Intraoperative Radiofrequency Ablation of Lung Metastases and Histologic Evaluation

Bronchoscopically delivered microwave ablation in an in vivo porcine lung model

Background

Percutaneous microwave ablation is clinically used for inoperable lung tumour treatment. Delivery of microwave ablation applicators to tumour sites within lung parenchyma under virtual bronchoscopy guidance may enable ablation with reduced risk of pneumothorax, providing a minimally invasive treatment of early-stage tumours, which are increasingly detected with computed tomography (CT) screening. The objective of this study was to integrate a custom microwave ablation platform, incorporating a flexible applicator, with a clinically established virtual bronchoscopy guidance system, and to assess technical feasibility for safely creating localised thermal ablations in porcine lungs in vivo.

Methods

Pre-ablation CTs of normal pigs were acquired to create a virtual model of the lungs, including airways and significant blood vessels. Virtual bronchoscopy-guided microwave ablation procedures were performed with 24–32 W power (at the applicator distal tip) delivered for 5–10 mins. A total of eight ablations were performed in three pigs. Post-treatment CT images were acquired to assess the extent of damage and ablation zones were further evaluated with viability stains and histopathologic analysis.

Results

The flexible microwave applicators were delivered to ablation sites within lung parenchyma 5–24 mm from the airway wall via a tunnel created under virtual bronchoscopy guidance. No pneumothorax or significant airway bleeding was observed. The ablation short axis observed on gross pathology ranged 16.5–23.5 mm and 14–26 mm on CT imaging.

Conclusion

We have demonstrated the technical feasibility for safely delivering microwave ablation in the lung parenchyma under virtual bronchoscopic guidance in an in vivo porcine lung model.

This paper demonstrates the technical feasibility of safely delivering microwave ablation in the lung parenchyma under virtual bronchoscopic guidance in an in vivo porcine lung modelhttps://bit.ly/32aruLf

Chinese expert consensus workshop report: Guidelines for thermal ablation of primary and metastatic lung tumors

Although surgical resection is the primary means of curing both primary and metastatic lung cancers, about 80% of lung cancers cannot be removed by surgery. As most patients with unresectable lung cancer receive only limited benefits from traditional radiotherapy and chemotherapy, many new local treatment methods have emerged, including local ablation therapy. The Minimally Invasive and Comprehensive Treatment of Lung Cancer Branch, Professional Committee of Minimally Invasive Treatment of Cancer of the Chinese Anti-Cancer Association has organized multidisciplinary experts to develop guidelines for this treatment modality. These guidelines aim at standardizing thermal ablation procedures and criteria for selecting treatment candidates and assessing outcomes; and for preventing and managing post-ablation complications.

Ultrasound-guided percutaneous laser ablation of papillary thyroid microcarcinoma: a feasibility study on three cases with pathological and immunohistochemical evaluation

BACKGROUND

Ultrasound-guided thermal laser ablation (LA) is a nonsurgical technique that has been proposed, but not fully assessed, for papillary thyroid microcarcinoma (PTMC) treatment. The objectives of this study were to evaluate the clinical feasibility of LA on PTMC as a primary treatment and to prove histologically the absence of residual viable tumor after LA procedure.

METHODS

Three patients with a Thy 6 diagnosis at fine-needle aspiration cytology with a single PTMC smaller than 10 mm volunteered after full explanation of the protocol. At ultrasound examination, patients had no extrathyroid extension and no evidence of lymph node metastasis. Patients underwent percutaneous ultrasound-assisted LA of the PTMC in the operating room under general anesthesia. One 300 μm plane-cut optic fiber was inserted through the sheath of 21G Chiba needle, exposing 5 mm of the nude fiber in direct contact with tumor tissue, and connected with a laser source operating at 1.064 μm with 3 W output power. Total energy delivery was 1800 J. The surgeon directly started a standard total thyroidectomy. During surgical inspection, no remarkable laser sign was observed in the muscles, the perithyroidal tissues, or the recurrent laryngeal nerves.

RESULTS

Conventional histology showed destructured and carbonized tissue. Lack of vitality was demonstrated by complete loss of TTF1 and antimitochondria antibody expression in the whole ablated area and in the rim of normal tissue surrounding the tumor. BRAF V600E mutation was detected in cases 1 and 2. Furthermore, in cases 2 and 3, incidental papillary microfoci were found. A lymph node micrometastasis (200 μm) was observed in case 2.

CONCLUSIONS

This study demonstrates that percutaneous LA is technically feasible for complete PTMC destruction. Now, LA may be useful in selected patients with PTMC, either when the surgeon or a patient refuses surgery, or when the patient is at high risk for an operation. LA may become a primary choice of treatment for PTMC only if future new knowledge would permit preoperative recognition of multifocality and lymph node metastasis.

[Radiofrequency of lung metastases: should initial pneumothorax predict treatment failure?]

In the management of lung metastases originating from colorectal cancer, RFA is particularly indicated in case of major comorbidities contraindicating thoracic surgery or recurrent disease after previous ipsilateral resection. The most frequent complication of RFA is pneumothorax, requiring chest tube insertion in 5% of cases. Interestingly, this proportion is very close to the rate of local recurrence, suggesting a possible association. We report a case of RFA followed by intractable pneumothorax requiring surgical management, and leading to the diagnosis of residual tumour. This case report illustrates this association and questions its relevance.

Thoracoscopic lobectomy has increasing benefit in patients with poor pulmonary function: a Society of Thoracic Surgeons Database analysis

OBJECTIVE

Using a national database, we asked whether video-assisted thoracoscopic surgery (VATS) lobectomy is beneficial in high-risk pulmonary patients.

BACKGROUND

Single-institution series demonstrated benefit of VATS lobectomy over lobectomy via thoracotomy in poor pulmonary function patients [FEV1 (forced expiratory volume in 1 second) or DLCO (diffusion capacity of the lung to carbon monoxide) <60% predicted].

METHODS

The STS General Thoracic Database was queried for patients having undergone lobectomy by either thoracotomy or VATS between 2000 and 2010. Postoperative pulmonary complications included those defined by the STS database.

RESULTS

In the STS database, 12,970 patients underwent lobectomy (thoracotomy, n = 8439; VATS, n = 4531) and met inclusion criteria. The overall rate of pulmonary complications was 21.7% (1832/8439) and 17.8% (806/4531) in patients undergoing lobectomy with thoracotomy and VATS, respectively (P < 0.0001). In a multivariable model of pulmonary complications, thoracotomy approach (OR = 1.25, P < 0.001), decreasing FEV1% predicted (OR = 1.01 per unit, P < 0.001) and DLCO% predicted (OR = 1.01 per unit, P < 0.001), and increasing age (1.02 per year, P < 0.001) independently predicted pulmonary complications. When examining pulmonary complications in patients with FEV1 less than 60% predicted, thoracotomy patients have markedly increased pulmonary complications when compared with VATS patients (P = 0.023). No significant difference is noted with FEV1 more than 60% predicted.

CONCLUSIONS

Poor pulmonary function predicts respiratory complications regardless of approach. Respiratory complications increase at a significantly greater rate in lobectomy patients with poor pulmonary function after thoracotomy compared with VATS. Planned surgical approach should be considered while determining whether a high-risk patient is an appropriate resection candidate.

Effects of radiofrequency ablation on normal lung tissue in a swine model

RATIONALE AND OBJECTIVES

To determine the effect of radiofrequency (RF) ablation on normal lung tissue in an animal model.

MATERIALS AND METHODS

RF ablation of lung tissue was performed on eight swine under computed tomographic control. Group A (n = 4) received peripheral ablation (subpleural needle placement) and group B (n = 4) received central ablation (hilar needle placement). RF ablation was applied via a single 4.5-gauge internally cooled electrode with a 2-cm tip for 12 minutes. The ablation was monitored with computed tomography at 3, 7, and 12 minutes, and 10 minutes after ablation. After 3, 7, 40, and 60 days, computed tomography was performed, and the animals were sacrificed to examine the lung tissue both macroscopically and histopathologically.

RESULTS

There were no deaths from RF ablation. In group A, coagulative necrosis was resorbed almost completely and transformed into a fibrotic scar after 60 days. No pneumothorax, pleural effusion, or lung abscess was observed. In group B, there was also a transformation of the necrosis into connective tissue. Neither the pulmonary vessels nor the bronchi of the hilum abutting the coagulative necrosis were damaged. After 60 days, no vascular thrombosis, bleeding, aneurysm, bronchial stenosis, or bronchopulmonary fistula was observed.

CONCLUSION

RF ablation of lung tissue affects coagulation necrosis, causing scar transformation. There was no damage to either great vessels or bronchi. The application of RF ablation for tumors located in or near functional structures appears feasible without severe complications.

The efficacy of bipolar and multipolar radiofrequency ablation of lung neoplasms - results of an ablate and resect study

OBJECTIVE

Radiofrequency ablation (RFA) has obtained increasing attention as an interventional approach for the local treatment of primary and secondary lung neoplasms. The local effect of the procedure is usually controlled by radiologic means. The objectives of this 'ablate and resect' study were to investigate the efficacy of bipolar and multipolar RFA by histologic evaluation and to compare the two techniques.

METHODS

In a total of 32 subjects with histologically proven non-small-cell lung cancer or pulmonary metastases from an extrathoracic primary tumor, bipolar, or multipolar RFA was performed during open thoracotomy. Curative resection (lobectomy or wedge resection including mediastinal lymph node dissection) was performed subsequently. The extent of cell death and early histologic findings following RFA were determined by histology and immunohistochemistry (nicotinamide adenine dinucleotide (NADH) and monoclonal anti-mitochondrial antibodies MAB 1273).

RESULTS

Intra-operative bipolar and multipolar RFA is a safe procedure, and there was no bleeding or thermal damage of the lung tissue. Routine histologic staining could not identify tumor cell death. However, immunohistochemistry was able to verify cell death in the ablated tumor tissue. Complete tumor cell necrosis was determined in 12 tumors (37.5%); and scattered vital tumor tissue was detected in 16 tumors (50%). Incomplete ablation with a ratio of >20% vital tumor tissue was found in four tumors (12.5%), particularly surrounding vascular structures within the tumor tissue or in marginal zones of the tumor tissue. The local efficacy of bipolar and multipolar RFA was comparable, and incomplete ablations were found only in adenocarcinoma.

CONCLUSIONS

Bipolar and multipolar RFA in an open thoracotomy setting is a technically feasible and safe procedure. Early immunohistochemical findings after RFA showed complete tumor cell necrosis in 38% of cases. The high rate of viable tumor cells remaining after ablation casts doubt on RFA as a curative concept. This approach should be reserved for palliative indications. Patients fulfilling the criteria for curative resection should not be denied surgery.

Long-term survival and prognostic factors after pulmonary metastasectomy in hepatocellular carcinoma

BACKGROUND

The lung is the most common site of extrahepatic recurrence from hepatocellular carcinoma (HCC), but the standard treatment for pulmonary metastasis (PM) from HCC has not been established. We analyzed patients who underwent pulmonary resection for HCC metastases to evaluate long-term survival and prognostic factors.

METHODS

We retrospectively reviewed patients who underwent pulmonary metastasectomy due to HCC at Samsung Medical Center between 1998 and 2008. Clinical/pathological features and prognoses were investigated.

RESULTS

Fifty-two pulmonary metastasectomies were performed in 45 patients (38 men) with PM. Average patient age was 50.9 ± 11.0 years. Video-assisted thoracic surgery was used in 24 patients. Lobectomy was performed in eight patients and wedge resection in the others. Median survival after pulmonary metastasectomies was 40.7 months, and the 5-year overall survival rate was 37%. First recurrence in lung (P = 0.03), a long disease-free interval (P = 0.02), and solitary PM (P = 0.03) were found to be favorably associated with overall survival by univariate analysis. However, multivariate analysis failed to identify any independent prognostic factor associated with survival. Nevertheless, first recurrence in lung was found to be a favorable factor of PM-free survival by univariate (P = 0.01) and multivariate analyses (P = 0.022, hazard ratio = 0.382).

CONCLUSIONS

Pulmonary metastasectomies in selected patients with HCC was found to have a relatively good survival rate. Although no independent prognostic factor was found to be associated with overall survival, pulmonary metastasectomy may be effective in patients with a single PM and a long disease-free interval.

[Development of thoracic surgery over the next 20 years]

Thoracic surgery is one of the self-contained surgical disciplines with an above average large potential over the next 20 years. An increase in mortality due to pulmonary diseases is to be expected worldwide. Bronchial carcinoma is the most common diagnosis in thoracic surgery patients and will remain a relevant topic for health politics for many years. However, the adequate treatment of these patients demands a high degree of interdisciplinary cooperation. In the future thoracic surgery will therefore be carried out in centres with an organ-dependent and interdisciplinary structure. From a surgical technical perspective minimally invasive operation strategies will become established for standard interventions, which are indispensible components of the repertoire for thoracic surgery. Thoracic surgery is traditionally a clinically oriented discipline with low academic superstructure and a high backlog demand in nearly all areas of research. It offers a large field of activity for the next scientifically interested generation with excellent chances to become established and succeed in this discipline with a very promising future.

Surgical resection of lung metastases: results from 529 patients

OBJECTIVE

The aim of this study is to determine clinical, pathological, and treatment-relevant variables associated with long-term (90-month) overall survival in patients with lung metastases undergoing pulmonary metastasectomy.

METHODS

A retrospective review was performed of patients who were admitted with lung metastases, and who underwent thoracotomy for resection, after treatment of a primary tumor. Data were collected regarding demographics, tumor features, treatment, and outcome.

RESULTS

Patients (n = 529) were submitted to a total of 776 thoracotomies. Median follow-up time across all patients was 21.6 months (range: 0-192 months). The postoperative complication rate was 9.3%, and the 30-day mortality rate was 0.2%. The ninety-month overall survival rate for all patients was 30.4%. Multivariate analysis identified the number of pulmonary nodules detected on preoperative CT-scan, the number of malignant nodules resected, and complete resection as the independent prognostic factors for overall survival.

CONCLUSION

These results confirm that lung metastasectomy is a safe and potentially curative procedure for patients with treated primary tumors. A select group of patients can achieve long-term survival after resection.