Thyroid Ca (DTC) 2025 Decision Support Tool

v1.0.1

Decision support built around the 2025 ATA guidelines (DATA model). This is an educational aide and not a substitute for clinical judgement.

Author & Contact: Professor Steven C. Boyages • steve.boyages@gmail.com

Patient & Tumor Basics

Patient name (optional) Tumor size (cm)

Intrathyroidal?

Gross ETE present?

Histology ⓘ

Vascular invasion (categorical) ⓘ

Pathology Findings

Record quantifiable features that refine ATA 2025 recurrence risk (vascular foci, nodal number/size, ENE, margin).

Number of vascular invasion foci (0–20) ⓘ

Nodes involved (number) ⓘ

Largest metastatic lymph node (cm) ⓘ

Micrometastases only (<2 mm) ⓘ

Extranodal extension (ENE) ⓘ

Margin distance (mm, if R0) ⓘ

Distant metastasis?

Resection status

Age

Molecular, Labs & Special

Actionable driver

Post-op Tg trend

TgAb

Pregnant?

Comorbidity burden

Plan & Rationale

Target–Therapy Map (Quick Reference)

RET fusion → Selpercatinib / Pralsetinib
NTRK1/3 fusion → Larotrectinib / Entrectinib
BRAF V600E → Dabrafenib + Trametinib (consider redifferentiation)
ALK fusion → Alectinib
No driver → Lenvatinib (first-line MKI) or Sorafenib; consider trials
Optional biomarkers: TMB-H / MSI-H (rare) → consider ICI; PD-L1 not routine

Provenance & Cautions

Simplified rules aligned to ATA 2025. Always apply clinical judgment and MDT review for complex cases.

Version 1.0.1 • Frozen release

Histology — How the system interprets categories

For healthcare professionals • Decision support only

Histology — How the system interprets categories

PTC — Papillary Thyroid Carcinoma (classical)

System interpretation

Lowest baseline aggressiveness among invasive DTC subtypes. Risk is driven primarily by extent, nodal burden, and extrathyroidal extension.

Key assumptions

High likelihood of RAI avidity. Vascular invasion is a weaker prognostic driver than in follicular-pattern tumours.

Risk logic highlights

Intrathyroidal disease with low-volume nodal involvement may remain low risk; large-volume nodes or extranodal extension upgrade risk.

FVPTC — Follicular Variant Papillary Thyroid Carcinoma

System interpretation

Intermediate biological behaviour between classical PTC and FTC. Behaviour depends on encapsulation and invasion pattern.

Key assumptions

Encapsulated FVPTC behaves indolently; infiltrative FVPTC behaves more aggressively. RAI responsiveness generally preserved.

Risk logic highlights

Encapsulated, non-invasive disease often low risk; infiltrative growth or vascular invasion upgrades risk.

NIFTP — Non‑Invasive Follicular Thyroid Neoplasm

System interpretation

Not treated as carcinoma within the system.

Key assumptions

Near‑zero recurrence risk; no role for RAI; lobectomy usually definitive.

Risk logic highlights

Excluded from ATA recurrence‑risk stratification.

FTC — Follicular Thyroid Carcinoma

System interpretation

Follicular‑pattern carcinoma with haematogenous spread. Vascular invasion burden is the dominant prognostic driver.

Key assumptions

Nodal disease uncommon; distant metastases more likely than in PTC; RAI responsiveness variable.

Risk logic highlights

No vascular invasion → lower risk; 1–3 foci → intermediate risk; ≥4 foci → high risk.

OTC — Oncocytic Thyroid Carcinoma (Hürthle cell)

System interpretation

Distinct subtype with higher baseline aggressiveness than FTC. Strong weighting of vascular invasion burden.

Key assumptions

Lower and less predictable RAI avidity; structural features carry greater weight.

Risk logic highlights

Any vascular invasion → ≥ intermediate risk; ≥4 foci → high risk.

Tall Cell Variant PTC

System interpretation

Aggressive papillary variant by definition.

Key assumptions

Higher recurrence risk and reduced RAI sensitivity.

Risk logic highlights

Cannot be classified as low risk.

Poorly Differentiated Thyroid Carcinoma (PDTC)

System interpretation

Not managed as standard differentiated thyroid cancer.

Key assumptions

Limited RAI responsiveness; early systemic therapy consideration.

Risk logic highlights

Automatically high risk.

PTC — Papillary Thyroid Carcinoma (classical)

System interpretation

Lowest baseline aggressiveness among invasive DTC subtypes in the tool. Risk is driven primarily by extent, nodal burden, and extrathyroidal extension.

Key assumptions

RAI avidity is usually preserved. Vascular invasion is generally a weaker prognostic driver than in follicular-pattern tumours.

Risk logic highlights

Intrathyroidal, low-volume nodal disease may remain low/intermediate; large-volume nodes or extranodal extension upgrade risk.

IEFVPTC — Infiltrative/Encapsulated Follicular Variant PTC

System interpretation

Behaviour depends on encapsulation and invasion pattern. Encapsulated disease tends to be indolent; infiltrative disease carries higher recurrence risk.

Key assumptions

RAI responsiveness is generally preserved, but risk can rise with infiltration, vascular invasion, or significant nodal disease.

Risk logic highlights

Encapsulated/non-invasive patterns lean lower risk; infiltrative growth and/or vascular invasion pushes toward intermediate risk.

FTC — Follicular Thyroid Carcinoma

System interpretation

Follicular-pattern carcinoma where vascular invasion burden is a dominant prognostic driver and haematogenous spread is more common.

Key assumptions

Nodal disease is uncommon; distant metastases risk is higher than in typical PTC. RAI responsiveness is variable but often present.

Risk logic highlights

Vascular invasion is handled both categorically and by foci count (e.g., ≥4 foci often treated as extensive).

OTC — Oncocytic Thyroid Carcinoma (Hürthle cell)

System interpretation

Distinct DTC subtype with higher baseline aggressiveness than FTC in the tool. Strong weighting is given to vascular invasion burden and adverse structural features.

Key assumptions

RAI avidity can be lower and less predictable; therefore structural risk features (vascular invasion, nodes, margins) carry greater weight.

Risk logic highlights

Any vascular invasion generally escalates risk; ≥4 foci is typically treated as extensive/high-risk biology.

Clinical Decision Support Disclaimer: This tool is intended for qualified healthcare professionals. It provides guideline-based decision support and does not replace clinical judgment, MDT discussion, or institutional protocols. Final decisions remain the responsibility of the treating clinician.

Radioactive Iodine (RAI) — Activity Selection

Intent-based guidance • Decision support only

Guideline framework

ATA guidelines support intent-based selection of radioactive iodine activity rather than fixed dosing. Administered activity should be individualised based on treatment intent, pathological risk features, disease burden, and MDT discussion with nuclear medicine expertise.

Remnant ablation

Intent: Elimination of normal thyroid remnant tissue following surgery.
Typical published practice: ~30 mCi (1.1 GBq).
Supported for low-risk and selected intermediate-risk patients, with comparable efficacy to higher activities and reduced toxicity.

Adjuvant therapy

Intent: Reduction of recurrence risk in the presence of adverse pathological features.
Typical published practice: ~75–150 mCi (2.8–5.5 GBq).
Activity selection is contextual and depends on integrated risk assessment rather than histology alone.

Treatment of known iodine-avid disease

Intent: Treatment of persistent or metastatic iodine-avid disease.
Activities are typically higher and may be empiric or dosimetry-guided, particularly in the setting of distant metastases or repeat treatment.

Clinical Decision Support Disclaimer:
This information is intended for qualified healthcare professionals and does not replace clinical judgment, MDT discussion, or institutional protocols. Final RAI activity selection remains clinician- and nuclear medicine–led.