Endocrine Abstracts

Introduction

The number of lymph node metastasis (NM) and the existence of extranodal extensión (ExEx) are not included among prognosis variables used in the most common staging systems for differentiated thyroid cancer as AJCC and ATA risk systems.

Objective

In patients with NM at diagnosis, to analyze the association between the number of NM and the presence of ExEx with response to therapy.

Patients and methods

Patients were included if they had undergone surgery at our center between december 2011 and january 2018 with a definitive diagnosis of thyroid follicular epitelial cell-derived carcinoma (TC) with NM and had had at least one follow-up after 12 months except for those died from TC. At one year, patients were classified in two groups according to the response to therapy: the group of Adequate Responders (AR) if they matched the definition of Excellent or Indeterminate Response and the group of Incomplete Responders (IR) in case of Biochemical or Estructural Incomplete Response based on the definitions endorsed by ATA. The variables evaluated at diagnosis for their potential relation to IR included: number of NM, ExEc and traditional factors as sex, age, presence of cancer (incidental or clinical), tumour size, unfavorable histology, distant metastasis (DM), multifocality, macro and microscopic extrathyroidal extension and incomplete surgical resection.

Results

103 patients (men: 26.2%) were included (median age of 49 ± 15.8 years) with a median of 3 (p25-p75: 2-6.25) resected MN. ExEx was demonstrated in 26.7 % of cases. Presence of Clinical cancer, incomplete resection, distant metastasis and macro and microscopic EE were found in 62.4%, 16.1%, 4.9%, 7.8 and 38.8% respectively. At one year, 19.6% of patients were classified into the IR group. Severals factors were clearly associated with IR: median tumoral size, presence of ExEx (18.8% in AR versus 62.5% in IR, P< 0.05) and DM (1.2% in AR versus 15% in IR, P<0.05). Multivariate analysis showed ExEx as an independent factor for IR (OR 5.6, IC 95% [1.2–26.3]). Specific mortality (3 cases) was associated with age (8.1 % versus 0 % in patients younger or older than 55 years of age respectively, P < 0.05) and unfavorable histology.

Conclusion

In CT patients with NM, the inclusion of ExEx to the variables frequently known at diagnosis could improve the prognosis value on mortality and recurrence of traditional AJCC and ATA risk systems.