A modified radiofrequency ablation approach for treating distant lymph node metastasis in two patients with late-stage cancer

Feasibility and safety of percutaneous computed tomography guided radiofrequency ablation of lymph nodes in oligometastatic patients: a single center's experience

OBJECTIVES

To retrospectively evaluate feasibility and safety of CT-guided percutaneous radiofrequency ablation (RFA) of metastatic lymph nodes (LN) in terms of achieving local tumor control.

METHODS

Institutional database research identified 16 patients with 24 metastatic LNs who underwent percutaneous CT-guided radiofrequency ablation. Mean patient age was 66.6 ± 15.70 years (range 40-87) and male/female ratio was 8/8. Contrast-enhanced CT or MRI was used for post-ablation follow-up. Patient and tumor characteristics and RFA technique were evaluated. Technical and clinical success on per tumor and per patient basis as well as complication rates were recorded.

RESULTS

Mean size of the treated nodes was 1.78 ± 0.83 cm. The mean number of tumors per patient was 1.5 ± 0.63. The mean procedure time was 56.29 ± 24.27 min including local anesthesia, electrode(s) placement, ablation and post-procedural CT evaluation. Median length of hospital stay was 1.13 ± 0.34 days. On a per lesion basis, the overall complete response post-ablation according to the mRECIST criteria applied was 75% (18/24) of evaluable tumors. Repeat treatment of an index tumor was performed on two patients (three lesions) with complete response achieved in 87.5% (21/24) of evaluable tumors following a second RFA. On a per patient basis, disease progression was noted in 10/16 patients at a mean of 13.9 ± 6.03 months post the ablation procedure.

CONCLUSION

CT-guided percutaneous RFA for oligometastatic LNs is a safe and feasible therapy.

ADVANCES IN KNOWLEDGE

With this percutaneous therapeutic option, metastatic LNs can be eradicated with a very low complication rate.

Effects of intratumoral injection of immunoactivator after microwave ablation on antitumor immunity in a mouse model of hepatocellular carcinoma

This study investigated the effects of intratumoral injection of immunoactivator after microwave ablation on antitumor immunity in a mouse model of hepatocellular carcinoma. Hepatocellular carcinoma cell line Hepa1-6 was subcutaneously injected into C57/B6 mice to establish a mouse model of hepatocellular carcinoma. When tumor diameter reached 8 mm, microwave ablation was performed for 3 min with temperature controlled at 55°C. Cytokine sustained-release microspheres (CytoMPS) containing human interleukin-2 (hIL-2) and mouse granulocyte macrophage colony-stimulating factor (mGM-CSF) were injected into the tumor of mice in the experimental group (n=5) at 3, 7 and 14 days after ablation, while sustained-release microspheres containing no cytokine were used in the control group (n=5). Mice were sacrificed on the 17th day after ablation, and CD4⁺ and CD8⁺ T cells in peripheral blood were counted by flow cytometry. Spleen was collected from the mice to isolate lymphocytes. Lactate dehydrogenase (LDH) release assay was used to determine the cytotoxicity of spleen cells to Hepal-6 cells. Injection of CytoMPS after ablation increased the percentage of CD4⁺ and CD8⁺ T cells in peripheral blood. Cytotoxicity of CD8⁺ CTL to Hepal-6 is significantly higher in experimental group than in control group (P<0.01). The results showed that intratumoral injection of CytoMPS containing hIL-2 and mGM-CSF can significantly increase the proportion of CD4⁺ and CD8⁺ T cells in blood and increase the cytotoxicity of CTL cells to tumor cells in mice with hepatocellular carcinoma.