Clinical Outcomes after Early and Delayed Radioiodine Remnant Ablation in Patients with Low-Risk Papillary Thyroid Carcinoma: Propensity Score Matching Analysis

다국어 초록 (Multilingual Abstract)

Background: The clinical outcomes of delayed radioiodine remnant ablation (RRA) therapy in patients with low-risk papillary thyroid carcinoma (PTC) are unclear. We aimed to evaluate the clinical impact of the interval between total thyroidectomy (TT) and RRA therapy in patients with low-risk PTC.
Methods: We included 526 patients who underwent TT and RRA for low-risk PTC with a primary tumor size of >1 cm between2000 and 2012. Patients were divided into the early (<90 days) and the delayed (≥90 days) RRA groups based on the interval between TT and RRA. The results of diagnostic whole-body scan (DxWBS), ongoing risk stratification (ORS; response to therapy), and disease-free survival (DFS) were evaluated before and after propensity score matching (PSM).
Results: Among the 526 patients, 75 (14.3%) patients underwent delayed RRA; they had more cervical lymph node metastasis and received a higher RRA dose than those who underwent early RRA. The median follow-up period was 9.1 years after initial therapy, and the structural recurrence rate was 1.9%. In DxWBS, 60 patients had focal iodine uptake limited in operative bed, with no significant difference between groups. According to ORS, 78%, 20%, 1%, and 1% patients were classified into excellent, indeterminate, biochemical incomplete, and structural incomplete response groups, respectively. There was no significant difference in ORS or DFS between groups before and after PSM.
Conclusion: The timing of the first RRA had no clinical impact in patients with low-risk PTC. Thus, the clinical decision for RRA can be determined >3 months after TT considering other prognostic factors.

참고문헌 (Reference)

1 Ibrahimpasic T, "Undetectable thyroglobulin after total thyroidectomy in patients with low- and intermediate-risk papillary thyroid cancer: is there a need for radioactive iodine therapy?" 152 : 1096-1105, 2012

2 Singer PA, "Treatment guidelines for patients with thyroid nodules and well-differentiated thyroid cancer. American Thyroid Association" 156 : 2165-2172, 1996

3 Scheffel RS, "Timing of radioactive iodine administration does not influence outcomes in patients with differentiated thyroid carcinoma" 26 : 1623-1629, 2016

4 Sacks W, "The effectiveness of radioactive iodine for treatment of lowrisk thyroid cancer : a systematic analysis of the peer-reviewed literature from 1966 to April 2008" 20 : 1235-1245, 2010

5 Schlumberger M, "Strategies of radioiodine ablation in patients with low-risk thyroid cancer" 366 : 1663-1673, 2012

6 Marti JL, "Selective use of radioactive iodine(RAI)in thyroid cancer : no longer"one size fits all"" 44 : 348-356, 2018

7 American Thyroid Association (ATA) Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer, "Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer" 19 : 1167-1214, 2009

8 Orosco RK, "Radioactive iodine in differentiated thyroid cancer : a national database perspective" 26 : 795-802, 2019

9 Taieb D, "Quality of life changes and clinical outcomes in thyroid cancer patients undergoing radioiodine remnant ablation (RRA) with recombinant human TSH (rhTSH): a randomized controlled study" 71 : 115-123, 2009

10 Leboulleux S, "Papillary thyroid microcarcinoma: time to shift from surgery to active surveillance?" 4 : 933-942, 2016

11 Jeon MJ, "Modified dynamic risk stratification for predicting recurrence using the response to initial therapy in patients with differentiated thyroid carcinoma" 170 : 23-30, 2013

12 Nicole M. Iñiguez-Ariza, "Management of Low-Risk Papillary Thyroid Cancer" 대한내분비학회 33 (33): 185-194, 2018

13 Cooper DS, "Management guidelines for patients with thyroid nodules and differentiated thyroid cancer" 16 : 109-142, 2006

14 Ahn J, "Long-term clinical outcomes of papillary thyroid carcinoma patients with biochemical incomplete response" 67 : 623-629, 2020

15 Miyauchi A, "Insights into the management of papillary microcarcinoma of the thyroid" 28 : 23-31, 2018

16 Oh HS, "Individualized follow-up strategy for patients with an indeterminate response to initial therapy for papillary thyroid carcinoma" 29 : 209-215, 2019

17 Schvartz C, "Impact on overall survival of radioactive iodine in low-risk differentiated thyroid cancer patients" 97 : 1526-1535, 2012

18 Tsirona S, "Impact of early vs late postoperative radioiodine remnant ablation on final outcome in patients with low-risk well-differentiated thyroid cancer" 80 : 459-463, 2014

19 Kim M, "Impact of delayed radioiodine therapy in intermediate-/highrisk papillary thyroid carcinoma" 91 : 449-455, 2019

20 Tuttle RM, "Estimating risk of recurrence in differentiated thyroid cancer after total thyroidectomy and radioactive iodine remnant ablation : using response to therapy variables to modify the initial risk estimates predicted by the new American Thyroid Association staging system" 20 : 1341-1349, 2010

21 Park S, "Dynamic risk stratification for predicting recurrence in patients with differentiated thyroid cancer treated without radioactive iodine remnant ablation therapy" 27 : 524-530, 2017

22 Li H, "Delayed initial radioiodine therapy related to incomplete response in low-to intermediate-risk differentiated thyroid cancer" 88 : 601-606, 2018

23 Higashi T, "Delayed initial radioactive iodine therapy resulted in poor survival in patients with metastatic differentiated thyroid carcinoma : a retrospective statistical analysis of 198 cases" 52 : 683-689, 2011

24 Sawka AM, "Clinical review 170 : a systematic review and metaanalysis of the effectiveness of radioactive iodine remnant ablation for well-differentiated thyroid cancer" 89 : 3668-3676, 2004

25 Ruel E, "Adjuvant radioactive iodine therapy is associated with improved survival for patients with intermediate-risk papillary thyroid cancer" 100 : 1529-1536, 2015

26 김태용, "Active Surveillance of Papillary Thyroid Microcarcinoma: A Mini-Review from Korea" 대한내분비학회 32 (32): 339-406, 2017

27 Jeon MJ, "A follow-up strategy for patients with an excellent response to initial therapy for differentiated thyroid carcinoma : less is better" 28 : 187-192, 2018

28 Haugen BR, "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" 26 : 1-133, 2016