Risk factors associated with complications and local tumour progression in image-guided triple-freezing cryoablation for lung tumour: a longitudinal study

PURPOSE

This study aimed to investigate the efficacy of triple-freezing cryoablation, the temporal changes of ablation zones, and their association with local tumor progression in patients with lung malignancy.

METHODS

This retrospective analysis included patients who underwent triple-freezing cryoablation for lung tumors between 2009 and 2017. The size, shape of the ablation zones, and procedure related complications were evaluated. Fine-Gray regression analysis was utilized to determine the risk factors associated with recurrence while considering mortality as a competing risk.

RESULTS

The study included 41 patients, with 58 ablation sessions for 76 lesions. A tumor size >2 cm was associated with a higher rate of local tumor progression (subdistribution hazard ratio [SHR], 2.623, 95% CI, 1.126-6.107, p = 0.025). An ablation zone-tumor ratio ≥2 emerged as an independent predictor of less local tumor progression (SHR, 0.384, 95% confidence interval [CI]; 0.168-0.877; p = 0.023). There was a 1.7% incidence of adverse events classified as CTCAE (v5.0) grade 3 or higher. Patients without subsequent local tumor progression showed a greater decrease in the ablation zone minor axis at the 6 month-follow up computed tomography (CT) than those with recurrence (25.8% decrease [interquartile range (IQR), 10.3-47.5%] vs 2.4% decrease [IQR, -10.0-7.9%]; p = 0.004).

CONCLUSION

An ablation zone-tumor ratio of ≥2 was associated with less local tumor progression, and a smaller decrease in the ablation zone at the 6-month follow-up CT indicated a higher rate of subsequent local tumor progression.

Lung Cryoablation: Patient Selection, Techniques, and Postablation Imaging

Image-guided percutaneous lung ablation has become increasingly common in the treatment of non-small cell lung cancer (NSCLC) and oligometastatic disease in recent years. Among the available techniques are well-described heat-based techniques, such as lung radiofrequency or microwave ablation, and lung cryoablation (LCA), based on the use of extreme cold to cause tissue necrosis. Although it is the least used of the three ablative techniques available for lung ablation, LCA has inherent characteristics that render it the preferred technique in certain situations. Due to the nature of cryoablation, the collagen extracellular matrix of the tissue adjacent to the ablation site is preserved during the intervention. Additionally, cryoablation may allow more precise imaging monitoring of the ablation zone compared with heat-based techniques. These intrinsic advantages potentially establish LCA as the preferred ablative technique for treating lung tumors located near sensitive vital structures, such as the heart, pulmonary hilum, pulmonary arteries, aorta, main bronchi, and pleura. The authors discuss the basic principles of LCA; the indications and contraindications of the technique; and the technical details of the treatment, including the expected findings and periprocedural complications. A standardized scheme for post-cryoablation imaging follow-up is proposed, detailing the expected findings of complete response and signs of tumor persistence and recurrence and specifying the differences seen with heat-based ablative techniques. ©RSNA, 2025 Supplemental material is available for this article. See the invited commentary by Parvinian and Eiken in this issue.

Image-Guided Transbronchial Pulmonary Cryoablation with a Flexible Cryoprobe in Swine: Performance and Radiology-Pathology Correlation

PURPOSE

To evaluate the performance of a prototype flexible transbronchial cryoprobe compared with that of percutaneous transthoracic cryoablation and to define cone-beam computed tomography (CT) imaging and pathology cryolesion features in an in vivo swine model.

MATERIALS AND METHODS

Transbronchial cryoablation was performed with a prototype flexible cryoprobe (3 central and 3 peripheral lung ablations in 3 swine) and compared with transthoracic cryoablation performed with a commercially available rigid cryoprobe (2 peripheral lung ablations in 1 swine). Procedural time and cryoablation success rates for endobronchial navigation and cryoneedle deployment were measured. Intraoperative cone-beam CT imaging features of cryolesions were characterized and correlated with gross pathology and hematoxylin and eosin-stained sections of the explanted cryolesions.

RESULTS

The flexible cryoprobe was successfully navigated and delivered to each target through a steerable guiding sheath (6/6). At 4 minutes after ablation, 5 of 6 transbronchial and 2 of 2 transthoracic cryolesions were visible on cone-beam CT. The volumes on cone-beam CT images were 55.5 cm3 (SE ± 8.0) for central transbronchial ablations (n = 2), 72.5 cm3 (SE ± 8.1) for peripheral transbronchial ablations (n = 3), and 79.5 cm3 (SE ±11.6) for peripheral transthoracic ablations (n = 2). Pneumothorax developed in 1 animal after transbronchial ablation and during ablation in the transthoracic cryoablation. Images of cryoablation zones on cone-beam CT correlated well with the matched gross pathology and histopathology sections of the cryolesions.

CONCLUSIONS

Transbronchial cryoablation with a flexible cryoprobe, delivered through a steerable guiding sheath, is feasible. Transbronchial cryoablation zones are imageable with cone-beam CT, with gross pathology and histopathology similar to those of transthoracic cryoablation.

Safety and efficacy of percutaneous cryoablation for primary and metastatic pleural based tumors

PURPOSE

Assess safety and local tumor progression-free survival (LTPFS) of percutaneous cryoablation for pleural-based thoracic malignancies.

MATERIALS AND METHODS

Retrospective study of 46 patients (17 treated for palliation; 9 for oligoprogression; 20 for curative intent), with 62 pleural-based thoracic lesions, treated in 59 cryoablation sessions. Patients were treated from 9/2005-11/2021 with CryoCare CS (Varian, Irvine, CA) or IceFORCE (Boston Scientific, Marlborough, MA) systems. For tumors treated with curative intent and/or oligoprogression, LTPFS of the treated tumor(s) and overall survival (OS) were estimated using Kaplan-Meier method. Post-operative complications were reported for all sessions, including those with palliative intent; univariate analyses were used to calculate factors associated with increased complication risk.

RESULTS

Median number of tumors treated in a single treatment session was 1 (range 1-4). Largest dimension of the treated tumor was 2.1 cm [IQR:0.9-5 cm]. Of the 59 treatments, 98.3 % were technically successful. Median LTPFS was 14.4 (95 % CI: 9.4-25.6) months. Tumor size was a significant predictor of LTPFS (HR: 1.21, 95 % CI: 1.03-1.44, p = 0.023). Median OS was 52.4 (28.1-NR) months. Complications occurred in 28/59 sessions (47.5 %); 2/59 (3.4 %) were ≥ grade D by Society of Interventional Radiology adverse event criteria (death; hypoxia requiring supplemental oxygen upon discharge). Pain and pneumothorax were the most common complications. The length of lung parenchyma traversed was a significant predictor of pneumothorax: HR 0.48 (95 %CI: 0.14-0.83), p = 0.0024.

CONCLUSION

Percutaneous cryoablation for pleural lesions is associated with a long duration of local control and most complications were minor and self-limited.

The safety and response of CT guided percutaneous cryoablation for lung nodules by 17-gauge needles

BACKGROUND

The safety and efficacy of 17-gauge needles used in CT-guided percutaneous cryoablation for lung nodules were explored in this study. The purpose of the study was to compare the findings with earlier research and multi-center clinical trials that used various needle sizes.

METHODS

Between 2016 and 2020, a retrospective study was conducted with approval from the institutional review board. A total of 41 patients were enrolled, and 71 lung nodules were treated in 63 cryoablation procedures using local anesthesia. Complication rates were recorded, and overall survival rates as well as tumor progression-free rates were calculated using the Kaplan-Meier method.

RESULTS

Self-limited hemoptysis was caused by 12.9% of the procedures, and drainage was required for pneumothoraces resulting from 11.3% of them. The overall survival rates at one, two, three, and four years were 97%, 94%, 82%, and 67%, respectively. The tumor progression-free rates at one, two, three, and four years were 86.2%, 77%, 74%, and 65%, respectively.

CONCLUSION

Cryoablation for lung nodules using 17-Gauge needles can achieve similar rates of survival and tumor control rates, similar or even lower complication rates as compared with other studies and multi-center trials using mixed sized needles.

Computed Tomography Evaluation of In Vivo Pulmonary Cryoablation Zone Sizes

PURPOSE

To evaluate ablation zone sizes in patients undergoing pulmonary tumor cryoablation with 14-gauge cryoablation probes.

MATERIALS AND METHODS

A single-center retrospective analysis of all consecutive patients who underwent cryoablation of pulmonary tumors with 1 or more 14-gauge probes (August 2017 to June 2020) was performed. Intraprocedural and 1-2-month postprocedural chest computed tomography (CT) scans were evaluated to characterize pulmonary lesions, ice balls, and ablation zones. Single-probe 14-gauge ablation zone volumes were compared with manufacturer reference isotherms and single- and 2-probe ablation zones from a prior investigation of 17-gauge probes. Overall survival and local recurrence-free survival were calculated to 3 years.

RESULTS

Forty-seven pulmonary malignancies in 42 patients (women, 50%; mean age, 75.2 years ± 11.5) underwent cryoablation with 1 (n = 35), 2 (n = 10), or 3 (n = 2) cryoablation probes. One- to 2-month follow-up CT images were available for 30 of the 42 patients. The mean cryoablation zone volumes at 1-2 months when 1 (n = 21), 2 (n = 8), and 3 (n = 1) probes were used were 5.0 cm³ ± 2.3, 37.5 cm³ ± 20.5, and 28.4 cm³, respectively. The mean single-probe follow-up ablation zone volume was larger than that previously reported for 17-gauge probes (3.0 cm³ ± 0.3) (P < .001) but smaller than manufacturer-reported isotherms (11.6 cm³ for -40 °C isotherm) and the 2-probe ablation zone volume with 17-gauge devices (12.9 cm³ ± 2.4) (for all, P < 001). The 3-year overall survival and local recurrence-free survival were 69% (95% confidence interval [CI], 53%-89%) and 87% (95% CI, 74%-100%), respectively.

CONCLUSIONS

Fourteen-gauge probes generate larger ablation volumes than those generated by 17-gauge probes. Manufacturer-reported isotherms are significantly larger than actual cryoablation zones. Cryoablation can attain low rates of local recurrence.

Cryoablation and immune synergistic effect for lung cancer: A review

The preferred treatment for lung cancer is surgical resection, but a large number of patients are not suitable for surgical resection in clinic. CT-guided cryoablation and immunotherapy can play an important role in patients with advanced lung cancer who are ineligible for surgery. CT-guided cryoablation has been widely used in the clinical treatment of lung tumors due to its advantages of less trauma, fewer complications, significant efficacy and rapid recovery. Cryoablation can not only cause tumor necrosis and apoptosis, but also promote the release of tumor-derived autoantigens into the blood circulation, and stimulate the host immune system to produce a good anti-tumor immune effect against primary and metastatic tumors. Since the study of immune checkpoint inhibitors has proved that lung cancer can be an immunotherapeutic response disease, the relationship between cryoablation and immunotherapy of lung cancer has been paid more attention. Therefore, we reviewed the literature on cryoablation for lung cancer, as well as the research progress of cryoablation combined with immunotherapy.

Current trends in image-guided chest interventions

Interventional radiology (IR) is a rapidly expanding medical subspecialty and refers to a range of image‐guided procedural techniques. The image guidance allows real‐time visualization and precision placement of a needle, catheter, wire and device to deep body structures through small incisions. Advantages include reduced risks, faster recovery and shorter hospital stays, lower costs and less patient discomfort. The range of chest interventional procedures keeps on expanding due to improved imaging facilities, better percutaneous assess devices and advancing ablation and embolization techniques. These advances permit procedures to be undertaken safely, simultaneously and effectively, hence escalating the role of IR in the treatment of chest disorders. This review article aims to cover the latest developments in some image‐guided techniques of the chest, including thermal ablation therapy of lung malignancy, targeted therapy of pulmonary embolism, angioplasty and stenting of mediastinal venous/superior vena cava occlusion, pulmonary arteriovenous malformation treatment and bronchial artery embolization for haemoptysis.

Imaging following thermal ablation of early lung cancers: expected post-treatment findings and tumour recurrence

Thermal ablation is a minimally invasive technique that is growing in acceptance and popularity in the management of early lung cancers. Although curative resection remains the optimal treatment strategy for stage I pulmonary malignancies, percutaneous ablative treatments may also be considered for selected patients. These techniques can additionally be used in the treatment of oligometastatic disease. Thermal ablation of early lung tumours can be achieved using several different techniques. For example, microwave ablation (MWA) and radiofrequency ablation (RFA) utilise extreme heat, whereas cryoablation uses extremely cold temperatures to cause necrosis and ultimately cell death. Typically, post-ablation imaging studies are performed within the first 1-3 months with subsequent imaging performed at regular intervals to ensure treatment response and to evaluate for signs of recurrent disease. Surveillance imaging is usually undertaken with computed tomography (CT) and integrated positron-emission tomography (PET)/CT. Typical imaging findings are usually seen on CT and PET/CT following thermal ablation of lung tumours, and it is vital that radiologists are familiar with these appearances. In addition, radiologists should be aware of the imaging findings that indicate local recurrence following ablation. The objective of this review is to provide an overview of the expected post-treatment findings on CT and PET/CT following thermal ablation of early primary lung malignancies, as well as describing the imaging appearances of local recurrence.

Active Versus Passive Thaw Following Percutaneous Cryoablation of Pulmonary Tumors: Effect on Incidence, Grade, and Onset of Hemoptysis

Background: Hemoptysis is common following percutaneous image-guided cryoablation of pulmonary tumors. Objective: To evaluate the effect of a final active thaw on the incidence, grade, and onset of hemoptysis following percutaneous cryoablation of pulmonary tumors. Methods: This retrospective cohort study included 60 consecutive CT-guided cryoablation sessions targeting 95 pulmonary tumors in 47 patients from 2017 to 2020. The final thaw of a triple-freeze protocol was active (electrical, helium-free) in 27/60 sessions (45%, active group) and passive in 33/60 sessions (55%, passive group). Incidence, onset, and management of hemoptysis were recorded using prospectively collected data. Hemoptysis, pneumothorax, and hemothorax within 30 days post ablation were graded per Common Terminology Criteria for Adverse Events version 5.0 (CTCAE). Volume of immediate post-treatment changes on CT was quantified using semi-automated segmentation. Outcomes were compared between groups using generalized estimating equation models. A parsimonious multivariable model for hemoptysis incidence was developed using purposeful selection of predefined covariates followed by bootstrap resampling. Local tumor control was compared between groups using the Kaplan-Meier method and logrank testing. Results: Hemoptysis occurred following 26/60 (43%) sessions and was self-limited (Grade 1) in 22/26 (85%). The incidence of hemoptysis was lower in the active than passive group (64% vs 19%, respectively; p=.002). The odds of hemoptysis adjusted for immediate post-treatment changes were 92% lower in the active group (OR, 0.08 [95% CI, 0.02-0.37], p=.004). The odds of hemoptysis greater than Grade 1 were 79% lower in the active group (OR, 0.21 [95% CI, 0.07-0.64], p=.006). In the active group, the onset of hemoptysis was significantly delayed (OR, 0.75 [95% CI, 0.61-0.91], p=.005). Pneumothorax (p=.60), hemothorax (p=.84), and local tumor control (p=.77) did not differ between groups. Conclusion: Active thaw following the final freeze reduces the incidence and grade of hemoptysis and delays the onset of hemoptysis following percutaneous cryoablation of pulmonary tumors without adversely affecting other procedural complications and local tumor control. Clinical Impact: Active thaw following the final freeze improves the safety profile of triple-freeze cryoablation of pulmonary tumors by reducing the incidence and grade of hemoptysis and by delaying the onset of hemoptysis beyond the immediate recovery period.

Cryoablation of Lung Metastases: Review of Recent Literature and Ablation Technique

This article reviews the current indications for image-guided thermal ablation of pulmonary metastatic disease. It also summarizes data regarding the efficacy and complications of lung cryoablation and present techniques for performing lung cryoablation as informed by the recent literature.