Original Research ARTICLE
Prognostic Impact of 131I Diagnostic Scan after Detection of Biochemical Recurrence in Intermediate or High-risk Differentiated Thyroid Cancer: a Retrospective Cohort Study.
- 1National Institute of Cancerology (INCan), Mexico
- 2Instituto Nacional de Cardiologia Ignacio Chavez, Mexico
Background: Patients treated for intermediate- or high-risk differentiated thyroid carcinoma (DTC) and Thyroglobulin (TG) elevation during follow-up, require a diagnostic whole-body scan (DWBS) and if positive, 131I treatment. This approach can lead to a delay in treatment and increased costs. The purpose of this study is to compare the oncologic outcomes associated to DWBS results in patients with DTC and a first biochemical recurrence.
Methods: Retrospective cohort study of patients with intermediate- or high-risk DTC treated with total thyroidectomy, 131I ablation and who developed TG elevation during follow-up, between January 2007 and December 2015. Cohort A included patients who underwent a DWBS with 5 mCi of 131I prior to the therapeutic dosage, and cohort B included those who only received a therapeutic dosage of 131I, without a DWBS. Main outcomes were second recurrence (SR) and disease-free survival (DFS). The diagnostic accuracy of DWBS was analyzed.
Results: Cohorts A and B had 74 and 41 patients, each. By multivariate analysis, age, differentiation grade, TN classification, ablation dose, and DWBS result (odds ratio 55.1; 95% CI 11.3-269) were associated with SR (p<0.0001); age, male gender, ablation dose and DWBS result (hazard ratio 7.79; 95% CI 3.67-16.5) were independent factors associated with DFS (p<0.0001). DWBS diagnostic accuracy was 36.48%.
Conclusion: 131I treatment in patients with DTC biochemical recurrence and no DWBS is associated with a significantly lower frequency of SR and an increased DFS. The diagnostic accuracy of DWBS is low, and its clinical efficiency should be defined in prospective phase III studies.
Keywords: differentiated thyroid cancer (DTC), 131I treatment, Cohort study [or longitudinal study], 131I diagnostic whole-body scan, Thyroglobulin - diagnosis
Received: 29 May 2019;
Accepted: 11 Oct 2019.
Copyright: © 2019 Carrillo, Vázquez-Romo, Ramírez-Ortega, Carrillo, Gómez-Argumosa and Oñate Ocaña. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Mx. Luis F. Oñate Ocaña, National Institute of Cancerology (INCan), Mexico, Mexico, email@example.com