Hartl, Dana1; Bohec, Hélène Diaz1; Badois, Nathalie2; Mamelle, Elisabeth3; Mirgani, Haïtham1; Breuskin, Ingrid1; Leboulleux, Sophie4
1 Department of Head and Neck Oncology, Thyroid Surgery Unit, Gustave Roussy and Paris Sud University, Villejuif, France
2 Otolaryngology Head and Neck Surgery, Curie Institute, Paris, France
3 Otolaryngology Head and Neck Surgery, Hôpital La Pitié Salpétrière, Paris, France
4 Department of Medical Imaging, Endocrine Oncology and Nuclear Medicine, Gustave Roussy and Paris Sud University, Villejuif, France
Therapeutic lateral neck dissection is recommended for N1b PTC, while prophylactic contralateral lateral neck dissection is not, in the absence of data regarding occult contralateral nodes.
We investigated the risk factors for occult LNM in the contralateral lateral neck for N1b patients who had total thyroidectomy, therapeutic central dissection, homo-lateral lateral neck dissection and prophylactic contralateral lateral neck dissection.
This retrospective study enrolled 63 patients treated in comprehensive cancer center between 1997 and 2016. Inclusion criteria were : unilateral PTC confirmed by ultrasound and fine-needle aspiration biopsy,and with homo-lateral lateral metastases. Patients with contralateral lateral metastases or bilateral tumor at diagnosis were excluded.
Occult contralateral lateral LNM were found in 23/63 patients (36.5%) and were significantly associated with the number of metastatic nodes in the central compartment ispilateral to the tumor (p=.02) and with microscopic tumor foci in the contralateral thyroid lobe (p=0,017). Using receiver operating characteristic analysis, a cutoff of 5 or more metastatic nodes in the ipsilateral level VI optimized sensitivity and specificity for predicting contralateral lateral nodal metastases, with a sensitivity of 74%, specificity of 65%, positive predictive value of 55%, a negative predictive value of 81% for an overall accuracy of 68%. For 8 or more nodes, specificity was 90%.
This study suggests that occult LNM in the contralateral lateral neck can be predicted. Five or more ipsilateral central lymph nodemetastases were correlated with a risk of contralateral lateral lymph node metastasis, as were the presence of microscopic contralateral tumor foci