Clinical practice guideline for the treatment and follow-up of individuals with differentiated thyroid cancer. Part II: treatment, follow-up and management of radioiodine-refractory DTC

Abstract

Introduction: Differentiated thyroid cancer (DTC) represents most thyroid malignancies and requires recommendations that integrate risk stratification and active surveillance for low risk microcarcinomas. This second installment addresses previously defined key questions: indications and frequency of active surveillance; treatment of thyroid nodules suspected of being cancerous; follow-up according to dynamic risk; and management of iodine-refractory DTC.

Objective: To generate evidence-based recommendations on the treatment and follow-up of adults with differentiated thyroid cancer.

Methodology: Development of clinical practice guideline through a systematic literature review (SLR) and expert consensus. The group defined the scope and 4 questions of interest. Each question was addressed through updates to existing guidelines, SLRs with and without meta-analyses, clinical trials, and observational studies (Medline/PubMed and Embase; last 10 years; English/Spanish). The selected documents were peer-reviewed by clinicians and methodologists based on consistency in scope, methodological transparency, and formulation/grading of recommendations.

Results: 51 recommendations were included, grouped according to four questions of clinical interest: 10 define eligibility criteria for active surveillance, ultrasound schedule and frequency, and data recording; 20 establish indications for treatment of suspicious thyroid nodules, differentiating lobectomy from total thyroidectomy, as well as radioiodine therapy and minimally invasive therapies, promoting multidisciplinary evaluation; 14 address follow-up according to dynamic risk, defining response categories (excellent, biochemical, or structural incomplete and indeterminate) and guidelines for ultrasound and thyroglobulin measurement with TSH adjustment; finally, 7 focus on the management of iodine-refractory thyroid cancer, including individualized doses of I¹³¹, minimally invasive techniques for oligometastases, and combined use of radiotherapy for symptomatic control.

Conclusion: All recommendations were graded as “strong” or “conditional” based on the quality of evidence, the risk-benefit balance, and feasibility in the Paraguayan context.