Risk assessment of pneumothorax in colorectal lung metastases treated by percutaneous thermal ablation: a multicenter retrospective cohort study

PURPOSE

To evaluate the risk of pneumothorax in the percutaneous image-guided thermal ablation (IGTA) treatment of colorectal lung metastases (CRLM).

METHODS

Data regarding patients with CRLM treated with IGTA from five medical institutions in China from 2016 to 2023 were reviewed retrospectively. Pneumothorax and non-pneumothorax were compared using the Student's t -test, χ 2 test and Fisher's exact test. Univariate logistic regression analysis was conducted to identify potential risk factors, followed by multivariate logistic regression analysis to evaluate the predictors of pneumothorax. Interactions between variables were examined and used for model construction. Receiver operating characteristic curves and nomograms were generated to assess the performance of the model.

RESULTS

A total of 254 patients with 376 CRLM underwent 299 ablation sessions. The incidence of pneumothorax was 45.5%. The adjusted multivariate logistic regression model, incorporating interaction terms, revealed that tumour number [odds ratio (OR)=8.34 (95% CI: 1.37-50.64)], puncture depth [OR=0.53 (95% CI: 0.31-0.91)], pre-procedure radiotherapy [OR=3.66 (95% CI: 1.17-11.40)], peribronchial tumour [OR=2.32 (95% CI: 1.04-5.15)], and emphysema [OR=56.83 (95% CI: 8.42-383.57)] were significant predictive factors of pneumothorax (all P <0.05). The generated nomogram model demonstrated a significant prediction performance, with an area under the receiver operating characteristic curve of 0.800 (95% CI: 0.751-0.850).

CONCLUSIONS

Pre-procedure radiotherapy, tumour number, peribronchial tumour, and emphysema were identified as risk factors for pneumothorax in the treatment of CRLM using percutaneous IGTA. Puncture depth was found to be a protective factor against pneumothorax.

Radiofrequency ablation for stage <IIB non-small cell lung cancer: Opportunities, challenges, and the road ahead

Pulmonary carcinoma represents the second common cancer for human race while its mortality rate ranked the first all over the world. Surgery remains the primary option for early-stage non-small cell lung cancer (NSCLC) in some surgical traditions. Nevertheless, only less than half of patients are operable subjected to the limited lung function and multiple primary/metastatic lesions. Recent improvements in minimally invasive surgical techniques have made the procedure accessible to more patients, but this percentage still does not exceed half. In recent years, radiofrequency ablation (RFA), one of the thermal ablation procedures, has gradually advanced in the treatment of lung cancer in addition to being utilized to treat breast and liver cancer. Several guidelines, including the American College of Chest Physicians (ACCP), include RFA as an option for some patients with NSCLC although the level of evidence is mostly limited to retrospective studies. In this review, we emphasize the use of the RFA technique in patients with early-stage NSCLC and provide an overview of the RFA indication population, prognosis status, and complications. Meanwhile, the advantages and disadvantages of RFA proposed in existing studies are compared with surgical treatment and radiotherapy. Due to the high rate of gene mutation and immunocompetence in NSCLC, there are considerable challenges to clinical translation of combining targeted drugs or immunotherapy with RFA that the field has only recently begun to fully appreciate.

Robotic versus freehand CT-guided radiofrequency ablation of pulmonary metastases: a comparative cohort study

PURPOSE

Radiofrequency ablation (RFA) is a curative treatment option for small lung metastases, which conventionally involves multiple freehand manipulations until the treating electrode is satisfactorily positioned. Stereotactic and robotic guidance has been gaining popularity for liver ablation, although has not been established in lung ablation. The purpose of this study is to determine the feasibility, safety, and accuracy of robotic RFA for pulmonary metastases, and compare procedures with a conventional freehand cohort.

METHODS

A single center study with prospective robotic cohort, and retrospective freehand cohort. RFA was performed under general anesthesia using high frequency jet ventilation and CT guidance. Main outcomes were (i) feasibility/technical success (ii) safety using Common Terminology Criteria for Adverse Events (iii) targeting accuracy (iv) number of needle manipulations for satisfactory ablation. Robotic and freehand cohorts were compared using Mann-Whitney U tests for continuous variables, and Fisher's exact for categorical variables.

RESULTS

Thirty-nine patients (mean age 65 ± 13 years, 20 men) underwent ablation of 44 pulmonary metastases at single specialist cancer center between July 2019 and August 2022. 20 consecutive participants underwent robotic ablation, and 20 consecutive patients underwent freehand ablation. All 20/20 (100%) robotic procedures were technically successful, and none were converted to freehand procedures. There were 6/20 (30%) adverse events in the robotic cohort, and 15/20 (75%) in the freehand cohort (P = 0.01). Robotic placement was highly accurate with 6 mm tip-to-target distance (range 0-14 mm) despite out-of-plane approaches, with fewer manipulations than freehand placement (median 0 vs. 4.5 manipulations, P < 0.001 and 7/22, 32% vs. 22/22, 100%, P < 0.001).

CONCLUSIONS

Robotic radiofrequency ablation of pulmonary metastases with general anesthesia and high frequency jet ventilation is feasible and safe. Targeting accuracy is high, and fewer needle/electrode manipulations are required to achieve a satisfactory position for ablation than freehand placement, with early indications of reduced complications.

Percutaneous ablation treatment in metastatic lung tumors: a single-center experience

BACKGROUND

In recent years, many studies have proven that percutaneous thermal ablation is an effective second-line treatment method with low complication rates in early-stage non-small cell lung carcinoma and lung metastases. Radiofrequency ablation and microwave ablation are commonly used for this purpose.

PURPOSE

To evaluate the factors affecting the success of the percutaneous thermal ablation treatment with technical success, complication rates, and long-term follow-up results in metastatic lung lesions.

MATERIAL AND METHODS

Computed tomography (CT)-guided percutaneous ablation was performed for 70 metastatic lung lesions in 35 patients (22 men, 13 women; mean age = 61.34 years; age range = 41-75 years). Radiofrequency ablation was performed in 53/70 (75.7%) lesions and microwave ablation in 17/70 (24.3%) lesions.

RESULTS

The technical success rate was 98.6%. Median overall survival, progression-free survival, and local recurrence-free survival of the patients were 33.9 months (range=25.6-42.1 months), 12 months (range=4.9-19.2 months), and 24.2 months (range=8.2-40.1 months), respectively. One- and two-year overall survival rates were 84% and 74%, respectively. Median progression-free survival times were 20.3 months and 11.4 months, respectively, according to the number of metastatic lung lesions being single and multiple, and the difference was statistically significant (P = 0.046). According to the number of lesions ≤3 and >3, the difference was also found statistically significant (P = 0.024) (14.3 months and 5.7 months, respectively).

CONCLUSION

In conclusion, CT-guided percutaneous thermal ablation is a safe and effective treatment method in metastatic lung lesions. The number of lesions is the most important factor in predicting treatment success.

Risk Factors for Operation Complications of High Dose Rate 3-Dimensional Interstitial Brachytherapy for Lung Cancer

BACKGROUND

The risk factors for operation complications of high-dose-rate dimensional (3D) interstitial brachytherapy for lung malignant tumors are still unclear. We aimed to provide a reliable reference for the preoperative safety assessment of interstitial brachytherapy.

PATIENTS AND METHODS

We analyzed the degree and incidence of operational complications in 120 eligible patients with lung carcinoma who underwent computed tomography (CT)-guided HDR interstitial brachytherapy. Univariate and multivariate analyses were used to study the relationships between patient-related factors, tumor-related factors, operation-related factors, and operational complications.

RESULTS

The most frequent complications of CT-guided HDR interstitial brachytherapy were pneumothorax and hemorrhage. In univariate analysis, smoking, emphysema, distance of implanted needles through the normal lung tissue, number of implanted needle adjustments, and distance of the lesion from the pleura were the risk factors for pneumothorax; the tumor size, distance of the tumor from the pleura, number of implanted needle adjustments, and distance of the implanted needle through the normal lung tissue were risk factors for hemorrhage. In multivariate analysis, the depth of the implanted needle through the normal lung tissue and distance of the lesion from the pleura were independent risk factors for pneumothorax. Tumor size, number of implanted needle adjustments, and distance through normal lung tissue were independent risk factors for hemorrhage.

CONCLUSION

This study provides a reference for the clinical treatment of lung cancer by analyzing the risk factors for complications of interstitial brachytherapy.

A study of microwave ablation for small cell lung cancer

PURPOSE

To reveal the survival and safety of percutaneous microwave ablation (MWA) combined with chemoradiotherapy (CRT) in treating small cell lung cancer (SCLC).

MATERIALS AND METHODS

Clinical data of 48 SCLC patients who underwent MWA were retrospectively collected; survival and incidence of major complications were analyzed.

RESULTS

Totally, 48 SCLC patients underwent 51 MWA procedures. The median overall survival (OS) for all SCLC was 27.0 months (95% confidence interval 22.4-31.6 months). The OS of limited-stage (LS-SCLC) was longer than the extensive-stage (ES-SCLC) (median 48.0 months vs. 25.0 months, P = 0.022). The OS of SCLC with tumor diameter ≤3.0 cm was longer than that of tumor diameter >3.0 cm (median 48.0 months vs. 27.0 months, P = 0.041). For LS-SCLC, the 1-, 2-, 3-, and 5-year survival rate was 91.67%, 72.22%, 66.67%, and 61.11%, respectively. For ES-SCLC, the 1-, 2-, and 3-year survival rates were 83.33%, 50.0%, and 8.33%. Major complications included pneumothorax needing tube placement (29.4%), rarely arrhythmia (2.0%), empyema (2.0%), pulmonary fungal infection (2.0%), and shingles (2.0%).

CONCLUSION

For SCLC patients, who received MWA combined with CRT, OS of LS-SCLC and tumor diameter ≤3.0 cm was better than that of the ES-SCLC and tumor diameter >3.0 cm. For inoperable SCLC, MWA was safe.

Computed tomography-guided microwave ablation for the treatment of non-small cell lung cancer patients with and without adjacent lobe invasion: A comparative study

BACKGROUND

The aim of the study was to explore the outcomes of computed tomography-guided microwave ablation (MWA) in non-small cell lung cancer (NSCLC) patients with adjacent lobe invasion (ALI), and to compare the outcomes of ALI-NSCLC and non-ALI NSCLC patients after MWA.

METHODS

A total of 319 NSCLC patients and 366 tumors treated with MWA were included in the study, comprising 34 ALI-NSCLC patients and 285 non-ALI NSCLC patients. Complications, local recurrence rates, progression-free survival (PFS), and overall survival (OS) were compared. Logistic regression analyses were used to investigate the correlation between ALI and the occurrence of pneumothorax after MWA.

RESULTS

The mean tumor diameter of ablated tumors was 3.6 ± 2.2 cm. There were 95 (29.8%) NSCLC patients in which pneumothorax occurred after MWA, and all patients recovered. Of these, the ALI group had a significantly higher incidence rate of pneumothorax than the non-ALI group (52.9% vs. 27.0%, p = 0.002). The median PFS and OS for the ALI group were 12.0 ± 10.2 and 15.5 ± 9.5 months, respectively, and that of the non-ALI group were 13.0 ± 10.6 and 17.0 ± 11.1 months, respectively, and no significant difference was found in PFS (p = 0.329) nor OS (p = 0.394) between the two groups. Local recurrence rates for ALI and non-ALI groups were 29.4% and 20.7%, respectively, and no significant difference was found (p = 0.244). Logistic regression analyses revealed that ALI can increase the risk of pneumothorax (hazard ratio [HR], 2.867; p = 0.012).

CONCLUSIONS

MWA is an effective and safe approach for ALI-NSCLC treatment. Although ALI can increase the risk of pneumothorax, ALI-NSCLC patients reveal a comparable outcome to non-ALI NSCLC patients after MWA.

Risk prediction of pneumothorax in lung malignancy patients treated with percutaneous microwave ablation: development of nomogram model

OBJECTIVES

To develop effective nomograms for predicting pneumothorax and delayed pneumothorax after microwave ablation (MWA) in lung malignancy (LM) patients.

METHODS

LM patients treated with MWA were randomly allocated to a training or validation cohort at a ratio of 7:3. The predictors of pneumothorax identified by univariate and multivariate analyses in the training cohort were used to develop a predictive nomogram. The C-statistic was used to evaluate predictive accuracy in both cohorts. A second nomogram for predicting delayed pneumothorax was developed and validated using identical methods.

RESULTS

A total of 552 patients (training cohort: n = 402; validation cohort: n = 150) were included; of these patients, 27.9% (154/552) developed pneumothorax, with immediate and delayed pneumothorax occurring in 18.8% (104/552) and 9.1% (50/552), respectively. The predictors selected for the nomogram of pneumothorax were emphysema (hazard ratio [HR], 6.543; p < .001), history of lung ablation (HR, 7.841; p= .025), number of pleural punctures (HR, 1.416; p < .050), ablation zone encompassing pleura (HR, 10.225; p < .001) and pulmonary fissure traversed by needle (HR, 10.776; p < .001). The C-statistics showed good predictive performance in the training and validation cohorts (0.792 and 0.832, respectively). Another nomogram for delayed pneumothorax was developed based on emphysema (HR, 2.952; p= .005), ablation zone encompassing pleura (HR, 4.915; p < .001) and pulmonary fissure traversed by needle (HR, 4.348; p = .015). The C-statistics showed good predictive performance in the training cohort, and it had efficacy for prediction in the validation cohort (0.719 and 0.689, respectively).

CONCLUSIONS

The nomograms could effectively predict the risk of pneumothorax and delayed pneumothorax after MWA.

Three-year Survival Rate after Radiofrequency Ablation for Surgically Resectable Colorectal Lung Metastases: A Prospective Multicenter Study

Background Although radiofrequency ablation (RFA) is widely performed for the treatment of colorectal cancer (CRC) lung metastases, its efficacy for candidates with surgically resectable disease is unclear. Purpose To evaluate the prognosis after RFA in participants with resectable CRC lung metastases. Materials and Methods For this prospective multicenter study (ClinicalTrials.gov identifier: NCT00776399), participants with five or fewer surgically resectable lung metastases measuring 3 cm or less were included. Participants with CRC and a total of 100 lung metastases measuring 0.4-2.8 cm (mean, 1.0 cm ± 0.5) were chosen and treated with 88 sessions of RFA from January 2008 to April 2014. The primary end point was the 3-year overall survival (OS) rate, with an expected rate of 55%. The local tumor progression rate and safety were evaluated as secondary end points. The OS rates were generated by using the Kaplan-Meier method. Log-rank tests and Cox proportional regression models were used to identify the prognostic factors by means of univariable and multivariable analyses. Adverse events were evaluated according to the Common Terminology Criteria for Adverse Events, version 3.0. Results Seventy participants with CRC (mean age, 66 years ± 10; 49 men) were evaluated. The 3-year OS rate was 84% (59 of 70 participants; 95% confidence interval [CI]: 76%, 93%). In multivariable analysis, factors associated with worse OS included rectal rather than colon location (hazard ratio [HR] = 7.7; 95% CI: 2.6, 22.6; P < .001), positive carcinoembryonic antigen (HR = 5.8; 95% CI: 2.0, 16.9; P = .001), and absence of previous chemotherapy (HR = 9.8; 95% CI: 2.5, 38.0; P < .001). Local tumor progression was found in six of the 70 participants (9%). A grade 5 adverse event was seen in one of the 88 RFA sessions (1%), and grade 2 adverse events were seen in 18 (20%). Conclusion Lung radiofrequency ablation provided a favorable 3-year overall survival rate of 84% for resectable colorectal lung metastases measuring 3 cm or smaller. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Gemmete in this issue.

Expert consensus on image-guided radiofrequency ablation of pulmonary tumors: 2018 edition

Lung cancer ranks first in incidence and mortality in China. Surgery is the primary method to cure cancer, but only 20-30% of patients are eligible for curative resection. In recent years, in addition to surgery, other local therapies have been developed for patients with numerous localized primary and metastatic pulmonary tumors, including stereotactic body radiation therapy and thermal ablative therapies through percutaneously inserted applicators. Percutaneous thermal ablation of pulmonary tumors is minimally invasive, conformal, repeatable, feasible, cheap, has a shorter recovery time, and offers reduced morbidity and mortality. Radiofrequency ablation (RFA), the most commonly used thermal ablation technique, has a reported 80-90% rate of complete ablation, with the best results obtained in tumors < 3 cm in diameter. Because the clinical efficacy of RFA of pulmonary tumors has not yet been determined, this clinical guideline describes the techniques used in the treatment of localized primary and metastatic pulmonary tumors in nonsurgical candidates, including mechanism of action, devices, indications, techniques, potential complications, clinical outcomes, post-ablation surveillance, and use in combination with other therapies. In the future, the role of RFA in the treatment of localized pulmonary tumors should ultimately be determined by evidence from prospective randomized controlled trials comparing sublobar resection or stereotactic body radiation therapy.

Radiofrequency ablation for lung tumors: outcomes, effects on survival, and prognostic factors

PURPOSE

We aimed to evaluate the survival benefit achieved with radiofrequency (RF) ablation of primary and metastatic lung tumors and determine significant prognostic factors for recurrence-free survival.

METHODS

Forty-nine patients with lung cancer (10 primary and 39 metastatic) underwent computed tomography-guided percutaneous RF ablation between June 2005 and October 2013. A total of 112 tumors (101 metastatic and 11 primary non-small cell lung cancer) were treated with RF ablation. Tumor diameter ranged from 0.6 to 4 cm (median 1.5 cm). Effectiveness of treatment, complications, and survival were analyzed.

RESULTS

Primary success rate was 79.5% and local tumor progression occurred in 23 tumors. Among tumors showing progression, 10 were re-treated with RF ablation and secondary success rate was 87.5%. One-, two-, and three-year overall survival rates of 10 patients with primary lung cancer were 100%, 86%, and 43%, respectively. One-, two-, three-, four-, and five-year overall survival rates for 39 patients with metastatic lung tumors were 90%, 73%, 59%, 55%, and 38%, respectively. One-, two-, three-, and four-year overall survival rates for 16 patients with colorectal pulmonary metastases were 94%, 80%, 68%, and 23%, respectively. Complications occurred in 30 sessions (24.6%). Pneumothorax occurred in 19 sessions with seven requiring image-guided percutaneous chest tube drainage. Tumor status (solitary or multiple) and presence of extrapulmonary metastasis at initial RF ablation were significant prognostic factors in terms of recurrence-free survival.

CONCLUSION

RF ablation is a safe and effective treatment with a survival benefit for selected patients with primary and secondary lung tumors.

Pleural puncture that excludes the ablation zone decreases the risk of pneumothorax after percutaneous microwave ablation in porcine lung

PURPOSE

To test the hypothesis that the geometry of probe placement with respect to the pleural puncture site affects the risk of pneumothorax after microwave (MW) ablation in the lung.

MATERIALS AND METHODS

Computed tomography-guided MW ablation of the lung was performed in 8 swine under general anesthesia and mechanical ventilation. The orientation of the 17-gauge probe was either perpendicular (90°) or parallel (< 30°) with respect to the pleural puncture site, and the ablation power was 30 W or 65 W for 5 minutes. After MW ablation, swine were euthanized, and histopathologic changes were assessed. Frequency and factors affecting pneumothorax were evaluated by multivariate analysis.

RESULTS

Among 62 lung MW ablations, 13 (21%) pneumothoraces occurred. No statistically significant difference was noted in the rate of pneumothorax between the perpendicular and the parallel orientations of the probe (31% vs 14%; odds ratio [OR], 2.8; P = .11). The pneumothorax rate was equal for 65-W and 30-W ablation powers (21% and 21%; OR, 1.0; P = .94). Under multivariate analysis, 2 factors were independent positive predictors of pneumothorax: ablation zone inclusive of pleural insertion point (OR, 7.7; P = .02) and time since intubation (hours) (OR, 2.7; P = .02).

CONCLUSIONS

Geometries where the pleural puncture site excluded the ablation zone decreased pneumothorax in swine undergoing MW ablation in the lung. Treatment planning to ensure that the pleural puncture site excludes the subsequent ablation zone may reduce the rate of pneumothorax in patients undergoing MW ablation in the lung.

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.

High-frequency jet ventilation under general anesthesia facilitates CT-guided lung tumor thermal ablation compared with normal respiration under conscious analgesic sedation

PURPOSE

To determine whether technical difficulty of computed tomography (CT)-guided percutaneous lung tumor thermal ablations is altered with the use of high-frequency jet ventilation (HFJV) under general anesthesia (GA) compared with procedures performed with normal respiration (NR) under conscious sedation (CS).

MATERIALS AND METHODS

Thermal ablation treatment sessions performed with NR under CS or HFJV under GA with available anesthesia records and CT fluoroscopic images were retrospectively reviewed; 13 and 33 treatment sessions, respectively, were identified. One anesthesiologist determined the choice of anesthesiologic technique independently. Surrogate measures of procedure technical difficulty--time duration, number of CT fluoroscopic acquisitions, and radiation dose required for applicator placement for each tumor--were compared between anesthesiologic techniques. The anesthesiologist time and complications were also compared. Parametric and nonparametric data were compared by Student independent-samples t test and χ(2) test, respectively.

RESULTS

Patients treated with HFJV under GA had higher American Society of Anesthesiologists classifications (mean, 2.66 vs 2.23; P = .009) and smaller lung tumors (16.09 mm vs 27.38 mm; P = .001). The time duration (220.30 s vs 393.94 s; P = .008), number of CT fluoroscopic acquisitions (10.31 vs 19.13; P = .023), and radiation dose (60.22 mGy·cm vs 127.68 mGy·cm; P = .012) required for applicator placement were significantly lower in treatment sessions performed with HFJV under GA. There was no significant differences in anesthesiologist time (P = .20), rate of pneumothorax (P = .62), or number of pneumothoraces requiring active treatment (P = .19).

CONCLUSIONS

HFJV under GA appears to reduce technical difficulty of CT-guided percutaneous applicator placement for lung tumor thermal ablations, with similar complication rates compared with treatment sessions performed with NR under CS. The technique is safe and may facilitate treatment of technically challenging tumors.

Major complications after lung microwave ablation: a single-center experience on 204 sessions

BACKGROUND

The purpose of this study is to retrospectively evaluate the incidence of and risk factors for major complications after microwave ablation (MWA) of lung tumors.

METHODS

From January 2011 to May 2013 in 184 consecutive patients (67 women and 117 men; mean age, 61.5 years; range, 19 to 85 years), 204 sessions of MWA were performed on 253 lung tumor lesions. Records were reviewed to evaluate prevalence of major complications and risk factors, which were analyzed using univariate and multivariate analyses.

RESULTS

Major complications developed after 42 sessions (20.6%), including 32 cases (15.7%) of pneumothorax requiring chest tube placement which that were associated with emphysema (p=0.001); 6 cases (2.9%) of pleural effusions requiring chest tube placement, which were associated with a distance of less than 1 cm from chest wall to target tumor (p=0.014); 6 cases (2.9%) of pneumonia which that were associated with target tumor maximal diameter (p=0.040); number of pleural punctures (p=0.001) and ablation time (p=0.006); and 1 case (0.5%) of pulmonary abscess. Two cases (1.0%) of the large pneumothorax occurred at the same time with extensive subcutaneous emphysema, including 1 case (0.5%) caused by bronchopleural fistula. Death related to the procedures occurred after 1 session (0.5%).

CONCLUSIONS

As a relatively practical and safe modality, lung tumor MWA can induce serious complications. Enough attention should be paid to patients with emphysema, subpleural, or large target tumor, but the indications for lung MWA need not be limited as most major complications were easily managed.

Lung cancer ablation: complications

Although radiofrequency ablation for lung cancer is generally safe (with a mortality rate <1%), it may cause various complications. Common complications include pneumothorax, pleural effusion, and parenchymal hemorrhage. Although most complications can be treated conservatively or with minimal therapy, physicians should be aware of rare but serious complications. Potentially fatal complications include massive hemorrhage, intractable pneumothorax due to bronchopleural fistula, pulmonary artery pseudoaneurysm, systemic air embolism, and pneumonitis. Other serious complications include injury to the nearby tissues (e.g., brachial nerve plexus, phrenic nerve, diaphragm, and chest wall), needle tract seeding, lung abscess, empyema, and skin burn. Although cavitation of the ablation zone is usually insignificant clinically, such a cavity occasionally ruptures, leading to pneumothorax and bleeding. Cavities may also serve as a scaffold for fungal colonization. Precautions to minimize risk should be taken whenever possible. Nevertheless, serious complications may occur, and thus physicians should be aware of the appropriate treatments for these complications. This article reviews complications associated with lung cancer ablation.

Alternative to surgery in early stage NSCLC-interventional radiologic approaches

Interventional radiologists have a variety of techniques in their armamentarium to treat pulmonary tumors. While most therapies are targeted to metastasis or palliation, percutaneous thermal ablation represents a potential therapy for not only palliation, but to treat inoperable early stage disease. Although radiofrequency ablation (RFA) is the most studied of these ablative techniques, newer technologies of thermal ablation, such as microwave and cryoablation have emerged as additional options. In this article, we will review the three different thermal ablative modalities, including patient selection, technique, outcomes, complications, and imaging follow-up. A brief discussion of state of the art techniques such as irreversible electroporation (IRE) and catheter directed therapies will also be included.

Ask the Experts: How important is radiofrequency ablation in lung cancer?

Terrance T Healey is the director of Thoracic Radiology at Rhode Island Hospital (RI, USA) and an Assistant Professor of Diagnostic Imaging at the Alpert Medical School of Brown University (RI, USA). Healey received his medical degree from the combined Dartmouth Medical School–Brown Medical School Program in 2003, completed his residency in radiology at Brown University in 2008 and a thoracic radiology fellowship at the Massachusetts General Hospital (MA, USA) in 2009. He joined the faculty staff at Rhode Island Hospital and Brown University in 2009.

Robert C Ward is one of the chief residents within the Department of Diagnostic Imaging at Rhode Island Hospital (RI, USA) and the Alpert Medical School of Brown University (RI, USA). Ward received his medical degree from the George Washington University (Washington, DC, USA) in 2010.

Damian E Dupuy is the director of Tumor Ablation at Rhode Island Hospital (RI, USA) and a Professor of Diagnostic Imaging at The Warren Alpert Medical School of Brown University (RI, USA). Dupuy received his medical degree from the University of Massachusetts Medical School (MA, USA) in 1988 and completed his residency in radiology at The New England Deaconess Hospital (MA, USA) and Harvard Medical School (MA, USA) in 1993. After residency, Dupuy joined the staff at Massachusetts General Hospital (MA, USA) where he worked in the Abdominal Imaging and Bone and Joint Divisions. In 1997, Dupuy joined the Department of Diagnostic Imaging at Rhode Island Hospital and Brown University. Dupuy, a pioneer in the use of image-guided ablation, helped broaden clinical applications to successfully combat cancer involving the kidney, liver, lung, head and neck, adrenal gland and skeleton. Other newer technologies, such as percutaneous microwave ablation, cryoablation and combination therapies using radiofrequency ablation with external radiation or brachytherapy, have been pioneered by Dupuy who has been the principal investigator of two National Cancer Institute-funded multicenter trials. Dupuy has received national awards for research and teaching from the American College of Radiology Imaging Network and the Radiological Society of North America where he is currently the Chair of the Interventional Oncology Symposium featured at the Annual Meeting of the Radiological Society of North America and a Fellow of the American College of Radiology. Dupuy is a member of the Radiological Society of North America, The New England Roentgen Ray Society, The American College of Radiology, Rhode Island Radiological Society and the Society of Interventional Radiology. Dupuy has published over 150 publications and given over 120 invited lectures in the field of radiology and image-guided ablation, both nationally and internationally.

Factors influencing local tumor control in patients with neoplastic pulmonary nodules treated with microwave ablation: a risk-factor analysis

OBJECTIVE

This study was performed to evaluate risk factors predictive of local tumor control after microwave ablation of primary and secondary lung malignancies up to 3 cm in maximal diameter.

MATERIALS AND METHODS

The single-antenna microwave ablation treatment of 91 index tumors in 57 patients was studied retrospectively. Time to local tumor progression was monitored on CT scans over the follow-up period. Estimation of overall time to local tumor progression was performed with the Cox regression model. Factors hypothesized to correlate with ablation response included tumor diameter, tumor shape (round or oval versus irregular), clear versus ill-defined tumor margin, adjacency to the pleura, adjacency to bronchi, presence of vessels at least 3 mm in diameter a maximum of 5 mm from the index tumor, energy applied to the index tumor, and the occurrence of cavernous formations after ablation. A logistic regression model was used to correlate the data.

RESULTS

Thirty of 91 (33.0%) index tumors, found in 21 of 57 (36.8%) patients, underwent local progression. The mean time to local tumor progression was 8.3 ± 5.5 months (range 2.1-25.2 months), and the estimated median time to local tumor progression was 22.6 ± 12.4 months. The risk factors that correlated significantly with local tumor progression were a maximal diameter greater than 15.5 mm (p < 0.01), irregular shape of the index tumor (p < 0.01), pleural contact (p = 0.02), and less than 26.7 J/mm(3) applied to the index tumor (p < 0.001). After regression analysis, shape of the index tumor (p = 0.03) and energy deployed per unit volume of the index tumor (p = 0.001) were found to be independent risk factors. Conversely, tumor margin definition (p = 0.06) and proximity of cavernous formations (p = 0.19), juxtatumoral vessels (p = 0.08), and bronchi (p = 0.89) did not affect tumor progression after ablation.

CONCLUSION

The independent predictive factors for local tumor progression in primary and secondary lung neoplasms up to 3 cm in diameter observed in this study were irregular shape of the index tumor and energy application of less than 26.7 J/mm(3) to the index tumor.

A minimally invasive multimodality image-guided (MIMIG) system for peripheral lung cancer intervention and diagnosis

BACKGROUND

Lung cancer is the leading cause of cancer-related death in the United States, with more than half of the cancers are located peripherally. Computed tomography (CT) has been utilized in the last decade to detect early peripheral lung cancer. However, due to the high false diagnosis rate of CT, further biopsy is often necessary to confirm cancerous cases. This renders intervention for peripheral lung nodules (especially for small peripheral lung cancer) difficult and time-consuming, and it is highly desirable to develop new, on-the-spot earlier lung cancer diagnosis and treatment strategies.

PURPOSE

The objective of this study is to develop a minimally invasive multimodality image-guided (MIMIG) intervention system to detect lesions, confirm small peripheral lung cancer, and potentially guide on-the-spot treatment at an early stage. Accurate image guidance and real-time optical imaging of nodules are thus the key techniques to be explored in this work.

METHODS

The MIMIG system uses CT images and electromagnetic (EM) tracking to help interventional radiologists target the lesion efficiently. After targeting the lesion, a fiber-optic probe coupled with optical molecular imaging contrast agents is used to confirm the existence of cancerous tissues on-site at microscopic resolution. Using the software developed, pulmonary vessels, airways, and nodules can be segmented and visualized for surgical planning; the segmented results are then transformed onto the intra-procedural CT for interventional guidance using EM tracking. Endomicroscopy through a fiber-optic probe is then performed to visualize tumor tissues. Experiments using IntegriSense 680 fluorescent contrast agent labeling αvβ3 integrin were carried out for rabbit lung cancer models. Confirmed cancers could then be treated on-the-spot using radio-frequency ablation (RFA).

RESULTS

The prototype system is evaluated using the rabbit VX2 lung cancer model to evaluate the targeting accuracy, guidance efficiency, and performance of molecular imaging. Using this system, we achieved an average targeting accuracy of 3.04 mm, and the IntegriSense signals within the VX2 tumors were found to be at least two-fold higher than those of normal tissues. The results demonstrate great potential for applying the system in human trials in the future if an optical molecular imaging agent is approved by the Food and Drug Administration (FDA).

CONCLUSIONS

The MIMIG system was developed for on-the-spot interventional diagnosis of peripheral lung tumors by combining image-guidance and molecular imaging. The system can be potentially applied to human trials on diagnosing and treating earlier stage lung cancer. For current clinical applications, where a biopsy is unavoidable, the MIMIG system without contrast agents could be used for biopsy guidance to improve the accuracy and efficiency.

Image-guided thermal ablation of lung malignancies

Primary and secondary lung malignancies are often treated with surgery. Many patients are poor surgical candidates owing to advanced age or medical comorbidities. Alternatives to surgery for localized disease include radiation therapy and the newer treatments known as image-guided thermal ablation. Image-guided thermal ablation involves the use of needlelike applicators that are placed directly into tumors by using imaging guidance. Tumors are destroyed by the application of either intense heat or cold. The specific ablative modalities of radiofrequency ablation, microwave ablation, laser ablation, and cryoablation are reviewed with respect to the various clinical indications for treatment of both primary and secondary lung malignancies.