Diagnostic ipsilateral central neck dissection may reduce undertreatment of initially low-risk papillary thyroid cancer.

Although small papillary thyroid cancer (PTC) patients are considered as low-risk population, approximately 5-20% of these patients relapse after surgery. The objective of this single-center retrospective study was to identify risk factors, which could help to distinguish patients who would need additional treatment after surgery. A total of 268 patients (39 men, 229 women, median age 49 years) underwent surgery between 2007-2015, and fulfilled inclusion criteria: tumor size ≤20 mm, absence of metastatic lymph nodes (LN) in the lateral neck compartment (LC), and absence of local invasion. Total thyroidectomy was performed in 252 cases, in 221 cases with central neck compartment (CC) dissection. The outcome - a more aggressive disease - was defined as the presence of metastases in the LNLC or in distant organs found during follow-up. A median follow-up was 117 months. Overall, 41 patients experienced the outcome with a median time-to-event of 18 months. Male gender (OR=2.2, p=0.049), extra-thyroidal extension ETE (OR=2.61, p=0.015), and metastases in LNCC (OR=4.21, p<0.001) were associated with worse outcome. Multivariable analysis and stratification according to ETE revealed an effect modification with a higher effect of the positive LNCC on the outcome among patients without ETE than in those with ETE. Our findings advocate placing greater emphasis on the role of LNCC metastases in the absence of ETE. In clinically node-negative tumors intraoperative examination of CC on the side of the tumor followed by CC dissection if metastatic lymphadenopathy is present could play an important role in the stratification of patients with small-size PTC.