PURPOSE
To identify changes in plasma cytokine levels following image-guided thermal ablation of human tumors and to identify the factors that independently predict changes in plasma cytokine levels.
MATERIALS AND METHODS
Whole blood samples were collected from 36 patients at 3 time points: pre-ablation, post-ablation (within 48 hours), and in follow-up (1â5 weeks after ablation). Plasma levels of IL-1a, IL-2, IL-6, IL-10 and TNFa were measured using a multiplex immunoassay. Univariate and multivariate analyses were performed using cytokine level as the dependent variable and sample collection, time, age, sex, primary diagnosis, metastatic status, ablation site, and ablation type as the independent variables.
RESULTS
There was a significant increase in the plasma level of IL-6 post-ablation when compared to pre-ablation (9.6+/â31 fold, p<0.002). IL-10 also showed a significant increase postablation (1.9 +/â2.8 fold, p<0.02). Plasma levels of IL-1a, IL-2, and TNFa were not significantly changed after ablation. Cryoablation resulted in the largest change in IL-6 level (>54 fold), while radiofrequency and microwave ablation showed 3.6 and 3.4-fold changes, respectively. Ablation of melanomas showed the largest change in IL-6 48 hours after ablation (92Ă), followed by ablation of kidney (26Ă), liver (8Ă), and lung (6Ă) cancers. Multivariate analysis revealed that ablation type (p<0.0003), and primary diagnosis (p<0.03) were independent predictors of changes to IL-6 following ablation. Age was the only independent predictor of IL-10 levels following ablation (p<0.019).
CONCLUSION
Image guided thermal ablation of tumors increases the plasma level of IL-6 and IL-10, without increasing the plasma level of IL-1a, IL-2, or TNFa.