Definition:
Cryoablation and radiofrequency ablation are the two techniques by which kidney tumors can be ablated today. The concept of ablation is relatively new in cancer surgery for any disease. Traditionally, surgeons have treated cancer by literally cutting it out. This is a process known as extirpation. In contrast to this approach, ablation is a different concept in that cold energy or heat energy is used to destroy the cancerous tissue at the exact site where it exists in the body. Ablation has been used for many cancers including lung, liver, and prostate. However, the technology is particularly well suited to kidney cancer.

The two currently available technologies that are FDA approved and are currently used for kidney treatments are cryoablation which is often referred to as simply “cryo” or “cryotherapy,” and radiofrequency ablation, which is often called “RF ablation” for short. While surgeons currently use both technologies, it is becoming clear to most kidney cancer specialists that cryoablation is a safer and more effective technology. When the world’s body of medical literature surrounding these two ablation technologies is evaluated, there are half as many patients who fail treatment with cryoablation compared to radiofrequency ablation.

Table: Comparison of world’s literature
comparing radiofrequency and cryoablation series.
From Weld and Landman, British Journal of Urology 96(9): 1224, 2006

Cryoablation technology uses ice to freeze tumors. The ice created during this procedure is unlike the ice that we see outdoors on cold days or the ice in our cold drinks. Standard ice that we all get from our refrigerators is 32 degrees Farenheit (0 degrees Celcius). Clearly, we can make snowballs or hold ice cubes without damage to our hands as this standard ice is not harmful to live tissues with short-term exposure. In contrast, the ice created for cryoablation procedures is colder than 100 degrees Celcius below zero and can destroy cancer tissue very efficiently. This ice can also be targeted very precisely so that it can be used to destroy a kidney cancer while preserving normal kidney and the normal structures that are near to the kidney.

Figure A

The ice for kidney cancer cryoablation is created by inserting small probes (like needles) into the tumor. Figure A represents a true to life sized cryoablation probe. This probe is less than 1.5mm in diameter and can destroy a large amount of cancer tissue. By clicking on the probe, you will see a life-sized representation of the amount of kidney cancer that this very small probe can eliminate. A single probe like the one demonstrated in the figure, or a group of several of these probes can be used to destroy kidney cancers while preserving the surrounding kidney.

Technique:
Kidney cryoablation can be performed by any technique. Open surgery (large incisions to expose the kidney) is rarely used by experienced kidney surgeons for kidney cryoablation procedures as open surgery is more painful, results in greater bleeding, and has a longer patient recovery time when compared to less invasive techniques such as laparoscopy and percutaneous treatment approaches.

By definition, open surgery is not a minimally invasive technique as it requires larger incisions to access and eliminate kidney cancer. Open surgery refers to the original approach used by surgeons by which a blade is used to create a large incision. Today, some kidney cancers still require open surgery to achieve the best outcome.

In contrast, laparoscopic surgery mimics the techniques of open surgery (surgery done with a large incision), but no large incision is required. Instead, small incisions approximately ½ inch (1cm) in size are created. Body spaces are gently expanded with inert gas and a small camera is inserted into the body. Small instruments can then be used to treat disease without the large incision associated with open surgery. While not suitable for all kidney cancers, the vast majority of kidney cancers can be treated with a laparoscopic procedure of some type in the hands of experienced surgeons.

Laparoscopic cryoablation is performed under general anesthesia and the procedure usually takes between one and three hours. Three or four small incisions are made to properly expose the cancer so that the cryoablation probe or probes can be precisely placed into the cancer. During the placement of the probes and the killing of the cancer with the ice, the entire procedure can be very precisely monitored using a device called a laparoscopic ultrasound probe. In experienced hands, this remarkable device which fits through the small laparoscopic incisions can show the surgeon exactly where the kidney cancer is located. Additionally, this laparoscopic ultrasound probe is used to assure that the entire tumor is destroyed with the iceball that is created. During the procedure, a biopsy of the kidney cancer is taken to determine the type of cancer that has been treated. While the laparoscopic approach to cryoablation does involve making several small incisions, the technique allows for protection of structures that surround the kidney to assure that complications remain at a minimum. Additionally, the laparoscopic approach allows for the most precise targeting of the probes and laparoscopic cyroablation has the lowest recurrence rate of any ablative technique.

Another minimally invasive approach is percutaneous ablation. With percutaneous access, no incisions are made. Indeed, the surgeon works with a radiologist using imaging technology such as MRI, CT or ultrasound to radiographically deploy ablation probes into the kidney cancer. The placement of the needles and the destruction of the tumor can then be monitored using with imaging. The purcutaneous approach is usually done under general anesthesia, but can be done under light anesthesia which is known as sedation. Percutaneous cryoablation is the least invasive intervention that can be done for kidney cancer.

Candidates for kidney cryoablation:
There are a number of important patient and tumor parameters that are critical in deciding the type of treatment that is best for a small renal mass. Considerations are numerous but include: the size and general radiographic appearance of the mass, the local anatomy of the mass, the overall age and health condition of the patient, overall kidney function, the number of lesions in the kidney, patient personal preference, etc.

Cryoablation is a very promising new approach to kidney cancer. Several large medical centers have produced data demonstrating that kidney cancer is cured in approximately 97% of patients who undergo laparoscopic cryoablation with a follow-up of three years. Five year data demonstrates success in the treatment of kidney cancer in 93% of patients. However, 10 year follow-up information on patients having undergone cryoablation is not yet available. As such, cryoablation is not usually performed in very young patients under normal circumstances. While there are no strict age criteria, slightly older patients who may have some associated medical problems are generally considered good candidates for kidney cryoablation. The cryoablation procedure is typically associated with very little bleeding, few complications, and a speedy recovery. As patients typically tolerate cryoablation very well, people with kidney masses and other associated medical conditions are generally good candidates for renal cryoablation.

Additionally, patients with renal masses who have poor kidney function or only one kidney are also good candidates for renal cryoablation as the technique does not require the surgeon to control the blood supply to the kidney. Other techniques such as open and laparoscopic partial nephrectomy require the surgeon to temporarily block the blood supply to the kidney which may have some negative effect on kidney function.

Patients who have inherited diseases like Von Hippel-Lindau disease often have multiple kidney cancers in one or both kidneys. Occasionally, people who do not have this type of inherited disease also can have more than one kidney cancer within a kidney. As cryoablation destroys only the cancer and leaves the majority of the kidney intact, it is a good approach for people with more than one cancer in a kidney.

Advantages and disadvantages of kidney cryoablation:
An advantage of kidney cryoablation is that it can be performed laparoscopically (with small incisions) or percutaneously (directly through the skin), thus making it is a minimally invasive procedure for the treatment of kidney cancer. The minimally invasive nature of the procedure means that it can be performed with minimal blood loss and without a large incision. After surgery, a minimally invasive approach translates into significantly less pain, a shorter hospital stay, and more rapid recovery when compared with open surgery.

Overall, the minimally invasive nature of cryoablation allows kidney cancer to be treated with minimal disruption in patients’ lives. Return to the routine activities of life is very much expedited by the minimally invasive surgical approach. Patients return to family, work, and routine activity in less than half the time that it takes to recover from open surgery.

Also, in contrast to “extirpative procedures” (procedures that cut out cancer such as laparoscopic and open partial nephrectomy or radical nephrectomy) in which the cancer is cut out, patients who undergo ablation have less risk of some complications such as bleeding and urine leakage. Clearly, any time the kidney undergoes surgery, there is a chance of bleeding. However, the risk of bleeding is decreased by not having to cut into the kidney as is typically done with laparoscopic or open partial or radical nephrectomy. Similarly, not cutting into the kidney minimizes the risk of disrupting the kidney’s “collecting system (plumbing within the kidney which transports urine), which is a complication known as “urine leak.”

While cryoablation is a very promising treatment for kidney cancer, there are some limitations to this treatment. Cryoablation is not a good treatment for larger tumors. Indeed, under most circumstances, cryoablation should not be considered for kidney cancers that are greater than 4-cm (1 3/4 inches) in size. Also, percutaneous (cryoablation through the skin) is only applicable to some kidney cancers depending on the location within the kidney.

As cryoablation is a new technique for treating kidney cancer, there is no information available on the long-term results of the technique. Certainly, this lack of information is a limitation of the technology. However, at present, several major centers have reported three year and even five year follow-up data that is very promising with high cure rates.

The cryoablation procedure:
Laparoscopic cryoablation for kidney cancer is performed by a Urologist (kidney surgeon) in an operating room. Prior to scheduling the procedure, each patient should have an extensive consultation with their Urologist regarding the nature of their kidney disease as well as all of the available treatment options. This discussion should review all the advantages and limitations of each surgical and non-surgical approach.

Once you and your Urologist have decided on kidney cryoablation, a date for surgery is chosen. Typically, a patient goes to the hospital on the day of surgery. General anesthesia (you are completely asleep) is required. The Procedure is then done through three or four small incisions which are either ½ a centimeter or 1 cm in length (less than ¼ to ½ and inch). The kidney is then identified so that the kidney cancer can be found. Once the target kidney cancer is identified, a biopsy is performed to establish the type of tissue that is being treated and one or several small probes are placed into the kidney. The cryoablation probes are very small being less than 1.5 mm in size (real size picture in figure A). An instrument known as a laparoscopic ultrasound is then inserted through one of the small incisions to help precisely place the cryoablation probes.

Once the cryoablation probes have been precisely placed, the cryoablation device is turned on and iceballs form. The ice covers the area of the kidney cancer and a small area of normal tissue around the kidney cancer to make sure that no cancer cells are left in the kidney. The laparoscopic ultrasound probe is used to confirm that the iceball has killed all of the kidney cancer tissue. Once the iceball has grown and killed the kidney cancer, the cryomachine is turned off and the iceball simply melts. The probes are removed from the kidney. As the probes are very small, there is very little risk of bleeding. The Procedure is then complete.

Once the procedure is complete, each patient is transferred to the recovery room for observation and then to a hospital room. Typically, on the day of surgery, the patient can drink liquids, walk around, and is relatively comfortable with limited pain. On the day after surgery it is common to have a regular diet. If everything has gone well, most people are discharged home on the first day after surgery with limited well-controlled pain, eating a regular diet, and feeling well. On discharge, oral antibiotics and oral pain medications are typically prescribed.

Percutaneous cryoablation is performed in a CT or MRI suite by a Urologist working with an interventional radiologist. Prior to scheduling the procedure, each patient should have an extensive consultation with their Urologist regarding the nature of their kidney disease as well as all of the available treatment options. This discussion should review all the advantages and limitations of each surgical and non-surgical approach. The patient arrives on the day of surgery and the procedure is usually performed under general anesthesia. Under some conditions, the procedure can be performed under light anesthesia (also known as sedation).

The skin is marked and the location of the tumor in relation to skin landmarks is determined by the CT or MRI scanner. After local anesthesia has been administered, a needle is placed in the skin to properly target the tumor. Once proper targeting has been established, a biopsy is taken and the cryoablation probes are placed into the kidney cancer. The ablation is then performed as described with the laparoscopic procedure, and the patient is transferred to the recovery room. Typically, the patient is observed in the hospital overnight and then discharged in the morning if all is well.

Follow-up after cryoablation:
Biopsy results - The results of the kidney biopsy are returned from the laboratory approximately one week after surgery. Your surgeon will usually call you at home with these results.

Activity after surgery - While patients will typically be able to do routine activities such as eating and taking care of every day needs, it is generally suggested that no heavy lifting or vigorous activity be performed for four to six weeks to allow the body to recover. While it is surgeon dependent, most surgeons will suggest only light lifting (less than 10lbs), gentle activity, and no driving for one to two weeks after surgery. It is typical for patients to feel drained or lack energy for several weeks after surgery, and complete and full return to activity will usually take four to six weeks. However, every patient is different and recovery is somewhat variable. Generally, the patient will feel better day by day.

Wound care and bandages - With laparoscopy, wound care is generally very easy. The dressings (bandages) are usually removed by the patient at home the second day after surgery. Under the bandages there are small pieces of surgical tape. Once these start to peel off on their own, the patient may remove them. Removing the tape in the shower may be helpful and the adhesive will soften and allow the tape to be removed gently and without pain. Under the tape are the small wounds. The stiches are below the skin and do not have to be removed as they absorb by themselves.

Bathing - Swimming and bathing in a tub should not be done for one week after surgery, but showering is usually permitted any time after the second day after surgery. The shower should be with regular soap and water. An effort should be made not to allow the shower to directly hit the wounds for the first several days. The wounds should be cleaned with a dry and clean towel and left uncovered. A small amount of oozing is possible for the first few days after surgery, and a clean gauze with surgical tape can be used to keep clothing dry. However, if there is any significant leakage from the wound or if the would should become red, hot, tender, or swollen, you should contact your doctor immediately.

Follow-up visit – Your doctor will typically call with the biopsy results one week after the surgery has been performed. A follow-up visit with the surgeon is usually scheduled approximately four weeks after the procedure has been done. At the follow-up visit wounds are checked and follow-up radiographic imaging is scheduled. Typically, an MRI or CT scan is scheduled for three months after the procedure has been performed. Depending on the biopsy results and the results of this radiographic evaluation, a future follow-up regimen is then established.

Copyright 2006 Kidney Cancer Institute