Fig 1.
Flow chart of enrollment of study participants.
Table 1.
The patient characteristics according to the RAI therapy response.
Table 2.
Significance of the several parameters in the response rate (RR) and disease control rate (DCR).
Table 3.
The response rate (RR) and disease control rate (DCR) at lesion-based analysis.
Fig 2.
The representative cases showing the predictive role of FDG uptake in RAI therapy.
A. The patient who has lung metastasis from papillary thyroid cancer was done RAI therapy after total thyroidectomy. After first therapy, there was quite amount of RAI in the metastatic lesion, expecting therapeutic effect of RAI. However, initial FDG PET scan showed there are also substantial FDG uptake in the metastasis. At the time of 2nd therapy, the RAI uptake was gone and the anatomical size of lung metastasis was not changed during serial follow-up CT scan. Even the unstimulated Tg level as well as stimulated Tg level was subsequently increased. B. The patient who has recurred metastatic lung nodules from papillary thyroid cancer after total thyroidectomy 10 years ago. The metastatic nodules had a significant amount of RAI uptake in the post-therapy scan, but did not show significant uptake in the FDG PET scan performed at the same time. At the time of 2nd therapy, the size of lesions was significantly decreased and stimulated Tg level was also lowered.