Thyroid Nodule · Surveillance vs Surgery + Approach

Step-by-step decision

Choose step by step as prompted; reaching an endpoint gives the management recommendation. You can go back a step or restart anytime.

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Full pathway

1. [Decision] US risk+size→FNA; Bethesda; compression/function
   US risk/size (FNA) + cytology Bethesda + compression/function? (FNA size thresholds: high-suspicion ≥1 cm, intermediate ≥1–1.5 cm, low ≥1.5 cm, very-low ≥2 cm or observe, benign no FNA.)
   • US benign/low-risk and below the FNA threshold → Low-risk below threshold → surveillance
   • FNA done: Bethesda II benign → Bethesda II benign → surveillance/RFA
   • Bethesda III/IV (indeterminate) → III/IV indeterminate → repeat/molecular/diagnostic lobectomy
   • Bethesda V/VI (suspicious/malignant) → V/VI suspicious/malignant · choose extent
   • Benign but large/compressive/substernal/cosmetic or autonomously hyperfunctioning → Large/compressive/hyperfunctioning → lobectomy or total
2. [End] Low-risk below threshold → surveillance
   US low-risk and below the FNA threshold → ultrasound surveillance; low-risk papillary microcarcinoma (<1 cm, no high-risk features) may have active surveillance.
3. [End] Bethesda II benign → surveillance/RFA
   Benign → surveillance (interval by US risk); a symptomatic benign solid nodule may have radiofrequency ablation (RFA) or lobectomy.
4. [End] III/IV indeterminate → repeat/molecular/diagnostic lobectomy
   Bethesda III (AUS/FLUS) → repeat FNA or molecular testing; IV (follicular neoplasm) → diagnostic lobectomy or molecular testing to triage, with management by the result.
5. [Decision] V/VI suspicious/malignant · choose extent
   Surgical extent (by size and high-risk features)?
   • Low-risk DTC 1–4 cm, unilateral, no extrathyroidal extension/nodal metastasis → Lobectomy
   • >4 cm / extrathyroidal extension / nodal or distant metastasis / bilateral / prior neck radiation / planned RAI → Total thyroidectomy
6. [End] Lobectomy
   Thyroid lobectomy — low-risk differentiated cancer 1–4 cm, unilateral, no extrathyroidal extension or nodal metastasis; preserves contralateral function, often avoids lifelong replacement; completion surgery decided by final pathology.
7. [End] Total thyroidectomy
   Total thyroidectomy — >4 cm / extrathyroidal extension / nodal or distant metastasis / bilateral / prior neck radiation / planned RAI; ± central neck dissection; postoperative replacement + Tg follow-up.
8. [End] Large/compressive/hyperfunctioning → lobectomy or total
   Large/compressive/substernal/cosmetic or autonomously hyperfunctioning adenoma → lobectomy or total thyroidectomy (by extent of involvement); a symptomatic benign small nodule may also have radiofrequency ablation (RFA).

Source guidelines & references

• Thyroid nodules and differentiated cancer (ATA 2015; ACR TI-RADS; Bethesda reporting system)

This pathway is our own synthesis of the decision logic in the guidelines above (not the guideline verbatim); thresholds and workflows change as guidelines update — in practice follow the latest guideline, your institution's protocol and the individual patient.

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