Impact of routine unilateral central neck dissection on preablative and postablative stimulated thyroglobulin levels after total thyroidectomy in papillary thyroid carcinoma

Abstract

Background: Prophylactic central neck dissection (CND) remains controversial in papillary thyroid carcinoma (PTC). Because postsurgical stimulated thyroglobulin (sTg) level is a good surrogate for recurrence, the study aimed to evaluate the impact of prophylactic CND on preablative and postablative sTg levels after total thyroidectomy.

Methods: Of the 185 patients retrospectively analyzed, 82 (44.3%) underwent a total thyroidectomy and prophylactic CND (CND-positive group) while 103 (55.7%) underwent total thyroidectomy only (CND-negative group). All patients had no preoperative or intraoperative evidence of lymph node metastases. Clinicopathological characteristics, postoperative outcomes, and preablative and postablative sTg levels were compared between the two groups. Preablative sTg level was taken at the time of radioiodine ablation, while postablative sTg level was taken 6 months after ablation. A multivariable analysis was conducted to identify factors for preablative athyroglobulinemia (sTg<0.5 μg/L).

Results: Relative to the CND-negative group, the CND-positive group had larger tumors (15 mm vs. 10 mm, P < 0.005), more extrathyroidal extension (26.8% vs. 14.6%, P<0.003), more tumor, node, metastasis system stage III disease (32.9% vs. 9.7%, P < 0.001), and more temporary hypoparathyroidism (18.3% vs. 8.7%, P=0.017). Fourteen patients (17.1%) in the CND-positive group were upstaged from stages I/II to III as a result of prophylactic CND. The CND-positive group experienced lower median preablative sTg (<0.5 μg/L vs. 6.7 μg/L, P < 0.001) and a higher rate of preablative athyroglobulinemia (51.2% vs. 22.3%, P = 0.024), but these differences were not observed 6 months after ablation. Prophylactic CND was the only independent factor for preablative athyroglobulinemia.

Conclusions: Although performing prophylactic CND in total thyroidectomy may offer a more complete initial tumor resection than total thyroidectomy alone by minimizing any residual microscopic disease, such a difference becomes less noticeable 6 months after ablation.

Fig. 1

Chart showing the breakdown of the number of undetectable and detectable stimulated thyroglobulin (sTg) between those who underwent a prophylactic central neck dissection (CND-positive group) and those who did not (CND-negative group) in the preablation period and 6 months after radioiodine (RAI) ablation. RAI+ RAI ablation provided, RAI− no RAI ablation provided