Postsurgical Risk Assessment
Thyrogen may be used as an adjunct to a Stim Tg test during post-operative risk assessment to determine if your patient needs RAI ablation. To enhance accuracy, Stim Tg testing is usually accompanied by a neck ultrasound
The Role of Postoperative Stimulated Thyroglobulin for Risk Stratification and RAI Selection in Patients with Low/Intermediate Differentiated Thyroid Cancer.
In the protocol shown below, Thyrogen was 1 of 3 stimulation methods used for stimulated thyroglobulin testing for the group that was not withdrawn from thyroid stimulating hormone. This highlights one example of the use of the Thyrogen in this setting. It should be noted that this study was not designed to evaluate the efficacy of Thyrogen in this setting. A description of the full study is provided below.
Personalized RAI Selection Protocol (PRSP)1
Example of Personalized RAI Selection Protocol (PRSP)
*Risk assessment based on the 2006 ATA Guidelines; Cooper DS, et al. Thyroid. 2006;16:109-142. CT, computed tomography; FNA, fine-needle aspiration; PET, positron emission tomography; THST, thyroid hormone suppression therapy
Study Overview: Postoperative stimulated thyroglobulin and neck ultrasound as personalized criteria for risk stratification and radioactive iodine selection in low- and intermediate-risk papillary thyroid cancer (PTC)2
90% of Patients Avoided RAI Ablation Initially with PRSP.
- The purpose of this study was to demonstrate the utility of a personalized risk- stratification and RAI selection protocol (PRSP) using postoperative stimulated Tg (Stim-Tg) and neck ultrasound (U/S) in low- and intermediate risk patients with PTC.
- This was a prospective study among 129 low- and intermediate-risk patients with PTC, defined as all PTC ≥1 cm (T1–T3) confined to the thyroid or central (level VI) lymph nodes (N0–N1a), irrespective of patient age or tumor size.
- 93% of patients were classified as low risk and 7% as intermediate riska
90% of Patients Avoided Ablation Initially With PRSP.2
In this study, 116 (90%) patients were able to avoid RAI ablation initially, with no evidence of residual/ recurrent disease.
Clinical Applications of the PRSP
Should Postoperative Disease Status be Considered in Decision-Making for RAI Therapy?
2015 American Thyroid Association (ATA) RECOMMENDATION 503
1. Postoperative disease status (i.e., the presence or absence of persistent disease) should be considered in deciding whether additional treatment (e.g., RAI, surgery, or other treatment) may be needed.
(Strong recommendation, Low-quality evidence)
2. Postoperative serum Tg (on thyroid hormone therapy or after TSH stimulation) can help in assessing the persistence of disease or thyroid remnant and predicting potential future disease recurrence. The Tg should reach its nadir by 3-4 weeks postoperatively in most patients.
(Strong recommendation, Moderate-quality evidence)
3. The optimal cutoff value for postoperative serum Tg or state in which it is measured (on thyroid hormone therapy or after TSH stimulation) to guide decision-making regarding RAI administration is not known.
(No recommendation, Insufficient evidence)
4. Postoperative diagnostic RAI whole-body scans (WBS) may be useful when the extent of the thyroid remnant or residual disease cannot be accurately ascertained from the surgical report or neck ultrasonography, and when the results may alter the decision to treat or the activity of RAI that is to be administered. Identification and localization of uptake foci may be enhanced by concomitant single photon emission computed tomography– computed tomography (SPECT/CT). When performed, pretherapy diagnostic scans should utilize 123I (1.5–3 mCi) or a low activity of 131I (1–3 mCi), with the therapeutic activity optimally administered within 72 hours of the diagnostic activity.
(Weak recommendation, Low-quality evidence)
Important Safety Information and Indications
Important Safety Information and Indications
IMPORTANT SAFETY INFORMATION
If Thyrogen is administered with radioiodine, the contraindications to radioiodine also apply to this combination regimen. Refer to the radioiodine prescribing information for a list of contraindications for radioiodine.
WARNINGS AND PRECAUTIONS
- There have been reports of death in non-thyroidectomized patients and in patients with distant metastatic thyroid cancer in which events leading to death occurred within 24 hours after administration of Thyrogen. Caution should be exercised in patients who have substantial thyroid tissue still in situ or functional thyroid cancer metastases, specifically in the elderly and those with a known history of heart disease.
- Hospitalization for administration of Thyrogen and post-administration observation in patients at risk should be considered.
- There are post marketing reports of stroke in young women with risk factors for stroke, and neurological findings suggestive of stroke (e.g., unilateral weakness) occurring within 72 hours of Thyrogen administration in patients without known central nervous system metastases. The relationship between Thyrogen administration and stroke is unknown. Patients should be well-hydrated prior to treatment with Thyrogen.
Sudden Rapid Tumor Enlargement:
- Sudden, rapid and painful enlargement of residual thyroid tissue or distant metastases can occur following treatment with Thyrogen. Pretreatment with glucocorticoids should be considered for patients in whom tumor expansion may compromise vital anatomic structures.
Risks Associated with Radioiodine Treatment:
- If Thyrogen is administered with radioiodine (RAI), the warnings and precautions for RAI apply to this combination regimen. Refer to the RAI prescribing information for a full list of the warnings and precautions for RAI.
The most common adverse reactions reported in clinical trials were nausea and headache.
USE IN SPECIFIC POPULATIONS
- If Thyrogen is administered with radioiodine, the combination regimen is contraindicated in pregnant women.
- Available data with Thyrogen use in pregnant women are insufficient to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes.
- The concomitant use of Thyrogen and radioiodine (RAI) is contraindicated in lactating women. If Thyrogen is administered with RAI for diagnostic use, discontinue breastfeeding after RAI administration because of the potential for serious adverse reactions from RAI in the breastfed infant.
- If Thyrogen is not administered with RAI, the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for Thyrogen and any potential adverse effects on the breastfed child. There are no available data on the presence of thyrotropin alfa in human milk, the effects on the breastfed infant, or the effects on milk production.
Pediatric Use: Safety and effectiveness in pediatric patients have not been established.
Geriatric Use: Results from controlled trials do not indicate a difference in the safety and efficacy of Thyrogen between adult patients less than 65 years and those over 65 years of age.
Renal Impairment: Elimination of Thyrogen is significantly slower in dialysis-dependent end stage renal disease patients, resulting in prolonged elevation of TSH levels.
INDICATIONS AND USAGE
Thyrogen® (thyrotropin alfa) is a thyroid stimulating hormone indicated for:
Adjunctive Diagnostic Tool for Well-Differentiated Thyroid Cancer: Use as an adjunctive diagnostic tool for serum thyroglobulin (Tg) testing with or without radioiodine imaging in the follow-up of patients with well-differentiated thyroid cancer who have previously undergone thyroidectomy.
Limitations of Use:
- Thyrogen-stimulated Tg levels are generally lower than, and do not correlate with Tg levels after thyroid hormone withdrawal.
- Even when Thyrogen-Tg testing is performed in combination with radioiodine imaging, there remains a risk of missing a diagnosis of thyroid cancer or underestimating the extent of the disease.
- Anti-Tg Antibodies may confound the Tg assay and render Tg levels uninterpretable.
Adjunct for Thyroid Remnant Ablation in Well-Differentiated Thyroid Cancer: Use as an adjunctive treatment for radioiodine ablation of thyroid tissue remnants in patients who have undergone a near-total or total thyroidectomy for well-differentiated thyroid cancer and who do not have evidence of distant metastatic thyroid cancer.
Limitations of Use:
- The effect of Thyrogen on thyroid cancer recurrence greater than 5 years post-remnant ablation has not been evaluated.
Click here for full Prescribing Information
1) Reprinted with permission of John Wiley and Sons, from Vaisman A, et al. Head Neck. 2010;32:689-698; permission conveyed through Copyright Clearance Center, Inc. ©2010 Wiley Periodicals, Inc.
2) Orlov S, et al. Endocrine. 2015;50:130-137.
3) Republished with permission of American Thyroid Association/Mary Ann Liebert, Inc., from 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer Haugen BR, et al. Thyroid. 2016;26(1):1-133; permission conveyed through Copyright Clearance Center, Inc.