Thyroid and Parathyroid Disease

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Parathyroid Disease and Thyroid Disease Commonly Occur Together

Patients with Both Thyroid and Parathyroid Disease

Importance of ultrasound evaluation of the thyroid and parathyroid glands prior to surgery

We have previously mentioned that patients with parathyroid disease (such as primary hyperparathyroidism) should seek treatment at endocrine surgery centers with expertise in both thyroid and parathyroid conditions (see Frequently asked questions about parathyroid surgery).  The reason for this is that both parathyroid disease and thyroid disease are highly prevalent (common) in women over 45 years of age, and thus the two conditions often overlap in individual patients.  Primary hyperparathyroidism and thyroid cancer affect women 3-4 times as often as men.  Primary hyperparathyroidism affects up to 3% of post-menopausal women.  About half of women aged 45 and older have thyroid nodules, and approximately 4% of these nodules will turn out to be malignant (cancerous).  Recent research shows that thyroid cancer rates have tripled in the United States since the 1970s (see Surgery for thyroid cancer)

Pre-op Ultrasound
Ultrasound evaluation of the thyroid and parathyroid glands prior to surgery.

For this reason, it is our opinion that every patient being evaluated for parathyroid disease should undergo ultrasound evaluation of the thyroid and parathyroid glands prior to surgery. 

Ideally this should be done by the surgeon during the initial consultation, or planning phase for surgery.  This is our standard practice at UCLA Endocrine Surgery, and it is rapidly gaining wide acceptance among other expert centers (see References).  An important study conducted at the University of Wisconsin showed that almost half of patients being evaluated for primary hyperparathyroidism had suspicious thyroid findings on ultrasound.  Thyroid cancer was discovered in several patients, allowing for appropriate treatment of both thyroid and parathyroid disease with a single operation.  Experts at the Cleveland Clinic conducted a similar study in which they found that routine pre-operative ultrasound evaluation actually reduced the need for unnecessary thyroid surgery.

Let’s take a moment to understand these two research findings a little better.  Ultrasound allows thyroid cancer to be detected in a small but significant number of patients being evaluated for parathyroid disease (primary hyperparathyroidism).  Those patients are at risk for inadequate initial surgery, i.e. if the thyroid cancer was missed the first time, those patients would potentially need a second operation to treat thyroid cancer.  Given how frequently parathyroid disease and thyroid cancer occur together, it is statistically inevitable that solely operating on the parathyroids without ultrasound evaluation of the thyroid will lead to thyroid cancers being left behind untreated.  On the other hand, many thyroid nodules are benign and do not require surgery.  Those patients are at risk for excessive surgery, for example if their surgeon discovers a thyroid nodule at the time of surgery and decides to remove the nodule or biopsy it surgically, which is often not the right thing to do (Why? See below).

Thyroid and Parathyroid Disease
Thyroid and Parathyroid Disease >

When it comes to any type of surgery, what patients need is not too little surgery, nor too much surgery.  Patients need just the right amount of surgery.  Ultrasound permits this in thyroid and parathyroid disease by creating a roadmap for the operation.  We would not contemplate performing this type of surgery without ultrasound guidance; in our opinion that would be tantamount to “flying blind” in the neck.

It is common for many surgeons to offer to inspect or evaluate the thyroid during parathyroid surgery.  We do not believe this represents best clinical practice, for several reasons.

Why ultrasound evaluation of the thyroid prior to parathyroid surgery is preferable to visual inspection of the thyroid during parathyroid surgery

  • Visual inspection of the thyroid during parathyroid surgery may only reveal problems on the surface of the thyroid, as opposed to ultrasound which can penetrate into the deep substance of the thyroid.
  • The discovery of a suspicious thyroid nodule during parathyroid surgery may lead to enucleation (also known as nodulectomy or surgical/open biopsy) of the thyroid nodule.  This is not considered standard of care for suspicious thyroid nodules.  Suspicious thyroid nodules are best treated with thyroid lobectomy (hemithyroidectomy or removal of half of the thyroid gland).  Lobectomy permits pathologic (microscopic) evaluation of the boundary between the suspicious nodule and the adjacent normal thyroid tissue, which often reveals the deciding factor between which nodules are malignant (cancerous) and which nodules are benign, that is, the presence or absence of invasion.
  • The presence of thyroid cancer is best detected by pre-operative ultrasound-guided fine-needle aspiration (FNA) of thyroid nodules.  This is widely accepted as best practice.  Having this knowledge in advance of surgery permits careful planning of the operation and mobilization of any additional resources necessary for a more complex cancer operation.  Thyroid cancer surgery generally involves a total thyroidectomy and often a lymph node dissection.  It is best for the surgeon to be prepared for this ahead of time, as an improvised thyroid cancer operation is unlikely to yield the best outcome for the patient.
  • Ultrasound affords the patient the best chance of having a single, definitive operation.  We have previously discussed the potential for leaving thyroid cancers behind.  Indeed, we see patients for re-do thyroid surgery every week at UCLA and sometimes we perform multiple re-do thyroid operations in a single day.  Re-do surgery is associated with risks that are several fold higher than initial neck surgery, and hence re-do surgery should be avoided whenever possible.
Pre-op Ultrasound

Specimen from a patient with both thyroid and parathyroid disease.

Intrathyroidal parathyroid adenomas (parathyroid tumors lodged within the substance of the thyroid gland) are found in about 1% of humans. This patient's thyroid nodule was determined to be benign.

All of the above points are common sense.  Before embarking on a neck operation, the surgeon should have complete knowledge of everything that is going on in the neck (the roadmap we discussed above).  This is just “doing one’s homework” in preparation for surgery, and certainly you deserve this level of quality and detail-oriented evaluation in your health care.  Ultrasound permits avoidance of almost all surprises or “spur of the moment” decision-making during surgery.  Now, obviously not everything can be anticipated, and surgery will always require surgeons to think well on their feet in the best interest of their patients.  However, with routine use of pre-operative ultrasound, we have been able to reduce the number of even minor unanticipated events to less than 5% during thyroid and parathyroid surgery.  We don’t like surprises.  In this sense, having surgery is a lot like taking a commercial air flight – the best possible experience is one with no surprises and no excitement (learn more about Health care quality and safety).

In summary, we recommend that all patients being evaluated for parathyroid surgery undergo routine ultrasound examination of the thyroid and parathyroid glands by a surgeon experienced in both thyroid and parathyroid surgery.  Careful planning of the operation in advance will maximize the likelihood of a good outcome.

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