Prophylactic central lymph node dissection for clinically node-negative papillary thyroid microcarcinoma: influence on serum thyroglobulin level, recurrence rate, and postoperative complications.

BACKGROUND

In papillary thyroid microcarcinoma (PTMC), regional lymph node metastasis (LNM) is associated with a increased locoregional recurrence rate. Yet, prophylactic central lymph node dissection (CLND) targeting subclinical central LNM continues to be a matter of debate in the treatment of PTMC, which generally carries an excellent prognosis. The aim of our study was to investigate the benefits and risks of prophylactic CLND in patients with clinically node-negative PTMC.

METHODS

This study included 232 patients who underwent surgery for clinically node-negative PTMC from 1999 to 2006. Of these 232 patients, 113 underwent only total thyroidectomy (TT) and 119 underwent TT in conjunction with prophylactic bilateral CLND (TT with CLND). We then compared serum thyroglobulin (Tg) levels, recurrence rates, and postoperative complications between the 2 groups (TT only and TT with CLND).

RESULTS

The postoperative stimulated serum Tg level was significantly less in the TT with CLND group than in the TT only group (1.07 vs. 2.24 ng/mL, respectively; P = .022). The stimulated Tg levels in the 2 groups became similar, however, after low-dose radioactive iodine treatment (0.44 ng/mL vs. 0.69 ng/mL, respectively; P = 0.341). There was no significant difference in 3-year locoregional control rates after TT with CLND and TT only (98.3% vs. 96.5%, respectively; P = .368). Although the frequency of permanent hypocalcemia was approximately 3 times greater in the TT with CLND group (5.6%) than in the TT only group (1.8%), this finding did not reach statistical significance.

CONCLUSION

With prophylactic CLND, the postoperative Tg level can significantly decrease. However, prophylactic CLND is not helpful in decreasing short-term locoregional recurrence in patients with clinically node-negative PTMC. Finally, the risk of permanent hypocalcemia may increase after CLND.