Freezing Nodal Disease: Local Control Following Percutaneous Image-Guided Cryoablation of Locoregional and Distant Lymph Node Oligiometastasis: A 10-Year, Single Center Experience
To retrospectively assess the technical feasibility, safety, and oncologic outcomes of percutaneous image-guided cryoablation (PCA) of locoregional and distant lymph node metastases (LNMs).
Take away point
The PCA of lymph node oligometastases is feasible and safe and offers promising local tumor control at midterm follow-up.
Autrusseau PA, Cazzato RL, Koch G, Ramamurthy N, Auloge P, De Marini P, Lipsker D, Gangi A, Garnon J. Freezing Nodal Disease: Local Control Following Percutaneous Image-Guided Cryoablation of Locoregional and Distant Lymph Node Oligometastases: A 10-Year, Single-Center Experience. J Vasc Interv Radiol. 2021 Oct;32(10):1435-1444. doi: 10.1016/j.jvir.2021.07.002. Epub 2021 Jul 13. PMID: 34271190.
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Single-center retrospective descriptive analysis of patients undergoing PCA of LNMs between February 2009 and December 2019. Waiver of consent for study participation was provided following institutional review board approval. All patients gave informed consent for procedures.
No reported funding
Academic setting. Hôpitaux Universitaires de Strasbourg, France
Oncologic care has trended towards more aggressive treatment of metastatic disease in patients with oligometastatic and oligo-progressive lymph node metastasis (LNM). Conventional measures including surgical lymphadenectomy and radiation treatment remain mainstays but may not be feasible options for all patients due to prior surgery, challenging anatomic location of disease, morbidity, and toxicity. Percutaneous image guided cryoablation (PCA) provides a suitable option by inducing thermal injury and cell death. PCA has many advantages including excellent ablation visualization which facilitates precise procedural monitoring, synergistic combination of multiple probes to tailor ablation zone, analgesic effects, safe application following surgery or radiation therapy, and maintenance of eligibility for subsequent conventional therapy.
39 patients who underwent PCA of oligometastatic LNMs were initially identified. Exclusion criteria included subsequent cytoreductive therapy and lack of follow up. The final study population was 29 patients, 14 women and 15 men. A total of 37 procedures were performed. 17 patients had prior surgery, radiation therapy or both in the same targeted lymphatic region. 16 patients had ongoing systemic therapy at time of referral for PCA.
Procedures were completed on an inpatient basis for organizational purposes and using either a combination of US and CT guidance or US and MR guidance. All cases were monitored for intraprocedural iceball formation. Single or multiple 17-gauge probes were deployed with a minimum 5 mm ablation margin. Ancillary thermoprotective measures including hydrodissection and pneumodissection were employed when critical structures were within 10 mm of the LNM to avoid collateral thermal damage or convectional dissipation of cold energy. Cryoablation was performed using a standard double freeze protocol, 2 freezing cycles of 10 minutes with 9 minute passive thawing and 1 minute active thawing.
Imaging follow up was performed with contrast enhanced MRI at 1-, 3-, 6- and 12-months post procedure. Restaging CT and/or PET/CT were performed every 3-6 months in addition to standard oncologic follow-up including applicable tumor markers.
Important oncologic outcomes that were outlined by the study. Notable study definitions included:
- Technical success: Complete LNM coverage by iceball, with a minimum 5 mm ablation margin on intraprocedural CT or MR imaging.
- Primary technique efficacy: Complete LNM ablation (nonenhancement of ablation zone) at 1-month contrast enhanced MR follow-up and absence of FDG uptake during the first PET-CT follow-up (typically 6–12 weeks after the procedure.
- Local tumor progression: New enhancement or uptake on CT, MR imaging, or PET-CT at the treated site following initial complete LNM ablation.
- Locoregional disease progression: New locoregional LNMs (distinct from previously treated lesions) on follow-up imaging.
- Distant disease Progression: New distant LNMs (distinct from previously treated lesions) and/or visceral metastases on follow-up imaging.
- Local tumor progression (LTP) free survival: Time from PCA to the first radiologic evidence of LTP.
- Disease-free survival (DFS): Time from PCA to the first radiologic evidence of disease progression at any site
- Overall survival: Time from PCA to death from any cause.
Primary technical efficacy was 100% with complete ablation of all treated LNMs at 1 month follow up. At median follow up of 23.4 months there were 2 instances of LTP (1 patient with new regional progressive disease and 1 with isolated LTP). The 1-, 2- and 3-year LTPFS was 100%, 94.3% and 94.3% respectively. The cohort demonstrated 1-, 2- and 3-year overall survival of 96.2%, 90.5% and 70% respectively. Stratifying by location, comparing the group with locoregional LNM to the group with distant LNM revealed no statistical difference in overall survival, LTPFS or DFS at 1-, 2- or 3- years. The study also found that patients achieving remission status with local disease control were eligible for a break from systemic therapy following 54% of procedures for an average duration of 19.1 months.
The study successfully outlines the technical feasibility and safety of PCA for LNMs with 100% technical success rate and minor complication rate of 5.4%. The noted complications were both in challenging locations with complex regional anatomy (neck and iliac/obturator LNM ablations). The results were similar to available data in recent literature with an obtained 3.7% LTP at median follow up of 23 months, compared to 4% in a smaller series. Evaluation of local disease control and recurrence rates were similar to studies focusing on HCC status post radiofrequency ablation and those evaluating stereotactic radiotherapy of LNMs. Additional direct comparison to available literature remains limited to due to heterogenous selection of response criteria between studies. Multiple factors were outlined in the study as relative strengths of PCA as a first line or salvage treatment for LNMs. The authors articulately described PCA as a useful technique in patients with high surgical morbidity, failed localization of nodal disease with alternative treatments, or patients with contraindications to full dose radiotherapy due to risks of toxicity. They also mention its utility as a mechanism to delay treatment intensification as 54% of procedures resulted in remission and halting systemic therapy. The limitations of the study include its relatively small sample size, power and retrospective design. The authors also describe selection bias, as patient selection may have leaned towards patients with better prognosis and limited disease. In the absence of a control group and due to the heterogenous stage, location and type of malignancies included, there was also a significant generalizability bias. Although the study offers promising results, future studies would be well suited to have a larger, prospective design.
Ahmad Hashmi, MD
University Hospitals Cleveland Medical Center
Case Western Reserve University