Abstract

Topicality: Malignant thyroid tumours account for more than 3% of all human cancers. Highly differentiated forms of early stage (T_1-3) thyroid cancer occur in more than 90% of cases_, and they don’t cause much difficulty for the surgeon. But in recent years, the number of advanced malignant thyroid tumours of T_4a-b stages with invasion or compression of the upper respiratory tract, recurrent nerves, has been increasing very rapidly. Most often, these are tumours with medium and low histological differentiation, which sharply worsens the prognosis of treatment of such patients.

Objective: To determine treatment tactics and improve its quality in patients with locally advanced malignant thyroid tumours with compression or invasion into the upper airways.

Materials and methods: From 2004 to 2023, 2300 patients with malignant thyroid tumours were treated in the endocrine surgery department of the I.I. Mechnikov Regional Clinical Hospital. All patients were divided into 2 groups according to the TNM classification of AJCC 8^th edition according to the extent of the primary tumour: Group 1 – without invasions (T_1-3) and group 2 – advanced invasive tumours (T_4a-b). In the 1^st group (T_1-3) were included 2130 patients, in the 2^nd group (T_4a-b) – 170 patients with locally advanced malignant thyroid tumours, which was 7.4% of all examined patients. 149 out of 170 patients in the T_4a-b group underwent radical surgical interventions as part of complex treatment, 21 patients with advanced stage T_4b tumours underwent non-radical cytoreductive surgery.

Results: In 84 (49.4%) patients in the _T4a-b group, there was tumour invasion into the trachea and in some cases into the cricoid cartilage and structures of the larynx, 20 (11.8%) patients had invasion of the recurrent nerves, which also worsened the patency of the upper respiratory tract (URT). 25 (14.7%) patients had stenosis of the URT due to their external compression by a large dense tumour mass. In 20 (11.8%) patients with invasion of the URT, the stenosis was aggravated by external compression of the tumour. The majority – 149 patients of T_4a-b group – underwent radical surgeries: extended thyroidectomies, lymphodissections of the neck, if necessary with upper sternotomy, Crile procedure, resection of the oesophagus, recurrent nerve and other affected organs and structures of the neck and upper mediastinum. 21 patients with extremely advanced cases with inoperable tumours underwent non-radical, cytoreductive surgery, in 11 patients with a permanent tracheostomy. All patients in the T_4a-b group received various adjuvant radiotherapy or radioiodine therapy, in some cases polychemotherapy and prolonged screening. In the group of radically operated patients, the mortality rate was 31.5%; recurrences, most often to regional lymph nodes, were observed in 38.3% of cases. At the same time, in the group of patients who underwent non-radical cytoreductive surgical interventions as part of complex treatment, the mortality rate was 85.7%.

Conclusions: Maximum radical, “aggressive” extended operations with tumour removal within healthy tissues with simultaneous partial resections of the upper respiratory tract as part of complex treatment significantly improves survival rates, quality and life expectancy of patients.

Keywords: locally advanced malignant thyroid tumours, tumour invasion, upper airway stenosis, surgical tactics, treatment results.