Introduction and Objectives
Advances in imaging have led to an increase in the use of minimally invasive technologies such as radiofrequency ablation (RFA) or cryoablation as a treatment of renal cell carcinoma (RCC). RFA is a thermal ablative technique that causes tumor destruction by heating and may be used as an alternative to a partial nephrectomy in peripherally located tumors not exceeding 4 cm in diameter. Most publications on RFA efficacy concentrate on the CT or MRI assessment of the local tumor destruction. In patients with liver tumors treated with RFA or cryoablation, together with the local tissue necrosis, a specific inflammatory response was also demonstrated. It has been shown that hepatic cryotherapy, but not RFA, rarely may cause cryoshock phenomenon with a high mortality rate which related to the release of toxic substances from the lesion and strong inflammatory reaction. The participation of the RFA in the specific inflammatory response induction has never been studied in patients with RCC. The evaluation of this response may lead to a better understanding of the thermoablation effect and improve its efficacy.
Material and Methods
Thirteen patients (6 men, 7 women) aged 50 to 86 (mean 67.4 years) with RCC underwent RFA. The tumors were diagnosed by contrast-enhanced CT and had radiological features in CT described by Bosniak as characteristic for renal cell carcinoma. Average tumor diameter was 36 mm (from 9 to 40 mm).The procedure was performed in the epidural anesthesia in the supine position under USG guidance. White blood cells count (WBC – neutrophiles, lymphocytes, monocytes), body temperature were measured at baseline and 24 hours after RFA. CRP (C-reactive protein) and LDH (Lactate dehydrogenase) were also measured in some patients. The t-Student test was used to compare them before and after thermoablation. A value for P less than 0.05 was considered significant.
We observed increase in number of WBC up to 17.6% (7.67 G/l vs 9.03; p < 0.01) and proportion of neutrophiles up to 19.3% (59.99% vs 71.55; p < 0.000001) and decrease in proportion of lymphocytes up to 36.5% (29.61% vs 18.81; p < 0.000001). The proportion of monocytes was unchanged. The levels of LDH and CRP were significantly increased in four of five patients. None of the patients had a fever 24 hours after the procedure.
In our study RFA causes moderate inflammatory response without any complications. It may be related to the presence of necrotic tissue left in the ablated kidney. It is possible that during RFA, in situ heat fixation of the surrounding tissue may prevent the release of intracellular compounds that are responsible for the exaggerated inflammatory syndrome as observed after cryoablation.
© 2009 European Association of Urology. Published by Elsevier Inc. All rights reserved.