Percutaneous cryoablation of kidney tumours
This booklet is intended to help you understand cryoablation of kidney tumors better by giving you the opportunity to go over the details at your leisure. We believe it is important for you to have as complete an understanding of your procedure as possible and hope that this booklet answers some of your questions.
Based on the results of your tests, it has been decided that it may be advisable to treat your kidney tumor by freezing it (cryoablation or cryotherapy).
Kidney Tumors
The kidneys are a pair of organs located in the back of the upper abdomen that filter blood to remove waste products which they convert into urine. Urine is then carried from the kidney to the bladder by a tube called the ureter.
You have been diagnosed with a tumor in the kidney. Most, but not all, tumors in the kidney are cancerous. Biopsies are usually taken at the time of the cryoablation procedure with the intention of determining whether the tumor is cancerous. In some circumstances, a biopsy is done before any treatment is carried out. Occasionally, the biopsy does not make a definite diagnosis. Your doctor will discuss the biopsy results with you after the procedure.
Small kidney tumors are usually cancerous and so most patients are advised to undergo treatment. Occasionally despite successful treatment of the tumor in the kidney, the cancer comes back elsewhere in the body and requires further treatment. Treatment of small kidney tumors is intended to reduce this risk as much as possible. Treatment is available for metastatic kidney cancer (cancer which has spread to other parts of the body), but it tends to be less effective than treatment for localized kidney cancer.
What are the alternatives?
Kidney tumors traditionally have been treated by removal of the entire kidney (radical nephrectomy). While this remains the most definitive form of treatment for kidney tumors, it may not be the best form of treatment for some patients with small tumors because it removes all of a properly functioning kidney. Radical nephrectomy can be carried out either through an open surgical incision or laparoscopically (keyhole surgery).
For smaller kidney tumors, it may not be necessary to remove the entire kidney. The part of the kidney containing the tumor may be removed while leaving the remainder of the kidney intact (partial nephrectomy). This may be of crucial importance in patients with a single kidney and/or poor kidney function. Partial nephrectomy can also be carried out through open or laparoscopic surgery.
Finally there are other techniques involving heating the tumor, namely, radiofrequency ablation (RFA) and high intensity focussed ultrasound (HIFU). It may be worthwhile discussing these options with your doctor. This booklet is directed towards informing patients about cryoablation of their kidney tumor.
How is Cryoablation Done?
Kidney tumors are treated with cryoablation by placing into the tumor one or more fine needles which are then cooled to below -100°C. Percutaneous cryoablation does not require surgical access to the tumor, as the needles are passed directly through the skin into the tumor. The procedure is performed with a radiological guidance, using ultrasound, CT-scan or MRI to position correctly the cryoprobes into the tumor, while avoiding puncturing nearby organs (lung, spleen, liver, bowel depending on the case), which are seen on imaging. Once all the needles are in position, the tumor is frozen using a double phase freezing protocol. The covering of the whole tumor by the ice can be monitored with CT-scan or MRI, which allow us to see very clearly the iceball. In some cases, nearby organs (such as the bowel for example) may have to be pushed away from the iceball using an injection of fluid (hydrodissection) and/or carbon dioxide (carbodissection).
How does cryoablation work?
Argon gas is delivered under pressure into a small chamber inside the tip of the needle where it expands and cools. The needles typically reach a temperature of -120°C. This produces a frozen area around the needle. Temperatures below -20°C result in the death of the tissue, a process similar to frostbite. The tumor is usually frozen twice during the procedure to ensure that the temperature in the tumor reaches below -40°C.
Scans are carried out at intervals following the treatment in order to ensure the treatment has been successful. Your doctor will discuss this with you in terms of setting out a schedule.
Is any special preparation needed prior to the intervention?
A percutaneous biopsy of the tumor will usually be performed prior to the intervention in order to see if the lesion is benign or malignant. In some cases, the biopsy will be performed during the cryoablation procedure.
No special diet is required prior to your procedure. You will be admitted to the hospital on the day before surgery or in the morning of your operation. You will be instructed when to stop eating and drinking.
How long will the intervention take and what will happen afterwards?
You will have a general anaesthetic or a conscious sedation depending on the case. A bladder catheter may be placed. The intervention usually takes two to three hours, sometimes longer. You will wake up in the recovery room. Your vital signs will be monitored regularly as will your urinary output. You will have dressings over the site where the cryoablation needles were placed.
Your will be able to eat and drink a few hours after surgery.
Will the intervention be painful?
Pain relief may be necessary after the intervention. Our aim will be to make you as comfortable as possible. It must be said that most patients experience very little pain after the procedure but each patient is treated individually.
How long will I be in the hospital?
After the intervention, patients are usually kept overnight in the hospital for observation. However, there may be complications after the intervention which may mean you stay in the hospital longer.
Are there any possible complications?
Complications can occur after any percutaneous intervention but your doctors and nurses will do everything possible to avoid these. Some complications may occur at the time of intervention and others at a later point during your recovery. Complications that can occur include problems with general anaesthesia or cardiovascular problems which include heart attack, stroke, deep vein thrombosis (blood clot in the leg) or pulmonary embolus (blood clot in the lung). While these problems rarely occur, the risk to you does depend on your fitness for surgery and any previous medical problems you may. This is worthwhile discussing with your doctor. The risks of these complications following this particular procedure are minimised compared to traditional surgery because of the small wounds and small risk of bleeding.
Other complications include pneumothorax (air around the lung), bleeding from the kidney, a urine infection, injury to nearby structures such as blood vessels, spleen, liver, pancreas or bowel. Great care is taken to avoid these injuries during the procedure. Any of these complications may require more extensive surgery, either at the time of the cryoablation procedure or later.
What can I expect when I go home?
By the time you leave the hospital you will usually be able to go back to normal daily activities. Sometimes, you may find that you are very tired when you go home and you will need to rest during the day. In most cases, there will be no stitches on the entry points of the probes.
Check with your insurance company to ensure that you have proper coverage before driving. It is wise not to do any heavy lifting or very strenuous activity for a month. There are no hard and fast rules but generally you can do activities provided they do not hurt.
Going back to work depends on the nature of your work and how fit you feel.
When will I be seen by my doctor after the intervention?
You will be seen a few weeks after the intervention to make sure that you are making a good recovery. You will have regular check ups which typically will involve either a CT scan or a MRI scan every few months for the first year. These become less frequent provided the results are satisfactory.
Will I need any further treatments?
Once you have had your operation there are no other treatments that are needed routinely. However, depending on the success of your operation based on the follow up scans, further treatment may be necessary. Occasionally, it is necessary to repeat the cryoablation procedure or even to remove the kidney if the tumor persists. The likelihood of needing further treatment depends in a large part on the size and location of the kidney tumor. Your doctor will discuss this with you.
Call your doctor or specialist nurse if you have:
- fever and chills
- nausea and vomiting
- your urine is cloudy or smells
- you have persistent abdominal or back pain
We hope that this leaflet has answered most of your questions and now that you know more about your surgery and what happens once you have been discharged home, if there is anything else that you would like to know please contact your doctor or specialist nurse.