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radioactive iodine-131 (I-131) ablation
Indications:
1) benign conditions of the thyroid
a) Graves' disease (toxic diffuse goiter)
b) toxic multinodular goiter or nontoxic nodular goiter
c) autonomously functioning toxic or non-toxic thyroid nodules
d) hyperthyroidism
2) thyroid cancer (radioiodine uptake +)
Contraindications:
- pregnancy
- lactation
- may aggravate Graves ophthalmopathy
Procedure:
- pretreatment with glucocorticoids to mitigate increase in thyroid-stimulating immunoglobulin if Grave's ophthamopathy
Complications:
- overall cancer risk not increased [2]
- excess risk for thyroid cancer (RR=1.86) [2]
- excess mortality risk for breast cancer & other solid cancers with higher radioactive iodine doses (400-500 vs 100-200 megabecquerels)*
* typical treatment dose is 200-300 megabecquerels
Management:
- levothyroxine after ablation to maintain serum TSH below normal [1]*
* thyroid follicular cells, the origin of papillary thyroid carcinoma & follicular thyroid carcinoma, are TSH-responsive [1]
General
radioablation (photodynamic ablation)
References
- Medical Knowledge Self Assessment Program (MKSAP) 16, 17, 19
American College of Physicians, Philadelphia 2012, 2015, 2022
- Medical Knowledge Self Assessment Program (MKSAP) 19
Board Basics. An Enhancement to MKSAP19.
American College of Physicians, Philadelphia 2022
- Shim SR, Kitahara CM, Cha ES et al.
Cancer risk after radioactive iodine treatment for hyperthyroidism:
A systematic review and meta-analysis.
JAMA Netw Open 2021 Sep 17; 4:e2125072.
PMID: 34533571 Free article
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2784269