Kathleen Su-Yen Sek1, Ingrid Tsang2, Xuan Yong Lee3, Omar H Albaqmi4, Yanina Jimena Morosan Allo5, Melanie Cinthia Rosmarin5, Azhar K Mahrous6, Rajeev Parameswaran7, David Chee Eng Ng8, Aaron Kian Ti Tong8, Kelvin Siu Hoong Loke8, Gabriela Brenta5, Abdullah Hassan Alghamdi4, Naif A Albati4, Stephanie A Fish9, R Michael Tuttle9, Samantha Peiling Yang10,11. 1. Department of Endocrinology, National University Health System Singapore, Singapore City, Singapore. 2. Department of Endocrinology, Tseung Kwan O Hospital, Hong Kong, Hong Kong. 3. Department of Medicine, National University Health System Singapore, Singapore City, Singapore. 4. Department of Surgery, Breast Endocrine Surgery Unit, Prince Sultan Military Medical City, Riyadh, Saudi Arabia. 5. Department of Endocrinology and Metabolism, Unidad Asistencial Dr. Cesar Milstein Buenos Aires, Buenos Aires, Argentina. 6. Department of Internal Medicine, Imam Muhammad Ibn Saud Islamic University, College of Medicine, Riyadh, Saudi Arabia. 7. Department of Endocrine Surgery, National University Hospital, Singapore City, Singapore. 8. Department of Nuclear Medicine, Singapore General Hospital, Singapore City, Singapore. 9. Endocrinology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York City, NY, USA. 10. Department of Endocrinology, National University Hospital, Singapore City, Singapore. 11. Yong Loo Lin School of Medicine, Singapore City, Singapore.
Abstract
BACKGROUND: American Thyroid Association (ATA) low-intermediate-risk papillary thyroid cancer (PTC) patients without structural and biochemical evidence of disease on initial post-treatment evaluation have a low risk of recurrence. Studies have shown that with current ultrasound scans (US) and thyroglobulin assays, recurrences mostly occurred 2-8 years after initial therapy. The ATA recommends that neck US be done 6-12 months after surgery to establish patient's response to therapy, then periodically depending on risk of recurrence. The lack of clarity in recommendations on timing of follow-up US and fear of recurrence leads to frequent tests. OBJECTIVES: To evaluate the utility of routine neck US in ATA low-intermediate-risk PTC patients with no structural disease on neck US and non-stimulated thyroglobulin <1.0 ng/mL after initial therapy. METHODS: A retrospective study of 93 patients from Singapore, Saudi Arabia and Argentina with ATA low (n = 49) to intermediate (n = 44) risk PTC was conducted between 1998 and 2017. The outcome was to measure the frequency of identifying structural disease recurrence and non-actionable US abnormalities. RESULTS: Over a median follow-up of 5 years, five of the 93 patients (5.4%) developed structural neck recurrence on US at a median of 2.5 years after initial treatment. Indeterminate US abnormalities were detected in 19 of the 93 patients (20.4%) leading to additional tests, which did not detect significant disease. CONCLUSION: In ATA low-intermediate-risk PTC with no suspicious findings on neck US and a non-stimulated thyroglobulin of <1.0 ng/mL after initial therapy, frequent US is more likely to identify non-actionable abnormalities than clinically significant disease.
BACKGROUND: American Thyroid Association (ATA) low-intermediate-risk papillary thyroid cancer (PTC) patients without structural and biochemical evidence of disease on initial post-treatment evaluation have a low risk of recurrence. Studies have shown that with current ultrasound scans (US) and thyroglobulin assays, recurrences mostly occurred 2-8 years after initial therapy. The ATA recommends that neck US be done 6-12 months after surgery to establish patient's response to therapy, then periodically depending on risk of recurrence. The lack of clarity in recommendations on timing of follow-up US and fear of recurrence leads to frequent tests. OBJECTIVES: To evaluate the utility of routine neck US in ATA low-intermediate-risk PTC patients with no structural disease on neck US and non-stimulated thyroglobulin <1.0 ng/mL after initial therapy. METHODS: A retrospective study of 93 patients from Singapore, Saudi Arabia and Argentina with ATA low (n = 49) to intermediate (n = 44) risk PTC was conducted between 1998 and 2017. The outcome was to measure the frequency of identifying structural disease recurrence and non-actionable US abnormalities. RESULTS: Over a median follow-up of 5 years, five of the 93 patients (5.4%) developed structural neck recurrence on US at a median of 2.5 years after initial treatment. Indeterminate US abnormalities were detected in 19 of the 93 patients (20.4%) leading to additional tests, which did not detect significant disease. CONCLUSION: In ATA low-intermediate-risk PTC with no suspicious findings on neck US and a non-stimulated thyroglobulin of <1.0 ng/mL after initial therapy, frequent US is more likely to identify non-actionable abnormalities than clinically significant disease.