A Systematic Review and Meta-analysis of Patient Survival and Disease Recurrence Following Percutaneous Ablation of Pulmonary Metastasis

Stereotactic body radiation therapy and thermal ablation for treatment of patients with pulmonary metastases: a systematic literature review and meta-analysis

OBJECTIVE

To compare local tumor progression (LTP) and overall survival (OS) after image-guided thermal ablation (IGTA; microwave/radiofrequency ablation) versus stereotactic body radiation therapy (SBRT) in patients with pulmonary metastases.

METHODS

A systematic literature review was performed to capture studies that used IGTA or SBRT for patients with pulmonary metastases and studies that reported one, two, and threeyear LTP/OS were included. Patients with pulmonary metastases, and a subgroup with metastases from colorectal or renal cell carcinoma, or sarcoma (termed subgroup) which are considered more radioresistant, were analyzed. Single-arm pooled analyses, univariable, and multivariable random-effects meta-regressions were conducted to compare LTP and OS between IGTA and SBRT treated patients.

RESULTS

Analyses included 3,264 IGTA and 5,486 SBRT patients. IGTA patients with pulmonary metastases had higher LTP than SBRT patients at one year, 13% and 9% respectively. At two years, the LTP for IGTA patients was 14% compared to 16% for SBRT patients. Three-year LTP remained lower for IGTA patients compared to SBRT patients (14% and 22% respectively). In the subgroup, SBRT patients had higher LTP than IGTA patients across all timepoints. OS was similar across analyses/subgroups in the single-arm pooled analyses. The multivariable analyses showed that SBRT was associated with significantly lower OS at one year; however nonsignificant differences were observed at years two and three.

CONCLUSIONS

In patients with pulmonary metastases, IGTA had lower LTP than SBRT at later timepoints. In patients with colorectal, renal cell carcinoma, or sarcoma pulmonary metastases, LTP was similar to overall LTP for IGTA, while it was higher for SBRT.

Patient-Specific Prediction of Immediate Phase Lung Microwave Ablation Zone Size

PURPOSE

To investigate the effect of patient and tumor-specific characteristics on the size of immediate phase lung microwave ablation (MWA) zone and establish a prediction model.

MATERIALS AND METHODS

This institutional review board (IRB)-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant cohort included 164 lesions from 99 patients who underwent computed tomography (CT)-guided lung MWA, and the 2-dimensional elliptical ground-glass opacity ablation zone was measured. Duration, maximum temperature, tumor depth, presence of emphysema, history of ipsilateral lung ablation, surgery, and radiotherapy were recorded. K-fold cross validation with k = 5 and Least Absolute Shrinkage and Selection Operator were used to build prediction models for the major and minor axes and area of the ablation zone.

RESULTS

The median of immediate phase ablation duration was 2 minutes (interquartile range, 1.5-4.25 minutes) with 65 W of power for all ablations. The mean major and minor axes and area of ablation zone were 3.1 cm (SD ± 0.6), 2.0 cm (SD ± 0.5), and 5.1 cm2 (SD ± 2.1), respectively. The major and minor axes and area of immediate phase ablation zone dimensions were significantly associated with duration (P < .001, P < .001, and P < .001, respectively), maximum temperature (P < .001, P < .001, and P < .001, respectively), tumor depth (P = .387, P < .001, and P < .001, respectively), history of ipsilateral lung ablation (P = .008, P = .286, and P = .076, respectively), and lung radiotherapy (P = .001, P = .042, and P = .015, respectively). The prediction model showed R2 values for major and minor axes and area of the ablation zone to be 0.50, 0.45, and 0.53, respectively.

CONCLUSIONS

Duration of ablation, maximum temperature, tumor depth, history of ipsilateral lung ablation, surgery, and radiotherapy were significantly associated with the ablation zone dimensions and size and can be used to build the prediction model to approximate the immediate phase lung MWA zone.

Clinical application of optical and electromagnetic navigation system in CT-guided radiofrequency ablation of lung metastases

PURPOSE

To evaluate the clinical value of CT-guided radiofrequency ablation (RFA) in the diagnosis and treatment of pulmonary metastases under optical and electromagnetic navigation.

METHODS

Data on CT-guided radiofrequency ablation treatment of 93 metastatic lung lesions in 70 patients were retrospectively analyzed. There were 46 males and 24 females with a median age of 60.0 years (16-85 years). All lesions were ≤3cm in diameter. 57 patients were treated with 17 G radiofrequency ablation needle puncture directly ablated the lesion without biopsy, and 13 patients were treated with 16 G coaxial needle biopsy followed by radiofrequency ablation. There were 25 cases in the optical navigation group, 25 in the electromagnetic navigation group, and 20 in the non-navigation group. The navigation group was performed by primary interventionalists with less than 5 years of experience, and the non-navigation group was performed by interventionalists with more than 5 years of experience.

RESULT

All operations were successfully performed. There was no statistically significant difference in the overall distribution of follow-up results among the optical, electromagnetic, and no navigation groups. Complete ablation was achieved in 84 lesions (90.3%). 7 lesions showed incomplete ablation and were completely inactivated after repeat ablation. 2 lesions progressed locally, and one of them still had an increasing trend after repeat ablation. No serious complications occurred after the operation.

CONCLUSIONS

Treatment with optical and electromagnetic navigation systems by less experienced operators has similar outcomes to traditional treatments without navigational systems performed by more experienced operators.

Robotic versus freehand CT-guided radiofrequency ablation of pulmonary metastases: a comparative cohort study

PURPOSE

Radiofrequency ablation (RFA) is a curative treatment option for small lung metastases, which conventionally involves multiple freehand manipulations until the treating electrode is satisfactorily positioned. Stereotactic and robotic guidance has been gaining popularity for liver ablation, although has not been established in lung ablation. The purpose of this study is to determine the feasibility, safety, and accuracy of robotic RFA for pulmonary metastases, and compare procedures with a conventional freehand cohort.

METHODS

A single center study with prospective robotic cohort, and retrospective freehand cohort. RFA was performed under general anesthesia using high frequency jet ventilation and CT guidance. Main outcomes were (i) feasibility/technical success (ii) safety using Common Terminology Criteria for Adverse Events (iii) targeting accuracy (iv) number of needle manipulations for satisfactory ablation. Robotic and freehand cohorts were compared using Mann-Whitney U tests for continuous variables, and Fisher's exact for categorical variables.

RESULTS

Thirty-nine patients (mean age 65 ± 13 years, 20 men) underwent ablation of 44 pulmonary metastases at single specialist cancer center between July 2019 and August 2022. 20 consecutive participants underwent robotic ablation, and 20 consecutive patients underwent freehand ablation. All 20/20 (100%) robotic procedures were technically successful, and none were converted to freehand procedures. There were 6/20 (30%) adverse events in the robotic cohort, and 15/20 (75%) in the freehand cohort (P = 0.01). Robotic placement was highly accurate with 6 mm tip-to-target distance (range 0-14 mm) despite out-of-plane approaches, with fewer manipulations than freehand placement (median 0 vs. 4.5 manipulations, P < 0.001 and 7/22, 32% vs. 22/22, 100%, P < 0.001).

CONCLUSIONS

Robotic radiofrequency ablation of pulmonary metastases with general anesthesia and high frequency jet ventilation is feasible and safe. Targeting accuracy is high, and fewer needle/electrode manipulations are required to achieve a satisfactory position for ablation than freehand placement, with early indications of reduced complications.

Pulmonary Metastasectomy

The lung represents the most common site for metastatic spread of extrathoracic primary malignancies. Pulmonary metastatic disease occurs in a wide breadth of cancers with a multitude of histologies, and, historically, has been managed predominantly with systemic therapy. However, in appropriately selected patients, pulmonary metastasectomy can provide extended disease-free intervals, relief from systemic therapy, and prolonged survival. Thus, pulmonary metastasectomy serves a vital role in the armamentarium against a multitude of primary malignancies. Moreover, as systemic agents improve and more patients live longer with stage IV cancer, pulmonary metastasectomy will likely have increasing relevance in the future.

CT-Guided Percutaneous Cryoablation for Lung Metastasis of Colorectal Cancer: A Case Series

PURPOSE

This study aimed to evaluate the efficacy of computed tomography (CT) guided percutaneous cryoablation (CA) for the management of lung metastases in patients with metastatic colorectal cancer (mCRC).

METHODS

Retrospective analysis was performed on 38 mCRC patients with lung metastases, who underwent CT-guided percutaneous CA at our center from May 1, 2020 to November 1, 2021. The technical success rate, 1-year local control (LC) rate, recurrence-free survival (RFS) and treatment-related complications were analyzed.

RESULTS

The CA procedure was successfully performed in all patients, with a technical success rate of 100%. The 1-year LC rate was 94.7% (36/38), while 16 patients experienced new distant lung metastases during the follow-up period. The median RFS was 20 months (95% CI: 13.0-27.0). The median RFS of patients with and without extrapulmonary metastasis was 15 and 23 months, respectively. Complications were reported in 18 (47.4%) patients following the CA procedure. Pneumothorax was discovered in 15 (39.5%) patients, and five of these patients (13.2%) required chest tube intubation. Two patients (5.3%) presented with hemoptysis during the CA procedure. One patient developed subcutaneous emphysema as detected in the post-procedure follow-up imaging. All patients tolerated the peri-procedural pain well under local anesthesia, and the mean visual analog scale (VAS) score was 2.8.

CONCLUSION

Lung CA is a safe and well-tolerated treatment with a satisfactory local control rate for patients with lung metastases derived from mCRC.

Up-to-date evidence on image-guided thermal ablation for metastatic lung tumors: a review

The aim of this review was to summarize the latest evidence on image-guided thermal ablation therapies for lung metastases. PubMed was used to search for relevant articles that reported the oncological outcomes of thermal ablation for metastatic lung tumors, and those published in 2010 or later were selected for review. Ablative therapies were applied for lung metastases from various types of primary tumors, but most commonly colorectal ones. Radiofrequency ablation (RFA) was the most evaluated technique, followed by microwave ablation (MWA). The local control rates of ablative therapies were generally favorable, approximately 80–90% in many studies. Representative studies demonstrated promising overall survival rates of approximately 50% or higher 5 years after ablation for lung metastases from colorectal cancer or mixed types of primary tumors. Nevertheless, the survival outcomes varied depending on the type of primary tumor and background factors of patients such as other metastases and comorbidities. Several studies had aimed to compare the outcomes of various ablative therapies such as RFA, MWA, and cryoablation; however, conclusive data are not yet available to determine the most appropriate ablation modality for lung metastases. Further data accumulation is needed, especially for long-term outcomes and comparisons with other therapies.