Thyroid Cancer Response To Therapy Calculator (Dynamic Risk)
Enter your follow-up results and get your response-to-therapy category. Skip anything you don't have:
Written and medically reviewed by Dr. Westin Childs, D.O. Last reviewed: August 28, 2026
How To Use This Calculator:
#1. Gather Your Follow-Up Results
You’ll need your most recent thyroglobulin (Tg) level, your thyroglobulin antibody status, and what your latest neck ultrasound or imaging showed. These come from the follow-up visits after your surgery.
#2. Enter What You Have
The calculator asks whether your Tg was drawn on thyroid medication (suppressed) or after stimulation, because the cutoffs differ. If you only have one of the two, that works.
#3. Read Your Response Category
Excellent, indeterminate, biochemical incomplete, or structural incomplete. This is the dynamic risk system your endocrinologist uses to update your original risk tier at every visit.[1]
#4. Bring The Questions To Your Doctor
Each category changes what your follow-up should look like, and the result gives you the questions that go with yours.
Why Your Response Matters More Than Your Starting Risk
Your initial recurrence risk tier was assigned once, from your pathology report, on the day you were staged. It never updates itself.
But your actual risk changes with every clean ultrasound and every undetectable thyroglobulin. That’s what dynamic risk stratification captures: how you actually responded to treatment.
And the response wins. An intermediate-risk patient with an excellent response has a recurrence risk of about 1 to 4%, nearly identical to a low-risk patient.[2] The reverse holds too, which is why your team keeps re-checking rather than treating the original tier as permanent.
Here’s the practical version: if your last visit showed an undetectable Tg, negative antibodies, and a clean ultrasound, your follow-up can usually loosen up, longer gaps between visits, less aggressive TSH suppression. If it didn’t, the category tells you exactly which kind of watching you need.
The Four Response Categories
- Excellent response: suppressed Tg under 0.2 (or stimulated Tg under 1), negative antibodies, clean imaging. Recurrence about 1 to 4%.
- Indeterminate response: the in-between zone. Suppressed Tg 0.2 to 1, stimulated Tg 1 to 10, stable antibodies, or nonspecific imaging findings. About 15 to 20% end up with identified disease over follow-up, meaning most never do.
- Biochemical incomplete response: the blood says something (suppressed Tg 1 or higher, stimulated Tg 10 or higher, or rising antibodies) but imaging finds nothing. About a third resolve on their own with no additional treatment.
- Structural incomplete response: imaging found something real. This is the category where additional treatment gets discussed, and even here the options and outcomes depend heavily on where and how large.
These definitions come from the classic system for patients who had a total thyroidectomy plus radioactive iodine.[2] If you had a lobectomy or skipped RAI, the Tg cutoffs are adapted, and the calculator notes that on your result.[3]
Frequently Asked Questions
It means your treatment did what it was supposed to: no biochemical signal (undetectable thyroglobulin, negative antibodies) and no structural evidence of disease on imaging. Your recurrence risk drops to about 1 to 4% regardless of what your initial risk tier was, and your follow-up usually gets lighter to match.
No. That’s the biochemical incomplete category, and about a third of these resolve on their own with no additional treatment. What it earns you is closer watching: your team follows the Tg trend, because the direction matters more than any single value. A stable or falling Tg is a very different situation from a doubling one.
Antibodies interfere with the Tg test itself, which makes the Tg number unreliable. When antibodies are present, your team leans harder on imaging and watches the antibody TREND instead: falling antibodies over time behave like good news, rising antibodies get attention. Enter yours in the calculator and it handles this for you.
The framework applies, but the classic Tg cutoffs don’t, because your remaining thyroid lobe makes thyroglobulin normally. Adapted definitions exist for lobectomy and no-RAI patients, with looser Tg thresholds and more weight on ultrasound.[3] The calculator asks about your treatment first for exactly this reason.
Related Calculators
- Thyroid Cancer Recurrence Risk Calculator: your initial ATA tier from the pathology report
- Thyroid Cancer Staging Calculator: your AJCC stage
- All Thyroid Calculators & Quizzes: the full set of free tools
Scientific References
- Haugen BR, Alexander EK, Bible KC, et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. 2016;26(1):1-133.
- Tuttle RM, Tala H, Shah J, et al. Estimating risk of recurrence in differentiated thyroid cancer after total thyroidectomy and radioactive iodine remnant ablation: using response to therapy variables to modify the initial risk estimates predicted by the new American Thyroid Association staging system. Thyroid. 2010;20(12):1341-1349.
- Momesso DP, Vaisman F, Yang SP, et al. Dynamic risk stratification in patients with differentiated thyroid cancer treated without radioactive iodine. J Clin Endocrinol Metab. 2016;101(7):2692-2700.