Microwave Ablation Shows Noninferiority to Surgery in Thyroid Cancer

"Our study has shown that microwave ablation offers a promising treatment option for multifocal papillary thyroid cancer," according to Ming-An Yu, MD.

Microwave ablation was associated with less blood loss and shorter incision lengths, as well as shorter procedure and hospitalization durations compared with surgery, and progression-free survival (PFS) rates were similar between the 2 approaches for patients with multifocal T1N0M0 papillary thyroid cancer, according to retrospective findings.¹

The results, which were published in Radiology, showed that the 1-year PFS rates with microwave ablation and surgery were 98.7% vs 98.5%, respectively (P = .39), and the 3-year PFS rates were 91.5% and 95.0%, respectively (P = .26). The 5-year PFS rates were 77.2% with microwave ablation vs 83.1% with surgery (P = .36).

Additionally, in the surgery group, 2.2% of patients experienced permanent hoarseness (P = .05), and 4.0% had hypoparathyroidism (P = .005).

The median amount of blood loss between the microwave ablation and surgery groups was 1 mL vs 10 mL, respectively (P <.001), and the median incision length was 0.4 cm vs 7 cm, respectively (P <.001). The median length of time for microwave ablation was 30 minutes (IQR, 30-40) compared with 90 minutes (IQR, 60-120) for surgery (P <.001), and the median length of hospitalization was 3 days (IQR, 3-3) vs 5 days (IQR, 4-7), respectively (P <.001).

"This study marks the first multicenter comparative analysis between microwave ablation and surgical resection for multifocal papillary thyroid cancer," senior author Ming-An Yu, MD, director of interventional medicine at China-Japan Friendship Hospital in Beijing, China, stated in a news release.² "These findings challenge traditional treatment paradigms and open new avenues for less invasive management strategies."

Papillary thyroid cancer is the most prevalent differentiated thyroid cancer subtype, and multifocality in this subtype occurs in anywhere between 23.5% and 60% of cases. Furthermore, multifocal papillary thyroid cancer is not defined as high-risk and is often treated with surgery.

Currently, microwave ablation is being investigated as a treatment for patients with multifocal papillary thyroid carcinoma and has previously demonstrated efficacy. Microwave ablation is described to be minimally invasive with the capability of preserving thyroid function.

In the retrospective trial, investigators compared microwave ablation with surgery for 775 patients with preoperative US-detected T1N0M0 multifocal papillary thyroid cancer. The key end points were 1-, 3-, and 5-year PFS and complication rates with each approach. Data were analyzed from patients across 10 centers in China between May 2015 and December 2021, and investigators used propensity score matching for patients in both groups followed by comparisons between the two.

Following propensity score matching, there were 229 patients in the microwave ablation group and 453 patients in the surgery group. The median age in both groups was 44 years (IQR, 36.5-50.5) and 45 years (IQR, 37-53), respectively; 179 and 367 patients, respectively, were female. A total of 205 patients with T1a disease had microwave ablation compared with 24 who had T1b disease; these proportions were 391 and 62 in the surgery group, respectively.

The median time for follow-up was 20 months (range, 12-74) for microwave ablation and 26 months (range, 12-64) for surgery.

In the surgical group, 35,3% of patients underwent hemithyroidectomy, 9.9% had subtotal thyroidectomy, and 54.7% had a total thyroidectomy. All patients had central lymph node dissection performed, and 35.5% of patients had lymph node metastasis, with a median of 3 (IQR, 2-4) metastatic lymph nodes.

Disease progression was reported in 4.8% of patients who had microwave ablation compared with 3.5% who had surgery. Rates of new tumor and lymph node metastasis were 4.8% and 0.4% in the microwave ablation group vs 2.2% and 1.3% in the surgery group.

"Our study has shown that microwave ablation offers a promising treatment option for multifocal papillary thyroid cancer," Yu concluded in the news release.² "Additionally, microwave ablation is associated with fewer complications and can preserve thyroid function, thereby enhancing patients’ quality of life. This represents a significant advancement in the field of interventional thyroid cancer treatment."

References

1. Zhao Z-L, Wang S-R, Dong G, et al. Microwave ablation versus surgical resection for US-detected multifocal T1N0M0 papillary thyroid carcinoma: a 10-center study. Radiology. 2024;311(1):e230459. doi:10.1148/radiol.230459
2. Minimally invasive procedure may spare patients from thyroid surgery. Radiological Society of North America. Published April 2, 2024. Accessed April 9, 2024. https://press.rsna.org/timssnet/media/pressreleases/14_pr_target.cfm?ID=2499