is given usually by mouth, and circulates in the system. Residual cancer cells that remains inside the thyroid bed where the gland was removed, found in lymph nodes in the neck or other parts of the body soak up the RAI, which then kills these cells. Like normal thyroid cells, the tumor cells in papillary and follicular gobble up iodine circulating in the bloodstream, and this includes the radioactive form of iodine.
However, RAI only works if there is NO residual thyroid gland. Thus, it only works if the entire gland is removed.
SURGERY: PARTIAL THYROIDECTOMY (LOBECTOMY) VERSUS TOTAL THYROIDECTOMY
Which then gets to the trickier aspect of thyroid surgery: should only the involved lobe or the entire gland be removed when suspecting cancer?
Many times a surgeon goes in with incomplete information. The pathology of a prior biopsied nodule may only be “suspicious” for cancer, rather than having a more conclusive diagnosis. Even with the addition of molecular or gene studies such as Affirma (see Thyroid Nodules: Evaluation and Workup) the result still can be inconclusive. Of course, if the biopsy results are benign, then surgery is not needed.
That’s the reason when preparing for surgery, we discuss certain expectations. Naturally, the risks and potential complications are discussed and these include but not limited to*: bleeding, infection, airway compromise; laryngeal, tracheal and esophageal injuries; recurrent laryngeal nerve injury causing voice changes or breathing problems, hypocalcemia causing tetany or breathing problems, and anesthesia risks including death. We also discuss that if later final pathology reveals a malignancy that was not discovered during intraoperative frozen section pathology, a completion thyroidectomy may be needed at a later date.
(*Note: “not limited to” is a common phrase in consents, since no one can predict every single imaginable problem; we still don’t have a complete understanding of the human body and all its hidden complexities, of which new findings are uncovered frequently)
See the cautionary note? “a completion thyroidectomy may be needed.” Particularly with follicular tumors, it is hard to distinguish the benign versus malignant forms on frozen section pathology. This is a type of study that requires freezing the specimen and then creating slides to evaluate under the microscope. This technique can provide a diagnosis while the surgeon is operating, usually in about 20 minutes. How the nodule behaves inside the gland is viewed by the pathologist, and the only features of malignancy are vascular invasion or invasion out of the nodules capsule.
If the tumor is benign, no additional surgery in required—there is no reason to remove the other lobe which can increase the risk of complications, since the recurrent laryngeal nerve and parathyroid glands need to be dissected upon on that opposite side. Potential risks of low calcium (hypocalcemia) and voice or breathing problems are higher if one operates on both sides. Thus, the surgeon should avoid operating on both sides unless there is a strong indication to do so.
Yet frozen section is not as accurate as the typical process where the specimen is placed in formaldehyde for a few days and then cut, stained and studied under the microscope later. This requires several days to a week or longer to come up with the diagnosis. And sometimes what was initially felt to be a benign intraop (during the surgery) is later found to be malignant. This occurs even with papillary carcinoma, where the frozen section path looks benign but the malignant features are noted later.
Then the question is whether to remove the opposite lobe which requires another surgery.
This all depends on the nature of the malignant nodule. Often times, smaller malignant nodules have an indolent course, meaning that without further surgery or RAI, the patient remains disease free, often indefinitely. Also studies have shown that additional surgery may not improve prognosis (ie, may not improve survival) especially since prognosis is relatively good anyway, and thus the risks of additional surgery may outweigh any potential benefit, if any. As such, these patients don’t need RAI and thus the indication for removing the entire gland is not present.
However, for larger cancers or those meeting the criteria for RAI, then a completion thyroidectomy is indicated. This requires reopening the prior incision and then dissecting out and removing the opposite thyroid lobe.
This is the tricky part about thyroid surgery, and the reason the surgeon needs to have a frank discussion with the possibility of additional surgery with the patient.
Preparation before any major event—whether it’s surgery or something else—is always helpful.
Due to the not-so-straight-forward aspects of thyroid surgery, it’s nice to have written information for the patient beforehand. Often when discussing things with a patient and their family, a lot of issues are not retained, so it helps to have them written down. This helps tremendously in their expectations after surgery and with their recovery. So below is the written handout that we provide to patients about to have thyroid surgery:
Your doctor has determined that you have an abnormality in your thyroid gland which requires surgery. Usually there is a nodule or mass within one or both lobes of the gland. However, these cannot be simply removed from the gland due to the highly vascular nature of the gland, which lead to problem-some bleeding if the gland is entered. Therefore, the entire lobe (or entire gland including both lobes and the isthmus) is removed.
The removal of the gland requires a surgical incision over the gland in the lower aspect of the front part of your neck. The recurrent laryngeal nerves and parathyroid glands are identified and dissected away from the gland. The gland is then carefully removed from the trachea, larynx and other structures of the neck. Afterwards, a drain is often placed and the surgical site is closed. The drain usually can be removed the next day.
Often times, only half of the gland needs to be removed, however if cancer or a malignancy is found, then the opposite side of the gland will require removal, thus the entire thyroid gland would be absent. During surgery, the pathologist will examine the gland by frozen sections to determine whether there is cancer. However, sometimes a thorough diagnosis cannot be made until the gland is examined several days later. Occasionally, the patient would need a second surgery to remove the opposite aspect of the gland if the later pathology results demonstrate a malignancy that was not noted by the frozen section analysis during the surgery.
INSTRUCTIONS PRIOR TO SURGERY (PRE-OP INSTRUCTIONS)
1. No aspirin or ibuprofen containing medications two weeks before surgery
2. Purchase a large bottle of Tums (Tums Extra-strength or Tums Ultra) for after surgery. Tums are a source of calcium replacement that you might need after surgery. Your doctor will instruct you on how to use this, if needed.
3. Nothing to eat or drink after midnight the night before surgery.
INSTRUCTIONS FOR AFTER SURGERY (POST-OP INSTRUCTIONS)
1. Your doctor will prescribe pain medication for after surgery. Patients often notice pain with swallowing, and this is due to the up and down movement of the voice box during swallowing.
2. You will need to sleep with your head elevated above the level of your heart. This can be accomplished by sleeping on several pillows or in a reclining chair. This helps to reduce swelling and pain to the neck.
3. You may shower or bath and wash your hair afterwards. You should place a layer of antibiotic ointment (such as Neosporin) over the incision before and afterwards. Try not to have water directly on the wound. If it gets wet, lightly dab dry it. Do not wash or vigorously rub the surgical site for about two weeks.
4. Diet: Start with liquids and soft food, and advance to a normal diet as you are able to tolerate.
5. Other medications: Sometimes you will need a thyroid replacement hormone after surgery. Your doctor will instruct you afterwards if this is needed. Often when only one lobe is removed, this type of medication may not be needed. Your doctor may need to place you on a vitamin D medication to maintain normal calcium levels along with the Tums (such as calcitriol).
6. You will need to make an appt for about a week after surgery for removal of the sutures.
WHEN TO CALL:
1. If you have pronounced redness, swelling, or drainage of the from the neck incision, temperature over 101, problems breathing, or pain that is not controlled with the prescription pain medication.
2. If you notice tingling or numbness around the lips, muscle twitching or cramping (these are signs of possible low calcium levels).
We’ll get into the gory details of the surgery itself in a future post (Thyroid Surgery, A Step-Wise Explanation). See you all then.
©Randall S. Fong, M.D.www.randallfong.com