Kidney cancer affects about
23,000 Americans each year. The most common
form of cancer arises in the tubules that
filter blood in the kidney and is known as
renal cell carcinoma (RCC). Typically, patients
with RCC are over 40 years of age. Men are
twice as likely to develop RCC as women.
Most patients with RCC do not develop symptoms
until the tumor becomes very large. Symptoms
at this point might include abdominal pain,
fatigue, blood in the urine, or a mass that
can be felt in the abdomen. However, with
modern medical imaging technology, very small
tumors are now being detected on ultrasound,
CAT scan, and MRI examinations that are performed
for some other reason. It is these small tumors
that are less likely to have spread to lung
and bone at the time of discovery. These smaller
tumors tend to present the best treatment
options, particularly if the tumor lies along
the outside edge of the kidney.
RCC is notorious for poor response to traditional
chemotherapy and radiation therapy options.
Standard treatment for the tumor has involved
complete removal of the kidney, known as radical
nephrectomy, until relatively recently when
surgeons have been able to demonstrate equal
effectiveness with removal of the only the
portion of the kidney containing the tumor,
allowing sparing of the remainder of the kidney.
Unfortunately, some patients will not be candidates
for surgery, possibly because of other medical
conditions which will not allow them to tolerate
surgery. It is often these patients for whom
interventional treatment has significant potential.
Radiofrequency
Ablation
Radiofrequency ablation
(RFA) has emerged as a new treatment for renal
cell carcinoma in appropriate patients, possibly
with less complication and less cost than
traditional surgery. Some literature suggests
outcomes similar to surgery for small tumors,
although only early data is available at this
time.
During the procedure the ablation
needle is advanced through the skin under
ultrasound or CAT scan guidance and positioned
in the tumor. An electric current is then
applied to the needle to cause heating of
the tumor around the needle, resulting in
tumor death. The needle is then removed
and a small bandage is placed. There are
no sutures. Most patients are discharged
the following morning.
While RFA has been shown to be very effective
in smaller tumors, particularly along the
outside edge of the kidney, larger tumors
(greater than 4-5cm) and tumors deeper in
the middle of the kidney may be much more
difficult to completely treat. The presence
of large blood vessels and urine in the
collecting system in the middle of the kidney
make it more difficult to achieve adequate
heating of tissue and possibly increases
the risk of complication.
Figure
1 – Small cancerous tumor
in left kidney (arrows)
Figure
2 – Ablation probe placed
into tumor under CAT scan guidance
(arrows)
Embolization
Embolization is another
technique which can be helpful in treating
renal tumor. The procedure can be used in
conjunction with RFA. In the procedure a tiny
catheter is advanced under x-ray guidance
in to the artery at the top of one leg and
then directed into the catheter to block blood
flow to the tumor. When used with ablation,
cell death is improved due to improved heating
of the tumor tissue when blood flow to the
tumor is decreased. Embolization can also
be used in tandem with surgery. When a tumor
is very large and there is concern about significant
blood loss during surgical removal, the surgeon
may request embolization prior to tumor removal.
In this case the procedure is similar to embolization
of smaller tumors, however the catheter is
usually placed in a larger artery supplying
a greater portion of or all of the kidney
and alcohol is typically used to kill the
tumor and the remainder of the kidney that
is to be removed. Several studies have shown
greatly reduced blood loss during surgery
when embolization is used prior to surgical
removal of appropriate tumors.
Embolization can also be used in the treatment
of some benign non-cancerous tumors of the
kidney. One tumor, angiomyolipoma, may have
a tendency to bleed when it becomes large
in size. Rather than remove the kidney, some
patients will be treated with embolization
of the benign tumor to stop bleeding, allowing
preservation of the remainder of the kidney
and its function.
