Radioactive iodine (I-131)
The original targeted radiotherapy: thyroid cells soak up iodine, so radioactive iodine destroys leftover thyroid tissue and metastases while sparing everything else.
In use since 1946 for differentiated thyroid cancer; the archetype of theranostics (I-123 or I-131 scans image the same uptake). Roles: remnant ablation after thyroidectomy (now omitted in low-risk disease after ESTIMABL2, IoN, HiLo), adjuvant treatment of intermediate/high-risk disease, and treatment of iodine-avid metastases. Given after TSH stimulation (withdrawal or recombinant TSH). Salivary damage, secondary malignancy at high cumulative doses, and refractoriness in dedifferentiated tumours are the limits.
1.TSH stimulation upregulates the sodium-iodide symporter on thyroid cells
- Route
- Oral capsule or solution
- Schedule
- 1.1 GBq (30 mCi) for remnant ablation (HiLo); 3.7-7.4 GBq for adjuvant or metastatic treatment; low-iodine diet and TSH stimulation beforehand
- Monitoring
- Post-therapy whole-body scan; thyroglobulin; salivary and marrow function
Source: www.thyroid.org/professionals/ata-professional-guidelines/. Doses are for orientation; the current label governs.
- Medicare
- Part B (clinician-administered)
Given by infusion or injection in a clinic or hospital outpatient department, so it is a Part B drug: Medicare pays 80% after the Part B deductible and the patient owes 20% coinsurance, uncapped in Original Medicare unless a Medigap policy applies. Oral capsule or solution, but administered in nuclear medicine, so it is a Part B radiopharmaceutical rather than a Part D drug. Inpatient isolation for high-dose treatment is Part A.
- Commercial insurance
- covered on label
Covered as a standard part of thyroid cancer care; higher doses for remnant ablation may need prior authorisation.
Sources: Medicare.gov: Chemotherapy · Medicare.gov: Prescription drugs (outpatient, Part B). Not medical or financial advice; verify with your plan.
- Notes
- Standard of care for differentiated thyroid cancer for 80 years; delivered through NHS nuclear medicine departments (BTA guideline). No TA.
- NHS England
- Routinely funded for the appraised indication (or via managed access)
Sources: NICE search: radioactive iodine (I-131). Funding decisions are indication-specific and change monthly; verify with NICE and your treating team.
- 1946ApprovalUS
First therapeutic use in thyroid cancer (Seidlin); formal approval followed
Approvals
| Region | Year | Indication |
|---|---|---|
| US | 1951 | Hyperthyroidism and thyroid carcinoma (first radiopharmaceutical approval) |
| Adverse event |
|---|
| Sialadenitis / xerostomia |
Dose-dependent; common after repeated high-activity treatment. Rates read from the source. Blank cells mean the figure was not sourced, not that it is zero.
Trials
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Landmark trials in OnCo
Latest papers
topQuery for this drug: (TITLE:"Radioactive iodine" OR ABSTRACT:"Radioactive iodine" OR TITLE:"I-131" OR ABSTRACT:"I-131" OR TITLE:"Sodium iodide I-131" OR ABSTRACT:"Sodium iodide I-131") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Radioactive iodine (I-131), not a curated reading list.
Pages like this
not linked directly; found by shared links- TrialASTRA
Shares MAPK inhibitor redifferentiation → radioiodine, Radioiodine therapy and whole-body iodine scanning, Thyroid cancer.
- TermPRRT (peptide receptor radionuclide therapy)
Shares Radioiodine therapy and whole-body iodine scanning, Theranostics, Somatostatin receptor 2, Radioligand therapy (beta emitters).
- TermTSH suppression
Shares Low-risk differentiated thyroid cancer (ATA risk), Thyroid cancer.
- TrialDECISION
Shares Radioiodine-refractory (RAI-R) thyroid cancer, Thyroid cancer.
- TermRadioiodine therapy (I-131)
Shares Radioiodine therapy and whole-body iodine scanning, Theranostics, Thyroid cancer.
- TrialSELECT
Shares Radioiodine-refractory (RAI-R) thyroid cancer, Thyroid cancer.
- ProductGallium-68 DOTATATE (and Cu-64 DOTATATE)
Shares Theranostics, Somatostatin receptor 2, Radioligand therapy (beta emitters).
- TermThyroidectomy
Shares Radioiodine therapy and whole-body iodine scanning, Thyroid cancer.