IMAGE-GUIDED
CRYOABLATION
RENAL TUMOR — Cryosurgery
Procedures
Image-Guided
Cryoablation of Renal Tumors
Image-guided
cryoablation is indicated as a treatment for
cortical or peripheral kidney tumors, for solid
lesions less than 4cm, and for patients with a
single kidney or poor kidney function. Kidney
cancer ablation eradicates the cancerous tissue
by freezing it. Very precise targeting and
control of the energy allows for efficient destruction
of tumor cells while leaving healthy kidney tissue
intact and functional.
To freeze the cancer, special 1.47mm
cryoablation needles are placed percutaneously
(through the skin, with no surgical incision)
into the tumor. Argon gas is delivered under
pressure into a small chamber inside the tip of
the needle where it expands and cools, reaching
a temperature well below -100o Celsius.
This produces an iceball of predictable size and
shape around the needle. This iceball engulfs
the tumor, killing the cancerous cells as well
as a small margin of surrounding tissue while
sparing healthy kidney structures. A double
freeze-thaw cycle is favored, since studies suggest
that consistently larger areas of cell death are
achieved with a double rather than single freeze-thaw
cycle. Ultra-thin thermal sensors may also
be placed at the margin of the tumor to monitor
tissue temperature and help ensure that the entire
tumor is destroyed.
Interventional radiologists are specially
trained in non-surgical, minimally invasive procedures
to treat a variety of medical conditions, including
many cancers. They use sophisticated imaging
techniques to guide the application of a treatment
to a specific targeted area of tissue. In
the case of kidney cryoablation, image guidance
refers to the use of intraprocedural ultrasound,
fluoroscopy, CT, or MRI to guide the percutaneous
placement of the cryoablation
needles into the tumor, and to monitor the
double freeze-thaw cycle. This gives the
physician precise control of the lethal freeze
zone and the ability to adjust the ablation parameters
during the procedure to further optimize treatment.
The patient is positioned in the
CT or MRI scanner. The cryoablation
needles and thermal
sensors are inserted through the skin and
positioned in the tumor under the guidance of
real-time ultrasound or CT fluoroscopy and the
entire procedure is monitored using CT or MRI.
Image-guided percutaneous cryoablation may be
performed under general anesthesia, or light sedation
with local or regional anesthesia.
The benefits of image-guided percutaneous renal tumor ablation are compelling. The percutaneous nature of the procedure means that it can be performed with little or no blood loss and without a surgical incision. After the procedure, a percutaneous approach translates into significantly less pain, a shorter hospital stay, and a more rapid recovery when compared with more invasive techniques. This can mean that effective kidney cancer treatment can be achieved with minimal disruption to patients’ lives. Patients usually are able to return to family, work, and routine activity in well less than half the time that it takes to recover from open surgery.
Kidney
cancer treatment that allows for the maintenance
of adequate renal function is of the utmost importance
to the patient’s ongoing quality of life. Because
only the cancer is destroyed during image-guided
cryoablation therapy and normal kidney tissue
is spared, remaining renal function is maximized.
This means that the kidneys can continue to perform
their many jobs more efficiently than if the entire
kidney, or a significant part of it, had been
removed. In addition, sparing a portion
of the affected kidney creates more options if
a new tumor develops in the patient's second kidney,
a risk confronting a small number of people with
kidney cancer.
In most cases, image-guided targeted
ablation and real time temperature monitoring
assure that only one session of cryotherapy ablation
is necessary. Should the patient’s cancer
recur, or if residual tumor is found on follow-up
visits, renal cryosurgery can be repeated at the
physician’s discretion with minimal trauma to
the patient.
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