Ipsilateral versus bilateral central neck lymph node dissection in papillary thyroid carcinoma

Many patients undergoing thyroidectomy for papillary thyroid carcinoma (PTC) have subclinical nodal disease at the time of surgery. Prophylactic bilateral central neck dissection (CND) is gaining acceptance in the treatment of PTC as studies have shown nodal disease increases the rate of local recurrence and may alter postsurgical radioactive iodine dosing. Given the potential complications of bilateral CND, we undertook a prospective study to determine the adequacy of prophylactic ipsilateral CND for PTC.

A total of 116 patients with PTC underwent total thyroidectomy and routine prophylactic CND at a tertiary referral center. Of these, 45 had right and left central neck lymph node basins submitted separately for pathologic examination. We examined the laterality of positive lymph nodes based on tumor location and size.

Overall, positive lymph nodes were found in 45% of patients. Of the patients having a lateralized CND, 33% had ipsilateral positive nodes only, while 20% had bilateral positive nodes. None of the patients with tumor size <=1 cm had bilateral positive lymph nodes compared with 31% of patients with tumors >1 cm (P = 0.02). Multifocality did not affect lymph node metastasis in tumors <=1 cm. Parathyroids were found in the pathology specimen of 34% of patients, 40% had parathyroids autotransplanted, 47% had temporary hypocalcemia, and 0% had permanent hypocalcemia. Rates of temporary and permanent recurrent laryngeal nerve injury were 5% and 0% respectively.

Ipsilateral CND appears to be sufficient in patients with tumors <=1 cm. In tumors >1 cm, bilateral CND should be considered as these patients are more likely to have bilateral positive nodes. If tumor size is used as criteria for prophylactic CND, approximately one-third of patients can be spared a bilateral CND.