Minimally Invasive Treatments Help Cancer Patients
Extend Life and Improve Quality
Procedures performed by interventional radiologists are being increasingly
used in the care of patients with cancer. These specially trained physicians use
X-rays, ultrasound or other imaging techniques to guide small tubes called
catheters and miniature tools directly to the site of the disease.
Interventional radiology procedures for patients with cancer include new
approaches for treatment, relieving pain and diagnosing cancer without surgical
biopsy.
Liver Cancer
Surgical removal of liver tumors offers the best chance for a cure.
Unfortunately, liver tumors are often inoperable because the tumor may be too
large, or has grown into major blood vessels or other vital structures.
Sometimes, many small tumors are spread throughout the liver, making surgery too
risky or impractical. Surgical removal is not possible for more than two-thirds
of primary liver cancer patients and 90 percent of patients with secondary liver
cancer.
Historically, chemotherapy drugs have been generally ineffective at curing
liver cancer.
Prevalence
Primary liver cancer:
About 18,500 cases of primary liver cancer are
diagnosed each year. The most common form is hepatocellular carcinoma (HCC).
This is a tumor that begins in the main cells of the liver (hepatocytes).
Primary liver cancer is twice as common in men as in women.
HCC most frequently occurs in those who have a form
of liver disease called cirrhosis. Cirrhosis occurs when the liver becomes
diseased and develops scarring, usually over a period of years. The liver
attempts to repair, or regenerate itself. This process can lead to the
formation of tumors. In the United States, the most common causes of cirrhosis
are alcohol abuse and chronic infection with the liver virus hepatitis B or C.
The incidence of primary hepatocellular carcinoma is on the rise
worldwide, because of the increase of hepatitis C.
Metastatic liver cancer
Cancer may spread from any part of the body to the liver. There the cancer
cells may grow for months or years before they are detected. One of the most
common sources of metastatic liver cancer is from tumors of the colon and
rectum. About 140,000 people in the United States are diagnosed with colon
cancer each year, and roughly half of these patients will develop tumors in
their liver at some time. About one in 10 of these patients will have a chance
for a cure by having the liver tumors removed surgically.
Patients with other types of cancer also are at risk for liver cancer. The
liver serves as a way-station for cancer cells that circulate through the
bloodstream. These cells may grow and form tumors in the liver. It is estimated
that as many as 70 percent of all people with uncontrolled cancer will
eventually develop secondary liver tumors, or metastases (tumors formed by
primary cancer cells that have spread from other cancer sites).
Diagnosis
There are a number of tests that can help in the diagnosis of cancer,
including blood tests, physical examination and a variety of imaging techniques
including X-rays (e.g., chest X-rays and mammograms); computed tomography (CT);
magnetic resonance (MR) and ultrasound. Usually, however, the final diagnosis
cannot be made until a biopsy is performed. 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.
An X-ray of a needle inserted into the lung to obtain a sample for
biopsy.
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.
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.
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.
Tumors need a blood supply, which they actively generate, to feed themselves
and grow. 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 by using embolization and radiofrequency heat.
Embolization is a well-established interventional radiology technique that is
used to treat trauma victims with massive bleeding, to control hemorrhage after
childbirth, to decrease blood loss prior to surgery and to treat tumors. In
treating cancer patients, interventional radiologists use embolization to cut
off the blood supply to the tumor (embolization), deliver radiation to a tumor
(radioembolization), or combine this technique with chemotherapy to deliver the
cancer drug directly to the tumor (chemoembolization).
Additionally, interventional radiologists can use imaging to guide them
directly to the tumor through the skin to administer radiofrequency heat to
"cook" and kill the cancer cells (radiofrequency ablation) or cyroablation to
freeze the tumor.
Click images to enlarge
Chemoembolization
Chemoembolization is a minimally invasive treatment for liver cancer that can
be used when there is too much tumor to treat with radiofrequency ablation
(RFA), when the tumor is in a location that cannot be treated with RFA, or in
combination with RFA or other treatments.
Chemoembolization delivers a high dose of cancer-killing drug (chemotherapy)
directly to the organ while depriving the tumor of its blood supply by blocking,
or embolizing, the arteries feeding the tumor. Using imaging for guidance, the
interventional radiologist threads a tiny catheter up the femoral artery in the
groin into the blood vessels supplying the liver tumor. The embolic agents keep
the chemotherapy drug in the tumor by blocking the flow to other areas of the
body. This allows for a higher dose of chemotherapy drug to be used, because
less of the drug is able to circulate to the healthy cells in the body.
Chemoembolization usually involves a hospital stay of two to four days. Patients
typically have lower than normal energy levels for about a month afterwards.
Chemoembolization is a palliative, not a curative, treatment. It can be
extremely effective in treating primary liver cancers, especially when combined
with other therapies. Chemoembolization has shown promising early results with
some types of metastatic tumors. Although the individual materials used in this
treatment are FDA approved, the treatment itself is not approved for
intra-arterial therapy of liver tumors.
Yttrium-90 Radioembolization
Radioembolization is very similar to chemoembolization but with the use of
radioactive microspheres. This therapy is used to treat both primary and
metastatic liver tumors.
This treatment incorporates the radioactive isotope Yttrium-90 into the
embolic spheres to deliver radiation directly to the tumor. Each sphere is about
the size of five red blood cells in width. These beads are injected through a
catheter from the groin into the liver artery supplying the tumor. The beads
become lodged within the tumor vessels where they exert their local radiation
that causes cell death. This technique allows for a higher, local dose of
radiation to be used, without subjecting healthy tissue in the body to the
radiation. The Yttrium-90 radiates from within and, since it is administered in
the hepatic artery, it can be viewed as "internal" radiation.
Radioembolization is a palliative, not a curative, treatment-but patients
benefit by extending their lives and improving their quality of life. It is a
relatively new therapy that has been effective in treating primary and
metastatic liver cancers. It is performed as an outpatient treatment. There are
fewer side effects from this treatment compared to standard cancer treatments,
with the main one being fatigue for seven to 10 days.
Click images to enlarge
Thermal Ablation
Treatments
Radiofrequency Ablation
For inoperable liver tumors, radiofrequency ablation (RFA) offers a
nonsurgical, localized treatment that kills the tumor cells with heat, while
sparing the healthy liver tissue. Thus, this treatment is much easier on the
patient 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 (similar to microwaves) is transmitted to the tip of the
needle, where it produces heat in the tissues. The dead tumor tissue shrinks and
slowly forms a scar. The FDA has approved RFA for the treatment of liver
tumors.
Efficacy
In a small number of cases, RFA can extend patients'
lives, but it is generally palliative. Depending on the size of the tumor, RFA
can shrink or kill the tumor, extending the patient's survival time and greatly
improving their quality of life while living with cancer.
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
BEFORE
AFTER
Because it is a local treatment that does not harm healthy tissue, the
treatment can be repeated as often as needed to keep patients comfortable. It is
a very safe procedure, with complication rates on the order of two to three
percent, and has been available since the late 1990s.
By decreasing the size of a large mass, or treating new tumors in the liver
as they arise, the pain and other debilitating symptoms caused by the tumors are
relieved. While the tumors themselves may not be painful, when they press
against nerves or interfere with vital organs, they can cause pain. RFA is
effective for small to medium-sized tumors and emerging new technologies should
allow the treatment of larger cancers in the future.
Benefits
Is most effective when all the cancer is localized in
the liver
Can be used to treat primary liver cancer and tumors
that have metastasized (spread) from other areas in the body to the liver
Usually does not require general anesthesia
Is well tolerated-most patients can resume their
normal routine the next day and may feel tired for a few days
Can be repeated if necessary
May be combined with other treatment options
Can relieve pain and suffering for many cancer patients
Cryoablation
Cryoablation is similar to RFA in that the energy is delivered directly into
the tumor by a probe that is inserted through the skin. But rather than killing
the tumor with heat, cryoablation uses an extremely cold gas to freeze it. This
technique has been used for many years by surgeons 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 nick 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.
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:
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.
Small mesh cylinders called stents are used to open
obstructed organs and allow fluids such as urine and bile to
drain.
Treating Organ Obstruction and
Infection
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:
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.
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