Interventional Radiology Treatments for Kidney Cancer
Kidney cancer is the eighth most common cancer in men and the
tenth in women. The most common type of kidney cancer is renal
cell carcinoma that forms in the lining of the renal tubules in
the kidney that filter the blood and produce urine. Approximately
85 percent of kidney tumors are renal cell carcinomas. When
kidney cancer spreads outside the organ, it can often be found in
nearby lymph nodes, lungs, bones or liver, as well as the other
kidney.
The current gold standard treatment is laparoscopic partial
nephrectomy surgery. However, some patients could benefit from
minimally invasive, kidney-sparing treatment, such as those with
high surgical risk, underlying illnesses, multiple recurrent
tumors, borderline kidney function or only one kidney.
Additionally given the recent success of percutaneous
cryoablation, patients with kidney cancer may elect to avoid
surgery and have their tumor treated this way. The urologist and
interventional radiologist work together in a multidisciplinary
team to determine whether a less invasive percutaneous ablation
can be done safely and effectively.
Prevalence and Risk Factors
More than 32,000 Americans each year are diagnosed with kidney
cancer-many of them don't have symptoms. Typically, those with
kidney cancer are past the age of 40 and twice as often are men.
Other risk factors include:
- Smoking
- Obesity
- High blood pressure
- Long-term dialysis
- Von Hippel-Lindau syndrome
Symptoms
The incidence of kidney cancer is on the rise. Fortunately,
the availability of modern imaging technology has led to more
frequent detection of small, asymptomatic tumors that otherwise
would be undetected. Often, small tumors do not cause symptoms
and are discovered on CTs, MRIs or ultrasounds that are performed
for some other reason, such as standard imaging studies (CT or
ultrasound) performed during many emergency room visits. These
small tumors are often the best candidates for nonsurgical
treatment options. Common symptoms may include:
- Blood in the urine
- Side pain that does not go away
- A lump or mass in the side of the abdomen
- Weight loss
- Fever
- Feeling very tired
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Kidney Cancer Diagnosis
In addition to a basic physical exam, urine test and blood
tests, several other techniques can be used to diagnose kidney
cancer. CT scan, MRI or ultrasound can be performed to see inside
the body and identify a tumor. An image-guided needle biopsy can
be done to remove tissue samples and look for cancer cells. At
the time of diagnosis, 25 to 30 percent of patients have
metastases.
In a biopsy, a sample of tissue from the tumor or other
abnormality is obtained and examined by a pathologist. By
examining the biopsy sample, pathologists and other experts also
can determine what kind of cancer is present and whether it is
likely to be fast or slow growing. This information is important
in deciding the best type of treatment. Open surgery is sometimes
performed to obtain a tissue sample for biopsy. But in most
cases, tissue samples can be obtained without open surgery with
interventional radiology techniques.
Needle biopsy
Needle biopsy, also called image-guided biopsy, is usually
performed using a moving X-ray technique (fluoroscopy) computed
tomography (CT), ultrasound or magnetic resonance (MR) to guide
the procedure. In many cases, needle biopsies are performed with
the aid of equipment that creates a computer-generated image and
allows radiologists to see an area inside the body from various
angles. This "stereotactic" equipment helps them
pinpoint the exact location of the abnormal tissue.
Needle biopsy is typically an outpatient procedure with very
infrequent complications; less than 1 percent of patients develop
bleeding or infection. In about 90 percent of patients, needle
biopsy provides enough tissue for the pathologist to determine
the cause of the abnormality.
Advantages of needle biopsy include:
- With image guidance, the abnormality can be biopsied
while important nearby structures such as blood vessels
and vital organs can be seen and avoided.
- The patient is spared the pain, scarring and
complications associated with open surgery.
- Recovery times are usually shorter and patients can more
quickly resume normal activities.
An X-ray of a needle inserted into the lung to obtain a sample for biopsy.
Large core needle biopsy. In this technique, a special
needle is used that enables the radiologist to obtain a larger
biopsy sample. This technique is often used to obtain tissue
samples from lumps or other abnormalities in the breast that are
detected by physical examination or on mammograms or other
imaging scans. Because approximately 80 percent of all breast
abnormalities turn out not to be cancer, this technique is often
preferred by women and their physicians because it:
- is less painful and requires less recovery time than open
surgical biopsy, and
- avoids the scarring and disfigurement that may result
from open surgery.
A similar technique called fine needle aspiration can
be used to withdraw cells from a suspected cancer. It also can
diagnose fluids that have collected in the body. Sometimes, these
fluid collections also may be drained through a catheter, such as
when pockets of infection are diagnosed.
Many interventional radiology procedures for the diagnosis and
treatment of cancer can be performed on an outpatient basis or
during a short hospital stay. In many cases, the procedures:
- offer new cancer treatment options
- are less painful and debilitating for patients
- result in quicker recoveries
- have fewer side effects and complications.
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Kidney Cancer Treatments
As vascular experts, interventional radiologists are uniquely
skilled in using the vascular system to deliver targeted
treatments via catheter throughout the body. In treating cancer
patients, interventional radiologists can attack the cancer tumor
from inside the body without medicating or affecting other parts
of the body. For breast cancer, interventional radiologists use
thermal ablation, as well as some laser therapy, to kill the
cancer cells. Although the devices used are FDA approved,
research to evaluate the long-term effects of these treatments is
still ongoing.
Cryoablation
Recent interventional cryoablation data are showing near 100
percent efficacy for tumors up to four centimeters if localized
to the kidney. Larger localized tumors can also be successfully
treated with cryoablation depending on size and location. Ablated
lesions show as dead tissue (scar) with no recurrences at
one-year follow-up on imaging, after one treatment.3 The one-year
benchmark is an established and well-accepted benchmark within
the medical community.3, 4
Studies are ongoing to compare cryoablation to partial
nephrectomy, and it is expected that the two treatments will be
shown to be equivalent in the future. The interventional
radiology treatment is less invasive and easier on the patient.
This treatment spares the majority of the healthy kidney tissue
and can be repeated if needed.
The treatment has an excellent safety profile, and most
patients are sent home the same day as the procedure or go home
the next day. The most common complication is a bruise (hematoma)
around the kidney that goes away by itself.
These interventional treatments also offer valuable benefits
to those patients with advanced or metastatic renal cell
carcinoma. While not considered curative for these patients, the
lesions can be re-treated as needed. Studies are underway on
combination treatments. One such study uses cryoablation to kill
the primary kidney tumor and immune system stimulation to treat
any metastases. Traditional chemotherapy drugs and radiation are
generally ineffective for kidney cancer.5
Cryoablation is delivered directly into the tumor by a probe
that is inserted through the skin using imaging to guide it
internally. Cryoablation uses an extremely cold gas to freeze the
tumor to kill it. This technique has been used for many years by
urologists in the operating room, but in the last few years, the
needles have become small enough to be used by interventional
radiologists through a small incision in the skin without the
need for an operation. The "ice ball" that is created
around the needle grows in size and destroys the frozen tumor
cells.
Thermal Ablation Treatments
The conventional treatment for kidney cancer without
metastases is surgical removal by a urologist. However, some
patients could benefit from minimally invasive, kidney-sparing
treatment, such as those with high surgical risk, underlying
illnesses, multiple recurrent tumors, borderline kidney function
or only one kidney. For these patients, interventional
radiologists may be able to treat the tumor with new, less
invasive treatments using specially designed needles to eliminate
the kidney cancer. The urologist and interventional radiologist
work together in a multidisciplinary team to determine whether a
less invasive percutaneous ablation can be done safely and
effectively.
Radiofrequency Ablation
For inoperable kidney tumors, radiofrequency ablation (RFA)
offers a nonsurgical, localized treatment that kills the tumor
cells with heat, while sparing the healthy kidney tissue. This
treatment is much easier on the patient and is more effective
than systemic therapy. Radiofrequency energy can be given without
affecting the patient's overall health and most people can resume
their usual activities in a few days.
In this procedure, the interventional radiologist guides a
small needle through the skin into the tumor. From the tip of the
needle, radiofrequency energy is transmitted into the tumor,
where it produces heat and kills the tumor cells. The dead tumor
tissue shrinks and slowly turns into a scar.
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Additional Facts About RFA
- Is most effective when the kidney cancer is small in size
(5cm or less)
- May be performed under conscious sedation or general
anesthesia
- Is well tolerated-most patients can resume their normal
routines the next day and may feel tired only for a few
days
- Can be repeated if necessary
- May be combined with other treatment options
Efficacy
If the tumor is small, RFA can shrink and likely kill the
tumor. Although early results are encouraging, long-term
follow-up is necessary to determine the precise role of RFA in
treating small kidney cancers. Current ongoing studies will
determine long-term survival.
Because it is a local treatment that does not harm healthy
tissue, the treatment can be repeated as often as needed. It is a
very safe procedure, with low complication rates, and it has
become more widely available over the last couple of years. The
FDA has approved RFA for use in soft tissue tumors, of which
renal cell carcinoma is one.
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A LIVER TUMOR TREATED WITH
RFA
Dead tissue appears
larger and darker than the living tumor.
Over time, the tumor shrinks as the body
absorbs and excretes dead cells
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Risks
The risks of RFA are similar to a biopsy, namely localized
bleeding and some pain. Bleeding that requires action is uncommon
partly because the heating from the radiofrequency energy
cauterizes the tissue and minimizes the risk of hemorrhage.
Heating of the tumor may cause heating of an adjacent structure,
which can lead to some healthy tissue damage. This can be avoided
by carefully reviewing the size and location of the tumor before
the procedure. Tumors adjacent to structures such as bowel may
not be candidates for RFA or may require special procedures
(injection of fluid) to create safe distances between the tumor
being treated and the adjacent bowel.
Cost/Insurance
Since RFA is new, many insurance companies may require
preapproval prior to the procedure.
Interventional radiologists use special X-ray equipment to guide therapy directly to the site of tumors
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Management of Advanced Renal Cell Carcinoma
Arterial Embolization
Advanced renal cell carcinoma tumors are often quite large and
invade adjacent structures and veins. They may even extend
through the veins into one of the heart chambers. Some patients
with advanced tumors may not be surgical candidates. Arterial
embolization is an invaluable treatment option for such patients.
During embolization, an interventional radiologist inserts a
small tube (catheter) into an artery in the groin and directs it
to the renal artery that supplies blood to the kidney and the
tumor. The doctor injects small solid particles or special liquid
agents into the artery to block the flow of blood into the
kidney. The blockage prevents the tumor from getting oxygen and
other substances it needs to grow, causing it to shrink.
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In some patients, arterial embolization may shrink the tumor
substantially, rendering the patient a suitable surgical
candidate. In others, arterial embolization effectively
eliminates tumor-related symptoms and improves patients' quality
of life.
Arterial embolization has also been used to facilitate
surgical resection of large tumors. Blocking the blood supply to
the tumor decreases the risk of bleeding and minimizes the amount
of blood transfusion during surgery. Similarly, arterial
embolization can facilitate ablation of larger tumors. Reduction
of blood supply to the tumor renders ablation procedures (RFA or
cryoablation) safer and more effective.
Surgery
Radical Nephrectomy: Kidney cancer may be treated with
radical nephrectomy, in which the entire kidney, along with the
adrenal gland and some tissue around the kidney, is surgically
removed. Some lymph nodes in the area also may be removed.
Simple Nephrectomy: Some patients with early kidney
cancer may have a simple nephrectomy which involves removing only
the kidney.
Partial Nephrectomy: A surgeon removes the section of
the kidney with the tumor. This procedure may be used when the
patient has only one kidney or the cancer affects both kidneys,
and only in patients with small kidney tumors.
Biological Therapy and Immunotherapy
Biological therapy is a systemic therapy that uses substances
injected into the bloodstream to reach and affect cells all over
the body. Biological therapy utilizes the body's natural ability,
such as using the immune system, to fight cancer.2 Recent
advances in immunotherapy have made a significant improvement in
survival of patients with inoperable renal cancer.
Chemotherapy
Chemotherapy is a systemic therapy in which anticancer drugs
enter the bloodstream and travel throughout the body. Anticancer
drugs have shown limited effectiveness against kidney cancer.
New Cancer Treatments on the Horizon
Interventional radiology is playing a role in developing new
techniques that may improve cancer treatment in the future,
including the use of magnetic particles to draw cancer-killing
agents into tumors; and the delivery of genetic material, called
gene therapy, to fight or prevent cancers. These techniques are
still investigational, but they offer new hope in the war against
cancer.
"Magnetic"Chemotherapy
Interventional radiologists are currently investigating a new
technique in which magnets are used to pull chemotherapy drugs
into tumors. Microscopic magnetic particles are attached to the
cancer-killing drugs and infused through a catheter into the
blood vessel that feeds the tumor. A rare earth magnet is
positioned over the patient’s body directly above the site
of the tumor. The magnet pulls the drug-carrying particles out of
the blood vessel so that they lodge in the tumor. Although the
technique is still experimental, early research is promising.
Physicians are hopeful that it will bolster the effects of
chemotherapy while avoiding some of the drugs’ side effects,
such as hair loss and nausea.
Gene Therapy
In recent years, scientists have gained a
new understanding about genes—the basic biological
units of heredity—and the role they play in disease.
This knowledge has set the stage for medical science to
alter patients’ genetic material to fight or prevent
cancer. Although the science of gene therapy is still in
the early, experimental stages, researchers are hoping
that in the future the therapy can be used to:
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Researchers in gene
therapy search for new ways to treat cancer and other
genetic diseases |
- alter the cells of a patient’s natural immune system
with cancer-fighting genes and returning them to the
body, where they could more forcefully attack the cancer;
- remove cancer cells from the body and alter them
genetically so that the patient’s own immune system
will mount a strong defense against them. In this
technique, the altered cancer cells would act as a cancer
vaccine;
- replace a faulty gene responsible for the growth of
cancer with a "good" gene;
- inject a tumor with genes that will make it more
susceptible to chemotherapy or other cancer-fighting
agents; and
- make bone marrow and other organs resistant to
chemotherapy, so that the drugs will destroy tumors
without damaging healthy tissue.
One of the challenges of gene therapy is finding safe and
effective ways to deliver genes or genetically altered cells to
the site of the tumor. Interventional radiologists, with their
special expertise in using X-rays and other imaging techniques to
guide catheters and other tools through the body are expected to
play an important role in this new technology.
Treatments for Cancer Complications
There are also a number of interventional radiology techniques
that are used to treat the complications of cancer, including
pain, bleeding, obstruction of vital organs, blood clots and
infection. Although these treatments do not cure cancer, they can
make patients more comfortable, extend life by treating serious
complications and improve the quality of life for cancer
patients.
Treating Pain
Control of pain is one of the most important aspects of cancer
care. Pain not only affects patients’ quality of life and
ability to function, it may also lower their tolerance for needed
cancer treatments.
In many cancer patients, pain results from the spread of the
tumor into surrounding nerves and other tissues. For example,
patients with cancer of the pancreas or stomach, sometimes
experience pain from the spread of the tumor into a network of
nerves and blood vessels in the abdomen called the celiac plexus.
To treat the pain, interventional radiologists insert catheters
or needles into the affected area and administer alcohol or other
agents that destroy the nerves causing the pain.
A particularly painful complication of cancer is when the
disease spreads (metastasizes) to bones. In a technique called transcatheter
embolization, interventional radiologists inject tiny
particles, the size of grains of sand, through a catheter and
into the artery that supplies blood to the tumor. The particles
cause clotting that decreases the tumor’s blood supply,
reducing pain and decreasing the likelihood of bone fracture.
Controlling Bleeding
If a cancer spreads to the blood vessels it may cause
hemorrhage or bleeding. An interventional radiology technique
called transcatheter embolization can be used to clot the
affected blood vessels and stop the bleeding.
Treating Organ Obstruction and Infection
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Cancers
can obstruct the normal flow of urine or bile, causing
these fluids to build up in the body. If left untreated,
these conditions are not only painful but may also result
in organ failure or infection. Under X-ray guidance,
catheters can be inserted to drain the collection of
fluids. Often, a small device called a stent is
inserted into the organ to bypass the obstruction and
allow fluids to drain internally.
Treating Blood Clots
One common side effect of cancer or
cancer treatments is the development of blood clots, or
emboli, that can be life-threatening if they travel to
the brain, lungs or heart. There are two interventional
radiology procedures that can reduce the risks posed by
blood clots:
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Small mesh cylinders
called stents are used to open obstructed organs and
allow fluids such as urine and bile to drain.
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- Intra-arterial thrombolysis. In
this technique, the interventional radiologist guides a
catheter through the blood vessels and to the site of a
blood clot. Clot-busting drugs are infused through the
catheter to break up the clot.
- Filter placement. This
technique is most often used when a blood clot is
detected in the blood vessels of the leg (a condition
called deep vein thrombosis). The interventional
radiologist guides a small filter into the blood vessel
that receives blood from the lower body (the vena cava)
and carries it to the heart. If the blood clot dislodges
from the vein in the leg, the filter will trap it before
it can reach the heart.
Interventional Radiologists are Minimally Invasive Experts
Interventional radiologists work with other specialists on a
multidisciplinary cancer team to determine the best treatment for
each individual patient. Interventional radiology is a recognized
medical specialty by the American Board of Medical Specialties.
Interventional radiologists are board-certified physicians with
extensive training in disease diagnosis, management and
treatment. Their board certification includes both Vascular and
Interventional Radiology and Diagnostic Radiology which are
administered by the American Board of Radiology. This training
marries state-of-the-art imaging and diagnostic expertise,
coupled with clinical experience across all specialties and
in-depth knowledge of the least invasive treatments.
Interventional oncology is a growing area within interventional
radiology.
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