Background: Since the last major review of literature on the benefit of I-131 therapy, the continued debate on postoperative radioiodine treatment (RIT) in differentiated thyroid carcinoma (DTC) has led to a number of further studies being published on this topic.
Aim: The aim of the present paper is to report the results of an updated structured review of the literature pertaining to the prognostic benefits of postoperative RIT in DTC in terms of recurrence-free and disease-specific survival.
Methods: A systematic search of the literature was performed using the Medline and Cochrane Library database. The search period started in August 2007 and ended on December 6, 2017. Search terms used included "differentiated thyroid cancer" and "radioiodine therapy" amended by specific terms for recurrence/disease-free survival or overall and/or cancer-specific survival. Included in the search were systematic reviews, randomized clinical trials, or cohort studies consisting of both patients who underwent postoperative RIT and patients treated by surgery alone.
Results: Eleven retrospective cohort studies met the defined inclusion criteria and were included in the present review. Results of the studies were mixed, with some showing a benefit of RIT even in microcarcinoma whereas others showed no benefit at all.
Conclusion: Literature published in the last decade offers data that support adjuvant postoperative RIT in DTC patients with a tumor diameter exceeding 1 cm. Therefore, at least until randomized prospective studies prove otherwise, the prescription of adjuvant I-131 treatment to all DTC patients with a primary tumor diameter exceeding 1 cm remains a reasonable option.
Keywords: Differentiated thyroid carcinoma; I-131 treatment; Prognosis; Recurrence rate.