LAUSR

We read with interest and enthusiasm the study by McDow et al. The decision making regarding the administration of radioactive iodine (RAI) to patients with lowor intermediate-risk papillary thyroid carcinoma is something we have studied for some time. We would therefore like to make some comments about the management proposal of the authors shown in Fig. 3. Patients with unstimulated thyroglobulin (u-Tg) B 0.2 ng/ml would not require RAI. In a first prospective study, we showed that the frequency of recurrence was\ 2% after 4 years of follow-up among 136 patients who did not receive RAI because they had stimulated Tg (s-Tg)\ 1 ng/ml. In a second prospective study, we found only 2% of recurrences after 5 years of follow-up among 222 patients who did not receive RAI because they had u-Tg\ 0.3 ng/ ml. Recently, in another prospective study, we also reported a recurrence rate of 2% during 6 years of followup among 182 patients with minimal extrathyroidal extension not treated with RAI because they had u-Tg\ 0.3 ng/ml after total thyroidectomy. One restriction we would make is that the intermediate-risk group included a subgroup of patients with findings indicating a poor prognosis for whom negative postoperative Tg and ultrasonography (US) may not ensure the absence of persistent disease. These patients would represent an exception of the management proposed by McDow et al. Patients with u-Tg[ 0.2 and B 2 ng/ml would receive RAI. We believe that if the management of administering RAI to these patients is adopted, the administration of a low activity would be sufficient. When we specifically evaluated patients with s-Tg between 1 and 10 ng/ml after total thyroidectomy who received 30 or 100 mCi I, the success rate of ablation was 94% in both groups. Using u-Tg, specifically in patients with u-Tg between 0.3 and 2 ng/ml, a low RAI activity achieved successful ablation in 80% of patients, and recurrences were detected in only 2% after 5.5 years of follow-up. Management of patients with u-Tg[ 2 ng/ml. As shown in Fig. 3, it appears that RAI would only be administered if the patient has known distant metastases. However, many patients with these Tg concentrations do not exhibit lymph node disease or distant metastases. In the absence of apparent disease, we believe that the authors also recommend RAI. In this situation, we observed that the success rate of adjuvant therapy in patients with s-Tg[ 10 ng/ml or u-Tg[ 2 ng/ml was much lower with a low RAI activity. Thus, if the latter is administered, a high activity might be more adequate. Finally, it is important to remember that this management of not administering RAI based on postoperative Tg has not yet been accepted by many authors, including in a recently published contrary position statement.