“Risk assessment should be based on both clinical and radiological investigations,” noted Dr Mohammadi. “In a patient with risk factors for thyroid cancer, clinicians have a lower threshold to do investigations and follow-up. We did not assess the effect of other risk factors of thyroid cancer than ultrasound features in this study, but it’s reasonable to consider all clinical, radiological, and pathological aspects to interpret risks and outline the best follow-up strategies.”

Keeping High-Risk DTC Patients Disease-Free

After thyroidectomy in intermediate- to high-risk patients with DTC, many patients receive radioactive iodine therapy, which has long been controversial. To further examine thyrotropin suppression in intermediate- to high-risk patients with DTC, endocrinologist Joanna Klubo-Gwiezdzinska, MD, PhD, MHSc, principal investigator–thyroid nodules and thyroid cancer at the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, Maryland, and colleagues examined progression-free and overall survival in patients treated with radioactive iodine therapy.6

The 7.2-year cohort study of 867 patients (mean age, 48.5; 64.2% women) followed patients who were treated with total thyroidectomy and radioactive iodine.6 Suppressing thyrotropin did not improve progression-free survival at 1.5- (P =.41), 3- (P =.51), and 5-year (P =.64) follow-up. In patients who did not progress in the first 1.5 or 3 years, advanced age, lateral neck lymph node metastases, and distant metastases were linked to later time to structural disease progression.6

“For patients who have an excellent response to treatment and no evidence of persistent or recurrent disease, the risks of continued TSH suppression with supraphysiologic doses of levothyroxine outweigh the benefits,” said Dr Klubo-Gwiezdzinska. “The adverse effects of TSH suppression may include exacerbation of angina in patients with ischemic heart disease, increased risk for arrhythmias such as atrial fibrillation in older patients, and increased risk for osteoporosis, particularly in postmenopausal women. The optimal follow-up strategy in such circumstances is to maintain a TSH goal within a low normal range of 0.5 to 2 mIU/mL with continued surveillance measurements of the tumor marker, thyroglobulin, and anti-thyroglobulin antibodies as well as performance of ultrasound of the neck on a yearly basis.”

Immune Checkpoint Inhibitor Treatment and Endocrine Emergencies

Thyroid disorders and other endocrinopathies may develop in patients who have been treated with immune checkpoint inhibitors (ICI) for advanced-stage cancers.7 In a review of 451 cases culled from 179 articles about ICI-induced endocrinopathies, Meng H. Tan, MD, clinical professor of medicine in the division of metabolism, endocrinology, and diabetes at the University of Michigan, Ann Arbor, and colleagues, reported 152 thyroid disorders.7 Most cases occurred within 5 months of ICI therapy and were irreversible.7

Dr Tan advised clinicians caring for cancer patients who have taken ICIs to “be vigilant for the occurrence of ICI-induced endocrinopathies which have increased markedly not only in numbers but in spectrum. These drug-induced endocrinopathies affect 5 endocrine glands and manifest as 10 endocrinopathies.”

Summary & Clinical Applicability

In patients who have had successful treatment for thyroid cancer, clinicians should consider scaling back extensive follow-up testing. Revised ATA guidelines encourage clinicians to individualize surveillance to avoid unnecessary procedures.

Limitations & Disclosures

None.

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References

1.      Lamartina L, Grani G, Durante C, Borget I, Filetti S, Schlumberger M. Follow-up of differentiated thyroid cancer – what should (and what should not) be done. Nat Rev Endocrinol. 2018;14(9):538-551.

2.      Haugen BR, Alexander EK, Bible KC, et al. 2015 American Thyroid Association management guidelines for adult patients with thyroid nodules and differentiated thyroid cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. 2016;26(1):1-133.

3.      Santhanam P, Ladenson PW. Surveillance for differentiated thyroid cancer recurrence. Endocrinol Metab Clin N Am. 2019;48(1):239-252.

4.      Eskander A, Hall SF, Manduch M, Griffiths R, Irish JC. A population-based study on NIFTP incidence and survival: is NIFTP really a “benign” disease? [published online January 28, 2019]. Ann Surg Oncol. doi:10.1245/s10434-019-07187-0

5.      Mohammadi M, Betel C, Burton KR, Higgins KM, Ghorab Z, Halperin IJ. Retrospective application of the 2015 American Thyroid Association guidelines for ultrasound classification, biopsy indications, and follow-up imaging of thyroid nodules: can improved reporting decrease testing? Can Assoc Radiol J. 2019;70(1):68-73.

6.      Klubo-Gwiezdzinska J, Auh S, Gershengorn M, et al. Association of thyrotropin suppression with survival outcomes in patients with intermediate- and high-risk differentiated thyroid cancer. JAMA Netw Open. 2019;2(2):e187754.

7.      Tan MH, Iyengar R, Mizokami-Stout K, et al. Spectrum of immune checkpoint inhibitors-induced endocrinopathies in cancer patients: a scoping review of case reports. Clin Diabetes Endocrinol. 2019;5:1.