Microscopic extrathyroid extension in papillary thyroid carcinoma: impact on response to therapy

Abstract

Objectives Evaluate the impact of microscopic extrathyroid extension (MEE) on outcome and therapy response in patients with cT1 and cT2 papillary thyroid carcinoma (PTC). Subjects and methods Retrospective study of 970 consecutive patients, who underwent surgery for PTC between 2000 and 2016. All patients had: tumours ≤ 4 cm, apparent complete tumour resection, without clinically apparent lymph node or distant metastasis at diagnosis and nonaggressive histologic variant. Results Based on the finding of MEE, 175 (18.0%) patients were upstaged to T3. They were older (53.9 versus 50.6 years; P = 0.004) and were more prone to have multifocal tumours (38.2% versus 24.8%; P = 0.001). Radioiodine ablation therapy (RAI) was administered more often to MEE patients (92% versus 40.5%; P < 0.001), as well as prophylactic lymph node resection (35.4% versus 28.6%, P = 0.048). They were more likely to have biochemical incomplete response (4% versus 0.3%; P = 0.03) at the end of the follow-up period. There was no significant association between MEE and recurrence rate, persistence of disease or disease-specific mortality. Conclusion These results support the changes made to the latest edition of the TNM staging system, regarding MEE. Although incomplete biochemical response is more common in these patients, it does not seem to affect their prognosis.

Can preoperative ultrasound predict extrathyroidal extension of differentiated thyroid cancer?

“…Microscopic ETE remains part of the American Thyroid Association risk stratification system and is listed within the intermediate risk features with an estimate of structural recurrence of 3-8% (5). Conflicting evidence exists on the topic with some studies that reported no significant difference between the absence or presence of ETE in terms of recurrence rates (30,31,32,33) and others that showed an increase in the rate of persistent/recurrent disease in the presence of minimal ETE (19,34,35). Some reports support the hypothesis that hemithyroidectomy may be as effective as total thyroidectomy in selected patients with microscopic ETE (36).…”

Correlates of Recurrence-Free Survival in Papillary Thyroid Carcinoma: A Cohort Study in an Iranian Population

“…During the follow-up, after initial risk stratification, serum thyroglobulin (Tg) level is used as an important tumor marker for ascertaining cases with persistent/recurrent disease (12). Ultrasonography (USG) is the key method for investigating cervical LN metastasis (13).…”

“…Ultrasonography (USG) is the key method for investigating cervical LN metastasis (13). Patients with PTC should be assessed 6-12 months after the primary treatment, and a follow-up schedule should be adopted to determine the initial risk of persistent/recurrent disease and responses to therapy (12). This study investigated clinicopathological characteristics, response to initial therapy, recurrence-free survival (RFS), and factors influencing recurrence-free years.…”