The Oncologic Outcomes of Bilateral Central Lymph Node Dissection in Unilobar Papillary Thyroid Cancer and Its Risks: A Prospective Cohort Study.

Background Indications for performing a prophylactic central neck dissection (pCND) in papillary thyroid cancer (PTC) remain controversial. Thyroidectomy and central neck dissection (CND) are often recommended in all cases with proven differentiated thyroid cancer (DTC) and clinically positive lymph nodes (LNs), as well as in high risk for micro-metastasis patients with T3-T4 tumors or established metastatic nodes in the lateral compartments. Aims The aims of this study were to ascertain the role of performing bilateral central LN dissection in unilobar PTC in improving the oncological outcomes and outline the risks involved. Methods This was a department-based, prospective cohort study. We included all 20 patients who had unilobar PTC and underwent total thyroidectomy with bilateral CND. A postoperative histopathological analysis was used to identify metastatic central LNs. Results Twenty total thyroidectomies plus bilateral CNDs were performed, of which 10 were prophylactic bilaterally (those with N0), and all 20 were prophylactic on the contralateral side of PTC. Conventional risk factors (age, tumor size, and extrathyroidal extension) were not associated with performing a pCND. The presence of unilobar PTC by preoperative FNAC was the only factor associated with performing bilateral CND. Positive ipsilateral LNs were retrieved in 55% of CNDs, while positive contralateral LNs were retrieved in only 15% of the patients. Conclusions The incidence of contralateral cervical LN metastasis in patients with unilateral PTC is low, while there is clear evidence of postoperative morbidity from routine contralateral CND in unilobar PTC. Contralateral CND in patients with unilobar PTC may be reserved for high-risk patients: males, those aged ≤45 years, tumors larger than 1.0 cm, and cases with extrathyroidal extension and micro-calcification on ultrasound.