Lateral neck sentinel lymph node biopsy in papillary thyroid carcinoma, is it really necessary? A randomized, controlled study

Background. Although occult metastasis to lymph node in the lateral neck compartment is common in papillary thyroid carcinoma (PTC), the clinical impact of these metastasis is unknown. We hypothesized that sentinel lymph node biopsy (SLNB) of the lateral neck compartment with radioisotopes may detect occult metastasis, which could prevent recurrence. Methods. This randomized, controlled study was conducted from June 2009 to January 2011 and included 283 patients with PTC who were receiving treatment at the Samsung Medical Center. Results. Of the 283 patients enrolled in the study, 141 were randomized to a lateral SLNB (LSLNB) group and 142 patients were to the control group. Lateral sentinel lymph nodes (LSLNs) were identified in 80 of the 127 patients (63.0%) for whom stimulated thyroglobulin (sTg) levels were available. Among the 80 patients with LSLNs, 24 (30.0%) had metastases and underwent an ipsilateral modified radical neck dissection. Among the 191 patients for whom repeated sTg test results were available, the first median level of sTg in the LSLNB study group was less compared with the control group (P = .012, adjusted for duration). However, the second sTg level (after the first radioactive iodine ablation) was not different between the 2 groups. Moreover, the sTg levels were not significantly different between the LSLN-positive (n = 23) and other patients (n = 168) after the first and second ablations. During patient follow-up (median, 39 months; range, 7-55), 3 cases of recurrence were observed in the control group and 1 case in the study group (a LSLN had not been detected in this case). Conclusion. Although LSLNB was able to remove occult metastasis in PTC, this procedure had no effect on either sTg levels or on recurrence rates at a mean follow-up of 39 months. Additional long-term studies are needed to explore fully the clinical usefulness of LSLNB in the prevention of PTC recurrence.