Background: Papillary thyroid microcarcinoma (PTMC) has high incidence and low disease-specific mortality. However, active surveillance is not accepted by most patients owing to high physical or psychological pressures. The emergence of ablation technologies is supplanting traditional surgery. Our goal was to compare the clinical outcomes of microwave ablation (MWA) and surgery for T1aN0M0 PTMC. Methods: A total of 92 consecutive patients with T1aN0M0 PTMC were studied retrospectively. Forty-six patients had been treated with MWA, and the other 46 had undergone surgery. MWA was performed using extensive ablation extending from the nodule’s lower pole to the upper pole. Surgery was performed by total thyroidectomy or thyroid lobectomy. We compared the two groups in terms of mean length of stay, cost, mean blood loss, surgical incision, operating room (OR) time, quality of life (QOL) assessment, complications, and therapeutic efficacy over a follow-up period of 42 months. Results: The mean length of stay, cost, mean blood loss, surgical incisions, OR time, and complications in the MWA group were significantly lower than those of the surgery group. The QOL after MWA was higher than it was after surgery. The nodule volume decreased significantly from 53.61 ± 48.43 mm³ to 4.84 ± 6.55 mm³ (p < .001) at the 42-month follow-up, exhibiting a percentage volume reduction of 81.33 ± 36.87%. No recurrence or metastasis occurred in either group during the follow-up period. Conclusions: MWA may be considered a minimally invasive alternative to surgery for solitary T1aN0M0 PTMC with low incidence of complications and good therapeutic effect.

Background: Although papillary thyroid microcarcinoma (PTMC) has a high incidence and excellent clinical outcome, debate continues as to the therapeutic approach that would be most appropriate after confirming the diagnosis. Methods: We retrospectively analyzed the medical records of 311 patients with T1aN0M0 PTMC between January 2013 and September 2018. In all, 168 underwent microwave ablation (MWA), and 143 underwent surgery. MWA was performed using extensive ablation with hydrodissection. The surgery comprised thyroid lobectomy (TL) with unilateral central lymph node dissection (CND). We examined clinical outcomes during mean follow-up periods of 824 ± 452 days for the TL group and 753 ± 520 days for the MWA group. Results: Postprocedural follow-up revealed that, in the MWA group, the tumors had completely disappeared in 34 patients, and the remainder were reduced to necrotic or carbonized tissue. The incidence of transient hypoparathyroidism was significantly lower in the MWA group than in the TL group (p < .001). In addition, during the follow-up, we found no statistically significant differences between the two groups (TL vs MWA) for PTMC recurrence (1 vs 2 cases), lymph node metastasis (5 vs 5 cases), or disease-free survival [2001 days (5.5 years) vs 1702 days (4.7 years)] (p = .659, p = .795, and p = .974, respectively). Conclusions: If low-risk thyroid carcinoma (i.e., T1N0M0 PTMC) is accurately diagnosed early, MWA could be a minimally invasive alternative to surgery based on our short-term follow-up regarding recurrence and the low rates of complications and disease-free survival.

Background Preoperative assessment of follicular thyroid neoplasms is challenging using the current US risk stratification systems (RSSs) that are applicable to papillary thyroid neoplasms. Purpose To develop a US feature-based RSS for differentiating between follicular thyroid adenoma (FTA) and follicular thyroid carcinoma (FTC) in biopsy-proven follicular neoplasm and compare it with existing RSSs. Materials and Methods This retrospective multicenter study included consecutive adult patients who underwent conventional US and received a final diagnosis of follicular thyroid neoplasm from seven centers between January 2018 and December 2022. US images from a pretraining data set were used to improve readers' understanding of the US characteristics of the FTC and FTA. Univariable and multivariable logistic regression analyses were used to assess the association of qualitative US features with FTC in a training data set. Features with P < .05 were used to construct a prediction model (follicular tumor model, referred to as F model) and RSS for follicular neoplasms using the Thyroid Imaging Reporting and Data System (TI-RADS). Area under the receiver operating characteristic curve (AUC) was compared between follicular TI-RADS (hereafter, F-TI-RADS) and existing RSS (American College of Radiology [ACR] TI-RADS, Korean Society of Thyroid Radiology and Korean Society of Radiology TI-RADS [hereafter, referred to as K-TI-RADS], and Chinese TI-RADS [hereafter, referred to as C-TI-RADS]) in a validation data set. Results The pretraining, training, and validation data sets included 30 (mean age, 47.6 years ± 16.0 [SD]; 16 male patients; FTCs, 30 of 60 [50.0%]), 703 (mean age, 47.9 years ± 14.5; 530 female patients; FTCs, 188 of 703 [26.7%]), and 155 (mean age, 49.9 years ± 13.3 [SD]; 155 female patients; FTCs, 43 of 155 [27.7%]) patients. In the validation data set, the F-TI-RADS showed improved performance for differentiating between FTA and FTC (AUC, 0.81; 95% CI: 0.71, 0.86) compared with ACR TI-RADS (AUC, 0.74; 95% CI: 0.66, 0.80; P = .02), K-TI-RADS (AUC, 0.69; 95% CI: 0.61, 0.76; P = .002), and C-TI-RADS (AUC, 0.68; 95% CI: 0.60, 0.75; P = .002). Conclusion F-TI-RADS outperformed existing RSSs for differentiating between FTC and FTA. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Baumgarten in this issue.

The optimal treatment method for papillary thyroid microcarcinoma (PTMC) is lacking consensus. Here we aimed to compare the efficacy and safety of surgery and microwave ablation (MWA) for PTMC.The ...

Background For patients with unresectable colorectal liver metastases (CRLM), clinical guidelines recommend imaging-guided thermal ablation combined with systemic therapy. However, the optimal thermal ablation strategy remains unclear. Purpose To compare long-term outcomes between patients who underwent upfront ablation or delayed ablation for unresectable CRLM. Materials and Methods This retrospective study included patients with unresectable CRLM (three or fewer lesions; diameter, <3 cm) admitted to one of seven hospitals between October 2009 and December 2020. Upfront ablation was performed 2-4 weeks before the start of systemic therapy, and delayed ablation was performed 2-3 months after the start of systemic therapy. Propensity score matching was applied to adjust for differences in baseline variables between groups. Disease-free survival (DFS) was the primary outcome. Overall survival (OS), complications, and adverse events were secondary outcomes. Outcomes were compared between groups by using the log-rank test. Results In total, 255 patients who underwent delayed ablation (mean age, 57 years ± 11 [SD]; 184 men [72%]) and 103 patients who underwent upfront ablation (mean age, 56 years ± 12; 72 men [70%]) were included. After propensity score matching (n = 100 in both groups), the 5-year DFS for patients who underwent upfront ablation was better compared with patients who underwent delayed ablation (36% vs 21%; P = .02). For 5-year OS, no evidence of a difference was observed between ablation strategies (delayed ablation, 59% vs upfront ablation, 64%; P = .49). Additionally, no differences were observed between ablation strategies with respect to the rates of ablative complications (delayed ablation, 6% vs upfront ablation, 5%; P = .76) or drug-related adverse events (delayed and upfront ablation both 9%; P = .99). Conclusion In patients with relatively few (three or fewer) and small (<3 cm) unresectable CRLM, upfront thermal ablation combined with adjuvant systemic therapy led to better DFS compared with delayed ablation. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Georgiades in this issue.