Strategies for surveillance after thyroid cancer ‘cure’ based on treatment type
Surveillance after treatment for low-risk thyroid cancer is a balancing act that must consider treatment modality and patient concerns about recurrence, but several considerations can help stratify who should receive follow-up screenings.
“For cancer patients and their physicians, being ‘cured of cancer’ is often the ultimate goal,” Megan R. Haymart, MD, professor of medicine, metabolism, endocrinology and diabetes and the Nancy Wigginton Endocrinology Research Professor of Thyroid Cancer at the University of Michigan and Endocrine Today Editorial Board Member, told Healio. “However, there is often a small amount of uncertainty regarding which patients are and are not ‘cured.’ Risk for recurrence and worry about recurrence drives long-term surveillance with clinic visits, laboratory work and imaging.”
Some patients are at risk for too much surveillance, which can lead to false positives, patient anxiety and distress, as well as increased health care costs, Haymart said during a virtual presentation at the ENDO annual meeting. More research is needed to define optimal surveillance strategies for patients with thyroid cancer.
“Ideally, we should have tailored surveillance strategies based on risk category, type of treatment and response to therapy,” Haymart said.
The amount of treatment a person with differentiated thyroid cancer receives has implications for how much information treating endocrinologists have about whether the patient is indeed “disease-free,” as well as implications for what the surveillance strategy should be, Haymart said.
“That is where the question arises,” Haymart said. “We often have a little uncertainty about whether a patient is truly disease-free. In addition, the type of treatment the patient received influences how much information we have about disease-free status. An individual who underwent total thyroidectomy with radioactive iodine treatment has more information available on thyroglobulin vs. a person who underwent total thyroidectomy without radioactive iodine, or a lobectomy.”
Additionally, there is higher-quality evidence on what should be expected if a patient is disease-free after undergoing total thyroidectomy with radioactive iodine vs. more contemporary treatment — total thyroidectomy alone or lobectomy, Haymart said.
“It is complex because we have to consider the treatment the patient received in addition to their disease status at initial presentation,” Haymart said.
For patients who underwent total thyroidectomy and radioactive iodine treatment with a “reassuring” posttreatment ultrasound and a thyroglobulin level of less than 0.2 ng/mL, that patient could be considered disease-free, she said.
“But we do know that even among these individuals, the risk for recurrence is 1% to 4%,” Haymart said. “That makes us uncertain. Is the particular patient that we are treating one of those individuals who is not, in fact, disease-free?”
Recurrence risk, patient worry
Recurrence is the main target of surveillance after thyroid cancer, and it is important to know when patients are at risk for recurrence, Haymart said. Most cancer recurrences appear within the first 10 years, primarily in the first 5 years. Recurrence during the first 2 years after treatment may represent disease that was previously treated inadequately.
Haymart said clinicians can categorize patients into low, intermediate and high risk for recurrence, with “low” risk having as low as 1% risk for recurrence and “high” risk as high as 55%.
“Understanding this recurrence risk can help us design tailored surveillance strategies,” Haymart said. “But we also know that patient worry about recurrence can drive some of our surveillance.”
A recent study of more than 2,600 patients seen in Georgia and Los Angeles 2 to 4 years after a low-risk thyroid cancer diagnosis showed that patient worry was very common, with more than 60% having “some worry” about recurrence. Younger patients, those with less education and those with more advanced disease or lymph node metastases were more likely to say they experienced worry about recurrence, Haymart said.
“We know this anecdotally — all of us who treat thyroid cancer patients — there are some patients who worry a lot, and we end up seeing them more often and ordering extra tests,” Haymart said.
A survey of endocrinologists and endocrine surgeons who treated patients with thyroid cancer showed that patient worry was associated with more referrals, more lab work, more imaging studies, more clinic visits and, in particular, longer clinic visit length.
“Worry about recurrence may be almost as important as recurrence risk itself in driving surveillance,” Haymart said. “We have to be aware of this and think of strategies to manage this when coming up with surveillance strategies.”
Long-term surveillance accounts for one-third of all expenditures on differentiated thyroid cancer in the U.S., Haymart said. The estimated cost of thyroid cancer surveillance in the U.S. was $600 million in 2013, with a projection of costs reaching $1.4 billion by 2030.
Because recurrence is less common among low-risk patients, the cost of detecting a recurrence is estimated to be seven times greater vs. high-risk patients, she said.
“In some instances, we would all agree that we are doing too much surveillance,” Haymart said. “What drives that?”
The answer is multifactorial, with patients and clinicians contributing, Haymart said. Some patients feel “less is more”; other patients want aggressive treatment for any disease.
Haymart said there is not strong evidence for the “best” strategies for optimal surveillance for disease-free patients; however, clinicians can start to define what is too much:
- If you have a sensitive thyroglobulin assay, in low-risk, disease-free patients who underwent total thyroidectomy, there is no need for thyrotropin alfa (Thyrogen, Genzyme)-stimulated thyroglobulin or a repeat radioactive iodine scan.
- Although neck ultrasound is key to long-term surveillance, avoid too many neck ultrasounds for low-risk patients without any sign of recurrence.
- Serum thyroglobulin is likely helpful after total thyroidectomy with or without radioactive iodine; however, its role after lobectomy is unclear.
“As we shift from more- to less-intensive treatment, it is important to define the optimal surveillance strategy,” Haymart said. “Ideally, we will have tailored surveillance strategies based on risk category, type of treatment and response to therapy. We do need to manage patient worry as well, because we know that worry can be a driver of too much surveillance.”