The report is a product of the VA/HSR Evidence Synthesis Program.

Percutaneous Ablation for Lung Metastasis-Directed Therapy: A Systematic Review

Takeaway: For adults who have lung tumors that originated from cancer elsewhere in the body (“pulmonary metastases from non-lung primary cancer”), this review found that there is insufficient evidence to compare the safety or effectiveness of image-guided percutaneous thermal ablation (IGTA; a procedure in which imaging is used to guide a needle or probe to a tumor and destroy it with extreme heat or cold) with stereotactic body radiation therapy (SBRT; high-dose radiation therapy that precisely targets tumors in fewer sessions than conventional radiation therapy). Clinicians treating lung metastases should continue to consider tumor characteristics, patient characteristics and preferences, and available clinical expertise—particularly regarding opportunities for multidisciplinary collaboration—when making treatment decisions. To address the lack of evidence, future research should prioritize well-designed comparative studies with standardized outcome reporting and patient-centered outcome measures. VHA might have the data needed to conduct a high-quality non-randomized comparative study of IGTA and SBRT, or meta-analysis of individual patient data from Veterans who underwent either treatment, which may give rise to future randomized controlled trials.

The lung is one of the most common organs for tumors to spread to from a site elsewhere in the body. While patients with lung metastases are often treated with systemic therapy alone, there are times when non-surgical treatments are used for this scenario (“pulmonary metastases from non-lung primary cancer”). The two most commonly used non-surgical local treatments are image-guided percutaneous thermal ablation (IGTA; a procedure in which imaging is used to guide a needle or probe to a tumor and destroy it with extreme heat or cold) and stereotactic body radiation therapy (SBRT; high-dose radiation therapy that precisely targets tumors in fewer sessions than conventional radiation therapy).

In response to a request from the VHA National Radiation Oncology Program, HSR’s Evidence Synthesis Program (ESP) Center in Providence, RI, conducted a systematic review on the safety and efficacy of IGTA compared to SBRT in patients with pulmonary metastases from non-lung primary cancer. To identify relevant articles, the ESP team searched Ovid MEDLINE, Ovid Embase, CENTRAL, and other databases, and hand-searched reference lists of related systematic reviews.

Summary of Findings

A total of 101 studies were included in this review.

The safety of IGTA compared to SBRT:

• The distribution of safety evidence was relatively balanced between IGTA and SBRT, with approximately 50 studies for each.
• Methods of measuring and reporting adverse events (AEs) varied across studies (e.g., standard grading systems were used far more commonly for SBRT than IGTA; most IGTA studies reported AEs per treatment session while SBRT studies reported AEs per patient, and follow-up was short-term for IGTA and often unclear for SBRT).
• Given the meaningful differences in AE reporting and the lack of head-to-head trials, it is not possible to directly compare AE rates between IGTA and SBRT for the treatment of pulmonary metastases.

The effectiveness of IGTA compared to SBRT:

• Only two studies included in this review directly compared IGTA and SBRT effectiveness. Both studies involved patients with lung tumors that had metastasized from colorectal cancer.
• One of the studies had a high risk of bias; the other study had a moderate risk of bias.
• Given the small number of studies and their risk of bias, it is not possible to draw conclusions regarding the comparative effectiveness of IGTA and SBRT for the treatment of pulmonary metastases.

Implications

Overall, patients who are eligible for both IGTA and SBRT—and their referring clinicians—face a lack of high-quality data to inform treatment decisions. Clinicians treating lung metastases from non-lung primary cancers should continue to consider tumor characteristics, patient characteristics and preferences, and the availability of technical expertise. Structured multidisciplinary collaboration (e.g., between interventional radiology and radiation oncology) can help address the lack of evidence informing this important clinical problem.

Limitations

This review has several limitations, such as the use of strict inclusion criteria, which might limit generalizability of the findings to broader clinical populations. Also, it’s possible that patient populations overlapped across studies, as publications might not have acknowledged sharing underlying data. In addition, due to widely variable reporting across studies, the ESP team did not collect specific treatment details for each intervention, which limits the ability to understand how, for instance, different radiation doses may impact AEs.

Future Research

Well-designed studies are needed to better understand the comparative safety and effectiveness of IGTA and SBRT. Future research should prioritize standardized outcome reporting and include patient-centered outcome measures. VHA, as the largest integrated healthcare system in the U.S., might have the data needed to conduct a high-quality non-randomized comparative study of IGTA and SBRT, or meta-analysis of individual patient data from Veterans who underwent either treatment, which may give rise to future randomized controlled trials.

Citation

Epstein-Lubow E, Rieke K, Rudolph J, et al. Percutaneous Ablation for Lung Metastasis-Directed Therapy: A Systematic Review. Washington, DC: Evidence Synthesis Program, Health Systems Research, Office of Research and Development, Department of Veterans Affairs. VA ESP Project 22-116; 2026.

To view the full report, go to https://vaww.hsrd.research.va.gov/publications/esp/lung-metastasis.cfm (This report is available via intranet only.)

How can VA leadership work with the ESP? Nominations for systematic review topics may be submitted to the program at any time. When you submit a topic nomination form, ESP Coordinating Center staff will work with you to determine the appropriate research approach and ESP product to address your questions of interest. Topics are selected and assigned to an ESP Center based on program capacity and alignment with VA national goals.

This Management Brief is provided to inform you about recent HSR findings that may be of interest. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs. If you have any questions or comments about this Brief, please email CIDER. The Center for Information Dissemination and Education Resources (CIDER) is a VA HSR Resource Center charged with disseminating important HSR findings and information to policy makers, managers, clinicians, and researchers working to improve the health and care of Veterans.

This report is a product of VA/HSR's Evidence Synthesis Program (ESP), which was established to provide timely and accurate synthesis of targeted healthcare topics of particular importance to VA managers and policymakers, and to disseminate these reports throughout VA.

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