The low risks and high rewards of thyroid cancer treatment

Ohwofiemu "Fiemu" Nwariaku, M.D., is recognized worldwide as an authority on thyroid cancer and other diseases of the endocrine system.​​
Ohwofiemu "Fiemu" Nwariaku, M.D., is recognized worldwide as an authority on thyroid cancer and other diseases of the endocrine system.​​

A recent article in The New York Times argues doctors treat thyroid cancer too aggressively. The article focuses on a study that appeared in The New England Journal of Medicine covering the increase in reported cases of thyroid cancer. The authors suggest many of these cases actually are overdiagnoses – or the diagnosis of small tumors that wouldn’t cause symptoms or death if left alone.

The conversation that results from this study is an important one: “What is the risk of treatment versus no treatment?” For small thyroid tumors in otherwise healthy patients, there usually is very little risk involved with treatment. That’s why I recommend treatment to the majority of my thyroid cancer patients.

Better diagnosis, not overdiagnosis

The study’s authors looked at the number of thyroid cancer diagnoses from the 1960s to the 1990s. Using these findings, they then projected the number of cases we should expect to have seen in the 2000s. The authors compared this projected number with how many cases were actually reported in the 2000s according to cancer registries for the United States and several other countries. They found that more cases of thyroid cancer were reported than the data suggested there should have been. The reason, they concluded, was overdiagnosis of thyroid cancers.

I believe the word “overdiagnosis” may be a misnomer in this situation, because the diagnosis of thyroid cancer is correct. Perhaps overtreatment may be a more appropriate term. We diagnose thyroid cancer more often today because we can screen more effectively for the disease. Ultrasound technology is more accurate, has higher resolution, and is less expensive compared to technology in the 1950s and ’60s. CT (computed tomography) scans weren’t routinely available until the 1970s. Today, better technology and frequent screening allows us to detect and diagnose more cancers at an earlier stage and generally reduces death and morbidity from these cancers. Breast cancer and colon cancer represent good examples. Despite the variable and often indolent behavior of these tumors, thyroid cancers detected in this manner are real cancers that can cause death and morbidity. As such, we avoid the use of the term overdiagnosis.

In addition to discussing the total number of cases, the study’s authors note the higher number of thyroid cancer diagnoses in women as compared to men and how women are more likely to have treatment they don’t need. For decades, we’ve observed that women are more likely to develop thyroid cancer compared to men. In fact, my lab colleagues have spent a number of years examining thyroid cancer cells in culture and their responses to sex hormones. We found that estrogen increases the growth rate of thyroid cancer cells. This observation suggests that hormones may play a part in the higher rate of thyroid cancer in women. There also could be genetic differences that still are unclear.

But men with thyroid cancer actually fare worse than women. In men, a thyroid tumor is more likely to:

  • Be larger
  • Be more aggressive
  • Spread (metastasize) to other areas

This means we tend to find more cases of thyroid cancer in women, while thyroid cancers in men are more likely to be advanced. Scientists continue to study these differences.

The low costs of thyroid cancer treatment …

It’s important to note any large thyroid cancer – more than about 2 centimeters (0.78 inch) – needs to be removed. The study’s authors discuss predominantly small tumors – less than 1 centimeter (0.4 inch).

This study argues doctors overdiagnose and overtreat thyroid cancer in small tumors that may never cause symptoms or death from the disease. But when we remove these small thyroid tumors before they’ve had a chance to grow and spread, we actually can cure thyroid cancer.

The risks of thyroid cancer treatment are low, when performed by a skilled team of healthcare providers with experience treating thyroid cancer. The main treatment for thyroid cancer is surgical removal of the thyroid gland, known as a thyroidectomy. This is a relatively simple surgery we usually perform as an overnight procedure. In addition, some patients may have it as an outpatient procedure – the patient comes in, has the thyroid removed, and goes home on the same day, with a full return to work within a few days. It’s not like more intense treatment for some cancers, which can include difficult or painful surgeries, hair loss, long hospital stays, and time away from work. In fact, we rarely give chemotherapy or radiation treatment for the majority of thyroid cancers.

Only about 1 to 4 percent of patients report any permanent complications from a thyroidectomy. Of those complications, hoarseness of the voice or low calcium levels from damage to the parathyroid glands are the most common. We can treat both of these.

The primary change in patients’ quality of life after a thyroidectomy is the need to take thyroid hormone therapy for the rest of their lives. In the 1970s and ’80s, people had problems like weight gain or loss because of inconsistent delivery of thyroid hormone from pill to pill. Today, the medication is much better, and most patients have no problems at all from the therapy. The medication is generic, so it’s far less expensive than name-brand medications.

… and the high costs of doing nothing

The alternative to potentially curing a patient’s thyroid cancer with surgery is watchful waiting, also known as active surveillance. In watchful waiting, we have to constantly monitor the thyroid and the tumor to make sure it’s not growing. This includes:

  • Continual checkups
  • Frequent imaging screenings
  • Repeat biopsies of the tumor

When my patients ask about watchful waiting for thyroid cancer, I tell them: “If you choose to wait, then you will need to be active in keeping appointments and following the tumor closely for a very long time.” The financial cost alone makes surgery an attractive option for small thyroid tumors. If you add up the office visits, ultrasound tests, blood tests, repeat biopsies, and so on over a 10-year period, it easily could exceed the cost of a short operation and an inexpensive daily pill.

There also is an emotional cost. Patient anxiety is a real concern with watchful waiting. I have patients who come to the clinic frequently to be tested, and they’re anxious with each visit. They ask, “Has my tumor grown? Has it changed? Do we need to do a biopsy?” That anxiety has to be factored into the decision-making and quality of life, compared with the alternative of undergoing a low-risk operation and short convalescence to cure the cancer.

Finding certainty with an uncertain disease

Prior to making generalizations about overtreatment for thyroid cancer, we need better information about which tumors should be removed and which tumors can be actively observed. Thyroid cancer is relatively slow-growing and has low mortality, both of which make it difficult to perform the necessary prospective clinical trials to obtain accurate and meaningful information about the disease. However, we do know that removing small tumors early allows us to cure the disease before it has a chance to grow and worsen.

For example, a colleague of mine recently treated a patient who came in with a large thyroid gland. Results from a biopsy indicated it was a benign enlargement of the thyroid, known as a goiter. The thyroid still needed to be removed because of the size of the goiter. During the thyroidectomy, the team found a tiny thyroid cancer that was just 3 millimeters (about 0.12 inch). This cancer had already spread to the lymph nodes in the patient’s neck, but my colleague would never have been able to see that during a CT scan or an ultrasound.

Even tumors that we cannot yet feel may already have spread to the lymph nodes around the thyroid. It is unclear how those lymph node tumor deposits will behave during the next 10 or 20 years. As such, when we are faced with the choice of leaving a cancer in a patient or removing it safely, we generally recommend removal of the cancer.

The future of thyroid cancer treatment

My hope for the future is that we will have better information about which forms of thyroid cancer will be aggressive and which ones will stay stable. No thyroid cancer will go away on its own, but this information will help us better determine which patients we should treat and which ones we can safely monitor.

One day, more research and more data may make that possible. For now, given what we know about thyroid cancer and its outcomes, I’ll continue to recommend surgery for my patients when safe and possible.

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