Impact of Routine Unilateral Central Neck Dissection on Preablative and Postablative Stimulated Thyroglobulin Levels after Total Thyroidectomy in Papillary Thyroid Carcinoma

Abstract

BackgroundProphylactic 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.MethodsOf 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).ResultsRelative 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.ConclusionsAlthough 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.

Current Innovations and Opinions in the Surgical Management of Differentiated Thyroid Carcinoma

“…(Zetoune et al,2010) Therefore, based on these findings, there might be a potential benefit of lower recurrence in those who underwent either unilateral or bilateral pCND, although larger-scale prospective studies are required to confirm this. (Lang et al,2011c) They found that the CND+ group had a significantly lower median pre-ablation stimulated Tg level (<0.5ug/L vs. 6.7ug/L,p<0.001) and achieved a higher rate of pre-ablation athyroglobulinemia (51.2% vs. 22.3%,p=0.024) than those who underwent a total thyroidectomy only but these differences were not observed 6 months after ablation. They also found that pCND was the only independent factor for pre-ablation athyroglobulinemia.…”

“…(Lang et al,2011c) In their experience, most of the residual microscopic disease, presumably not removed by the initial pCND, was still able to be ablated by RAI ablation and so the group without pCND achieved similar stimulated Tg levels and similar rate of athyroglobulinemia 6 months after ablation. (Lang et al,2011c) The authors concluded that although performing pCND in total thyroidectomy may offer a more complete initial tumor resection than total thyroidectomy alone by minimizing any residual microscopic disease, such difference becomes less noticeable 6 months after RAI ablation. (Lang et al,2011c) The other advantage of performing pCND is the fact that the status of central lymph nodes or pN1a is better known and so more accurate staging is possible.…”

“…In fact, total thyroidectomy and pCND is increasingly being performed for DTC to achieve lower recurrences, better disease-free survival and enhanced postoperative athyroglobulinemia. (Roh et al 2007;Lang et al, 2011c) However, it has been shown that up to 60% of patients after pCND could develop transient hypocalcemia secondary to the frequent occurrence of unintentional or incidental parathyroidectomy. (Pereira et al,2005) Therefore, in the presence of such a high incidence of postoperative hypoparathyroidism, the need of routine postoperative inpatient calcium monitoring remains questionable after thyroid cancer surgery while the early routine administration of oral calcium and/or vitamin D supplements seems to be relevant and can facilitate the early discharge from hospital shortly after surgery without developing unpleasant hypocalcemic symptoms.…”

“…(Lang et al,2011c) The authors concluded that although performing pCND in total thyroidectomy may offer a more complete initial tumor resection than total thyroidectomy alone by minimizing any residual microscopic disease, such difference becomes less noticeable 6 months after RAI ablation. (Lang et al,2011c) The other advantage of performing pCND is the fact that the status of central lymph nodes or pN1a is better known and so more accurate staging is possible. (Lang et al,2007b) Increased patient morbidity is one of the major concerns.…”

“…Increased risk of transient hypoparathyroidism has been consistently shown in many studies. (Sywak et al, 2006;Hughes et al 2010;Lang et al,2011c;Palestini et al,2008;Roh et al,2007;Moo et al,2010;Rosenbaum et al,2009) The higher rate of temporary hypoparathyroidism could be explained by the higher rate of unintentional removal of parathyroid glands (i.e. unintentional parathyroidectomy) and subsequent auto-transplantation.…”