Use in Post Surgical Risk Assessment

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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below, Thyrogen was 1 of 3 stimulation methods used for stimulated thyroglobulin testing for the group that was not withdrawn from thyroid stimulating hormone.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)

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*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.

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  • 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)