ORIGINAL ARTICLE Intermediate-risk differentiated thyroid carcinoma patients who were surgically ablated do not need adjuvant radioiodine therapy: long-term outcome study Sanjana Ballal*, Ramya Soundararajan*, Aayushi Garg†, Saurav Chopra† and Chandrasekhar Bal* *Department of Nuclear Medicine, All India Institute of Medical Sciences, and †Medical Student, All India institute of Medical Sciences, New Delhi, India Summary Objective The mute question is whether patients with DTC of intermediate risk of recurrence, second most common presenta- tion, who were surgically ablated in the first place, ever needed adjuvant RAI therapy? This study exclusively evaluated the long- term outcome in intermediate-risk patients with DTC. Design Two-arm retrospective cohort study conducted between years 1991 and 2012. Setting Institutional practice. Patients Intermediate-risk DTC patients, with pathologically proven T1/2 N1 M0, T3 with/without N1 M0 disease, with a minimum follow-up of 12 months, were included. Of 254 patients who fulfilled the inclusion/exclusion criteria, 125 patients were surgically ablated (Gr-I) and 129 patients had sig- nificant remnant and/nodal disease (Gr-II). No radioiodine in Gr-I and adjuvant RAI therapy was administered in Gr-II patients. Measurements Baseline characteristics were compared and overall survival, event-free survival, disease-free survival/overall remission rates and recurrence rates were calculated for both the groups. Results All baseline patient characteristics were comparable except 24-h RAIU between two groups. Depending on adjuvant radioiodine therapy outcome, Gr-II patients were subclassified as Gr-IIa (ablated) and Gr-IIb (not ablated). With a median fol- low-up duration of 10Á3 years (range: 1–21 years), 12/125 (9Á6%) patients had disease recurrence and 10 (8%) showed per- sistent disease in Gr-I. In Gr-IIa, 6/102 (5Á9%) patients recurred but only one of them was successfully ablated with 131 I, and 5 (4Á9%) had persistent disease. However, in Gr-IIb, 27 patients who failed first-dose adjuvant RAI therapy, 8/27 (29Á6%) showed persistent disease (P = 0Á000). Overall survival was 100%; however, disease-free survival rates were 92% and 90%, in Gr-I and Gr-II, respectively. Conclusion Intermediate-risk surgically ablated patients do not need adjuvant RAI therapy and patients who failed to achieve ablation with first dose of 131 I may be dynamically risk stratified as high-risk category and managed aggressively. (Received 15 December 2014; returned for revision 11 January 2015; finally revised 18 February 2015; accepted 19 March 2015) Introduction Management of differentiated thyroid cancer (DTC) has under- gone paradigm shift in last 2 decades. 1–3 The treatment strategy has been individualized based on risk stratification: low-risk patients undergo lesser surgery with or without radioiodine rem- nant ablation (RRA); high-risk patients managed aggressively with total thyroidectomy, compartment-based neck dissection and high-dose radioiodine (RAI) treatment; however, in view of paucity of good quality published data in intermediate-risk patients, management is not clearly defined. Moreover, interme- diate-risk DTC constitutes the second most common presenta- tion, varying from 25 to 35% of all DTCs. 4 According to the American Thyroid Association (ATA) revised guidelines, inter- mediate-risk DTC is defined as having one or more of the fol- lowing characteristics: (i) age >45 years, (ii) vascular invasion, (iii) microscopic extrathyroidal extension (T3), (iv) the presence of cervical lymph node metastases (pN1) and (v) the presence of aggressive histological variants. 3 Vast majority of thyroid surgeons believe that differentiated thyroid cancer is a surgical disease and can be cured by surgery alone. 5–7 Thus, achievement of surgical ablation is considered as an ideal surgical goal. However, in large number of patients sig- nificant remnant is left in situ, in such a situation, administra- tion of RAI therapy, whether yields beneficial effect in terms of reduction in recurrence rate or improvement in survival out- come, is controversial. In case of low-risk patients, radioiodine remnant ablation may be considered as ‘over treatment’, but in case of intermediate-risk patients, RAI therapy may be Correspondence: Chandrasekhar Bal, Department of Nuclear Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India. Tel.: +919868397182; Fax: 011-26588664; E-mail: csbal@hotmail.com 408 © 2015 John Wiley & Sons Ltd Clinical Endocrinology (2016) 84, 408–416 doi: 10.1111/cen.12779