BACKGROUND
Papillary thyroid cancer is the most common type of thyroid cancer. Overall, papillary thyroid cancer has an excellent prognosis, mainly due to very effective treatments. Initial treatment of small papillary thyroid cancers is usually surgery, which is often curative. Data from many studies have been used to separate papillary thyroid cancer into low, intermediate or high risk of cancer recurrence. These risk levels help guide treatment options. Small, low risk papillary thyroid cancer is common and usually follows a very slow-growing course with a low risk of spreading of the cancer outside of the thyroid gland. As such, these low-risk cancers are treated with surgery alone or active surveillance (following the cancer with ultrasound and deferring surgery until the cancer grows significantly).

The use of thermal ablation techniques has become an option for treating small benign thyroid nodules. These techniques use using heat delivered by a needle to destroy the thyroid nodule. There are 3 types of thermal ablation: radiowave-based heat (radiofrequency ablation, RFA), microwave-based heat (microwave ablation, MVA) and laser-based heat. Recently, studies reported the use of these thermal ablation techniques to treat small thyroid cancers. Long term comparison data with surgery has been limited.

In this study, the authors compared the long-term cancer outcomes and complications of MWA versus surgical resection (total thyroidectomy or lobectomy) in patients with small, low risk thyroid cancers.

THE FULL ARTICLE TITLE
Fei YL et al. Propensity-matched comparison of microwave ablation and surgical resection for preoperative T1N0M0 papillary thyroid carcinoma: 5-year follow-up. Eur Radiol. Epub 2025 Aug 6.

SUMMARY OF THE STUDY
This single-center study followed patients with low risk papillary thyroid cancer treated with MWA or surgery between 2016 and 2019, with follow-up through August 2024. Patients with high-risk features, insufficient follow-up, and incomplete data were excluded. MWA was performed under ultrasound guidance, targeting the cancer and a surrounding safety margin. Surgical resection included lobectomy or total thyroidectomy according to cancer characteristics and patient preference.

Primary end points were disease progression– free survival (DFS), defined as the time from treatment initiation to disease progression or death; thyroid recurrence–free survival (TRFS), defined as the time to local cancer progression, new cancer or death; and lymph node recurrence–free survival (LRFS), defined as the time to spread to the neck lymph nodes or death, and complication rates. Statistical analysis was used for subgroup comparisons of MWA versus total thyroidectomy (TT) or lobectomy (LT).

The outcomes of 464 patients (175 MWA patients versus 289 surgery patients) were compared after an average follow-up of 69 months. There was no significant difference in 5-year DFS (93.7% vs. 97.2%) or LRFS (98.3% vs. 98.6%) between the MWA and surgery groups. TRFS was slightly lower in the MWA group than in the TT group, but not significantly different from lobectomy. In the MWA group, complete cancer disappearance was observed on ultrasonography in 162 patients (92.6%) and was significantly lower in patients with multiple cancers rather than single cancers (69.6% vs. 96.1%). Local cancer recurrences were managed with repeat MWA, initial or repeat surgery, radioactive iodine, or active surveillance. No cases of distant metastasis were observed in either group during follow-up.

Procedural metrics significantly favored MWA: average operative time was shorter (32 vs. 90 minutes), incisions were smaller (0.2 vs. 7 cm), and average hospital stay was reduced (2 vs. 6 days). The surgery group had significantly more complications than the MWA group (26.6% vs. 6.9%), with a significantly higher rate of permanent hoarseness (2.8% vs. 0%).

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This study shows that MWA achieved long-term cancer control comparable to that for surgery in low-risk papillary thyroid cancer, with fewer complications and faster recovery, supporting its role as a potential alternative in selected patients. This is an important treatment option for patients with low-risk papillary thyroid cancer to go along with the options of surgery and active surveillance.

— Alan P. Farwell, MD

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