Levels I-VII following thyroidectomy for papillary thyroid cancer

Introduction. Cervical lymph node metastases can occur not only in patients when they are first diagnosed with papillary thyroid cancer but also in patients who have undergone thyroidectomy. Objective. The aim of this study was to assess the potential utility of neck ultrasound in diagnosing cervical lymph node metastases (levels I-VII) in patients who underwent surgical treatment for papillary thyroid cancer. Material and Methods. B-mode sonography of all nodal levels in the neck was performed using a linear array transducer in the frequency range of 7.5-13 MHz, power mapping and panoramic scan to locate regional lymph node metastases. All lymph nodes removed during reoperations were submitted for histological evaluation. Sonographic examinations of cervical lymph nodes of the levels I-VII were performed in 2875 patients who had undergone thyroidectomy in different regions of the Russian Federation. The patients were admitted to our clinic to receive radioactive iodine therapy. All neck levels were assessed by ultrasound. Results. Sonography revealed cervical lymph node metastases in 267 (9.2 %) of 2875 patients with papillary thyroid cancer who had undergone thyroidectomy. Nodal metastasis in level VI only occurred in 70 (2.4 %) patients, in levels II-III-IV only in 150 (5.21 %), in level VB only in 32 (1.11 %), and at the same time in level VI and in levels II-III-IV in 15 (0.52 %) patients. There were no metastases in levels I, VA, VII of the neck. Solitary metastases to all levels were found in 7.5 %, multiple metastases in 1.2 %, and conglomerates in 0.6 % of cases. Solitary metastases in level VI were noted in 56 (1.9 %), in levels II-III-IV in 125 (4.3 %), and in level VB in 29 (1.0 %) patients. Multiple metastases in level VI were detected in 11 (0.38 %), in levels II-III-IV in 21 (0.73 %), and in level VB in 3 (0.1 %) patients. Median metastasis size was 2.1 ± 1.6 cm. Conclusion. Post-thyroidectomy patients were found to have cervical lymph node metastases. Ultrasound scanning of the neck should be considered a key examination if there are cicatricial changes as it enables to identify metastasis and to determine its location. The maximal number of metastases was noted in levels II-III-IV. Cervical lymph node metastases occurred less frequently in the central level and level VB. The predominant metastatic pattern was solitary. There was an essential difference in metastatic spread to cervical lymph nodes between post-thyroidectomy patients and patients who were first diagnosed with papillary thyroid cancer.