On freeze-thaw sequence of vital organ of assuming the cryoablation for malignant lung tumors by using cryoprobe as heat source

Large apical lung cancer treated with CT-guided percutaneous cryoablation

Percutaneous lung ablation is increasingly used in the treatment of lung malignancies with good outcomes, but recurrence is commonly reported in ablation of lesions size larger than 3 cm. We report a 50-year-old female with a 9 cm nonsmall cell lung cancer involving the right upper lobe and apical chest wall causing severe neuropathic shoulder pain and significantly disturbing her daily activities. CT-guided percutaneous cryoablation was performed using a 4-phase protocol with complete eradication of the tumor. Follow-up imaging showed no evidence of recurrence 6 months after the procedure. The neuropathic pain was significantly improved after the procedure, and she was pain-free until her death due to metastatic disease elsewhere. To our knowledge, this is the first case of successful cryoablation for an exceptionally large lesion.

Evaluation of a transbronchial cryoprobe for the ablation of pulmonary nodules: an in vitro pilot study

BACKGROUND

Ablation of malignant pulmonary nodules is a novel therapeutic option for patients who cannot undergo surgery. Current transthoracic approaches cause pneumothorax and/or bleeding in a significant number of cases.

OBJECTIVE

Our purpose with this study was to evaluate cryoablation under in vitro conditions with a commercially available cryosurgery system.

METHODS

We used ballistic gelatin to model the thermal conduction of lung tissue. The cryoprobe was inserted in the ballistic gelatin with two thermal sensors, they were placed 0.5 cm and 1.0. cm from the probe, respectively, temperature was measured on both sides. We used single-, double- and triple-freeze protocols to see if we could freeze it to -20 °C.

RESULTS

We achieved - 18.6 ± 3.26 °C on the closer sensor (sensor 1) and - 3.7 ± 4.61 °C on the sensor further away (sensor 2) after 15 min using the single-freeze protocol. Using the dual-freeze protocol, we achieved - 23.2 ± 2,23 °C on sensor 1 and - 16.5 ± 2.82 °C on sensor 2. With the triple-freeze protocol we obtained - 23.5 ± 2.38 °C on sensor 1 and - 19.05 ± 3.22 °C on sensor 2.

CONCLUSION

With dual-freeze, values above - 20 °C were achieved using nearer sensor data, but a plateau phase occurred as with continuous freezing. Using triple freeze, we reached - 20 °C at a distance of 0.5 cm from the probe, but not at 1 cm; therefore, we did not expand the diameter of the predicted necrosis zone.

Experimental Investigation on Thermal Conductivity and Thermal Diffusivity of Ex-Vivo Bovine Liver from Room Temperature down to -60 °C

Ex vivo animal tissues (e.g., bovine liver) as well as water-agar gel are commonly used to simulate both experimentally and numerically the response of human tissues to cryoablation treatments. Data on the low temperature thermal properties of bovine liver are difficult to find in the literature and very often are not provided for the whole temperature range of interest. This article presents the thermal conductivity and thermal diffusivity measurements performed on ex-vivo bovine liver samples using the transient plane source method. Regression coefficients are provided to determine these properties in different temperature ranges except for the phase transition during which no results were obtained, which suggests an ad hoc calorimetric analysis. A quick procedure is also suggested to determine the water mass fraction in the tissue. Moreover, an attempt to estimate the liver density in the frozen state using measurements performed solely at room temperature is also presented. The measured thermal conductivity and thermal diffusivity values are compared with data reported in literature highlighting a spread up to 40%. Moreover, it emerges that water-agar gel usually made with 2% by weight of agar does not show the same thermal properties as the bovine liver.

Evaluation of Temperature Distribution Around the Probe in Cryoablation of Lipiodol-Mixed-Tissue Phantom

PURPOSE

To determine whether lipiodol, which has low thermal conductivity, influences ice ball formation during cryoablation of a lipiodol-mixed-tissue phantom.

MATERIALS AND METHODS

Lipiodol-mixed-tissue phantoms were created by injecting lipiodol (4-6 ml) into the renal arteries of ex vivo porcine kidneys (lipiodol group). A cryoprobe (CryoHit^™ Needle S) with a holder that was set with thermocouples at various positions around the cryoprobe was inserted. After freezing for 300 s, the followings were evaluated: ice ball size on CT, temperature distribution around the cryoprobe, and calculated distances at 0 °C and - 20 °C. Each variable was compared between lipiodol group (n = 6) those obtained in a control group without lipiodol injection (n = 6).

RESULTS

Mean ice ball diameter (width/length) on CT was 22.1 ± 2.3/22.9 ± 2.3 mm in the lipiodol group and 21.6 ± 0.7/22.2 ± 1.3 mm in the control group. Mean cryoprobe temperature was - 118 ± 3.0 °C in the lipiodol group and - 117 ± 2.6 °C in the control group. In both groups, temperature at the 3 mm thermocouple reached approximately - 50 °C and was < 0 °C within ~ 10 mm of the cryoprobe. Temperature of 0/- 20 °C occurred at a mean distance from the cryoprobe of 11.1 ± 0.5/6.9 ± 0.4 mm in the lipiodol group and 11.0 ± 0.2/6.9 ± 0.2 mm in the control group. There was no significant difference in any variable between the groups.

CONCLUSION

The inclusion of lipiodol in a tissue phantom had no negative effects on ice ball formation that were related to thermal conductivity.

Cryoablation for T1N0M0 non-small cell lung cancer using liquid nitrogen

OBJECTIVES

To evaluate local control and complications of cryoablation for T1N0M0 non-small cell lung cancer using liquid nitrogen.

METHODS

This is a retrospective observational study on 101 patients with T1N0M0 NSCLC who underwent cryoablation between 2013 and 2019. Exclusion criteria included tumors without pathological diagnosis. The study population was divided into 4 groups according to the quartile of maximum tumor diameter. The study outcomes included local control, recurrence-free survival (RFS), treatment complications, and change in pulmonary function. Median follow-up period was 35 months.

RESULTS

Tumor diameter was divided into ≤0.9 cm (n = 21), 1.0-1.2 (n = 29), 1.3-1.7 (n = 24), and ≥1.8 (n = 27). Ten patients experienced local recurrences, which were observed none in both the groups of ≤0.9 cm and 1.0-1.2 cm (0%), one in the group of 1.3-1.7 cm (4%), and the other 9 in the group of ≥1.8 cm (33 %), indicating the local control to be better in smaller tumors (p < 0.001). The 3-year RFS was 86 % in ≤0.9 cm, 97 % in 1.0-1.2 cm, 92 % in 1.3-1.7 cm, and 53 % in≥1.8 cm, indicating the survival to be better in smaller tumors (p < 0.001). No patient had treatment-related mortality. The most frequent complication was pneumothorax, with a rate of 24 %. Forced expiratory volume in 1 s at 6 months after cryoablation was 97 ± 10 % of the pretreatment one.

CONCLUSION

The local control and recurrence-free survival of cryoablation for T1N0M0 NSCLC was satisfactory for tumors <1.8 cm. While main complication was pneumothorax, the decrease of pulmonary function was just 3%.

Acute Phase Response and Postprocedural Evaluation of Open and Laparoscopic Cryoablation Procedures in Porcine Pancreases

OBJECTIVES

Cryoablation is a potentially less invasive locoregional ablation modality. Although cryoablation has been used to treat malignancy in various organs, a limited application of this modality in the pancreas has been reported.

METHODS

Acute phase response assessments and postprocedural course evaluations of 2 experimental locoregional ablation methods were conducted. In one method, open and laparoscopic cryoablation of a porcine pancreas using an argon-helium gas-based cryoablation system and monitoring of tissue temperature during the procedure were performed. In the other method, open cryoablation of a porcine pancreas using liquid nitrogen was performed. The animals were evaluated postoperatively.

RESULTS

The size of the cryolesion was larger in the second treatment than in the first. Laparoscopic cryoablation was associated with the formation of an iceball, which possibly affected the surrounding structures. The ablated region was adequately cooled with 10 minutes of freeze/repeat cycles. The area cooled to a temperature of less than -40°C was approximately half the size of the cryolesion in diameter. The swine used for the evaluation of the postprocedural course survived 3 weeks after the procedure with a temporal elevation of the serum lipase level.

CONCLUSIONS

Cryoablation of the pancreas was experimentally practicable without severe complications under direct or laparoscopic vision.

Liquid Nitrogen-Based Cryoablation in In Vivo Porcine Tissue: A Pilot Study

Introduction:

Liquid nitrogen-based cryoablation induces freezing evenly throughout the probe tip surface, resulting in larger ablation volumes and faster treatment times. The purpose of this preliminary investigation is to determine the efficacy of the liquid nitrogen-based Visica2 Cryoablation System (Sanarus Technologies, Pleasanton, CA) in in vivo porcine kidney, liver, and fibro-fatty tissue.

Methods:

Ablations were performed under ultrasound guidance in 4 Yorkshire pigs. The target lesion cross-section width (W) and depth (D) were 1 cm for liver (n=8), kidney (n=4), and head-neck (n=5) and 2 cm for kidney (n=4). Expected axial length (L) of the resulting lesion is approximately 4 cm. After three-day survival, the ablated tissue was harvested and histologically analysed. The mean width and depth were compared with the target diameter using a one-sample t-test.

Results:

All animals survived the procedure. For the 1 cm target, mean dimensions (L x W x D) were 3.8±1.5 x 1.7±0.3 x 1.7±0.7 for liver, 3.0±0.5 x 2.0±0.4 x 1.7±0.6 for kidney, and 3.3±0.8 x 1.8±0.4 x 1.8±0.4 for head-neck. Mean width and depth were significantly greater than desired dimension. For the 2 cm target, mean dimensions were 3.2±0.5 x 3.1±0.8 x 1.9±0.7. Mean width and depth were not significantly different to desired target.

Conclusion:

Our preliminary results show that the Visica2 liquid nitrogen-based cryoablation system can efficiently and reproducibly create ablation volumes in liver, kidney, and fibro-fatty tissue within 4 minutes and 12 minutes for 1cm and 2cm targeted diameters, respectively. Further investigation is necessary to determine the optimal freeze-thaw-freeze protocol for larger ablation volumes.

Lung Ablation: Indications and Techniques

Lung ablation is ever more recognized since its initial report and use almost two decades ago. With technological advancements in thermal modalities, particularly microwave ablation and cryoablation, better identification of the cohort of patients who best benefit from ablation, and understanding the role of imaging after ablation, image-guided thermal ablation for primary and secondary pulmonary malignancies is increasingly recognized and accepted as a cogent form of local therapy.

Initial experience with transbronchial cryoablation as a novel local treatment for malignant peripheral lung lesions

Introduction

Percutaneous cryoablation has been adopted for small, malignant peripheral pulmonary lesions and has yielded favourable results as a less invasive local treatment. A transbronchial approach may reduce the risks of complications, such as pneumothorax and pleural haemorrhage. A fundamental animal experiment on transbronchial cryoablation was performed to examine its immediate safety and effectiveness.

Methods

Experimental cryoablation was performed on swine lungs using a rigid cryoprobe, 2.4 mm in diameter. The probe was introduced from the right main bronchus into the distal bronchus via thoracotomy, perforated the end of the conducting bronchus and reached the lung parenchyma. The temperature of the cryoprobe tip reaches approximately −130°C during freezing and approximately 20°C during thawing. After three freeze-thaw cycles, the cryoprobe was removed.

Results

No significant haemorrhage was bronchoscopically observed in the airways throughout the experiment. The chronological changes and spatial distribution of the temperature of the pulmonary tissue circumferential to the point of the cryoprobe were similar to those seen with transpleural cryoablation and the less than −20°C thermal zone seemed to be established within a radius of at least 12 mm. The central destruction zone of alveolar structures was histologically similar to the thermal zone, while the conducting bronchus structure and the accompanying pulmonary artery were not severely affected.

Conclusion

Experimental transbronchial cryoablation with a rigid cryoprobe could effectively freeze and destroy peripheral lung alveoli without any significant immediate adverse effects. This may suggest the potential clinical application of transbronchial cryoablation for peripheral malignant lung lesions.

Ablation Planning Software for Optimizing Treatment: Challenges, Techniques, and Applications

Percutaneous ablation can deliver effective anticancer therapy with minimal side effects; however, undertreatment can lead to disease recurrence and overtreatment can lead to unnecessary complications. Ablation planning software can support the procedure during the planning, treatment, and follow-up phases. In this review, 2 examples of microwave ablation software are described with attention to how the software can influence procedural choices. In the future, ablation software will entail larger source datasets and more refined algorithms to better model the in vivo ablation zone. Moreover, ablation simulation has the potential to augment clinical care beyond the interventional suite, such as procedural demonstration for patients, clinical consultation with referring providers, documentation for the medical record, and educational simulation for trainees.

The cryoablation of lung tissue using liquid nitrogen in gel and in the ex vivo pig lung

PURPOSES

To examine the efficiency of cryoablation using liquid nitrogen in lung tissue, we measured the size and temperature distribution of the frozen area (iceball) in gel and in the ex vivo pig lungs.

METHODS

Cryoprobes with diameters of 2.4 and 3.4 mm (2.4D and 3.4D, respectively) were used. Three temperature sensors were positioned at the surface of the cryoprobe and at distances of 0.5 and 1.5 cm from the cryoprobe. The ex vivo pig lungs were perfused with 37 °C saline and inflated using ventilator to simulate in vivo lung conditions.

RESULTS

In gel, the 2.4D and 3.4D probes made iceballs of 3.9 ± 0.1 and 4.8 ± 0.3 cm in diameter, respectively, and the temperature at 1.5 cm from those probes reached -32 ± 8 and -53 ± 5 °C, respectively. In the pig lung, the 2.4D and 3.4D probes made iceballs of 5.2 ± 0.1 and 5.5 ± 0.4 cm in diameter, respectively, and the temperature at 1.5 cm from these probes reached -49 ± 5 and -58 ± 3 °C, respectively.

CONCLUSION

Liquid nitrogen cryoablation using both 2.4D and 3.4D probes made iceballs that were of sufficient size, and effective temperatures were reached in both gel and the ex vivo pig lung.

Non-extended cryoablation could be a new strategy in lung cancer management: An experiment on green fluorescent protein-labeled Lewis lung cancer-bearing mice

Modern cryoablation has been performed in solid tumor management for more than two decades. Following the surgical spirits, it seems natural to pursue radical procedures in clinical practice, which results in unnecessary adverse effects. The attempt to use non-extended procedure made some marked achievements in practice but was criticized severely, because it was supposed to induce residual tumors, which would trigger the rapid development of cancer. Oncologists favored this procedure, however, claiming that non-extended cryoablation let lung cancer patients have higher quality of lives and longer survivals, in light of clinical observations. Therefore, this study was conducted trying to solve this controversy. In this study, fifty female C57BL/6J mice were grafted green fluorescent protein (GFP)-labeled Lewis lung cancer and randomized into two groups. The bidirectional diameters and fluorescence intensity of tumors, and the body weight of mice were recorded. Two weeks after the intervention, tumor volumes increased 20.95% in the cryoablation group, significantly different from that in the control group; the fluorescence intensity decreased 49.85% in the cryoablation group but increased 125.07% in the control group. Lung metastases could be observed in only 20% of mice in the cryosurgery group, contrasted to 64% in the control group. The non-extended lung cancer cryoablation does induce marginal tumor residuals, but will not trigger rapid tumor development. Inversely, the residual tumor cells are severely struck and the metastases are suppressed after the intervention. It could be a new strategy in lung cancer management, even for patients not in early stage.

Cryoablation of early-stage primary lung cancer

Worldwide, lung cancer is the most commonly diagnosed cancer, and lobectomy is the gold-standard treatment for early-stage non-small cell lung cancer (NSCLC). However, many patients are poor surgical candidates for various reasons. Recently, image-guided ablation is being used for lung tumors. Cryoablation has been applied for the treatment of cancer in various nonaerated organs; recently it has been adapted to the treatment of lung tumors. Since an ice ball can be detected by computed tomography (CT), cryoablation of lung tumors is performed under CT guidance. Its first clinical application was reported in 2005, and it has been reported to be feasible in a few studies. Minor complications occurred at a high frequency (up to 70.5%), but major complications were rare (up to 1%). The most common complication is pneumothorax, and most cases need no further intervention. Local efficacy depends on tumor size and presence of a thick vessel close to the tumor. Midterm survival after cryoablation is 77%–88% at 3 years in patients with early-stage NSCLC. Although surgery is the gold-standard treatment for such patients, the initial results of cryoablation are promising. In this paper, the current status of cryoablation for primary lung tumors is reviewed.

Prevention of needle-tract seeding by two-step freezing after lung cancer biopsy

Fine-needle aspiration biopsy is a method to detect malignancy for undetermined pulmonary nodules, but has the potential to spread malignant cells from the tumor to the pleural cavity or chest wall. We developed a two-step freezing method to avoid needle-tract seeding, by use of percutaneous cryoablation after biopsy but before the biopsy needle was removed. A man aged 72 years was admitted because of a large mass in right upper lobe. After biopsy, the patient underwent surgery. Pathological assessment of the resected tumor showed that tissue around the biopsy probe and cryoprobe had been killed before needle withdrawal.

Percutaneous cryoablation as a salvage therapy for local recurrence of lung cancer

A 66-year-old male was diagnosed with inoperable non-small cell lung cancer, and underwent chemoradiotherapy, to which he achieved a partial response. During subsequent follow-up, positron emission tomography showed a fluorodeoxyglucose uptake lesion within the primary tumor, without evidence of metastatic foci elsewhere in the body. As local disease progression was most suspected, cryoablation was performed for the lesion with high fluorodeoxyglucose uptake. After treatment, there has been no evidence of recurrence for 12 months. Herein, we present a case of percutaneous cryoablation as a salvage therapy for recurrent lung cancer after chemoradiotherapy.

Comparison of dual- and triple-freeze protocols for pulmonary cryoablation in a Tibet pig model

The purpose of this study was to compare a dual-freeze protocol with a triple-freeze protocol for pulmonary cryoablation in a porcine lung model. Five dual- (10-5-10-5) and five triple-freeze (5-5-5-5-10-5) cryoablations were performed on an exposed operation field in normal porcine lung. Changes in the temperature of the cryoprobes and the diameter of the iceballs were measured during the ablation and pathologic changes in the cryozones (zones of tissue destruction) were reviewed 7 days after the procedure. The diameter of the iceball surface differed between the two protocols. Pathologically, the triple-freeze protocol was associated with a longer complete necrosis zone than the dual-freeze protocol, though the two protocols produced cryolesions and cryozones of similar length, and in both cases there were five areas of tissue destruction. With the same duration of freezing (20 min), the triple-freeze protocol may be better for pulmonary cryoablation than the dual-freeze protocol.

Percutaneous cryoablation of pulmonary metastases from colorectal cancer

OBJECTIVE

To evaluate the safety and efficacy of cryoablation for metastatic lung tumors from colorectal cancer.

METHODS

The procedures were performed on 24 patients (36-82 years of age, with a median age of 62; 17 male patients, 7 female patients) for 55 metastatic tumors in the lung, during 30 sessions. The procedural safety, local progression free interval, and overall survival were assessed by follow-up computed tomographic scanning performed every 3-4 months.

RESULTS

The major complications were pneumothorax, 19 sessions (63%), pleural effusion, 21 sessions (70%), transient and self-limiting hemoptysis, 13 sessions (43%) and tract seeding, 1 session (3%). The 1- and 3-year local progression free intervals were 90.8% and 59%, respectively. The 3-years local progression free intervals of tumors ≤15 mm in diameter was 79.8% and that of tumors >15 mm was 28.6% (p = 0.001; log-rank test). The 1- and 3-year overall survival rates were 91% and 59.6%, respectively.

CONCLUSION

The results indicated that percutaneous cryoablation is a feasible treatment option. The local progression free interval was satisfactory at least for tumors that were ≤15 mm in diameter.