Influence of endoscopic total thyroidectomy on postoperative thyroid remnant

Objectives Recently endoscopic total thyroidectomy (ET) was introduced to thyroid cancer as a less invasive surgery for conventional open total thyroidectomy (OT). However, it is a concern whether ET leaves more thyroid remnant. We compared thyroid remnant between ET and OT by evaluating I-131 ablation therapy.

Methods A total of 45 patients with thyroid microcarcinoma was enrolled, of which 23 (age 41±7 y) underwent ET and the other 22 (age 49±6 y) underwent OT. There was no difference in the clinical factors such as disease extent, LN metastasis, and size of tumor. Both the groups underwent I-131 ablation therapy with the same protocol. Thyroid remnant was compared on the first postoperative I-131 ablation scan, in which neck-to-skull count ratios were calculated. Total number and dose of I-131 therapy to achieve complete ablation were also compared.

Results There were no significant differences in postoperative major complications. In the first postoperative I-131 ablation scan, the neck-to-skull ratio was slightly higher in ET (26.6±20.7) than in OT (20.0±16.0), but with no significance (P=n.s.). Furthermore, the number and total dose of I-131 ablation were lower in ET than in OT (2.26±0.62 times for ET and 2.82±0.92 times for OT, P=0.02; 71±22 mCi for ET, 83±26 mCi for OT, P=n.s.).

Conclusions The burden of thyroid remnant was not heavier in ET than in OT, in terms of I-131 ablation therapy. Therefore, ET can be a feasible alternative in indicated thyroid caner without concern about incomplete surgery.