Radiofrequency ablation of pulmonary metastases from sarcoma: single-center retrospective evaluation of 46 patients

Update on Percutaneous Ablation for Sarcoma

PURPOSE OF REVIEW

To provide an update on the current state of percutaneous thermal ablation in the treatment of sarcoma.

RECENT FINDINGS

Data continue to accrue in support of ablation for local control and palliation of specific sarcoma subtypes such as extra-abdominal desmoid fibromatosis and for broader indications such as the treatment of oligometastatic disease. The synergistic possibilities of various combination therapies such as cryoablation and immunotherapy represent intriguing areas of active investigation. Histotripsy is an emerging non-invasive, non-thermal ablative modality that may further expand the therapeutic arsenal for sarcoma treatment. Percutaneous thermal ablation is a valuable tool in the multidisciplinary management of sarcoma, offering a minimally invasive adjunct to surgery and radiation therapy. Although there remains a paucity of high-level evidence specific to sarcomas, ablation techniques are demonstrably safe and effective for achieving local tumor control and providing pain relief in select patients and are of particular benefit in those with metastatic disease or requiring palliative care.

Ablative Techniques for Sarcoma Metastatic Disease: Current Role and Clinical Applications

Sarcomas are heterogenous mesenchymal neoplasms with more than 80 different histologic subtypes. Lung followed by liver and bone are the most common sites of sarcoma metastatic disease. Ablative techniques have been recently added as an additional alternative curative or palliative therapeutic tool in sarcoma metastatic disease. When compared to surgery, ablative techniques are less invasive therapies which can be performed even in non-surgical candidates and are related to decreased recovery time as well as preservation of the treated organ’s long-term function. Literature data upon ablative techniques for sarcoma metastatic disease are quite heterogeneous and variable regarding the size and the number of the treated lesions and the different histologic subtypes of the original soft tissue or bone sarcoma. The present study focuses upon the current role of minimal invasive thermal ablative techniques for the management of metastatic sarcoma disease. The purpose of this review is to present the current minimally invasive ablative techniques in the treatment of metastatic soft tissue and bone sarcoma, including local control and survival rates.

Up-to-date evidence on image-guided thermal ablation for metastatic lung tumors: a review

The aim of this review was to summarize the latest evidence on image-guided thermal ablation therapies for lung metastases. PubMed was used to search for relevant articles that reported the oncological outcomes of thermal ablation for metastatic lung tumors, and those published in 2010 or later were selected for review. Ablative therapies were applied for lung metastases from various types of primary tumors, but most commonly colorectal ones. Radiofrequency ablation (RFA) was the most evaluated technique, followed by microwave ablation (MWA). The local control rates of ablative therapies were generally favorable, approximately 80–90% in many studies. Representative studies demonstrated promising overall survival rates of approximately 50% or higher 5 years after ablation for lung metastases from colorectal cancer or mixed types of primary tumors. Nevertheless, the survival outcomes varied depending on the type of primary tumor and background factors of patients such as other metastases and comorbidities. Several studies had aimed to compare the outcomes of various ablative therapies such as RFA, MWA, and cryoablation; however, conclusive data are not yet available to determine the most appropriate ablation modality for lung metastases. Further data accumulation is needed, especially for long-term outcomes and comparisons with other therapies.

Image-Guided Percutaneous Ablation for Primary and Metastatic Tumors

Image-guided percutaneous ablation methods have been further developed during the recent two decades and have transformed the minimally invasive and precision features of treatment options targeting primary and metastatic tumors. They work by percutaneously introducing applicators to precisely destroy a tumor and offer much lower risks than conventional methods. There are usually shorter recovery periods, less bleeding, and more preservation of organ parenchyma, expanding the treatment options of patients with cancer who may not be eligible for resection. Image-guided ablation techniques are currently utilized for the treatment of primary and metastatic tumors in various organs including the liver, pancreas, kidneys, thyroid and parathyroid, prostate, lung, bone, and soft tissue. This article provides a brief review of the various imaging modalities and available ablation techniques and discusses their applications and associated complications in various organs.

A Systematic Review and Meta-analysis of Patient Survival and Disease Recurrence Following Percutaneous Ablation of Pulmonary Metastasis

BACKGROUND

Pulmonary metastasectomy has been widely adopted in the treatment of metastatic disease. In recent years image guided ablation has seen increased use in the treatment of thoracic malignancies. The objective of this study was to evaluate oncological outcomes following percutaneous ablation (PA) of pulmonary metastasis.

METHODS

A comprehensive search of the PubMed, MEDLINE and EMBASE databases from January 2000 to August 2021 was performed to identify studies evaluating patient survival following ablation of lung metastasis. Pooled outcomes have been presented with a random effects model to assess primary outcomes of overall survival, progression free survival and 1-year local control. Secondary outcomes included procedural mortality, major complications, and the incidence of pneumothorax.

RESULTS

A total of 24 studies were identified. The pooled median overall survival was 5.13 [95% confidence interval (CI): 4.37-6.84] years, and the 1-, 3-, 5-year progression free survival rates were 53%, 26% and 20% respectively. The 1-year local control rate was 91% (95%CI: 86-95%). Periprocedural mortality was rare (0%; 95%CI: 0-1%), as were major complications excluding pneumothorax (1%; 95%CI: 1-2%). Pneumothorax developed in 44% of ablation sessions, although only half of these required chest tube placement. Most patients were able to be discharged day one post-procedurally.

CONCLUSION

PA demonstrates high overall, progression free and local tumour survival in patients with lung metastasis. Complications and mortality are also rare. Consideration of its use should be made in a tumour board meeting in conjunction with surgical and radiotherapy perspectives for targeted local control of metastases.

Comparison of Percutaneous Image-Guided Microwave and Cryoablation for Sarcoma Lung Metastases: 10-Year Experience

Background: Outcomes between percutaneous microwave (MWA) and cryoablation of sarcoma lung metastases have not been compared to our knowledge. Objective: To compare technical success, complications, local tumor control, and overall survival (OS) following MWA versus cryoablation of sarcoma lung metastases. Methods: This retrospective cohort study included 27 patients (16 women, 11 men; median age 64 years; Eastern Cooperative Oncology Group performance score 0-2) who underwent 39 percutaneous CT-guided ablation sessions (21 MWA, 18 cryoablation; 1-4 sessions per patient) to treat 65 sarcoma lung metastases (median 1 tumor per patient, range 1-12; median tumor diameter 11 mm, range 5-33 mm; 25% non-peripheral) from 2009 to 2021. We compared complications by ablation modality using generalized-estimating equations. We evaluated ablation modality, tumor size, and location (peripheral vs non-peripheral) in relation to local tumor progression using proportional Cox hazard models with death as competing risk. We estimated OS using the Kaplan-Meier method. Results: Primary technical success was 97% for both modalities. Median follow-up was 23 months (range: 1-102 months; interquartile range: 12, 44 months). A total of 7/61 (12%) tumors progressed. Estimated 1-year and 2-year local control rates were, for tumors >1 cm, 97% and 95% following MWA versus 99% and 98% following cryoablation, and for tumors ≤1 cm, 74% and 62% following MWA versus 86% and 79% following cryoablation. Tumor size ≤1 cm was associated with decreased cumulative incidence of local progression (p =.048); ablation modality and tumor location were not associated with progression (p =.86; p =.54). Complications (CTCAE grade ≤3) occurred in 17/39 sessions (44%), prompting chest tube placement in nine (23%). No complications with grade ≥4 occurred. OS at 1-, 2-, and 3-years was 100%, 89%, and 82%, respectively. Conclusion: High primary technical success, local control, and OS support MWA and cryoablation for treating sarcoma lung metastases. Ablation modality and tumor location did not affect local progression. Treatment failure was low, especially for small tumors. No life-threatening complications occurred. Clinical Impact: Percutaneous MWA and cryoablation are both suited for treatment of sarcoma lung metastases, especially for tumors ≤1 cm, whether peripheral or non-peripheral. Complications, if they occur, are not life-threatening.

Non-surgical Treatments for Lung Metastases in Patients with Soft Tissue Sarcoma: Stereotactic Body Radiation Therapy (SBRT) and Radiofrequency Ablation (RFA)

BACKGROUND

Radio-frequency ablation (RFA) and Stereotactic Body Radiation Therapy (SBRT) are two emerging therapies for lung metastases.

INTRODUCTION

Aliterature review was performed to evaluate the outcomes and complications of these procedures in patients with lung metastases from soft tissue sarcoma (STS).

METHODS

After selection, seven studies were included for each treatment encompassing a total of 424 patients: 218 in the SBRT group and 206 in the RFA group.

RESULTS

The mean age ranged from 47.9 to 64 years in the SBRT group and from 48 to 62.7 years in the RFA group. The most common histologic subtype was, in both groups, leiomyosarcoma. In the SBRT group, median overall survival ranged from 25.2 to 69 months and median disease- free interval was from 8.4 to 45 months. Two out of seven studies reported G3 and one G3 toxicity, respectively. In RFA patients, overall survival ranged from 15 to 50 months. The most frequent complication was pneumothorax. Local control showed a high percentage for both procedures.

CONCLUSION

SBRT is recommended in patients unsuitable to surgery, in synchronous bilateral pulmonary metastases, in case of deep lesions and patients receiving high-risk systemic therapies. RFA is indicated in case of a long disease-free interval, in oligometastatic disease, when only the lung is involved, in small size lesions far from large vessels. Further large randomized studies are necessary to establish whether these treatments may also represent a reliable alternative to surgery.

Recent Imaging Advancements for Lung Metastases in Children with Sarcoma

In children and adolescents affected by musculoskeletal sarcomas (both soft tissue and bone sarcomas), the presence of lung metastases is a frequent complication, that should be known since the patient's prognosis, as management, and treatment depend on it. During the staging phase, the detection of lung metastases should be sensitive and specific, and it should be carried out by minimizing the radiation exposure. To deal with this problem, imaging has reached important goals in recent years, thanks to the development of cone-beam CT or low-dose computed tomography, with some new iterative reconstruction methods, such as Veo and ASIR. Imaging is also fundamental for the possibility to perform lung biopsies under CT guidance, with less morbidity, less time-consumption, and shorter recovery time, compared to surgical biopsies.Moreover, important results have also been demonstrated in the treatment of lung metastases, due to the improvement of new mini-invasive image-guided percutaneous thermal ablation procedures, which proved to be safe and effective also in young patients.

A Simple Prognostic Benefit Scoring System for Sarcoma Patients with Pulmonary Metastases: Sarcoma Lung Metastasis Score

BACKGROUND

Pulmonary metastasectomy could be considered one of the treatment options for disease control in sarcoma patients with pulmonary metastases; however, there is little consensus regarding the suitable criteria for predicting the likely outcomes in these patients. The aim of this study was to establish a prognostic benefit scoring system based on preoperatively examined prognostic factors for sarcoma patients with pulmonary metastases.

METHODS

This was a single-center, retrospective cohort study conducted in a cohort of 135 sarcoma patients who underwent a first pulmonary metastasectomy at Okayama University Hospital between January 2006 and December 2015. Based on the results of a multivariable logistic regression analysis performed to determine the factors influencing 3-year mortality, a Sarcoma Lung Metastasis Score was created and its correlation with 3-year survival was analyzed.

RESULTS

The results of the multivariate analysis revealed significant differences in the disease-free interval (< 2 years vs. ≥ 2 years; odds ratio (OR) 4.22, 95% confidence interval (CI) 1.67-10.70), maximum tumor diameter (≥ 15 mm vs. < 15 mm; OR 3.86, 95% CI 1.75-8.52), and number of pulmonary metastases (≥ 6 vs. < 6; OR 2.65, 95% CI 1.06-6.620). The Sarcoma Lung Metastasis Score, which was defined as the total score of these three factors, reliably predicted 3-year survival (score: 0, 89.5%; 1, 63.2%; 2, 39.0%; 3, 10.5%).

CONCLUSIONS

Our newly proposed simple Sarcoma Lung Metastasis Score appears to be a useful prognostic predictor for sarcoma patients with pulmonary metastases, in that it could be helpful for the selection of appropriate treatments for these patients.

The neutrophil-to-lymphocyte ratio as a novel independent prognostic factor for multiple metastatic lung tumors from various sarcomas

PURPOSE

Sarcomas are among the most refractory malignant tumors and often recur as pulmonary metastasis. Although the presence of a high neutrophil-to-lymphocyte ratio (NLR) has been associated with the prognosis of several malignancies, the relationship between the NLR and sarcoma with pulmonary metastasis is unclear. We investigated the impact of the NLR in patients who underwent surgical resection for metastatic lung tumors from various sarcomas.

METHODS

The subjects of this retrospective study were 158 patients with metastatic lung tumors from various sarcomas, who underwent initial pulmonary metastasectomy between 2006 and 2015. We examined the clinicopathological variables, including the NLR and the characteristics of surgical procedures. Survival was estimated by the Kaplan-Meier method and prognostic factors were evaluated by multivariate analysis.

RESULTS

Multivariate analysis revealed significantly better survival of the group with an NLR < 2.26 immediately before the most recent pulmonary metastasectomy, in addition to such factors as the largest resected lesion being < 22 mm, a disease-free interval of > 2 years, and 3 or more pulmonary metastasectomies.

CONCLUSION

The NLR immediately before the most recent pulmonary metastasectomy is a novel independent prognostic factor, which may be helpful when considering repeated pulmonary metastasectomy.

Analysis of the Chemotherapy-Free Interval following Image-Guided Ablation in Sarcoma Patients

One way to enhance quality of life for patients with metastatic sarcoma is to maximize time off chemotherapy—a chemotherapy-free interval. While image-guided ablation of sarcoma metastases may reduce the need for chemotherapy, it remains unknown how long ablation could extend the chemotherapy-free interval. The purpose of our study was to determine the chemotherapy-free interval in comparison to overall survival and progression-free survival in sarcoma patients who undergo ablation procedures. An IRB-approved, single institution, HIPAA compliant database was queried for sarcoma patients who underwent image-guided ablation procedures between 2007 and 2018. Patient demographics, histologic subtype, and other clinical characteristics were recorded. Kaplan-Meier analysis was performed to compute median overall survival, median progression-free survival (local and distant), and the median chemotherapy-free interval (systemic and cytotoxic) after ablation. Univariate and multivariate analyses were performed using the log-rank test and Cox proportional-hazards model, respectively. A total of 100 sarcoma patients were included in the analysis. The most common histologic subtype was leiomyosarcoma (38%). Median overall survival after ablation of sarcoma metastases was 52.4 months (95% CI: 46.9–64.0 months). The median systemic chemotherapy-free interval following ablation of sarcoma metastases was 14.7 months (95% CI: 8.6–34.3 months). The median cytotoxic chemotherapy-free interval following ablation of sarcoma metastases was 81.3 months (95% CI: 34.3-median not reached). In conclusion, ablation of sarcoma metastases can provide an extended systemic chemotherapy-free interval of greater than 1 year. Ablation of sarcoma metastases may improve patient quality of life by extending the chemotherapy-free interval.

Image-Guided Thermal Ablative Therapies in the Treatment of Sarcoma

OPINION STATEMENT

Percutaneous thermal ablation, including microwave ablation (MWA), radiofrequency ablation (RFA), and cryoablation, is a well-established focal treatment option for primary and metastatic malignancies. While published literature specific to ablation of sarcomas is relatively lacking compared with non-sarcomatous malignancies, what is available is promising. In situations where a focal treatment option is desired, strong consideration should be given to percutaneous thermal ablation, in addition to surgery and radiation therapy. A significant advantage of percutaneous thermal ablation over surgery and radiation includes the repeatability of ablation, as there is no absolute limit on the number of times an ablation can be performed. Compared with surgery, ablation offers the potential of decreased recovery time, a less invasive procedure, and is often performed in patients deemed not medically fit for surgery.