Comparison of expected imaging findings following percutaneous microwave and cryoablation of pulmonary tumors: ablation zones and thoracic lymph nodes

Lung Needle Biopsy and Lung Ablation: Indications, Patient Management, and Postprocedure Imaging Findings

The clinical role and use of percutaneous transthoracic needle biopsy (TTNB) and ablation of lung tumors are evolving. Here we discuss important considerations for referring providers, including current and emerging indications supported by guidelines, critical aspects of pre and postprocedure patient management, and expected postprocedure imaging findings.

High-Frequency Jet Ventilation Versus Spontaneous Respiration for Percutaneous Cryoablation of Lung Tumors: Comparison of Adverse Events and Procedural Efficiency

BACKGROUND. High-frequency jet ventilation (HFJV) facilitates accurate probe placement in percutaneous ablation of lung tumors but may increase risk for adverse events, including systemic air embolism. OBJECTIVE. The purpose of this study was to compare major adverse events and procedural efficiency of percutaneous lung ablation with HFJV under general anesthesia to spontaneous respiration (SR) under moderate sedation. METHODS. This retrospective study included consecutive adults who underwent CT-guided percutaneous cryoablation of one or more lung tumors with HFJV or SR between January 1, 2017, and May 31, 2023. We compared major adverse events (Common Terminology Criteria for Adverse Events grade ≥ 3) within 30 days postprocedure and hospital length of stay (HLOS) of 2 days or more using logistic regression analysis. We compared procedure time, room time, CT guidance acquisition time, CT guidance radiation dose, total radiation dose, and pneumothorax using generalized estimating equations. RESULTS. Overall, 139 patients (85 women, 54 men; median age, 68 years) with 310 lung tumors (82% metastases) underwent 208 cryoablations (HFJV, n = 129; SR, n = 79). HFJV showed greater rates than SR for the treatment of multiple tumors per session (43% vs 19%, respectively; p = .02) and tumors in a nonperipheral location (48% vs 24%, p < .001). Major adverse event rate was 8% for HFJV and 5% for SR (p = .46). No systemic air embolism occurred. HLOS was 2 days or more in 17% of sessions and did not differ significantly between HFJV and SR (p = .64), including after adjusting for probe number per session, chronic obstructive pulmonary disease, and operator experience (p = .53). Ventilation modalities showed no significant difference in procedure time, CT guidance acquisition time, CT guidance radiation dose, or total radiation dose (all p > .05). Room time was longer for HFJV than SR (median, 154 vs 127 minutes, p < .001). For HFJV, the median anesthesia time was 136 minutes. Ventilation modalities did not differ in the frequencies of pneumothorax or pneumothorax requiring chest tube placement (both p > .05). CONCLUSION. HFJV appears to be as safe as SR but had longer room times. HFJV can be used in complex cases without significantly impacting HLOS of 2 days or more, procedure time, or radiation exposure. CLINICAL IMPACT. Selection of the ventilation modality during percutaneous lung ablation should be based on patient characteristics and anticipated procedural requirements as well as operator preference.

Computed tomography-guided microwave ablation for right middle lobe pulmonary nodules: a retrospective, single-center, case-control study

PURPOSE

This retrospective, single-center, case-control study evaluated the safety and efficacy of Computed tomography (CT)-guided microwave ablation (MWA) for pulmonary nodules located in the right middle lobe (RML), a challenging location associated with a high frequency of complications.

METHODS

Between May 2020 and April 2022, 71 patients with 71 RML pulmonary nodules underwent 71 MWA sessions. To comparison, 142 patients with 142 pulmonary nodules in non-RML were selected using propensity score matching. The technical success, technique efficacy, complications, and associated factors were analyzed. The duration of the procedure and post-ablation hospital stay were also recorded.

RESULTS

Technical success was achieved in 100% of all patients. There were no significant differences in technique efficacy rates between the RML and non-RML groups (97.2% vs. 95.1%, p = 0.721). However, both major (47.9% vs. 19.7%, p < 0.001) and minor (26.8% vs. 11.3%, p = 0.004) pneumothorax were more common in the RML group than non-RML group. MWA for RML pulmonary nodules was identified as an independent risk factor for pneumothorax (p < 0.001). The duration of procedures (51.7 min vs. 35.3 min, p < 0.001) and post-ablation hospital stays (4.7 days vs. 2.8 days, p < 0.001) were longer in the RML group than non-RML group.

CONCLUSIONS

CT-guided MWA for RML pulmonary nodules showed comparable efficacy compared with other lobes, but posed a higher risk of pneumothorax complications, necessitating longer MWA procedure times and extended hospital stays.

Imaging Follow-Up of Nonsurgical Therapies for Lung Cancer: AJR Expert Panel Narrative Review

Lung cancer continues to be the most common cause of cancer-related death worldwide. In the past decade, with the implementation of lung cancer screening programs and advances in surgical and nonsurgical therapies, the survival of patients with lung cancer has increased, as has the number of imaging studies that these patients undergo. However, most patients with lung cancer do not undergo surgical re-section, because they have comorbid disease or lung cancer in an advanced stage at diagnosis. Nonsurgical therapies have continued to evolve with a growing range of systemic and targeted therapies, and there has been an associated evolution in the imaging findings encountered at follow-up examinations after such therapies (e.g., with respect to posttreatment changes, treatment complications, and recurrent tumor). This AJR Expert Panel Narrative Review describes the current status of nonsurgical therapies for lung cancer and their expected and unexpected imaging manifestations. The goal is to provide guidance to radiologists regarding imaging assessment after such therapies, focusing mainly on non-small cell lung cancer. Covered therapies include systemic therapy (conventional chemotherapy, targeted therapy, and immunotherapy), radiotherapy, and thermal ablation.

Outcomes following cryoablation of stage IA non-small cell lung cancer in patients with and without interstitial lung disease: A retrospective single-center cohort study

OBJECTIVE

To compare the safety and efficacy of cryoablation of treatment-naïve stage IA non-small cell lung cancer (NSCLC) in patients with and without interstitial lung disease (ILD).

MATERIALS AND METHODS

This retrospective single-center cohort study evaluated 33 consecutive patients (24 females, median age 75 years, Eastern Cooperative Oncology Group performance score 0-3) with ILD (9 patients) and without ILD (24 patients) who underwent 39 percutaneous cryoablations to treat 42 stage IA (8th IASLC edition) NSCLC measuring 1.2 cm (range 0.5-2.6 cm) from 2018 to 2022. Presence of ILD was determined according to 2018 American Thoracic Society Criteria on pre-ablation CT scans. The primary outcome was 90-day adverse events graded by the Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Secondary outcomes were hospital length of stay (LOS), local recurrence-free survival, overall survival, and the cumulative incidence of local recurrence with death as a competing risk.

RESULTS

Adverse events ranged from grade 1-3 and occurred more often in the non-ILD group (p <.001). No acute exacerbation of ILD or death occurred within 90 days after cryoablation. The median LOS was 1 day (interquartile range 1-2 days) and did not differ between groups. One patient with ILD and two patients without ILD died after 22, 26, and 27 months from causes unrelated to cryoablation. Median imaging follow-up was 11 months (range, 0-47 months) and three tumors (7%) showed local recurrence after 4, 17, and 22 months. No difference in the cumulative incidence of local recurrence (p =.56) was found. Among all patients, local recurrence-free survival on a per-tumor basis and overall survival were 97% and 100% at 1 year, respectively.

CONCLUSION

Adverse events and local recurrence following percutaneous cryoablation of stage IA NSCLC did not differ between patients with and without ILD. No acute exacerbation of ILD or death within 90 days were observed.