Correlation between cervical uptake values on whole body scan, ultrasound and thyroglobulin levels in post-thyroidectomy patients with differentiated thyroid carcinoma

Abstract

TITLECorrelation between cervical uptake values on whole body scan, ultrasound and thyroglobulin levels in post-thyroidectomy patients with differentiated thyroid carcinomaSUMMARYIntroduction: Differentiated thyroid carcinoma (DTC) is the most common thyroid tumor, with the papillary subtype being the most frequent. Staging is based on characteristics of the primary tumor and lymph node and/or distant metastatic involvement. These characteristics are directly related to the severity of the disease and the risk of tumor recurrence after treatment. Total thyroidectomy (TT) is the treatment of choice for most cases, as it facilitates monitoring using thyroid hormones such as thyroglobulin (TG) and antithyroglobulin (ATG). Only thyroid cells produce these hormones, so they are the main marker of the presence of recurrence or the appearance of metastases.Other follow-up exams are ultrasound (US), which assesses the presence of remaining thyroid tissue and regional lymph nodes, which is limited after surgery due to the presence of distortion and the impossibility of assessing the whole body. Whole body scanning with iodine 131 (WBS-131 I) is a functional method that is widely used in the investigation and follow-up of post thyroidectomized patients. It is a functional method that assesses the whole body and determines the amount of thyroid remnant by percentage. It is also an important tool for indicating surgical reapproach in cases of large amounts of thyroid remnant. Although the above methods are of paramount importance in the diagnosis and monitoring of surgical remnants, they all have particular limitations. Laboratory tests indirectly identify the presence of functioning thyroid tissue, but do not discriminate between sites. Cervical US does not identify distant metastases and is limited in its specific identification of smaller remnants, while PCI, although highly specific in identifying thyroid tissue in all functioning sites, is slightly less sensitive Objective: To compare 24-hour cervical uptake values obtained by PCI-131 I, US results and TG blood values in patients (CDT) undergoing total thyroidectomy (TT) without cervical or distant metastases. Methods: This is a cross-sectional, observational and descriptive study with retrospective data collection from medical records of CDT patients treated between 2012 and 2021. This study is a subproject of the project entitled Positivity of whole-body iodine-131 scanning (WBIT -131 I) in patients with differentiated thyroid carcinoma and associated variables, focusing on cervical uptake of WBIT, TG and post-TT US. This project was approved by the institutional CEP with an attached opinion on the platform. Blood variables, US results and PCI results will be described using descriptive statistics and correlated using inferential statistics, considering significance when p< 0.05.