A. A tumor suspicious for cancer is seen in the kidney.B. The ablation needle is seen coming in through the back and a dark area is seen around the tumor. This dark area corresponds to the ice ball that is created which kills the tumor cells.C. The needle is removed and the treatment area can be seen. Note that the tumor is gone.
Ablation refers to "destroying" the tumor. This is typically performed by freezing it (Cryoablation) or by cooking it (Radiofrequency Ablation). Ablation can be performed percutaneously (through the skin) or via surgical exposure (open or laparoscopic surgery).
Not all tumors are suitable for ablation and thus a discussion with a kidney cancer expert regarding all options is always best prior to selecting a treatment.
In percutaneous ablation, an experienced interventional radiologist places a needle through the skin in the back and into the tumor. This is done under CT scan or ultrasound guidance. The ablation machine is then turned on and the tumor is destroyed. At Johns Hopkins, percutaneous ablation is typically an outpatient procedure that does not require general anesthesia.
During laparoscopic cryoablation, an iceball is formed on the kidney after the bowel is moved out of the way. This iceball then destroys the tumor.
Surgical ablation is usually performed as a minimally invasive laparoscopic procedure. Under general anesthesia, small keyhole incisions are made and the kidney is exposed. A needle is then placed into the tumor under direct vision. An ultrasound is used to monitor the ablation. A short hospital stay is typically necessary for this procedure.
Since percutaneous ablation does not require general anesthesia or a hospital stay, why does anyone choose surgical ablation?
This is a great question with a simple answer. Percutaneous ablation works well if the tumor is towards the back of the kidney (posterior position). If the tumor is in the front (anterior position) then it is difficult to get the needle into it without going through the critical central structures of the kidney. Also, tumors in the front of the kidney are typically very close to other important organs like the pancreas, bowel, spleen, diaphragm, and liver. If the area is frozen or cooked without moving those structures out of the way, they can be damaged and major complications can result. With surgical ablation, the surgeon can move these important structures out of the way before placing the needle into the tumor.
If I am having a surgical ablation (eg. Laparoscopic cryoablation) and I am under anesthesia already, should I not just have the tumor cut out?
Partial nephrectomy remains the gold standard treatment for these tumors and has the highest success rate to remove the cancer completely. However there are scenarios where a quick "in and out" is preferable to a longer and more involved procedure such as partial nephrectomy. At Johns Hopkins, most of the time when surgery is selected a partial nephrectomy is performed. This is because of our vast experience with this procedure and our low complication rate and short operative times. Laparoscopic cryoablation may be preferable for some patients. It is important to know that partial nephrectomy is a lot harder to master and surgeons may not be comfortable doing this procedure—as a result they may recommend laparoscopic cryoablation as it is an easier procedure to perform. It is important to see a surgeon in a center that offers all the options so that the optimal decision is made. You should not let the inexperience of a surgeon guide you to the wrong procedure.
If I choose ablation, should I have cryoablation or radiofrequency ablation?
Both of these procedures seem to have a similar success rate. In general we prefer cryoablation because it is easier to monitor the iceball that forms. Radiofrequency ablation heats the tissue and is harder to monitor to ensure that the entire tumor is killed. Additionally, a study by Johns Hopkins urologists found that the pain caused during cryoablation is significantly less than that of radiofrequency ablation during percutaneous ablation. Lastly, the data for cryoablation is more mature. Radiofrequency ablation, however, still remains an option as well.
# Allaf ME, Varkarakis IM, Bhayani SB, Inagaki T, Kavoussi LR, Solomon SB. Pain control requirements for percutaneous ablation of renal tumors: cryoablation versus radiofrequency ablation--initial observations. Radiology. 2005 Oct;237(1):366-70. Epub 2005 Aug 26.