Association of radioactive iodine treatment with survivorship symptoms and primary care utilisation in women of reproductive age with thyroid cancer: a retrospective cohort study.

Abstract

Objectives: Radioactive iodine (RAI) is commonly administered after thyroid cancer surgery and is generally considered low risk. Its use in women of reproductive age, however, is increasingly debated. Most research has focused on cancer outcomes, fertility or short-term psychological effects, with limited attention to symptoms relevant to primary care after treatment. Evidence describing post-treatment symptom burden, mental health outcomes and primary care utilisation in this population is limited. This study examines whether RAI treatment after thyroid cancer surgery in women of reproductive age is associated with an increase in disease-related symptom burden, new mental health diagnoses and greater primary care utilisation within the first year following treatment.

Methods: This retrospective cohort study used the TriNetX database to compare adult women of reproductive age (18-49) with thyroid cancer who underwent thyroidectomy from 1 January 2000 to 1 January 2024 by RAI treatment status. Propensity score matching was performed to balance baseline demographic and clinical characteristics. Outcomes within 1 year included new diagnoses of fatigue and malaise, generalised anxiety disorder, depressive episodes, sleep disorders, cognitive symptoms, adjustment disorders and primary care utilisation. Standardised mean differences (SMD) compared baseline characteristics and risk differences with 95% CIs and risk ratios (RR) with 95% CIs compared outcomes between cohorts.

Results: Before propensity score matching, patients receiving RAI had higher prevalence of obesity (SMD 0.269), hypertension (SMD 0.189), diabetes (SMD 0.127) and mental health conditions (SMD 0.370). After matching, 10 882 patients were analysed. RAI-treated patients experienced significantly higher rates of fatigue and malaise (RR 1.239, 95% CI 1.031 to 1.490; p=0.022), depressive episodes (RR 1.344, 95% CI 1.043 to 1.732; p=0.022), sleep disorders (RR 1.281, 95% CI 1.006 to 1.630; p=0.044) and primary care visits (RR 1.476, 95% CI 1.330 to 1.638; p<0.001).

Conclusion: RAI treatment in women of reproductive age may be associated with increased symptom burden and primary care utilisation in the first year following thyroid cancer treatment. These findings underscore the importance of anticipatory guidance, symptom screening, coordinated survivorship care and further research to define optimal survivorship care pathways for this population.