Ultrasound-Guided Microwave Ablation Vs. Surgery for Low-Risk PapilaryThyroid Carcinoma

The inclusion criteria of this study were as followed:

1. PTC confirmed by fine-needle aspiration (FNA);
2. Confirmed low-risk mutation types by next-generation sequencing (NGS) before surgery;
3. No severe functional diseases, such as heart failure, severe respiratory diseases, or renal failure;
4. Availability of complete follow-up data.

The exclusion criteria were as followed:

1. No local or distant metastasis assessed by imaging evaluations, including ultrasound or computed tomography (CT);
2. Lacking of preoperative genetic testing or inability to assess genetic test results;
3. Inability to complete follow-up or lost to follow-up during the study.

Low-risk PTC is defined as:

1. Maximum tumor diameter ≤1 cm;
2. Solitary lesion;
3. No local or distant metastasis;
4. No tumor invasion into extrathyroidal tissues;
5. No vascular invasion;
6. Non-invasive pathological subtype for the primary lesion (invasive subtypes include tall cell, columnar cell, diffuse sclerosing, solid/trabecular, and oncocytic vari ants);
7. No history of head and neck radiotherapy during adolescence;
8. No family history of thyroid cancer;
9. Genetic testing showing BRAF V600E mutation (without concurrent TERT mutation), RAS family gene mutations, (HRAS, NRAS, KRAS), or other low-risk mutations, such as isolated RET/PTC) rearrangements.

Intermediate-high risk PTC is defined as:

1. Maximum tumor diameter \>1 cm;
2. Multifocal thyroid cancer;
3. Local or distant metastasis;
4. Primary lesion with extrathyroidal extension;
5. Vascular invasion;
6. Primary lesion with an invasive pathological subtype;
7. History of head and neck radiotherapy during adolescence;
8. Family history of thyroid cancer;
9. Genetic testing revealing high-risk mutation combinations, such as BRAF V600E or RAS mutations with concurrent TERT or TP53 mutations, or RAS mutations combined with EIF1AX mutations.