Endocrine Abstracts

Introduction

Response to Therapy, according to ATA’s dynamic classification, provides a description of the clinical situation in patients with thyroid cancer (TC) a year or more after treatment. It gives us more accurate information than the obtained at diagnosis by static staging systems as AJCC and ATA risk system.

Objetives

To analyse the association between some factors collected at diagnosis and the type of Response to Therapy in TC patients.

Patients and methods

Subjects included in the study underwent TC surgery in our hospital between January 2011 and December 2018 with a minimum follow-up of 18 months, except those who died from CT. Response to Therapy was evaluated a year after diagnosis and at the last visit. Two types of Response to Therapy were defined based on dynamic risk stratification: Adequate Response (AR) and Incomplete Response (IR). AR included both Excellent Response and Indeterminate Response, while IR included Biochemical and Structural Incomplete Responses. The variables evaluated at diagnosis for their potential association with IR were demographic variables, cancer presentation (clinical or incidental), maximum tumour size, and the presence or absence of: nodal and distant metastases, macro and microscopic extrathyroidal extension (EE), multifocality and incomplete resection.

Results

We describe 340 patients (5.6% men) with an average age of 54 ±15 years. A year after diagnosis, 91.2% of subjects were in the AR group, rising to 94.4% at the last visit. 12 months later, IR was significantly associated with clinical presentation of cancer, tumour size, presence of nodal and distant metastasis, presence of macro and microscopic EE and incomplete surgical resection. At the last visit, except for microscopic EE, same variables were found associated with IR in addition to male gender. Multivariate analysis showed that nodal metastasis represented independent risk factors for IR at both one year (OR: 3.2, CI 95% [1.1–9.6] and the last visit (OR: 5.3, CI 95% [1.4-20.3]. Other independent risk factors found were macroscopic EE at one year (OR : 7.6, CI 95% [1.1-51.4 ] and incomplete resection at the last visit (OR: 5.9, IC 95% [1.3–26.9]

Conclusions

Evidence of nodal metastases, macroscopic EE and incomplete resection are independent factors and lead to a worse Response to Therapy in patients with TC. Based on these findings, a more aggressive therapy during the initial stage should be considered.