Second Radioiodine Treatment: Limited Benefit for Differentiated Thyroid Cancer with Loforegional Persistent Disease.

Second Radioiodine Treatment: Limited Benefit for Differentiated Thyroid Cancer with Loforegional Persistent Disease.

J Clin Endocrinol Metab. 2017 Nov 03;:

Authors: Hirsch D, Gorshtein A, Robenshtok E, Masri-Iraqi H, Akirov A, Duskin Bitan H, Shimon I, Benbassat C

Abstract
Purpose: Radioactive iodine (RAI) treatment is often indicated after total thyroidectomy in differentiated thyroid cancer (DTC). However, its role in biochemical or loco-regional persistent DTC is unclear. We aimed to investigate the impact of a second RAI treatment in patients with incomplete response to initial treatment and no evidence of distant metastases.
Methods: Patients who underwent at least two RAI treatments over a 20-year period at a tertiary hospital were identified. Thyroglobulin levels and neck imaging were compared before and 1-2 years after RAI retreatment and evaluated at the last visit.
Results: The cohort included 164 patients (103 female, mean age 46.6±17 years). Of 114 patients retreated without prior reoperation, 53 had structural disease. At 1-2 years after RIA retreatment, 10 of the 41 patients with sufficient data had structural progression, 5 resolution/shrinkage, and 26 stable disease. Stimulated thyroglobulin (stTg) measured 93.7.1±108 ng/ml before and 102.2±124 ng/ml after retreatment (p=NS). The other 61 patients had biochemical-only persistence. Their stTg level decreased from 41.9±56 to 24.6±54 ng/ml (p=0.003). The 50 patients who underwent neck reoperation before RAI retreatment showed no significant change in stTg; 21 (42%) still had imaging findings 1-2 years later. At final follow-up, despite additional treatment in 63/164 patients (38.4%), only 56/164 (34.1%) had no evidence of disease.
Conclusions: This comprehensive study showed very limited benefit of second RAI treatment in DTC patients with biochemical or loco-regional structural persistent disease. Prospective studies are needed to distinguish patients for whom repeated RAI may be indicated to avoid unnecessary exposure.

PMID: 29126111 [PubMed - as supplied by publisher]

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