Determinants of local progression after computed tomography-guided percutaneous radiofrequency ablation for unresectable lung tumors: 9-year experience in a single institution

Role of Repeated Radiofrequency Ablation for Patients with Lung Metastases of Head and Neck Adenoid Cystic Carcinoma: Long-term Single-center Study in 16 Patients with 289 Tumors

Purpose: To retrospectively assess the clinical outcomes of repeated radiofrequency ablation for lung metastases of head and neck adenoid cystic carcinoma. Material and Methods: Consecutive 16 patients (mean age, 55.3 years) who were treated with radiofrequency ablation for 289 lung metastases were included. A 17-gauge electrode was used in all radiofrequency ablation procedures and placed under computed tomography fluoroscopic guidance. Evaluated were safety, technical success, local tumor control, and survival. Results: In total, 143 radiofrequency ablation sessions were performed for 289 lung metastases. One session of radiofrequency ablation was not completed due to pleural hemorrhage during the procedure, resulting in a technical success rate of 99.3% (142/143). Major complications (pneumothorax and hemorrhage) occurred in 40 sessions (27.9%, 40/143). During the mean follow-up period of 5.5 ± 3.6 years (range, 0.4-13.4 years), local tumor progression was observed in 16 tumors (5.5%, 16/289) and repeated radiofrequency ablation (93.8%, 15/16) or metastasectomy (6.2%, 1/16) was performed for all locally progressed lung metastases. The local tumor control rates were 97.1% (95% confidence interval, 95.1%-99.2%) and 89.5% (95% confidence interval, 84.0%-95.0%) at 1- and 5-year. Median survival time after initial lung radiofrequency ablation was 9.8 years and 1-, 3-, 5-, and 10-year overall survival rates were 100% (95% confidence interval, 100%), 91.7% (95% confidence interval, 76.0%-100%), 64.3% (95% confidence interval, 35.7%-92.9%), and 35.7% (95% confidence interval, 0%-70.8%), respectively. Conclusions: Repeated radiofrequency ablation for multiple lung metastases of adenoid cystic carcinoma was feasible and safe and may allow survival with good local control of lung metastases.

CT-based radiomics and cluster analysis for the prediction of local progression in stage I NSCLC patients treated with microwave ablation

To predict local progression after microwave ablation (MWA) in patients with stage I non-small cell lung cancer (NSCLC), we developed a CT-based radiomics model. Postoperative CT images were used. The intraclass correlation coefficients, two-sample t-test, least absolute shrinkage and selection operator (LASSO) regression, and Pearson correlation analysis were applied to select radiomics features and establish radiomics score. The Radiomics score was used to classify patients into new radiomics labels. The k-means cluster algorithm was employed to cluster patients into new cluster labels based on radiomics features. Logistic regression was used to build prediction models. The optimal model incorporating clinical risk factors, radiomics labels, and cluster labels achieved the best discrimination. This study proposes a radiomics model that accurately predicts local progression in patients with stage I NSCLC treated with MWA. This prediction tool may be helpful in determining MWA efficacy and individualized risk classification and treatment.

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.

Stereotactic ablative brachytherapy versus percutaneous microwave ablation for early-stage non-small cell lung cancer: a multicenter retrospective study

BACKGROUND

To analyze the efficacy of stereotactic ablative brachytherapy (SABT) and percutaneous microwave ablation (MWA) for the treatment of early-stage non-small cell lung cancer (NSCLC).

METHODS

Patients with early-stage (T1-T2aN0M0) NSCLC who underwent CT-guided SABT or MWA between October 2014 and March 2017 at four medical centers were retrospectively analyzed. Survival, treatment response, and procedure-related complications were assessed.

RESULTS

A total of 83 patients were included in this study. The median follow-up time was 55.2 months (range 7.2-76.8 months). The 1-, 3-, and 5-year overall survival (OS) rates were 96.4%, 82.3%, and 68.4% for the SABT group (n = 28), and 96.4%, 79.7%, and 63.2% for MWA group (n = 55), respectively. The 1-, 3-, and 5-year disease-free survival (DFS) rates were 92.9%, 74.6%, and 54.1% for SABT, and 92.7%, 70.5%, and 50.5% for MWA, respectively. There were no significant differences between SABT and MWA in terms of OS (p = 0.631) or DFS (p = 0.836). The recurrence rate was also similar between the two groups (p = 0.809). No procedure-related deaths occurred. Pneumothorax was the most common adverse event in the two groups, with no significant difference. No radiation pneumonia was found in the SABT group.

CONCLUSIONS

SABT provided similar efficacy to MWA for the treatment of stage I NSCLC. SABT may be a treatment option for unresectable early-stage NSCLC. However, future prospective randomized studies are required to verify these results.

A prognostic model for predicting progression-free survival in patients with advanced non-small cell lung cancer after image-guided microwave ablation plus chemotherapy

OBJECTIVES

This study aimed to build and validate a prediction model that can predict progression-free survival (PFS) in patients with advanced non-small cell lung cancer (NSCLC) after image-guided microwave ablation (MWA) plus chemotherapy.

METHODS

Data from a previous multi-center randomized controlled trial (RCT) was used and assigned to either the training data set or the external validation data set according to the location of the centers. Potential prognostic factors were identified by multivariable analysis in the training data set and used to construct a nomogram. After bootstraps internal and external validation, the predictive performance was evaluated by concordance index (C-index), Brier Score, and calibration curves. Risk group stratification was conducted using the score calculated by the nomogram. Then a simplified scoring system was built to make risk group stratification more convenient.

RESULTS

In total, 148 patients (training data set: n = 112; external validation data set: n = 36) were enrolled for analysis. Six potential predictors were identified and entered into the nomogram, including weight loss, histology, clinical TNM stage, clinical N category, tumor location, and tumor size. The C-indexes were 0.77 (95% CI, 0.65-0.88, internal validation) and 0.64 (95% CI, 0.43-0.85, external validation). The survival curves of different risk groups also displayed significant distinction (p < 0.0001).

CONCLUSIONS

We found weight loss, histology, clinical TNM stage, clinical N category, tumor location, and tumor size were prognostic factors of progression after receiving MWA plus chemotherapy and constructed a prediction model that can predict PFS.

CLINICAL RELEVANCE STATEMENT

The nomogram and scoring system will assist physicians to predict the individualized PFS of their patients and decide whether to perform or terminate MWA and chemotherapy according to the expected benefits.

KEY POINTS

• Build and validate a prognostic model using the data from a previous randomized controlled trial to predict progression-free survival after receiving MWA plus chemotherapy. • Weight loss, histology, clinical TNM stage, clinical N category, tumor location, and tumor size were prognostic factors. • The nomogram and scoring system published by the prediction model can be used to assist physicians to make clinical decisions.

Impact of the Ablative Margin on Local Tumor Progression after Radiofrequency Ablation for Lung Metastases from Colorectal Carcinoma: Supplementary Analysis of a Phase II Trial (MLCSG-0802)

PURPOSE

To explore what extent of ablative margin depicted by computed tomography (CT) immediately after radiofrequency (RF) ablation is required to reduce local tumor progression (LTP) for colorectal cancer (CRC) lung metastases.

MATERIALS AND METHODS

This retrospective study was undertaken as a supplementary analysis of a previous prospective trial. Seventy patients (49 men and 21 women; mean age ± standard deviation, 64.9 years ± 10.6 years) underwent RF ablation for CRC lung metastases, and 95 tumors that were treated in the trial and followed up with CT at least 12 months after RF ablation were evaluated. The mean tumor size was 1.0 cm ± 0.5 cm. The ablative margin was estimated as the shortest distance between the outer edge of the tumor and the surrounding ground-glass opacity on CT obtained immediately after RF ablation. The impact of the ablative margin on LTP was evaluated using logistic regression analysis. Multivariate logistic regression analysis was also performed to identify the risk factors for LTP. The result was validated with multivariate logistic regression applying a bootstrap method (1,000 times resampling).

RESULTS

The mean ablative margin was 2.7 mm ± 1.3 (range, 0.4-7.3 mm). LTP developed in 6 tumors (6%, 6/95) 6-19 months after RF ablation. The LTP rate was significantly higher when the margin was less than 2 mm (P = .023). A margin of <2 mm was also found to be a significant factor for LTP (P = .048) on multivariate analysis and validated using the bootstrap method (P = .025).

CONCLUSIONS

An ablative margin of at least 2 mm is important to reduce LTP after RF ablation for CRC lung metastases.

Comparison of stereotactic body radiotherapy and radiofrequency ablation for early-stage non-small cell lung cancer: a systematic review and meta-analysis

Background

Stereotactic body radiation therapy (SBRT) and radiofrequency ablation (RFA) are recommended for patients with inoperable early-stage non-small cell lung cancer (NSCLC), with both offering promising results. However, it is largely unknown which of these two treatment modalities provides superior benefits for patients. Therefore, this systematic review and meta-analysis compared clinical outcomes and safety between SBRT and RFA in patients with inoperable early-stage NSCLC.

Methods

Eligible studies published between 2001 and 2020 were obtained through a comprehensive search of the PubMed, Medline, Embase, and Cochrane Library databases. Original English-language studies on the treatment of early-stage NSCLC with SBRT or RFA were included. Local control (LC) rates, overall survival (OS) rates, and adverse events were obtained by pooled analyses.

Results

Eighty-seven SBRT studies (12,811 patients) and 18 RFA studies (1,535 patients) met the eligibility criteria. For SBRT, the LC rates (with 95% confidence intervals) at 1, 2, 3, and 5 years were 98% (97-98%), 95% (95-96%), 92% (91-93%), and 92% (91-93%), respectively, which were significantly higher than those for RFA [75% (69-82%), 31% (22-39%), 67% (58-76%), and 41% (30-52%), respectively] (P<0.01). There were no significant differences in short-term OS between SBRT and RFA [1-year OS rate: 87% (86-88%) versus 89% (88-91%), P=0.07; 2-year OS rate: 71% (69-72%) versus 69% (64-74%), P=0.42]. Regarding long-term OS, the 3- and 5-year OS rates for SBRT were 58% (56-59%) and 39% (37-40%), respectively, which were significantly (P<0.01) superior to those for RFA [48% (45-51%) and 21% (19-23%), respectively]. The most common complication of SBRT was radiation pneumonitis (grade ≥2), making up 9.1% of patients treated with SBRT, while pneumothorax was the most common complication of RFA, making up 27.2% of patients treated with RFA.

Discussion

Compared with RFA, SBRT has superior LC and long-term OS rates but similar short-term OS rates. Prospective randomized trials with large sample sizes comparing the efficacy of SBRT and RFA are warranted.

Local progression after computed tomography-guided microwave ablation in non-small cell lung cancer patients: prediction using a nomogram model

OBJECTIVES

To develop an effective nomogram model for predicting the local progression after computed tomography-guided microwave ablation (MWA) in non-small cell lung cancer (NSCLC) patients.

METHODS

NSCLC patients treated with MWA were randomly allocated to either the training cohort or the validation cohort (4:1). The predictors of local progression identified by univariable and multivariable analyses in the training cohort were used to develop a nomogram model. The C-statistic was used to evaluate the predictive accuracy in both the training and validation cohorts.

RESULTS

A total of 304 patients (training cohort: n = 250; validation cohort: n = 54) were included in this study. The predictors selected into the nomogram for local progression included the tumor subtypes (odds ratio [OR], 2.494; 95% confidence interval [CI], 1.415-4.396, p = 0.002), vessels ≥3 mm in direct contact with tumor (OR, 2.750; 95% CI, 1.263-5.988; p = 0.011), tumor diameter (OR, 2.252; 95% CI, 1.034-4.903; p = 0.041) and location (OR, 2.442; 95% CI, 1.201-4.965; p = 0.014). The C-statistic showed good predictive performance in both cohorts, with a C-statistic of 0.777 (95% CI, 0.707-0.848) internally and 0.712 (95% CI, 0.570-0.855) externally (training cohort and validation cohort, respectively). The optimal cutoff value for the risk of local progression was 0.39.

CONCLUSIONS

Tumor subtypes, vessels ≥3 mm in direct contact with the tumor, tumor diameter and location were predictors of local progression after MWA in NSCLC patients. The nomogram model could effectively predict the risk of local progression after MWA. Patients showing a high risk (>0.39) on the nomogram should be monitored for local progression.

Thermal ablation in non-small cell lung cancer: a review of treatment modalities and the evidence for combination with immune checkpoint inhibitors

Lung cancer is the leading cause of cancer death worldwide, with approximately 1.6 million cancer related deaths each year. Prognosis is best in patients with early stage disease, though even then five-year survival is only 55% in some groups. Median survival for advanced non-small cell lung cancer (NSCLC) is 8–12 months with conventional treatment. Immune checkpoint inhibitor (ICI) therapy has revolutionised the treatment of NSCLC with significant long-term improvements in survival demonstrated in some patients with advanced NSCLC. However, only a small proportion of patients respond to ICI, suggesting the need for further techniques to harness the potential of ICI therapy. Thermal ablation utilizes the extremes of temperature to cause tumour destruction. Commonly used modalities are radiofrequency ablation (RFA), cryoablation and microwave ablation (MWA). At present thermal ablation is reserved for curative-intent therapy in patients with localized NSCLC who are unable to undergo surgical resection or stereotactic ablative body radiotherapy (SABR). Limited evidence suggests that thermal ablative modalities can upregulate an anticancer immune response in NSCLC. It is postulated that thermal ablation can increase tumour antigen release, which would initiate and upregulated steps in the cancer immunity cycle required to elicit an anticancer immune response. This article will review the current thermal ablative techniques and their ability to modulate an anti-cancer immune response with a view of using thermal ablation in conjunction with ICI therapy.

Magnetic resonance imaging-guided microwave ablation for lung tumor: a case report

Thoracoscopic surgery is considered to be the best treatment option for pulmonary lesions. However, for patients with clinical stage IIIA, surgery is not always feasible, due to a lack of sufficient lung function. Microwave ablation (MWA) is an appropriate, minimally invasive treatment option for these patients. In this case study, we present our initial experience with MWA guided by magnetic resonance imaging (MRI), in a patient with a lesion located in the right lower lobe. The patient was successfully ablated and achieved a long progression-free period.

Percutaneous radiofrequency ablation for hepatic tumors: factors affecting baseline impedance

PURPOSE

We aimed to evaluate factors that affect baseline impedance of percutaneous radiofrequency ablation.

METHODS

In this retrospective study, we analyzed 51 patients with 55 hepatic tumors from November 2015 until April 2018. We measured the baseline impedance nine times with three adjustable tip sizes (2 cm, 2.5 cm, 3 cm) and three different pad locations (two pads attached on the thigh, four on the thigh, two on the back). The first roll-off time was measured with two grounding pads attached on the back. Body mass index, cirrhotic or non-cirrhotic liver parenchyma, previous procedure, tumor location, artificial ascites, active tip size, and the pad location were evaluated as potential factors affecting baseline impedance using the Mann-Whitney U test, t-test and analysis of variance test.

RESULTS

Complete radiofrequency ablation was achieved in 51 patients. Body mass index (p = 0.897), cirrhotic or non-cirrhotic liver parenchyma (p = 0.767), previous procedure (p = 0.957), tumor location (p = 0.906), and artificial ascites (p = 0.882) did not significantly affect baseline impedance. Grounding pads located on the back showed the lowest baseline impedance (p < 0.001). Increase in active tip size showed gradual decrease in baseline impedance (p = 0.016).

CONCLUSION

The factors affecting baseline impedance were the pad location and the tip size. Positioning pads on the back lowers the baseline impedance and can shorten the first roll-off time, ultimately resulting in reduced total ablation time.

Risk factors for local tumor progression after RFA of pulmonary metastases: a matched case-control study

OBJECTIVES

Curative treatment of oligometastatic pulmonary disease aims at eradication of all metastases. Radiofrequency ablation (RFA) has been shown to be an efficient method and the frequency of local tumor progression (LTP) should be minimized. The objective of this study was to determine the morphological and treatment-related risk factors for LTP after RFA of pulmonary metastases.

MATERIALS AND METHODS

All patients treated with RFA for pulmonary metastases from 2002 to 2014 were reviewed. All LTPs from 2011 to 2014 were individually matched on the basis of tumor size, number, and histology. In total, 48 LTPs and 112 controls were blindly analyzed for morphological factors including vicinity of bronchus and vessels as well as treatment-related factors such as the size of the ablation zone and ablation margins.

RESULTS

In the simple regression analysis, the significant predictive variables were ≤ 5-mm distance to a large bronchus (OR = 4.94; p = 0.0095) or large vessel (OR = 7.09; p < 0.001), minimal ablation margin (≤ 5 mm (OR = 42.67; p < 0.001), and a central-peripheral ablation offset/ablation zone size > 0.36 (OR = 13.83; p = 0.013). In the multiple regression model, only a minimal ablation margin ≤ 5 mm remained a significant risk factor for LTP.

CONCLUSION

Only the minimal ablation margin remains significant in the multiple regression analysis; the other factors are presumably surrogates of an insufficient ablation margin. Improvement of lung RFA outcomes can probably be obtained by immediate post RFA evaluation of ablation margins to ensure a minimal ablation margin of at least 5 mm.

KEY POINTS

• A distance < 5 mm to a bronchus or vessel of over 3 mm diameter is associated with insufficient ablation margin and thus risk factors for local tumor progression after pulmonary radiofrequency ablation. • A minimal ablation margin of > 5 mm after pulmonary RFA is associated with significantly less local tumor progression and should be looked for at the end of treatment session before needle removal in order to decrease local tumor progression. • Tumor location, pleural contact, occurrence of intra-alveolar hemorrhage, pulmonary atelectasis, and pneumothorax are not associated with an increased risk of local tumor progression.

Advances in study of the sequence of lung tumor biopsy and thermal ablation

Percutaneous thermal ablation is an important treatment for lung cancer and is widely used in hospitals. Puncture biopsy is generally required for pathological diagnosis before or after thermal ablation. Pathological diagnosis provides both evidence of benign and malignant lesions for ablation therapy and is of important significance for the next step in disease management. Furthermore, the sequence of ablation and biopsy affects the accuracy of pathological diagnosis, the complete ablation rate of thermal ablation, and incidence of surgery‐related complications. Ultimately, it may affect the patient's benefit from local treatment. This article reviews the research progress of traditional asynchronous biopsy followed by ablation, the emerging methods of synchronous biopsy followed by ablation, and synchronous ablation followed by biopsy in the last decade.

Key points

The sequence of ablation and biopsy affects the accuracy of pathological diagnosis, the complete ablation rate of thermal ablation, and the incidence of surgical‐related complications.

This article reviewed the recent 10 years' literature on the surgical sequence of biopsy and ablation for lung tumors, the advantages, disadvantages and indications of different orders were analyzed.

Survival Benefit of Radiofrequency Ablation with Intratumoral Cisplatin Administration in a Rabbit VX2 Lung Tumor Model

PURPOSE

This study evaluated the survival benefit of a combination therapy with radiofrequency ablation (RFA) and intratumoral cisplatin (ITC) administration for lung tumors by using a rabbit VX2 tumor model.

MATERIALS AND METHODS

Experiments were approved by the institutional animal care committee. VX2 tumor suspension was injected into the lungs of Japanese white rabbits under CT guidance to create a lung tumor model. Thirty-two rabbits bearing a transplanted VX2 lung tumor were randomly assigned to four groups of eight: control (untreated); RFA alone; ITC alone; and RFA with ITC. All treatments were performed one week after tumor transplantation. Kaplan-Meier survival curves were compared by the log-rank test.

RESULTS

The median survival time was 24.5 days (range 17-33 days) in the control group, 40 days (30-80 days) in the RFA alone group, 31.0 days (24-80 days) in the ITC alone group, and not reached (53-80 days) in the RFA with ITC group. The median survival was significantly longer with the RFA/ITC combination compared to the control group (P < 0.001), RFA alone (P = 0.034), and ITC alone (P = 0.004). The survival time after RFA alone was also significantly longer than that of the control group (P < 0.001). There was no significant difference in tumor size or the rate of pneumothorax between each group.

CONCLUSION

RFA prolonged the survival of rabbits with lung VX2 tumors when combined with ITC.

Stereotactic body radiotherapy versus percutaneous local tumor ablation for early-stage non-small cell lung cancer

OBJECTIVES

To compare patterns of care and overall survival (OS) between stereotactic body radiotherapy (SBRT) and percutaneous local tumor ablation (LTA) for non-surgically managed early-stage non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

The National Cancer Database (NCDB) was queried from 2004 to 2014 for adults with non-metastatic, node-negative invasive adenocarcinoma or squamous cell carcinoma of the lung with primary tumor size ≤5.0 cm who did not undergo surgery or chemotherapy and received SBRT or LTA. Patterns of care were assessed with multivariate logistic regression. After propensity-score weighting with generalized boosted regression, OS was assessed with univariate and doubly-robust multivariate Cox regression.

RESULTS

Of 15,792 patients, 14,651 (93%) received SBRT and 1141 (7%) received LTA. Increasing age (OR 1.01, p = .035), treatment at an academic institution (OR 2.94, p < .001), increasing tumor size (OR 1.05, p < .001), and more recent year of diagnosis (OR 1.43, p < .001) were predictive of treatment with SBRT, whereas comorbidities (OR 0.74, p = .003) and treatment at a high-volume facility (OR 0.05, p < .001) were predictive for LTA. At a median follow-up of 26.2 months, SBRT was associated with improved OS relative to LTA within a propensity-score weighted doubly-robust multivariate analysis (HR 0.71, p < .001). On weighted subgroup analyses, improved OS was observed with SBRT for tumor sizes >2.0 cm (HR 0.72, p < .001) and for those treated at high-volume facilities (HR 0.71, p < .001). No OS difference was found with SBRT or LTA in tumor sizes ≤2.0 cm (HR 0.90, p = .227).

CONCLUSION

Within the NCDB, SBRT was more commonly utilized and was associated with improved OS when compared to percutaneous LTA for patients with non-surgically managed early-stage NSCLC. Patients with small tumor volumes likely represent an appropriate population for future prospective randomized comparisons between SBRT and LTA.

Lung Ablation: Indications and Techniques

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

Traitement focal et traitement systémique dans la prise en charge du cancer du rein métastatique : une question de complémentarité

FOCAL TREATMENT AND SYSTEMIC THERAPY IN METASTATIC KIDNEY CANCER

COMPLEMENTARY APPROACHES: To treat metastatic renal cell carcinoma, therapies used are with an oral intake, for the vast majority, and have many side effects that may compromise observance. Strategies of drug holiday have been studied and, in case of an indolent and oligometastatic tumor, studies have shown that active surveillance is possible to delay the introduction of systemic treatment, without compromising the patient survival. A multimodal approach combining systemic and focal treatments can be done with several objectives: to delay even more introduction of systemic treatment by focally treating metastases, to allow drug holiday after partial response to medical treatment by local control of persistent metastases, and to permit drug continuation even in case of dissociated response to systemic therapy, by focal treatment of metastasis(es) in progression. Technics that can be used for focal treatment are metastasectomy, radiofrequency ablation or cryotherapy, and stereotactic radiotherapy. In literature, studies that evaluated this approach are for almost retrospective studies, but they have reported interesting results in terms of local control and low morbidity. In the era of checkpoint's inhibitors, it seems important to make prospective collections of data to validate these practices. In any case, and because international recommendations about multimodal approach are poor, discussions between the different actors of the patient care are essential to find the most beneficial treatment for him.

Patient and Facility Demographics Related Outcomes in Early-Stage Non-Small Cell Lung Cancer Treated with Radiofrequency Ablation: A National Cancer Database Analysis

PURPOSE

To determine facility and patient demographics associated with survival in early-stage non-small cell lung cancer (NSCLC) treated with radiofrequency (RF) ablation.

MATERIALS AND METHODS

The National Cancer Database was queried for cases of stage 1a NSCLC treated with RF ablation without chemotherapy or radiotherapy from 2004 to 2014. High-volume centers (HVCs) were defined as the top 95^th percentile of facilities by number of procedures performed. Overall survival (OS) was estimated with the Kaplan-Meier method, and comparisons between survival curves were performed with the log-rank test. Propensity score-matched cohort analysis was performed. P values less than .05 were considered statistically significant.

RESULTS

In the final cohort, 967 cases were included. Estimated median survival and follow-up were 33.1 and 62.5 months, respectively. Of 305 facilities, 15 were determined to be HVCs, treating 13 or more patients from 2004 to 2014. A total of 335 cases (34.6%) were treated at HVCs. On multivariate Cox regression analysis, treatment at an HVC was independently associated with improved OS (hazard ratio [HR] = 0.766; P = .006). After propensity score adjustment, 1-, 3-, and 5-year OS was 89.8%, 51.2%, and 27.7%, respectively, for patients treated at HVCs, compared to 85.2%, 41.5%, and 19.6%, respectively, for patients treated at non-HVCs (P = .015). Increasing age (HR = 1.012; P = .013) and higher T-classification (HR = 1.392; P < .001) were independently associated with worse OS.

CONCLUSION

Patients with early-stage NSCLC treated with RF ablation at HVCs experienced a significant increase in OS, suggesting regionalization of lung cancer management as a means of improving outcomes.

Combination therapy involving radiofrequency ablation and targeted chemotherapy with bevacizumab plus paclitaxel and cisplatin in a rabbit VX2 lung tumor model

Objective

Radiofrequency ablation (RFA) is less effective for large tumors > 3 cm in diameter. Various studies of combination therapy using RFA and other treatments have been conducted to improve the results of RFA treatment of lung tumors, survival was extended in a tumor model when RFA was followed by concomitant use of systemic chemotherapy. Bevacizumab (BCM) is a one of molecular target drugs. Numerous clinical trials and reports have shown BCM’s effect when used in combination with cisplatin (CDDP) in lung tumor. Our objective is to evaluate the survival of concurrent, combined use of radiofrequency ablation and BCM, and platinum-doublet chemotherapy [CDDP/paclitaxel (PTX)] in a rabbit VX2 lung tumor.

Results

Survival times of the RFA alone, CDDP/PTX, CDDP/PTX/BCM, RFA/CDDP/PTX, and RFA/CDDP/PTX/BCM groups were significantly prolonged compared to that of the control group (P = 0.0055, P = 0.0055, P = 0.0004, P = 0.0002, P = 0.0019, respectively). Survival of the RFA/CDDP/PTX/BCM group was not significantly prolonged compared to the RFA alone (P = 0.53) and CDDP/PTX/BCM group (P = 0.68), while showing a significantly shorter survival time than that of the RFA/CDDP/PTX group (P = 0.017). The addition to BCM with combination RFA and systemic therapy with CDDP/PTX did not have a positive effect on survival.

Efficacy and safety of thermal ablation of lung malignancies: A Network meta-analysis

OBJECTIVE:

The objective of this study was to compare the efficacy and safety of radiofrequency ablation (RFA), cryoablation, and microwave ablation (MWA) for patients with lung malignancies.

METHODS:

We performed a network meta-analysis to identify both direct and indirect evidence from relevant trials by searching PubMed, Embase, and the Cochrane Library to December 31, 2017, for the treatment of malignant lung tumors with the use of RFA, MWA, or cryoablation. We extracted the relevant information from the published studies with a predefined data sheet and assessed the risk of bias with the Cochrane risk of bias tool. The primary outcomes were efficacy (local progression rate and overall survival rate) and safety (major complications rate). We did a random-effects network meta-analysis within a Bayesian framework as well as assessed the quality of evidence contributing to each network estimate using GRADE framework.

RESULTS:

We collected 34 studies eligible which included 1840 participants and 2520 lung malignancies (1318 primary lung cancer and 1202 pulmonary metastatic tumors). The quality of evidence was rated as very low in most comparisons. From the point of local progression rate, RFA and MWA were significantly more effective than cryoablation with odds ratio (OR) of 0.04 (95% confidence interval [CI]: 0.004, 0.38; P = 0.005) and 0.02 (95% CI: 0.002, 0.24; P = 0.001), respectively. No significant difference was found between MWA and RFA with an OR of 0.63 (95% CI: 0.04, 10.39; P = 0.745). Regarding the major complications, RFA, MWA, and cryoablation showed the comparable safety (P > 0.05).

CONCLUSION:

RFA and MWA offer an advantage over cryoablation for patients with malignant lung tumors.

Pathologic Diagnosis and Genetic Analysis of a Lung Tumor Needle Biopsy Specimen Obtained Immediately After Radiofrequency Ablation

PURPOSE

To evaluate the possibility of pathologic diagnosis and genetic analysis of percutaneous core-needle biopsy (CNB) lung tumor specimens obtained immediately after radiofrequency ablation (RFA).

MATERIALS AND METHODS

Patients who underwent CNB of lung tumors immediately after RFA from May 2013 to May 2016 were analyzed. There were 19 patients (8 men and 11 women; median age, 69 years; range, 52-88 years) and 19 lung tumors measuring 0.5-2.6 cm (median, 1.6 cm). Thirteen tumors were solid, and 6 were predominantly ground-glass opacity (GGO) on computed tomography. All specimens were pathologically examined using hematoxylin and eosin (H&E) staining and additional immunostaining, as necessary. The specimens were analyzed for EGFR and KRAS genetic mutations. The safety and technical success rate of the procedure and the possibility of pathologic diagnosis and genetic mutation analysis were evaluated.

RESULTS

Major and minor complication rates were 11% (2/19) and 53% (10/19), respectively. Tumor cells were successfully obtained in 16 cases (84%, 16/19), and technical success rate was significantly lower for GGO-dominant tumors (50%, 3/6) compared with solid lesions (100%, 13/13, p = 0.02). Pathologic diagnosis was possible in 79% (15/19) of cases based on H&E staining alone (n = 12) and with additional immunostaining (n = 3). Although atypical cells were obtained, pathologic diagnosis could not be achieved in 1 case (5%, 1/19). Both EGFR and KRAS mutations could be analyzed in 74% (14/19) of the specimens.

CONCLUSION

Pathologic diagnosis and genetic analysis could be performed even for lung tumor specimens obtained immediately after RFA.

The Importance of Biopsy in the Era of Molecular Medicine

Recent advances in the molecular characterization of cancers have triggered interest in developing a new taxonomy of disease in oncology with the goal of using the molecular profile of a patient's tumor to predict response to treatment. Image-guided needle biopsy is central to this "precision medicine" effort. In this review, we first discuss the current role of biopsy in relation to clinical examples of molecular medicine. We then outline important bottlenecks to the advancement of precision medicine and highlight the potential role of image-guided biopsy to address these challenges.

Radiofrequency ablation of pulmonary tumors near the diaphragm

PURPOSE

To retrospectively evaluate the feasibility, safety, and efficacy of radiofrequency ablation (RFA) of lung tumors located near the diaphragm.

MATERIALS AND METHODS

A total of 26 patients (15 men, 11 women; mean age, 61.5 years±13.0 [SD]) with a total of 29 lung tumors near the diaphragm (i.e., distance<10mm) were included. Mean tumor diameter was 11.0mm±5.3 (SD) (range, 2-23mm). Efficacy of RFA, number of adverse events and number of adverse events with a grade≥3, based on the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0, were compared between patients with lung tumors near the diaphragm and a control group of patients with more distally located lung tumors (i.e., distance≥10mm).

RESULTS

RFA was technically feasible for all tumors near the diaphragm. Four grade 3 adverse events (1 pneumothorax requiring pleurodesis and 3 phrenic nerve injuries) were observed. No grade≥4 adverse events were reported. The median follow-up period for tumors near the diaphragm was 18.3 months. Local progression was observed 3.3 months after RFA in 1 tumor. The technique efficacy rates were 96.2% at 1 year and 96.2% at 2 years and were not different, from those observed in control subjects (186 tumors; P=0.839). Shoulder pain (P<0.001) and grade 1 pleural effusion (P<0.001) were more frequently observed in patients with lung tumor near the diaphragm. The rates of grade≥3 adverse events did not significantly differ between tumors near the diaphragm (4/26 sessions) and the controls (7/133 sessions) (P=0.083).

CONCLUSION

RFA is a feasible and effective therapeutic option for lung tumors located near the diaphragm. However, it conveys a higher rate of shoulder pain and asymptomatic pleural effusion by comparison with more distant lung tumors.

Evaluation of carcinoembryonic antigen (CEA) density as a prognostic factor for percutaneous ablation of pulmonary colorectal metastases

OBJECTIVES

To evaluate the prognostic value of carcinoembryonic antigen (CEA) density and other clinicopathological factors for percutaneous ablation of pulmonary metastases from colorectal cancer.

METHODS

CEA density was calculated as: "absolute serum CEA pre-ablation/volume of all lung metastases [mm3]". Median CEA density was the cut-off for high and low groups. Cox-regression was used to determine prognostic factors for survival.

RESULTS

A total of 85 patients (102 ablation sessions) were followed for a median of 27 months. High CEA density was significantly associated with worse overall survival compared to low CEA density (adjusted HR: 2.12; 95 % CI: 1.22-3.70, p=0.002; median survival: 25.7 vs. 44.3 months). The interval between primary resection of the colorectal carcinoma and first ablation was also a prognostic factor, a duration >24 months being associated with better survival compared to a shorter interval (0-24 months) (adjusted HR: 0.55; 95 % CI: 0.31-0.98, p=0.04). Moreover, a disease-free interval >24 months was significantly associated with low CEA density compared to a shorter interval (0-24 months) (adjusted OR: 0.29; 95 % CI: 0.11-0.77, p=0.01).

CONCLUSIONS

Serum CEA density and interval between primary resection of a colorectal carcinoma and pulmonary ablation are independent prognostic factors for overall survival. In two patients with identical CEA serum levels, the patient with the lower/smaller pulmonary tumour load would have a worse prognosis than the one with the higher/larger pulmonary metastases.

KEY POINTS

• CEA density is an independent prognostic factor for colorectal pulmonary metastases. • A lower CEA density is associated with better overall survival. • CEA may play a functional role in tumour progression. • High CEA density is associated with smaller tumours. • Interval between pulmonary ablation and primary colorectal carcinoma is a prognostic factor.

Comparison of the Effectiveness of Radiofrequency Ablation With Stereotactic Body Radiation Therapy in Inoperable Stage I Non-Small Cell Lung Cancer: A Systemic Review and Pooled Analysis

PURPOSE

To performed a systematic review and pooled analysis to compare clinical outcomes of stereotactic body radiation therapy (SBRT) and radiofrequency ablation (RFA) for the treatment of medically inoperable stage I non-small cell lung cancer.

METHODS AND MATERIALS

A comprehensive literature search for published trials from 2001 to 2012 was undertaken. Pooled analyses were performed to obtain overall survival (OS) and local tumor control rates (LCRs) and adverse events. Regression analysis was conducted considering each study's proportions of stage IA and age.

RESULTS

Thirty-one studies on SBRT (2767 patients) and 13 studies on RFA (328 patients) were eligible. The LCR (95% confidence interval) at 1, 2, 3, and 5 years for RFA was 77% (70%-85%), 48% (37%-58%), 55% (47%-62%), and 42% (30%-54%) respectively, which was significantly lower than that for SBRT: 97% (96%-98%), 92% (91%-94%), 88% (86%-90%), and 86% (85%-88%) (P<.001). These differences remained significant after correcting for stage IA and age (P<.001 at 1 year, 2 years, and 3 years; P=.04 at 5 years). The effect of RFA was not different from that of SBRT on OS (P>.05). The most frequent complication of RFA was pneumothorax, occurring in 31% of patients, whereas that for SBRT (grade ≥3) was radiation pneumonitis, occurring in 2% of patients.

CONCLUSIONS

Compared with RFA, SBRT seems to have a higher LCR but similar OS. More studies with larger sample sizes are warranted to validate such findings.

Lung Adenocarcinoma: Predictive Value of KRAS Mutation Status in Assessing Local Recurrence in Patients Undergoing Image-guided Ablation

Purpose To establish the relationship between KRAS mutation status and local recurrence after image-guided ablation of lung adenocarcinoma. Materials and Methods This study consisted of a HIPAA-compliant institutional review board-approved retrospective review of 56 primary lung adenocarcinomas in 54 patients (24 men, 30 women; median age, 72 years; range, 54-87 years) treated with percutaneous image-guided ablation and with available genetic mutational analysis. KRAS mutation status and additional clinical and technical variables-Eastern Cooperative Oncology Group (ECOG) status, smoking history, stage at diagnosis, status (new primary or not), history of radiation, history of surgery, prior systemic treatment, modality of ablation, size of nodule, ablation margin, and presence of ground-glass appearance-were recorded and evaluated in relation to time to local recurrence, which was calculated from the time of ablation to the first radiographic evidence of recurrence. Predictors of outcome were identified by using a proportional hazards model for both univariate and multivariate analysis, with death as a competing risk. Results Technical success was 100%. Of the 56 ablated tumors, 37 (66%) were wild type for KRAS and 19 (34%) were KRAS mutants. The 1-year and 3-year cumulative incidences of recurrence were 20% and 35% for wild-type KRAS compared with 40% and 63% for KRAS mutant tumors. KRAS mutation status was a significant predictor of local recurrence at both univariate (P = .05; subdistribution hazard ratio [sHR], 2.32) and multivariate (P = .006; sHR, 3.75) analysis. At multivariate analysis, size (P = .026; sHR, 2.54) and ECOG status (P = .012; sHR, 2.23) were also independent significant predictors, whereas minimum margin (P = .066) was not. Conclusion The results of this study show that there is a relationship between KRAS mutation status and local recurrence after image-guided ablation of lung adenocarcinoma. Specifically, KRAS mutation status of the ablated lesion is a significant predictor of time to local recurrence, independent of size and margin. ^© RSNA, 2016.

Transosseous Route for CT Fluoroscopy-Guided Radiofrequency Ablation of Lung Tumors

PURPOSE

To retrospectively evaluate radiofrequency (RF) ablation of lung tumors performed via the transosseous approach.

MATERIALS AND METHODS

Twelve lung tumors (mean diameter, 1.0 cm; range, 0.4-1.6 cm) in 12 patients were treated by RF ablation via a transscapular and/or transrib route with the use of a bone biopsy needle under computed tomographic fluoroscopy guidance. Therapeutic outcomes evaluated included feasibility, safety, and local efficacy. Complications were assessed based on the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0.

RESULTS

The transosseous route was successfully employed in all patients, and the electrode was successfully advanced into all tumors with this approach. The mean distance of penetrated bone was 0.57 cm (range, 0.19-1.16 cm). Complications occurred in eight RF ablation sessions, including six grade 1 events (two cases of pneumothorax and one case each of asymptomatic rib fracture 6 mo after treatment, neuralgia, pulmonary hemorrhage, and hemothorax), two grade 2 events (pneumonia and high fever), and one grade 3 event (pneumothorax requiring pleurodesis). No adverse events of grade ≥ 4 occurred. The mean and median tumor follow-up periods were 19.5 and 15.2 mo (range, 3.0-41.5 mo). Local progression occurred in two cases at 3 and 12 mo after treatment and was successfully treated with a second RF ablation procedure. The technique efficacy rates were 91.7% at 6 mo, 81.5% at 1 y, and 81.5% at 2 y.

CONCLUSIONS

The transosseous approach was feasible in computed tomographic fluoroscopy-guided RF ablation of select lung tumors when no other option was available.

Radiofrequency Ablation of Lung Tumors Using a Multitined Expandable Electrode: Impact of the Electrode Array Diameter on Local Tumor Progression

PURPOSE

To retrospectively investigate the impact of the electrode array diameter on local tumor progression after lung radiofrequency ablation.

MATERIALS AND METHODS

This study included 651 lung tumors treated using multitined expandable electrodes and followed for ≥ 6 months. The mean long-axis tumor diameter was 12 mm ± 7 (range, 2-42 mm). The difference between electrode array diameter and tumor diameter (DAT) was used to investigate the impact of the electrode array diameter. All tumors were classified into 2 groups according to various variables including DAT (≥ 10 mm or < 10 mm). The primary technique efficacy rates were calculated using Kaplan-Meier analysis and compared between the 2 groups of each variable using the log-rank test. In addition, crude and multivariate multilevel survival analyses were performed by sequentially including DAT and the other variables in 5 models.

RESULTS

The median DAT for 651 tumors was 12 mm (range, -15 to 24 mm). The technique efficacy rate was significantly lower in the < 10 mm DAT group than in the ≥ 10 mm group (P < .001). In the crude and multivariate multilevel survival analyses, < 10 mm DAT was a significant risk factor for local progression in all models except model 5 (P = .067). In the ≥ 10 mm group, the technique efficacy rates were not significantly different between the 2 ≥ 10 mm DAT subgroups (10 to <15 mm DAT vs ≥ 15 mm DAT).

CONCLUSIONS

DAT is an important risk factor for local progression. We recommend an electrode that is ≥ 10 mm larger than the tumor diameter.

The efficacy of radio-frequency ablation for metastatic lung or liver tumors of male germ cell tumors as an alternative minimally invasive therapy after salvage chemotherapy

BACKGROUND

The aim of this study was to assess the efficacy of radio-frequency ablation (RFA) for metastatic lung or liver tumors of germ cell tumors (GCTs) after chemotherapy.

METHODS

RFA with computed tomography guidance and monitoring was performed in 24 patients with 48 metastatic lung or liver tumors of GCTs. Group A consisted of 9 patients with tumor marker normalization after salvage chemotherapy and group B consisted of 15 patients without tumor marker normalization in spite ofintensive treatment.

RESULTS

Out of 48 tumors, 41 tumors in 21 patients were evaluated for the efficacy of the RFA treatment. Of the 41 tumors, successful ablation was achieved in 34 (82.9 %). The patients in group A had significantly better survival than the patients in group B (p = 0.0003). In group A, all 9 patients are still alive with no evidence of disease (NED). Patients with a solitary tumor had significantly better survival than those with multiple tumors (p = 0.0247). In group B, 2 patients are alive with NED, 1 patient is alive with disease, and the remaining 12 patients have died a tumor-related death. Three cases of pneumothorax requiring intubation were observed.

CONCLUSIONS

RFA is less invasive than surgery and is an effective treatment option for curative and palliative therapy as an alternative to invasive salvage surgery for post-chemotherapeutic metastatic lung or liver lesions from GCT.

Radiofrequency ablation of lung metastases from adenoid cystic carcinoma of the head and neck: retrospective evaluation of nine patients

PURPOSE

To retrospectively evaluate the outcomes of radiofrequency (RF) ablation of lung metastases from head and neck adenoid cystic carcinoma (ACC).

MATERIALS AND METHODS

Nine patients (two men and seven women; mean age, 61.6 y) with 45 lung metastases (mean diameter, 1.1 cm; range, 0.4-2.7 cm) from head and neck ACC underwent RF ablation in 30 sessions. Primary endpoints were technical success, technique effectiveness, and procedural complications. Secondary endpoints included overall survival (OS).

RESULTS

RF ablation was technically successful for all 45 metastases. The median tumor follow-up period was 37.1 months (range, 12.9-128.3 mo). Local progression occurred in six tumors, two of which were treated again and subsequently showed complete response. Major complications (pneumothorax requiring chest tube placement) occurred in five sessions (16.7%). The median patient follow-up period was 61.6 months (range, 20.5-134.5 mo). Two patients died of disease progression at 38.9 and 61.6 months after RF ablation, respectively, whereas the other seven remained alive at the end of the study. OS rates from the initial RF ablation were 100% at 3 years and 83.3% at 5 years (mean survival time, 106.4 mo). OS rates from the treatment of the primary site were 100% at 5 years and 62.5% at 10 years (mean survival time, 210.1 mo).

CONCLUSIONS

Radiofrequency ablation is an acceptable and effective local treatment for lung metastases from head and neck ACC. However, further study is needed to evaluate its effect on patient survival.

Radiofrequency ablation of metastases from osteosarcoma in patients under 25 years: the SCFE experience

BACKGROUND

Radiofrequency ablation (RFA) has demonstrated its effectiveness in controlling metastases measuring less than 3 cm in several adult malignancies but not yet in osteosarcoma. We report our experience of RFA in the treatment of metastases in adolescents and young adults (AYA) with osteosarcoma.

PROCEDURE

Sixteen patients treated for osteosarcoma in French Society of Childhood Cancer centers had undergone an RFA procedure between 2006 and 2012.

RESULTS

Thirteen sessions were performed in 10 patients to treat 22 lung metastases. Seven patients were in complete remission at last follow up (range 19-51 months; median, 24 months after RFA). None had a recurrence at RFA sites. We report three cases each of hemoptysis and pneumothorax. Eight sessions were performed in seven patients to treat bone lesions. PROCEDURE was intended as: curative for a small metastatic lesion (n = 3, all in remission more than 3 years after); local control of small bone lesions in multi-metastatic diseases (n = 3); analgesia (n = 1). Complications included one first-degree burn, one fracture, and one soft tissue infection.

CONCLUSIONS

RFA is feasible in AYA with osteosarcoma. It efficiently achieved local control of small peripheral lung metastases. Its role in the curative care of small secondary bone lesions remains to be confirmed.

Lung radiofrequency and microwave ablation: a review of indications, techniques and post-procedural imaging appearances

Lung ablation can be used to treat both primary and secondary thoracic malignancies. Evidence to support its use, particularly for metastases from colonic primary tumours, is now strong, with survival data in selected cases approaching that seen after surgery. Because of this, the use of ablative techniques (particularly thermal ablation) is growing and the Royal College of Radiologists predict that the number of patients who could benefit from such treatment may reach in excess of 5000 per year in the UK. Treatment is often limited to larger regional centres, and general radiologists often have limited awareness of the current indications and the techniques involved. Furthermore, radiologists without any prior experience are frequently expected to interpret post-treatment imaging, often performed in the context of acute complications, which have occurred after discharge. This review aims to provide an overview of the current indications for pulmonary ablation, together with the techniques involved and the range of post-procedural appearances.

Lung cancer ablation: what is the evidence?

Percutaneous ablation of small non-small cell lung cancer (NSCLC) has been demonstrated to be both feasible and safe in nonsurgical candidates. Radiofrequency ablation (RFA), the most commonly used technique for ablation, has a reported rate of complete ablation of ~90%, with best results obtained in tumors <2 to 3 cm in diameter. The best reported 1-, 3-, and 5-year overall survival rates after RFA of NSCLC are 97.7%, 72.9%, and 55.7%, respectively. It is noteworthy that in most studies, cancer-specific survival is greater than overall survival due to severe comorbidities in patients treated with RFA for NSCLC. Aside from tumor size and tumor stage, these comorbidities are predictive of survival. Other ablation techniques such as microwave and irreversible electroporation may in the future prove to overcome some of the limitations of RFA, namely for large tumors or tumors close to large vessels. Stereotactic body radiation therapy has also been demonstrated to be highly efficacious in treating small lung tumors and will need to be compared with percutaneous ablation. This article reviews the current evidence regarding RFA for lung cancer.

Percutaneous radiofrequency ablation of lung cancer presenting as ground-glass opacity

PURPOSE

We retrospectively evaluated the outcomes of lung cancer patients presenting with ground-glass opacity (GGO) who received radiofrequency ablation (RFA).

METHODS

Sixteen patients (5 men and 11 women; mean age, 72.6 years) with 17 lung cancer lesions showing GGO (mean long axis diameter, 1.6 cm) underwent a total of 20 percutaneous computed tomography (CT) fluoroscopy-guided RFA sessions, including three repeated sessions for local progression. Lung cancer with GGO was defined as a histologically confirmed malignant pulmonary lesion with a GGO component accounting for >50 % of the lesion on high-resolution CT. Procedure outcomes were evaluated.

RESULTS

There were no major complications. Pneumothorax occurred in 15 of 20 treatment sessions: 14 were asymptomatic, and 1 required chest tube placement but resolved satisfactorily within 48 h. Minor pulmonary hemorrhage occurred in two and mild pneumonitis in one. The median tumor follow-up period was 61.5 (range 6.1-96.6) months. The effectiveness rates of the primary and secondary techniques were 100 and 100 % at 1 year, 93.3 and 100 % at 2 years, and 78.3 and 92.3 % at 3 years, respectively. The median patient follow-up period was 65.6 (range 6.1-96.6) months. One patient died owing to recurrent other cancer 11.7 months after RFA, whereas the other 15 remained alive. Overall survival and disease-specific survival rates were 93.3 and 100 % at 1 year and 93.3 and 100 % at 5 years, respectively.

CONCLUSIONS

RFA for lung cancer with GGO was safe and effective, and resulted in promising survival rates.

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

Surgery is considered the best choice for stage I non-small cell lung cancer and also in treatment of selected patients with lung metastasis. However, surgery is often a high-risk procedure because of severe medical comorbidities affecting this cohort of patients. Thermal ablation (TA) has recently been proposed to achieve destruction of lung tumours whilst avoiding the use of general anaesthesia, thereby limiting the invasiveness of the procedure. For pulmonary malignancies, there are two methods of TA based on tissue heating: radio frequency ablation (RFA) and microwave ablation (MWA). Both are mini-invasive procedures, delivering energy to the tumour through single or multiple percutaneous needles introduced under guidance of computed tomography. The procedure may be performed under conscious sedation or general anaesthesia to avoid pain caused by needle insertion and tissue heating. Local efficacy is directly correlated to tumour target size: for RFA, tumours smaller than 2 cm can be completed ablated in 78-96% of cases; for MWA-according to the largest available study-95% of initial ablations are reported to be successful for tumours smaller than 5 cm. Very few series provide survival data beyond 3 years. For nodules smaller than 3 cm, the registered survival rate is higher: 50% at five years. The data collected in the last 10 years allow us to conclude that TA is an established alternative treatment for patients who cannot undergo surgery because of their compromised general condition. In the case of pulmonary metastasis, most authors agree to offer TA only if lesions are smaller than 5 cm.

Radiofrequency ablation of lung tumours

Pulmonary radiofrequency ablation (RFA) has become an increasingly adopted treatment option for primary and metastatic lung tumours. It is mainly performed in patients with unresectable or medically inoperable lung neoplasms. The immediate technical success rate is over 95%, with a low periprocedural mortality rate and 8–12% major complication rate. Pneumothorax represents the most frequent complication, but requires a chest tube drain in less than 10% of cases. Sustained complete tumour response has been reported in 85–90% of target lesions. Lesion size represents the most important risk factor for local recurrence. Survival data are still scarce, but initial results are very promising. In patients with stage I non-small-cell lung cancer, 1- and 2-year survival rates are within the ranges of 78–95% and 57–84%, respectively, with corresponding cancer-specific survival rates of 92% and 73%. In selected cases, the combination of RFA and radiotherapy could improve these results. In patients with colorectal lung metastasis, initial studies have reported survival data that compare favourably with the results of metastasectomy, with up to a 45% 5-year survival rate. Further studies are needed to understand the potential role of RFA as a palliative treatment in more advanced disease and the possible combination of RFA with other treatment options.

Evaluation of treatment response after nonoperative therapy for early-stage non-small cell lung carcinoma

Nonsurgical management of early primary lung cancer has grown tremendously in recent years, and today, available options extend far beyond that of conventional radiation therapy (CRT) to include minimally invasive image-guided delivery of thermal energies, specifically radiofrequency ablation, microwave ablation, and cryoablation, and more conformal stereotactic body radiation therapy. Because the tumor is never resected with these nonoperative interventions, histopathological evaluation of tumor margins for the presence of residual tumor is impossible, and as such, tumor response after each of these therapies is largely based on imaging. To date, computerized tomography and computerized tomography-positron emission tomography remain the most readily available modalities for assessment of therapeutic efficacy, and to this end as detailed within this article, strict imaging survey and familiarity with the expected imaging characteristics of the treated tumor will aid in recognition of unexpected findings, specifically those of incomplete therapy and/or tumor recurrence.