Local Tumor Progression of Hepatocellular Carcinoma After Microwave Percutaneous Ablation: A Preliminary Report

Assessment of Ablative Margin After Microwave Ablation for Hepatocellular Carcinoma Using Deep Learning-Based Deformable Image Registration

Aim: To assess the ablative margin (AM) after microwave ablation (MWA) for hepatocellular carcinoma (HCC) with a deep learning-based deformable image registration (DIR) technique and analyze the relation between the AM and local tumor progression (LTP).

Patients and Methods: From November 2012 to April 2019, 141 consecutive patients with single HCC (diameter ≤ 5 cm) who underwent MWA were reviewed. Baseline characteristics were collected to identify the risk factors for the determination of LTP after MWA. Contrast-enhanced magnetic resonance imaging scans were performed within 1 month before and 3 months after treatment. Complete ablation was confirmed for all lesions. The AM was measured based on the margin size between the tumor region and the deformed ablative region. To correct the misalignment, DIR between images before and after ablation was achieved by an unsupervised landmark-constrained convolutional neural network. The patients were classified into two groups according to their AMs: group A (AM ≤ 5 mm) and group B (AM > 5 mm). The cumulative LTP rates were compared between the two groups using Kaplan–Meier curves and the log-rank test. Multivariate analyses were performed on clinicopathological variables to identify factors affecting LTP.

Results: After a median follow-up period of 28.9 months, LTP was found in 19 patients. The mean tumor and ablation zone sizes were 2.3 ± 0.9 cm and 3.8 ± 1.2 cm, respectively. The mean minimum ablation margin was 3.4 ± 0.7 mm (range, 0–16 mm). The DIR technique had higher AUC for 2-year LTP without a significant difference compared with the registration assessment without DL (P = 0.325). The 6-, 12-, and 24-month LTP rates were 9.9, 20.6, and 24.8%, respectively, in group A, and 4.0, 8.4, and 8.4%, respectively, in group B. There were significant differences between the two groups (P = 0.011). Multivariate analysis showed that being >65 years of age (P = 0.032, hazard ratio (HR): 2.463, 95% confidence interval (CI), 1.028–6.152) and AM ≤ 5 mm (P = 0.010, HR: 3.195, 95% CI, 1.324–7.752) were independent risk factors for LTP after MWA.

Conclusion: The novel technology of unsupervised landmark-constrained convolutional neural network-based DIR is feasible and useful in evaluating the ablative effect of MWA for HCC.

A novel nomogram to predict the local tumor progression after microwave ablation in patients with early-stage hepatocellular carcinoma: A tool in prediction of successful ablation

OBJECTIVES

To develop a nomogram for the local tumor progression (LTP) in patients with early-stage hepatocellular carcinoma (HCC) after computed tomography-guided percutaneous microwave ablation (CT-PMWA) and to assess clinical-pathologic risk factors for individual LTP estimation. Furthermore, we compared the prognostic predictive ability for LTP between the nomogram and the traditional staging systems.

METHODS

This retrospective study was approved by the institutional review board. Five hundred and forty treatment-naïve patients with HCC according to the Milan criteria, who subsequently underwent CT-PMWA were reviewed from 2009 to 2019. Baseline characteristics were collected to identify the risk factors for the determination of LTP after CT-PMWA. The multivariate Cox proportional-hazards model based on significant prognostic factors of LTP was used to construct the nomogram, which was then assessed for its predictive accuracy using mainly the Harrell's C-index and time-dependent area under the curve (tAUC).

RESULTS

After a median follow-up time of 28.7 months, 6.5% (35/540) patients had LTP. The nomogram was developed based on the tumor size, tumor number, Child-Turcotte-Pugh (CTP) grade, platelet, and alanine aminotransferase (ALT). The nomogram had good calibration and discriminatory abilities in the training set, with C-indexes of 0.799 (95% confidence interval (CI): 0.738, 0.860), and tAUCs of 0.844 (CI: 0.728, 0.895), that were greater than those of traditional staging systems. Internal validation with 1000 bootstrap resamples had a good C-index of 0.735 (CI: 0.648, 0.816).

CONCLUSIONS

The nomogram model can be used to predict accurately LTP after CT-PMWA for early-stage HCC, as well as to assist physicians during the therapeutic decision-making process.

CT-guided percutaneous laser ablation of metastatic lung cancer: three cases report and literature review

Objective

To report the efficacy and safety of CT-guided percutaneous laser ablation (PLA) for metastatic lung tumors.

Methods

Three cases of metastatic lung cancer underwent CT-guided PLA, and we searched for previously published articles on the minimally invasive CT-guided RFA or MWA for lung tumors in recent five years.

Results

With the guidance of CT, all lesions had good prognosis under laser ablation. Case 1 suffering from severe pulmonary dysfunction and diffuse pulmonary bullae, had small pneumothorax. CT scan obtained four months following the ablation showed two lesions had complete responses and one partial response. Case 2 had successful complete response with absent lung mass, and also had a good postoperative condition without any discomfort in the two-month follow-up. Case 3 showed partial response and improved greatly after five months. 962 cases (mean age of 45.7 years, 62.2% male) of 1297 lung tumors with detailed information were identified from 27 articles. Of these cases, the minority manifested complications such as pneumothorax, hemoptysis, hemothorax, pneumonia, pain and fever.

Conclusions

Percutaneous CT-guided PLA could be a safe and promising minimally invasive treatment for patients with primary lung cancer or unresectable pulmonary metastases, especially multineedle PLA in large tumors, which still needs more large-scale prospective studies to convince this method in the future.

EUS dating with laser ablation against the caudate lobe or left liver tumors: a win-win proposition?

Endoscopic ultrasound (EUS) have been not only a diagnostic tool, but also available in interventional therapy, which often previously needed surgical approaches to achieve. The study aimed to evaluate the effectiveness and safety of EUS-guided Nd:YAG laser ablation in unresectable tumors of the caudate lobe and left liver. We discussed ten cases of the caudate lobe and left liver tumors underwent laser ablation with EUS guidance. And we also have reviewed previous publication of EUS-guided thermal ablation for liver tumors in several decade years. EUS-guided Nd:YAG laser ablation (LA) of these tumors were successfully completed in ten patients, who had favourable prognosis with no complications in two-month follow-up. Based on our early observations, this suggested that EUS-guided LA might be technically feasible in selected patients with tumors of the caudate lobe and left liver. However, the safety of this technique need to be further confirmed in the future and if possible larger, prospective trials.

Percutaneous laser ablation: a new contribution to unresectable high-risk metastatic retroperitoneal lesions?

BACKGROUND & AIMS

Metastasis in retroperitoneal lymph nodes is one of the signs of advanced stage or terminal stage of malignancy. We performed a trial to assess the safety and efficacy of ultrasonography (US)-guided local neodymium-doped yttrium aluminum garnet (Nd:YAG) laser ablation for metastatic lymph nodes in the retroperitoneal region.

METHODS

We evaluated 4 cases of retroperitoneal metastatic lymph nodes treated using US-guided Nd:YAG laser ablation. Additionally, we reviewed the PubMed database for articles on thermal ablation of retroperitoneal lesions until March 2016, without language limitations.

RESULTS

In our study, all lesions were nearly completely ablated with mild discomfort, including pain and fever at the 3-month follow-up. In the literature review, a total of 398 patients with 491 retroperitoneal tumors were identified, and complications after the procedure included enterovesical fistula, fecal incontinence, and hematoma.

CONCLUSIONS

Percutaneous laser ablation could be a theoretically promising approach for retroperitoneal metastatic lesions. ClinicalTrials.gov number: NCT02822053.