Optimization of staging of the neck with prophylactic central and lateral neck dissection for papillary thyroid carcinoma.

OBJECTIVE: To analyze the yield and rate of node metastases (pN1) for prophylactic central (CND) and lateral neck dissection (LND) for papillary thyroid carcinoma, the risk factors for pN1, and outcomes.
BACKGROUND: Prophylactic CND and LND are not routinely employed. Adjuvant radioiodine treatment may be modulated, however, by surgical staging of the neck.
METHODS: Retrospective study, consecutive patients ultrasonographically classified cN0 treated with prophylactic CND, and lateral LND (levels III and IV). The number of nodes was resected and the incidence of pN1 was recorded.
RESULTS: For 317 patients (254 women, mean age 44 years, mean tumor size 17 mm), the number of lymph nodes was 5 for unilateral CND, 9 for bilateral CND, and 12 for LND. pN1 stage was 42% overall: 23% for unilateral CND, 39% for bilateral CND, and 23% for LND (median number of metastatic nodes = 2 for each). Fifty-five percent of the patients staged pN1 had metastatic nodes in the lateral neck. Ten percent had more than 10 metastatic nodes and/or more than 3 nodes with extra capsular spread. pN1 was correlated with tumor size (P = 0.0025), extrathyroidal tumor extension (P < 0.0001), male sex (P = 0.0006), and age younger than 45 years (P = 0.0003). Permanent hypoparathyroidism and unintentional recurrent nerve paralysis occurred in 2 cases each. Patients staged pN0 received less radioiodine than patients staged pN1 (median 30 vs 100 mCi, P < 0.0001).
CONCLUSIONS: For staging, bilateral prophylactic CND is preferable to unilateral CND. Prophylactic CND with LND optimizes staging providing a basis for a personalized approach for adjuvant radioiodine.