RFA - Radio Frequency Ablation bewijst waarde (94.6% lokale controle en succesvolle verwijdering) bij niertumoren kleiner dan 4 cm bij studie met 49 nierkanker patiënten met totaal 60 tumoren.

18 augustus 2005: Bron: Medscape en J Urol 2005;174:456-460 en J Chin Med Assoc. 2005 May;68(5):221-5

Nieuwe studie uit het Department of Urology van het Johns Hopkins Medical Institutions, Baltimore, bij 49 nierkanker patiënten bewijst dat RFA - Radio Frequency Ablation in plaats van operatie uitstekende resultaten geeft bij het verwijderen van kleinere tumoren in de nieren (< 4 cm.). Bij 48 van de 49 deelnemende patiënten, gemiddelde leeftijd 63.9 jaar (met totaal 60 tumoren) werd een lokale controle en volledige verwijdering bewerkstelligd (53 van de 60 tumoren = 94.6%) bij een follow-up van 27,5 maanden. Slechts drie van de 49 deelnemers kreeg binnen twee jaar een recidief. En deze drie hadden allemaal een centrale tumor groter dan 3 cm. Een andere Chinese studie komt met dezelfde resultaten bij een kleinschalige studie bij 12 nierkanker patiënten. Algemeen vertoont nierkanker ook na operatieve ingreep een groot percentage recidieven. Vooral wanneer de verwijderde tumoren groter zijn dan 4 cm. Plus dat een operatie vaak leidt tot permanente stoma welke door veel mensen als hinderljk wordt ervaren. Ook deze studie pleit dus voor RFA als eerste operatieve ingreep bij kleine niertumoren.

J Endourol. 2005 Jul-Aug;19(6):643-52; discussion 652-3. Treatment of renal tumors with radiofrequency ablation.

Wagner AA, Solomon SB, Su LM.
Department of Urology, Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA. awagne14@jhmi.edu BACKGROUND: Radiofrequency (RF) energy has been investigated as a minimally invasive modality for ablating small renal tumors. Recent advances in the application of this technology have improved its safety and effectiveness.
MATERIALS AND METHODS: We describe the technology of RF application and review the current delivery systems as applied to renal tumor ablation. We also review relevant animal studies, which have revealed the natural history of ablated renal tissue. Finally, we examine recent human trials with an emphasis on longer-term follow-up, imaging, complications, and successful ablation according to tumor location within the kidney; i.e., central v peripheral.
RESULTS: Radiofrequency ablation can be performed safely in a minimally invasive fashion either percutaneously or laparoscopically. Energy delivery varies, and available systems include dry, wet, cooled-tip, and bipolar electrodes. Heat rise and subsequent charring in the tissue adjacent to the electrode is limited by temperature or impedance-based feedback systems. In animal studies, ablation results in complete cell kill, as judged by nicotinamide adenine dinucleotide diaphorase staining. Clinical trials with intermediate follow-up show excellent success rates. Tumors >3 cm and central tumors have a higher recurrence rate after RFA than smaller, more peripheral tumors.
CONCLUSIONS: The current literature suggests that RFA is a promising minimally invasive method of treating small renal tumors. Nevertheless, long-term follow-up is still required, and questions remain regarding the optimal delivery system, duration of ablation, and method of surveillance.

PMID: 16053352 [PubMed - in process]

Bron: Medscape:

RF Ablation Promising Against Small Renal Tumors
By David Douglas

NEW YORK (Reuters Health) Aug 17 - Percutaneous radio frequency (RF) ablation guided by computerized tomography appears to be an effective means of dealing with small renal tumors, researchers report in the August issue of the Journal of Urology. Dr. Stephen B. Solomon and colleagues at the Johns Hopkins Medical Institutions, Baltimore, note that the need for less invasive approaches than surgery to treat such patients has led to the development of percutaneous tumor ablation techniques with various energy sources. Among these is RF ablation. The researchers analyzed the results of this approach in 49 of their patients. Their mean age was 63.9 years and they had a total of 60 tumors, all of less than 4 cm. Indications for percutaneous RF ablation included severe comorbidities or previous abdominal surgery which precluded operative management. Altogether, 46 patients (56 tumors) were available for evaluation at a mean follow-up of 27.5 months. Overall, local control was achieved in 53 (94.6%) of the tumors. Recurrence after initial successful treatment was seen in three patients, all of whom had a central tumor of 3.0 cm or more. Summing up, Dr. Solomon told Reuters Health that "our average follow-up time for tumors treated with ablation has been 2 years, and while that is still early, it appears that patients with small renal tumors may be treatable with 'cooking' their tumors rather than cutting them out with surgery." J Urol 2005;174:456-460.

J Chin Med Assoc. 2005 May;68(5):221-5.

Percutaneous radiofrequency ablation of renal cell carcinoma.

Chiou YY, Hwang JI, Chou YH, Wang JH, Chiang JH, Chang CY.
Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC.

BACKGROUND: Preliminary data regarding the use of percutaneous radiofrequency ablation (RFA) for the treatment of renal cell carcinoma (RCC) are encouraging, and show the technique to be associated with minimal morbidity. Thus, the current study was designed to evaluate the clinical applications, treatment efficacy, and complications of percutaneous RFA in RCC.

METHODS: From February 2003 to February 2004, 12 consecutive patients with histopathologically proven RCC underwent imaging-guided percutaneous RFA. The mean age of the patients (8 men and 4 women) was 76 years (range, 56-87 years), and mean tumor diameter was 3.7 cm (range, 2.2-8.0 cm). The efficacy of RFA was evaluated with contrast-enhanced, dynamic computed tomography (CT) performed 1 month after treatment, and then every 3 months. A Radionics device with an internally cooled electrode was used in 7 patients, and a radiofrequency interstitial tissue ablation (RITA) device with an expandable needle electrode was used in 5. Complete necrosis was defined as a lack of contrast enhancement in the treated region on follow-up CT studies.

RESULTS: Overall, 16 sessions of RFA were performed for 12 solitary renal tumors in 12 patients: 8 patients underwent a single RFA session, whereas 4 had 2 sessions. Dynamic CT after RFA showed complete necrosis in 9 of 12 tumors. In 3 patients with tumors of 4.5-8.0 cm in diameter, enhancement of residual tissue was observed after RFA treatment, thus indicating residual tumor. Complete tumor necrosis was seen in all 5 tumors (100%) of diameter < or = 3.0 cm; 3 of 4 tumors (75%) of diameter 3.1-5.0 cm; and 1 of 3 tumors (33%) of diameter > 5.0 cm. A big subcapsular hematoma, which was found in 1 patient after RFA, resolved completely within 10 months without treatment; no serious complications occurred in the other 11 patients.
CONCLUSION: Percutaneous RFA is effective in the treatment of RCC. It is most successful for tumors not larger than 3 cm in diameter, and has a satisfactory success rate in tumors of 3-5 cm in diameter. The rate of serious complications of RFA is low. Further studies are necessary to determine the long-term efficacy of RFA in RCC. PMID: 15909727 [PubMed - indexed for MEDLINE]