Published in:
01-02-2014 | Original Article
131I treatment for thyroid cancer and risk of developing primary hyperparathyroidism: a cohort study
Authors:
Chien-Mu Lin, Pat Doyle, Yu-Tse Tsan, Chang-Hsing Lee, Jung-Der Wang, Pau-Chung Chen, Health Data Analysis in Taiwan (hDATa) Research Group
Published in:
European Journal of Nuclear Medicine and Molecular Imaging
|
Issue 2/2014
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Abstract
Purpose
To evaluate the association between 131I therapy for thyroid cancer and risk of developing primary hyperparathyroidism.
Methods
This was a nationwide population-based cohort study of patients with thyroid cancer diagnosed during the period 1997–2008. The data were obtained from the Taiwan National Health Insurance Research dataset. The cumulative 131I dose in each patient was calculated. Hazard ratios (HRs) were calculated using a proportional hazards model to estimate the effect of 131I therapy on the risk of developing primary hyperparathyroidism in the cohort.
Results
A total of 8,946 patients with thyroid cancer were eligible for the final analysis. Among these patients, 8 developed primary hyperparathyroidism during the follow-up period that represented 38,248 person-years giving an incidence rate of 20.9 per 105 person-years. 131I was used in the treatment of 6,153 patients (68.8 %) with a median cumulative dose of 3.7 GBq. The adjusted HRs were 0.21 (95% CI 0.02–1.86) and 0.46 (95% CI 0.10–2.10) for those receiving a cumulative 131I dose of 0.1–3.6 GBq and ≥3.7 GBq, respectively, compared to no therapy. The risk of developing primary hyperparathyroidism did not increase with increasing 131I dose (test for trend p = 0.51). No interaction was found between 131I dose and age (p = 0.94) or 131I dose and sex (p = 0.99).
Conclusion
131I treatment for thyroid cancer did not increase risk of primary hyperparathyroidism during a 10-year follow-up in this study population. Further research with a longer follow-up period is needed to assess late adverse effects beyond 10 years.