CT guided percutaneous cryoablation is a safe, effective, and minimally invasive alternative for the surgical resection of a renal tumor. The main goal of the presented study is to check the safety, technique, and effectiveness of treatment. Researchers selected thirty patients between the ages of 34 to 89 with 32 tumors, 30 of which are renal cell carcinomas that were referred for percutaneous cryoablation. During cryoablation one or more cryoprobes are applied directly to the lesion. The cryoprobe cools the surrounding area of the needle tip. The cold is significant enough to cause tumor necrosis and complete ablation. As for recovery, cryoablation advantages include a reduction in pain and clear view of the affected area during the procedure. CT, MRI, and ultrasound can be used to guide the ablation. The risk of damaging the collecting system is minimal. Cryoablation can come with complication as with all procedures, however it is comparable to a partial nephrectomy.
One radiologist performed all cryoablation procedures after the diagnosis of a renal tumor was made according to testing. The patients were admitted the day before the procedure and blood work was performed to determine current renal function and hemoglobin. The procedure was performed with CT guidance and an argon-based cryoablation machine and probes. The cryoprobes were placed around the edges of the tumor and went through a 10 minute freeze followed by a 10 minute thaw and another 10 minute freeze cycle. After the procedure patients were placed on bed rest for at least 4 hours. The next morning blood work was performed to compare to preop levels. Most patients were discharged the following morning. Technical success meaning completeness of the freeze cycle and ice ball extension of 5cm past the tumor margin was present in all patients. Follow up included 1 month, 3 months, 6 months and 1 year after visits. Follow up included renal function tests and a CT or MRI exam. Out of 30 patients 7 had signs of complications making the complication rate 23.3%. Complications include one occurrence of a local hematoma and a thermal nerve injury to the iliohypogastric nerve, neither of which required medical treatment. Some other complications include 2 urinary tract infections and 2 decreases in hemoglobin. Only one patient experienced a vascular injury. For the 22 patients with RCC 2 patients were considered to have an incomplete ablation due to enhanced tumors on their follow up image within 6 months. 2 patients had local tumor recurrence after 6 months. Overall the tumor control rate was 80.9% and the survival rate was 95.2% overall.
Most percutaneous cryoablations are performed when a partial nephrectomy is not practical. Based on this study it is recommended to have a safety margin over 5mm and use CT guidance. Suggested risk factors include larger tumors, increased age, and using multiple probes. During this study no patients had any damage to the collecting system or required ureter stents due to damage. The primary advantage to cryoablation over surgery is preserving renal function which has been achieved. There was no significant change in GFR 3-6 months after the procedure. Overall CT-guided percutaneous cryoablation is safe and effective for use on renal tumors.
I would like to see this study reproduced on a larger scale to gain more accurate numbers. I would also like to see a similar study done on various stages of renal cell carcinoma and how cryoablation affects each stage and their prognosis I would also like to see more info on how cryoablation affects surrounding healthy tissue if at all.
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