Post-operative radioiodine therapy (RaIT) as adjuvant therapy in low–intermediate risk differentiated thyroid cancer

Abstract

Aim

For many years, thyroid surgery and radioiodine therapy for thyroid remnant ablation (i.e. post-operative RaIT) have been the first-line therapeutic approaches in differentiated thyroid carcinoma (DTC). In the latest American Thyroid Association Guidelines (ATA), post-operative RaIT is not indicated in low-risk DTC, while no clear indication is postulated regarding low- to intermediate-risk patients, even if it is discouraged in most of them. The European Association of Nuclear Medicine did not endorse ATA guidelines since the role of nuclear medicine was marginalized in patients affected by low- or low- to intermediate-risk cancers. The present review evaluates the adjuvant role of post-operative RaIT in low and low- to intermediate-risk DTC patients.

Materials and methods

The terms radioiodine adjuvant therapy, radioiodine adjuvant treatment, thyroid remnant ablation, radioiodine thyroid remnant ablation, radioiodine therapy and radioiodine treatment were used to search MEDLINE for papers published from January 2008 to May 2018. Among 895 papers, we considered 8 in which patients underwent post-operative RaIT and the results of post-therapy whole body scans (pT-WBS) were reported.

Results

pT-WBS identified metastases in 282 out of 1622 patients (17.4%). All except 28 metastatic patients were affected by either low- or low- to intermediate-risk DTC. Metastases were confirmed by (targeted)-morphological and/or morphofunctional and/or morphometabolic studies in about 40% of patients.

Conclusion

According to the presented data, slightly less than 20% of low- or low- to intermediate-risk DTC patients showed metastases at pT-WBS. Thus, in our opinion post-operative RaIT should be considered as an adjuvant therapy also in low and low- to intermediate-risk DTC patients.