Low and intermediate Risk Differentiated Thyroid Cancer and Radioiodine Remnant Ablation: A systematic review of the literature

Background: Radioiodine remnant ablation (RRA) has traditionally been one of the cornerstones of differentiated thyroid cancer (DTC) treatment. The decision to use RRA in low (LR) and intermediate risk (IR) patients is controversial. The aim of this review is to examine the evidence of RRA benefit in the staging, follow up, and recurrence prevention in LR and IR DTC patients. Methods: From a PubMed research we selected original papers (OP) using the following inclusion criteria: a) DTC; b) LR and IR patients; C) non-RRA treated patients or RRA vs non-RRA treated groups; d) reporting of the outcome of cancer recurrence; e) published since 2008. Results: Neck ultrasonography is superior to WBS for disease detection in the neck. A rising or declining serum thyroglobulin (Tg) over time provide an excellent positive or negative predictive value, respectively, even in non-RRA treated patients. No OP demonstrating RRA benefit on recurrence in LR patients was found; two OP found no evidence of benefit. We found 11 OP that observed some benefit in reducing recurrence rates with RRA in IR patients, and 13 OP that failed to show benefit from RRA in this group. Conclusions: Neck ultrasonography and serum Tg measurement are equivalent or superior in detecting and localizing residual disease compared to RxWBS. There is no evidence of RRA benefit in recurrence prevention for LR patients. There are conflicting data on IR patients, and only a few studies with homogenous and properly stratified populations. A careful evaluation of tumor pathologic features and patient characteristics and preferences should guide RRA decision making.