Sensitivity of preparation with rhTSH or thyroid hormone withdrawal using 131I-whole body scans to identify metastases of differentiated thyroid cancer

• No approval of rhTSH in radioiodine of metastatic thyroid cancer and data are rare.
• Several papers showed similar sensitivity of rhTSH in comparison hormone withdrawal.
• Van Nostrand et al. published a lower sensitivity for rhTSH in radioiodine therapy.
• The presented paper is relativizing this data.
• The author found no significant differences between rhTSH and hormone withdrawal.

It has been reported that there is a higher sensitivity for Thyroid Hormone Withdrawal (THW) in detection of metastases of Differentiated Thyroid Cancer (DTC) when compared to Recombinant Human Thyroid-Stimulating Hormone (rhTSH). This study aims to confirm this reported difference in the sensitivity using radioiodine whole body scans (WBS).Materials and methodsIn a retrospective study forty three patients with evidence or suspicion of metastatic differentiated thyroid cancer DTC (evaluated by thyroglobulin or abnormal findings in previous WBS) underwent WBS using of 24 h after oral administration of 370 MBq 131I. The WBS was interpreted by two independent experienced observers categorizing their findings into a positive or negative for metastatic disease. The findings were controlled by stimulated thyroglobulin (TG) measurement and a two years follow-up.ResultsOf the evaluated patients, 14 patients were prepared with rhTSH and 29 with THW. No statistical differences in patient characteristics were documented between the two groups (age, sex, thyroglobulin level, TSH level, type of cancer). In this study, no differences in the sensitivity of WBS of patients prepared with rhTSH or THW were found. There were 11 of 14 patients (78%) that were positive after rhTSH and 19 of 29 patients (65%) after THW. Metastatic disease was confirmed by stimulated thyroglobulin value and follow-up.ConclusionIn contrast to previously published data, this study couldn't found any differences in the sensitivity of rhTSH or THW for the preparation of DTC patients undergoing 131I imaging.