Thermal ablation in the treatment of lung cancer: present and future

The combined application of electromagnetic navigation and porcine fibrin sealant in microwave ablation of lung tumors

Purpose

This retrospective study aims to assess the efficacy of the combined application of electromagnetic navigation (EMN) and porcine fibrin sealant (PFS) in the microwave ablation (MWA) treatment of lung tumors.

Material and methods

In our department from January 2022 to August 2023, 73 patients underwent MWA under standard computed tomography (CT) guidance (CT group) or CT guidance with additional application of EMN and PFS (CT-EMN-PFS group), respectively. The basic data of patients were recorded and analyzed using the Student's t-test and Chi-square test between the two groups, and single factor and multi-factors binary logistic regression analyses were conducted to determine the risk factors of pneumothorax; meanwhile the incidence of complications, the number of CT scans and dose length product (DLP) were calculated and compared between the two guidance modes.

Results

Forty-seven patients underwent standard CT-guided MWA, meanwhile the remaining 26 patients underwent CT-guided MWA with combined application of EMN and PFS. The patients with lesions close to the bronchi or interlobar fissures, and underlying emphysema had a higher risk of pneumothorax, the corresponding odds ratio (OR) was 23.290 (p = 0.004), 33.300 (p = 0.019), and 8.007 (p = 0.012), respectively; the combined use of EMN and PFS could reduce the incidence of pneumothorax, with an OR of 0.094 (95 % confidence interval [CI]: 0.015-0.602, p = 0.013). The incidence rates of pneumothorax, pneumorrhagia and pleural effusion were 59.57 %, 61.70 %, and 19.15 % respectively in the CT group, and 30.77 %, 50.00 % and 7.69 % respectively in the CT-EMN-PFS group. The incidence rate of pneumothorax in the CT-EMN-PFS group was significantly lower than that in the CT group (p = 0.017). The median number of CT scans was 9 in the CT group and 5 in the CT-EMN-PFS group, respectively, meanwhile the median DLP was 1060.69 mGy*cm in the CT group and 600.04 mGy*cm in the CT-EMN-PFS group, respectively, which indicated there was a statistical difference in the amount of radiation exposure between the two groups (p < 0.001).

Conclusion

The combined application of EMN and PFS demonstrates for the first time that there is a lower incidence rate of pneumothorax and significantly less radiation exposure during the MWA of the lung tumors.

Safety and efficacy of CT-guided percutaneous radiofrequency ablation for non-small cell lung cancer: a single-center, single-arm analysis

Non-small cell lung cancer (NSCLC) is a prevalent malignant tumor, and the commonly treatment modalities include surgery, radiotherapy, chemotherapy, etc. Currently, CT-guided percutaneous radiofrequency ablation (RFA) for the treatment of cancers has been widely performed. This study aimed to evaluate the safety and efficacy of this therapy in NSCLC patients. Thirty-five NSCLC patients were enrolled in this study and all received CT-guided percutaneous RFA therapy. The outcome measures included the changes in forced respiratory volume in the first second (FEV1), total lung volume (TLC), lesion size and computed tomography (CT) values of the region of interest (ROI) before and after treatment. The main efficacy measures comprised complete tumor ablation and local recurrence after initial treatment, as well as the objective response rate (ORR) and disease control rate (DCR) after 6 months of treatment. After receiving CT-guided percutaneous RFA therapy, the target lesion was effectively controlled and CT values gradually decreased. Besides, no significant changes were observed in the patient's lung function, postoperative complications were experienced by a total of 10 patients, primarily including pneumothorax, infection, lung hollowing. Fortunately, all these complications were successfully managed with appropriate treatment. Following the initial RFA treatment, 31 patients (88.57%) achieved complete ablation, while 6 patients experienced local recurrence. After 6 months of treatment, the ORR and DCR were found to be 68.57% and 82.86% respectively. CT-guided percutaneous RFA has demonstrated favorable safety and efficacy in the treatment of patients with NSCLC at different stages, which represented a promising therapeutic modality.

Clinical efficacy of thermal ablation for the treatment of pulmonary carcinoid tumor: a propensity-matched analysis

OBJECTIVE

To investigate the clinical efficacy of thermal ablation in the treatment of pulmonary carcinoid (PC) tumor.

METHODS

Data of patients with inoperable PC diagnosed from 2000 to 2019 were obtained from the SEER database and analyzed according to different therapeutic modality: thermal ablation vs non-ablation. Propensity score matching (PSM) was used to reduce intergroup differences. Kaplan-Meier curves and the log-rank test were used to compare intergroup differences of overall survival (OS) and lung cancer-specific survival (LCSS). Cox proportional risk models were used to reveal prognostic factors.

RESULTS

After PSM, the thermal ablation group had better OS (p < .001) and LCSS (p < .001) than the non-ablation group. Subgroup analysis stratified by age, sex, histologic type and lymph node status subgroups showed similar survival profile. In the subgroup analysis stratified by tumor size, the thermal ablation group showed better OS and LCSS than those of the non-ablation group for tumors ≤3.0 cm, not statistically significant for tumors >3.0 cm. Subgroup analysis by M stage showed that thermal ablation was superior to non-ablation in OS and LCSS for patients with M0 stage, but no significant difference was found in subgroups with distant metastatic disease. Multivariate analysis showed that thermal ablation was an independent prognostic factor for OS (HR: 0.34, 95% CI: 0.25-0.46, p < .001) and LCSS (HR: 0.23, 95%CI: 0.12-0.43, p < .001).

CONCLUSION

For patients with inoperable PC, thermal ablation might be a potential treatment option, especially in M0-stage with tumor size ≤3 cm.

Advances in lung cancer screening and early detection

Lung cancer is associated with a heavy cancer-related burden in terms of patients' physical and mental health worldwide. Two randomized controlled trials, the US-National Lung Screening Trial (NLST) and Nederlands-Leuvens Longkanker Screenings Onderzoek (NELSON), indicated that low-dose CT (LDCT) screening results in a statistically significant decrease in mortality in patients with lung cancer, LDCT has become the standard approach for lung cancer screening. However, many issues in lung cancer screening remain unresolved, such as the screening criteria, high false-positive rate, and radiation exposure. This review first summarizes recent studies on lung cancer screening from the US, Europe, and Asia, and discusses risk-based selection for screening and the related issues. Second, an overview of novel techniques for the differential diagnosis of pulmonary nodules, including artificial intelligence and molecular biomarker-based screening, is presented. Third, current explorations of strategies for suspected malignancy are summarized. Overall, this review aims to help clinicians understand recent progress in lung cancer screening and alleviate the burden of lung cancer.

Transbronchial lung parenchyma cryoablation with a novel flexible cryoprobe in an in vivo porcine model

PURPOSE

The purpose of this study was to evaluate the feasibility and safety of transbronchial cryoablation with a novel flexible cryoprobe using nitrogen as the refrigerant in an in vivo porcine model of lung parenchyma.

MATERIALS AND METHODS

A novel flexible cryoprobe using nitrogen as the refrigerant was used for transbronchial cryoablation of lung parenchyma in six normal female pigs. The cryoprobe was delivered to the distal bronchus in the bilateral porcine lungs via the bronchoscopic working channel under virtual bronchoscopy guidance. The position was confirmed with real-time computed tomography (CT). The whole procedure included two freeze-thaw cycles (15 min and 2 min, respectively). CT images were obtained during cryoablation and at 24 h, one week, two weeks and four weeks after the treatment to assess the effectiveness and safety of the procedure. Ablation zone tissue samples were obtained at 24 h and four weeks after the cryoablation for further histopathological analysis.

RESULTS

All ablation procedures (12/12; 100%) were performed successfully. No major complications occurred during the procedure or the observation period. The ablation zones were clearly depicted on CT with a maximal ablation zone volume at 24 h (21.88 ± 12.61 [SD] cm³) compared to 3.64 ± 2.06 (SD) cm³ and 10.73 ± 3.84 (SD) cm³ at the end of the 1st and 2nd freeze-thaw cycles, respectively (P < 0.001). Histopathological analysis revealed that a coagulative necrotic zone was formed along the target bronchus, with obvious vascular occlusion and hemorrhage 24 h after treatment. The lesions gradually formed fibrosis after four weeks.

CONCLUSION

The novel flexible bronchoscopy-guided cryoablation is a feasible, safe and effective modality in an in vivo porcine model of peripheral normal lung parenchyma, suggesting potential capabilities for the treatment of peripheral lung cancer in humans.

Computed tomography guided interstitial percutaneous high-dose-rate brachytherapy in the management of lung malignancies. A review of the literature

A growing number of patients with lung cancer are not amenable to surgery due to their age or comorbidities. For this reason, local ablative techniques have gained increasing interest recently in the management of inoperable lung tumors. High-dose-rate percutaneous interstitial brachytherapy, performed under CT-guidance, is a newer form of brachytherapy and is a highly conformal radiotherapy technique. The aim of this study was to describe this method and review the existing literature. Eight articles comprising 234 patients reported toxicity and clinical outcome. The follow-up ranged from 6 to 28 months. Diverse fractionation schemes were reported, with 20 Gy in a single fraction being the most frequently utilized. Toxicity was limited; major pneumothoraces occurred after only 8% of the interventions. Local control rates at one year ranged between 37% and 91%. In conclusion, high-dose-rate percutaneous interstitial brachytherapy is a safe, fast, and efficient treatment option for inoperable lung tumors.

Standardizing percutaneous Microwave Ablation in the treatment of Lung Tumors: a prospective multicenter trial (MALT study)

OBJECTIVES

To prospectively assess reproducibility, safety, and efficacy of microwave ablation (MWA) in the treatment of unresectable primary and secondary pulmonary tumors.

METHODS

Patients with unresectable primary and metastatic lung tumors up to 4 cm were enrolled in a multicenter prospective clinical trial and underwent CT-guided MWA. Treatments were delivered using pre-defined MW power and duration settings, based on target tumor size and histology classifications. Patients were followed for up to 24 months. Treatment safety, efficacy, and reproducibility were assessed. Ablation volumes were measured at CT scan and compared with ablation volumes obtained on ex vivo bovine liver using equal treatment settings.

RESULTS

From September 2015 to September 2017, 69 MWAs were performed in 54 patients, achieving technical success in all cases and treatment completion without deviations from the standardized protocol in 61 procedures (88.4%). Immediate post-MWA CT scans showed ablation dimensions smaller by about 25% than in the ex vivo model; however, a remarkable volumetric increase (40%) of the treated area was observed at 1 month post-ablation. No treatment-related deaths nor complications were recorded. Treatments of equal power and duration yielded fairly reproducible ablation dimensions at 48-h post-MWA scans. In comparison with the ex vivo liver model, in vivo ablation sizes were systematically smaller, by about 25%. Overall LPR was 24.7%, with an average TLP of 8.1 months. OS rates at 12 and 24 months were 98.0% and 71.3%, respectively.

CONCLUSIONS

Percutaneous CT-guided MWA is a reproducible, safe, and effective treatment for malignant lung tumors up to 4 cm in size.

KEY POINTS

• Percutaneous MWA treatment of primary and secondary lung tumors is a repeatable, safe, and effective therapeutic option. • It provides a fairly reproducible performance on both the long and short axis of the ablation zone. • When using pre-defined treatment duration and power settings according to tumor histology and size, LPR does not increase with increasing tumor size (up to 4 cm) for both primary and metastatic tumors.

A new radiofrequency balloon angioplasty device for atherosclerosis treatment

Background

Restenosis remains a challenge in the treatment of atherosclerosis due to damage to the endothelial layer and induced proliferation of smooth muscle cells. A novel radiofrequency (RF) heating strategy was proposed to selectively ablate atherosclerosis plaque and to thermally inhibit the proliferation of smooth muscle cells while keeping the endothelial cells intact.

Methods

To realize the proposed strategy, a new radiofrequency balloon catheter, consisting of three ports, a three-channel tube, a balloon and an electrode patch, was designed. To evaluate the feasibility of this new design, a phantom experiment with thermocouples measuring temperatures with different voltages applied to the electrodes was conducted. A numerical model was established to obtain the 3D temperature distribution. The heating ability was also evaluated in ex vivo diseased artery samples.

Results

The experimental results showed that the highest temperature could be achieved in a distance from the surface of the balloon as designed. The temperature differences between the highest temperature at 0.78 mm and those of the surface reached 9.87 °C, 12.55 °C and 16.00 °C under applied 15 V, 17.5 V and 20 V heating, respectively. In the circumferential direction, the heating region (above 50 °C) spread from the middle of the two electrodes. The numerical results showed that the cooling effect counteracted the electrical energy deposition in the region close to the electrodes. The thermal lesion could be directed to cover the diseased media away from the catheter surface. The ex vivo heating experiment also confirmed the selective heating ability of the device. The temperature at the targeted site quickly reached the set value. The temperature of the external surface was higher than the inner wall surface temperature of the diseased artery lumen.

Conclusion

Both the experimental and numerical results demonstrated the feasibility of the newly designed RF balloon catheter. The proposed RF microelectrodes heating together with the cooling water convection can realize the desired heating in the deeper site of the blood vessel wall while sparing the thin layer of the endothelium.

RFA of primary and metastatic lung tumors: long-term results

The aim of our study is a retrospective evaluation of effectiveness and safety of Computed Tomography (CT)-guided radiofrequency ablation (RFA) therapy of primary and metastatic lung lesions in patients that cannot be considered surgical candidates. From February 2007 to September 2017, we performed 264 CT-guided ablation sessions on 264 lesions in 174 patients (112 M and 62 F; mean age, 68 years; range 36-83 years) affected by primary and metastatic lung lesions. The 45% of patients was affected by primary lung cancer, with size range lesion of 10-50 mm, and the 55% by metastatic lung lesions with size range of 5-49 mm. All patients had no more than three metastases in the lung and pulmonary relapses were treated up to three times. Overall Survival (OS), Progression-Free Survival (PFS), Local Progression-Free Survival (LPFS) and Cancer-specific survival (CSS) at 1, 3 and 5 years were calculated both in primary lung tumors and in metastatic patients. Immediate and late RFA-related complications were reported. Pulmonary function tests were evaluated after the procedures. The effectiveness of RFA treatment was evaluated by contrast-enhanced CT. In patients affected by primary lung lesions, the OS rates were 66.73% at 1 year, 23.13% at 3 years and 16.19% at 5 years. In patients affected by metastatic lung lesions, the OS rates were 85.11%, 48.86% and 43.33%, respectively, at 1, 3 and 5 years. PFS at 1, 3 and 5 years were 79.8%, 60.42%, 15.4% in primary lung tumors and 78.59%, 51.8% and 6.07% in metastatic patients. LPFS at 1, 3 and 5 years were 79.8%, 64.69%, 18.87% in primary lung tumors and 86.29%, 69.15% and 44.45% in metastatic patients. CSS at 1, 3 and 5 years was 95.56%, 71.84%, 56.72% in primary lung tumors and 94.07%, 71% and 71% in metastatic patients. Immediate RFA-related complications (pneumothorax, pleural effusion and subcutaneous emphysema) were observed, respectively, in 42, 53 and 13 of 264 procedures (15.9%, 20% and 5%). There also occurred one major complication (lung abscess, 0.36%). No significant worsening of pulmonary function was noted. Our retrospective evaluation showed long-term effectiveness, safety and imaging features of CT-guided RFA in patients affected by primary and metastatic lung cancer as an alternative therapy in non-surgical candidates.

Comparing cryoablation and microwave ablation for the treatment of patients with stage IIIB/IV non-small cell lung cancer

The aim of the present study was to compare the safety and efficacy of cryoablation (CA) and microwave ablation (MWA) as treatments for non-small cell lung cancer (NSCLC). Patients with stage IIIB or IV NSCLC treated with CA (n=45) or MWA (n=56) were enrolled in the present study. The primary endpoint was progression-free survival (PFS); the secondary endpoints included overall survival (OS) time and adverse events (AEs). The median PFS times between the two groups were not significantly different (P=0.36): CA, 10 months [95% confidence interval (CI), 7.5-12.4] vs. MWA, 11 months (95% CI, 9.5-12.4). The OS times between the two groups were also not significantly different (P=0.07): CA, 27.5 months (95% CI, 22.8-31.2 months) vs. MWA, 18 months (95% CI, 12.5-23.5). For larger tumors (>3 cm), patients treated with MWA had significantly longer median PFS (P=0.04; MWA, 10.5 months vs. CA, 7.0 months) and OS times (P=0.04; MWA, 24.5 months vs. CA, 14.5 months) compared patients treated with CA. However, for smaller tumors (≤3 cm), median PFS (P=0.79; MWA, 11.0 months vs. CA, 13.0 months) and OS times (P=0.39; MWA, 30.0 months vs. CA, 26.5 months) between the two groups did not differ significantly. The incidence rates of AEs were similar in the two groups (P>0.05). The number of applicators, tumor size and length of the lung traversed by applicators were associated with a higher risk of pneumothorax and intra-pulmonary hemorrhage in the two groups. Treatment with CA resulted in significantly less intraprocedural pain compared with treatment with MWA (P=0.001). Overall, the present study demonstrated that CA and MWA were comparably safe and effective procedures for the treatment of small tumors. However, treatment with MWA was superior compared with CA for the treatment of large tumors.

A New RF Heating Strategy for Thermal Treatment of Atherosclerosis

OBJECTIVES

Restenosis remains a challenge for the treatment of atherosclerosis due to the damage of the endothelial layer and induced proliferation of the smooth muscle cell.

METHODS

A new RF heating strategy was proposed to selectively ablate the atherosclerosis plaque, and to thermally inhibit the proliferation of smooth muscle cells, while keeping the endothelial cells intact. To achieve the goal, an internal cooling agent and distributed electrodes have been integrated in the new designed balloon catheter to focus the shape conformal energy onto the plaque shape. A three-dimensional (3-D) model with experimentally fitted parameters has been established to demonstrate the heating ability of the design and evaluate the microelectrodes configurations for different plaque geometries.

RESULTS

The 3-D shape of the lesions resulting from different electrodes settings is obtained. It is found that by individual control of the micro-electrodes, special shapes of the lesions can be formed, which can match the eccentric crescent plaques. Besides, through changing of the polarity of the electrodes, separate lesions can be reached. This suggests the possibility for treatment of disconnected plaques in situ.

CONCLUSION

By the control of RF heating and convection coefficient of the internal cooling agent, a targeted heating region away from the inner surface of the blood vessel can be realized.

SIGNIFICANCE

This study has illustrated the possibility of achieving a precision thermal treatment of atherosclerosis in favor of inhibiting further restenosis.

Is segmentectomy the future?

The role of anatomic segmentectomy as an acceptable, lung parenchymal sparing alternative to pulmonary lobectomy for the small peripheral stage I lung cancer is under great scrutiny today. This is not a new consideration, particularly for the patient with impaired cardiopulmonary reserve where preservation of lung function may be a critical issue in deciding on surgical resection for local/regional control of their cancer. In this review, we discuss the oncologic issues along with past and present evidence supporting "anatomic" lung preservational surgery in the management of lung cancer.

Ablation therapy of non-colorectal cancer lung metastases: retrospective analysis of tumour response post-laser-induced interstitial thermotherapy (LITT), radiofrequency ablation (RFA) and microwave ablation (MWA)

PURPOSE

To retrospectively compare the local tumour response and survival rates in patients with non-colorectal cancer lung metastases post-ablation therapy using laser-induced thermotherapy (LITT), radiofrequency ablation (RFA) and microwave ablation (MWA).

MATERIAL AND METHODS

Retrospective analysis of 175 computed tomography (CT)-guided ablation sessions performed on 109 patients (43 males and 66 females, mean age: 56.6 years). Seventeen patients with 22 lesions underwent LITT treatment (tumour size: 1.2-4.8 cm), 29 patients with 49 lesions underwent RFA (tumour size: 0.8-4.5 cm) and 63 patients with 104 lesions underwent MWA treatment (tumour size: 0.6-5 cm). CT scans were performed 24-h post-therapy and on follow-up at 3, 6, 12, 18 and 24 months.

RESULTS

The overall-survival rates at 1-, 2-, 3- and 4-year were 93.8, 56.3, 50.0 and 31.3% for patients treated with LITT; 81.5, 50.0, 45.5 and 24.2% for patients treated with RFA and 97.6, 79.9, 62.3 and 45.4% for patients treated with MWA, respectively. The mean survival time was 34.14 months for MWA, 34.79 months for RFA and 35.32 months for LITT. In paired comparison, a significant difference could be detected between MWA versus RFA (p = 0.032). The progression-free survival showed a median of 23.49 ± 0.62 months for MWA,19.88 ± 2.17 months for LITT and 16.66 ± 0.66 months for RFA (p = 0.048). The lowest recurrence rate was detected in lesions ablated with MWA (7.7%; 8 of 104 lesions) followed by RFA (20.4%; 10 of 49 lesions) and LITT (27.3%; 6 of 22 lesions) p value of 0.012. Pneumothorax was detected in 22.16% of MWA ablations, 22.73% of LITT ablations and 14.23% of RFA ablations.

CONCLUSION

LITT, RFA and MWA may provide an effective therapeutic option for non-colorectal cancer lung metastases with an advantage for MWA regarding local tumour control and progression-free survival rate.

Apoptosis of Lewis Lung Carcinoma Cells Induced by Microwave via p53 and Proapoptotic Proteins In vivo

Background:

Microwave therapy is a minimal invasive procedure and has been employed in clinical practice for the treatment of various types of cancers. However, its therapeutic application in non-small-cell lung cancer and the underlying mechanism remains to be investigated. This study aimed to investigate its effect on Lewis lung carcinoma (LLC) tumor in vivo.

Methods:

Fifty LLC tumor-bearing C57BL/6 mice were adopted to assess the effect of microwave radiation on the growth and apoptosis of LLC tumor in vivo. These mice were randomly assigned to 10 groups with 5 mice in each group. Five groups were treated by single pulse microwave at different doses for different time, and the other five groups were radiated by multiple-pulse treatment of a single dose. Apoptosis of cancer cells was determined by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. Western blotting was applied to detect the expression of proteins.

Results:

Single pulse of microwave radiation for 5 min had little effect on the mice. Only 15-min microwave radiation at 30 mW/cm² significantly increased the mice body temperature (2.20 ± 0.82)°C as compared with the other groups (0.78 ± 0.29 °C, 1.24 ± 0.52 °C, 0.78 ± 0.42 °C, respectively), but it did not affect the apoptosis of LLC tumor cells significantly. Continous microwave radiation exposure, single dose microwave radiation once per day for up to seven days, inhibited cell division and induced apoptosis of LLC tumor cells in a dose- and duration-dependent manner. It upregulated the protein levels of p53, Caspase 3, Bax and downregulated Bcl-2 protein.

Conclusions:

Multiple exposures of LLC-bearing mice to microwave radiation effectively induced tumor cell apoptosis at least partly by upregulating proapoptotic proteins and downregulating antiapoptotic proteins. Continuous radiation at low microwave intensity for a short time per day is promising in treating non-small-cell lung cancer.

Clinical analysis on 113 patients with lung cancer treated by percutaneous CT-guided microwave ablation

BACKGROUND

Lung Cancer is a primary tumor with poor prognosis. For early stage lung cancer, treatment options include surgical resection and microwave techniques. Percutaneous ablative techniques emerged as best therapeutic options for nonsurgical patients.

METHODS

The aim of this study was to retrospectively analyze the clinical effect of CT-guided microwave ablation (MWA) treatment for patients with lung cancer who were not eligible for surgical resection. MWA was used to treat the tumor lesion of 113 patients with lung cancer who were in our hospital from Jan, 2013 to Jun, 2015. The median diameter of tumors was 3.1 cm (0.7-6 cm). Follow-up were paid to all the patients who received MWA therapy. The average follow-up was 22.1±8.6 months, and the median follow-up was 18 (7-40) months.

RESULTS

All of 113 cases of patients with lung cancer experienced MWA therapy, and their tumors were found to have vacuolization, lower density and much smaller distinct shrinkage of tumor size with varying degrees. The local progression rate or relapse rate of the whole group was 15.9%. The counterpart of patients in the early-stage group was 5.7% (2/35), and the diameter of tumors in the two patients was more than 3 cm. The local progression rate or relapse rate of patients in advanced-stage group was 20.5%, wherein, 81.3% of local progression or relapse occurred to the patients with a tumorous diameter of more than 3 cm. The results indicated that the patients in advanced-stage group were vulnerable to local progression or relapse, the tumorous with greater diameter had higher incidence of local relapse. No mortality occurred within 30 days after surgery, the survival rate of patients in early-stage group at first, second, third year was respectively 97.1%, 94.1% and 84.7%. The counterpart of patients in advanced-stage group was respectively 93.6%, 87.7% and 71.7%. The difference of survival rate between both groups was not statistically significant (P=0.576). No perioperative deaths occurred, and the main complications i.e., fever, pneumothorax, pleural effusion, hemoptysis, pneumonia, and pain were slight and tolerable.

CONCLUSIONS

MWA is an effective, safe and minimally invasive treatment for the patients with lung cancer who cannot be tolerated by surgical resection.

Incomplete radiofrequency ablation accelerates proliferation and angiogenesis of residual lung carcinomas via HSP70/HIF-1α

Radiofrequency ablation (RFA) therapy has been proved effective and feasible for lung cancer. However, the molecular mechanisms of local lung cancer recurrence following RFA are poorly understood. The present study aimed to evaluate the ability of HSP70/HIF-1α to affect the proliferation and angiogenesis of non-small cell lung cancers (NSCLCs) following insufficient RFA to uncover the molecular mechanisms of local recurrence. In vitro heat treatment was used to establish sublines of NCI-H1650 cells. The NCI-H1650 subline that was established by heat treatment at 54°C had a relatively higher viability and significantly elevated heat tolerance (compared to the parental strain). After treatment with the HSP70 inhibitor VER-155008, the HIF-1α inhibitor YC-1 and PI3K/Akt inhibitor wortmannin, the viability and proliferation rate of the cells was measured. At the same time, HSP70, HIF-1α and Akt were detected by real-time PCR and western blotting. In vivo xenograft tumors were created by subcutaneously inoculating nude mice with NCI-H1650 cells. HSP70, HIF-1α and Akt were detected by western blotting, and CD34 expression was detected by immunohistochemistry before and after RFA or treatment with the VER-155008, YC-1 or wortmannin inhibitors. The heat-adapted NCI-H1650 subline established in vitro had a higher viability and proliferative activity compared to parental cells. Inhibiting HSP70/HIF-1α abolished this difference. Blocking the PI3K/Akt signaling pathway decreased HSP70/HIF-1α expression levels. In vivo, we found that incomplete RFA treatment promoted HSP70/HIF-1α and CD34 expression. Additionally, the combination of RFA and treatment targeting HSP70/HIF-1α resulted in a synergistic reduction in tumor growth compared to incomplete RFA alone. The PI3K/Akt signaling pathway is also involved in regulating HSP70/HIF-1α expression during this process. We conclude that the accelerated proliferation and angiogenesis potential of residual lung carcinomas following RFA treatment was induced by HSP70/HIF-1α, expression of which is regulated by the PI3K/Akt signaling pathway.

THE USE OF RADIO-FREQUENCY ABLATION IN THE TREATMENT OF MALIGNANT TUMORS OF LUNGS AND PLEURA

Aim of the work. Analysis of the possibilities of the different methods of RFA of lung and pleura tumors. Material and methods. There were considered the different methods of radio-frequency ablations using FOTEK-150 apparatus in 186 patients with the malignant tumors of lungs and pleura. Results. In the result of use of the different methods of radio-frequency ablation the direct positive effect was attained in 91 % of observations. The complications were observed in 9 % of patients. This method must be used for patients with the malignant tumors of lungs and pleura when the radical surgical treatment is impossible. Conclusions. The radio-frequency ablation can be used as a palliative method of treatment of the malignant tumors of lungs and pleura.

Pulmonary radiofrequency ablation (Part 1): current state

The risks involved in surgical treatment and conventional radiotherapy in patients with early lung cancer or lung metastases often make these treatments difficult to justify. However, on the other hand, it is also unacceptable to allow these lesions to evolve freely because, left untreated, these neoplasms will usually lead to the death of the patient. In recent years, alternative local therapies have been developed, such as pulmonary radiofrequency ablation, which has proven to increase survival with a minimal risk of complications. There are common recommendations for these treatments, and although the specific indications for using one technique or another have yet to be established, there are clearly defined situations that will determine the outcome of the treatment. It is important to know these situations, because appropriate patient selection is essential for therapeutic success. This article aims to describe the characteristics and constraints of pulmonary radiofrequency ablation and to outline its role in thoracic oncology in light of the current evidence.

High temperature hyperthermia treatment for canines exhibiting superficial tumors: A report of three cases

High temperature hyperthermia (HTH) treatment has previously been demonstrated to suppress tumor growth in a tumor-bearing rat model. In the present study, the effects of HTH therapy for the treatment of spontaneous tumors in canines was evaluated. In case 1, an 18-year-old female Papillon presented with a right forelimb rhabdomyosarcoma. Case 2 was a 13-year-old male English Cocker Spaniel with a right external auditory canal ceruminous adenocarcinoma and case 3 was a 14-year-old male Golden Retriever that exhibited a perianal gland adenocarcinoma, which surrounded the anus. HTH treatment was performed in all three cases for 10 min at 45–65°C with or without the inhalation of isoflurane. In case 1, the tumor disappeared four weeks following HTH treatment. In case 2, the tumor volume had decreased by day 21, and in case 3, HTH was performed three times and the tumor disappeared following the third procedure. HTH is considered to be a simple procedure with no severe side effects. Consequently, this treatment modality is hypothesized to become a useful alternative therapy for superficial tumors in companion animals.

Radiofrequency ablation for pulmonary metastases from gastrointestinal cancers

The lung is one of the most common targets of metastases from gastrointestinal (GI) cancers. Surgical treatment (i.e., metastasectomy) is an accepted therapeutic option for pulmonary metastases from GI cancers. However, surgery may be contraindicated in advanced stages of cancer, compromised lung function, and/or comorbidities. This issue has prompted the search for innovative and less invasive ways of treating pulmonary metastases. Image-guided radiofrequency ablation (RFA) has attracted great interest as a minimally invasive approach against intrathoracic malignancies. In this technique, radiofrequency energy is applied via a needle electrode inserted into the target tissue. As the cells are agitated by the applied energy, they release heat, causing denaturation and cell death. Recently, this technique has been used on patients with pulmonary metastatic disease arising from GI cancers such as colorectal cancer, esophageal cancer, and hepatocellular carcinoma, as well as on patients with primary lung cancer. The present review updates the clinical outcomes and advances in RFA therapy of lung metastases from GI cancers.

Radiofrequency ablation for stage I non-small-cell lung cancer in the functionally inoperable patient

SUMMARY Aim: Surgical resection represents the gold standard for the treatment of early-stage non-small-cell lung cancer (NSCLC). However, approximately a fifth of the patients cannot afford a major lung resection because of functional limits related to one or more comorbidities. Radiofrequency ablation (RFA) has been described since 2004 for the palliative treatment of lung neoplasms as an alternative to external beam radiotherapy. We report the results of a retrospective analysis on a series of patients who underwent RFA for stage I NSCLC in a single referral center. Materials & methods: All patients referred for a suspected lung cancer underwent computed tomography (CT) scan of the thorax, PET–CT scanning and complete functional evaluation. Patients with a clinical stage I lung cancer and considered not eligible for surgery due to one or more of the following conditions were included: advanced-stage chronic obstructive pulmonary disease (forced respiratory volume in 1 s <40% of predicted value, carbon monoxide diffusion <40% and a need for continuous [24 h] oxygen administration) and heart failure (New York Heart Association class III and IV). Tumor dimension should be <3.5 cm in its major diameter. All lung RFA were performed under CT guidance using a 15 G trocar containing extendible electrodes that deploy from the tip of the trocar (Le Veen Needle Electrode; Radio Therapeutics Corporation, CA, USA). Results: From January 2009 to June 2013, 22 patients (17 males) underwent 24 procedures of RFA for stage Ia NSCLC. The mean diameter of the lesions was 2.48 ± 0.7 cm (range: 1.1–3.2 cm). The patient was considered not suitable for surgery for advanced stage heart disease (New York Heart Association class >3) in nine cases, and for advanced chronic obstructive pulmonary disease in the remaining 13 cases (forced respiratory volume in 1 s <40% of predicted value, carbon monoxide diffusion <40% and a need for continuous [24 h] oxygen administration). Treatment was successfully performed in all cases. The whole procedure was completed with a mean time of 25 min (range: 18–32 min). No mortality was observed. We registered a complication in five out of 24 procedures (20.8%). We observed six cases of local tumor progression out of 24 lesions treated (25%) according to the modified Response Evaluation Criteria In Solid Tumors criteria and PET–CT assessment. No difference in local tumor progression was related to dimension of the lesion; in particular, we did not observe any difference between Ia and Ib tumors. In two cases, systemic relapse was observed and at present, 12 patients were alive. Four patients died of cancer relapse, three patients died for complications related to chronic obstructive pulmonary disease and three for heart failure. Median overall survival time was 36.5 months, with an overall proportion survival of 83% at 1 year, 64% at 2 years and 48% at 3 years. Disease-free interval was 23 months with a disease-free proportion survival of 78% at 1 year, 51% at 2 years and 39% at 3 years. Conclusion: RFA for treatment of lung cancer in functionally inoperable patients proved to be feasible, reproducible, with low morbidity. The limit of the procedure, in our opinion, is its strictly local effect and reported limited efficacy in treating greater lesions.

[Change of ERCC1 expression of residual VX2 squamous carcinoma cells in rabbit lung after radiofrequency ablation]

背景与目的

残存肿瘤是影响射频消融（radiofrequency ablation, RFA）治疗肺恶性肿瘤效果的重要因素，联合铂类药物化疗是减少残存肿瘤的重要手段之一。核苷酸切除修复交叉互补基因1（excision repair cross-complementation group 1, ERCC1）的表达水平是影响铂类药物化疗效果的重要因素之一。RFA治疗后残存肿瘤会发生一些生物学特性变化，但有关ERCC1表达变化的研究尚无报道。本研究旨在探讨RFA治疗后兔肺内残存VX2鳞癌细胞ERCC1表达水平的变化。

方法

应用组织块悬液注射法建立兔VX2鳞癌肺内移植瘤模型。58只荷瘤新西兰白兔随机分为对照组（n=10）和RFA组（n=48）。在RFA治疗时，通过控制电极展开范围、输出功率、治疗时间的方法，造成肿瘤残存。应用免疫组织化学方法检测残存肿瘤细胞在不同时间点ERCC1表达的阳性率。

结果

RFA组残存肿瘤组织ERCC1表达阳性率在1 d-5 d呈一过性升高（53.7%±1.6% & 32.9%±2.5%），5 d后恢复至对照组水平。

结论

因在RFA治疗后1 d-5 d内残存肿瘤细胞ERCC1表达增高，在此期间给予铂类药物化疗可能效果不佳。