Cancer Therapy Procedures
- Liver Chemoembolization - Minimally Invasive Surgical Solutions & Liver Chemoembolization (Jump down)
- Radiofrequency Ablation - Minimally Invasive Surgical Solutions and Radiofrequency Ablation (Jump down)
- Vascular Access - Minimally Invasive Surgical Solutions and Central Venous Access Catheters (CVAC) (Jump down)
Liver Chemoembolization - Minimally Invasive Surgical Solutions (MISS) & Liver Chemoembolization
Embolization
is the process of injecting small solid particles or special liquid
agents into the blood vessel feeding the tumor to stop the blood
flow. The lack of blood deprives the tumor of needed oxygen and
nutrients and eventually cancerous causes cells to die. The tumor blood
supply is stopped with small pieces of material that have been saturated
with chemotherapy drugs. Once the blood flow has stopped, the tumor is
soaked in a very high concentration of drugs for a prolonged period of
time. Thus, the tumor cells die very quickly. Below is a sketch that
demonstrates the mechanism of chemoembolization:
A
variety of materials may be used in the embolization process. Most
embolization materials only cause temporary blockage of blood flow to
the tumor cells, though in some cases materials will be used that can
cause permanent blockage.
Chemoembolization attacks the
cancerous cells in two ways: it delivers a very high concentration of
chemotherapy drugs directly into the tumor without exposing the entire
body to the effects of those drugs, and it cuts off blood supply to the
tumor, depriving it of oxygen and nutrients and trapping the drugs at
the tumor site so that they can act more effectively. This procedure is
most beneficial to patients whose disease is limited to the liver. Some
success has been demonstrated with patients whose cancer has spread to
other areas. Patients with kidney disease, blood coagulation problems,
or known allergies to contrast agents are not good candidates for this
procedure.
The chemoembolization procedure takes place in a
hospital setting. The actual procedure depends on the embolizing agent
being used. Such issues as drug administration, anesthetic requirements,
length of time of procedure, and potential side effects differ with
each agent. Chemoembolization is considered to be a relatively safe and
effective method of treating unresectable liver tumors. The overall risk
of the procedure is related to your general underlying health. People
with jaundice, severe cirrhosis or kidney failure have an increased
chance of complications.
Under x-ray guidance a small catheter
is inserted into the femoral artery (located in the groin) and advanced
into the liver artery. The embolic material and drugs are then injected
through the catheter into the liver tumor. The procedure usually lasts 2
- 3 hours.
The majority of patients experience some side
effects which may include abdominal pain, nausea, vomiting or fever.
Various drugs can be administered that will control these symptoms and
keep you comfortable. The symptoms will stop after 3 - 5 days. Studies
show that patients with hepatocellular cancer undergoing this procedure
may experience tumor shrinkage as well as an increased survival rate.
The effectiveness of this therapy for patients with metastatic colon
cancer is currently undergoing active investigation.
Radiofrequency Ablation - Minimally Invasive Surgical Solutions (MISS) and Radiofrequency Ablation
What is RF?
Radiofrequency (RF) ablation is a new technique for treating tumors localized to certain organs such as the liver, kidney, and adrenal glands. With this technique, relatively small probes are placed into the tumor, and RF energy is deposited. The RF energy causes the tissue around the tip of the probe to heat up to a high temperature at which cells break apart and die. Since RF kills both tumor and nontumor cells, the goal is to place the probes so that they destroy all of the tumor plus an adequate "rim" of nontumorous tissue around it. RFA treatment is highly localized relative to systemic therapy, which means that the procedure is much easier on the patient and can be administered with minimal damage to noncancerous cells and a minimal impact on the patient's overall health.
Figure 1 - Diagram showing the probe inserted into a tumor (gray) in the liver (red) and the corresponding thermal zone (white) cause by heating the tissue with RF energy resulting in cellular death.
This procedure is usually performed by placing one or more probes through small (less than 1/4 inch) incisions in the skin and using either ultrasound or a CT scanner to guide the tip into the tumor. For those tumors difficult to visualize by either US or CT, this procedure can also be performed in the operating room using a standard and much larger upper abdominal incision.
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Figure 2
- 76 year old man with a throat cancer. He has previously
undergone surgery for removing a tumor from his liver. Figure 2 is
CT scan which reveals a small but new tumor nodule in the liver
(arrow). |
Figure 3 - demonstrates what the liver looks after the RF ablation. The much larger dark area represents dead tumor and a small amount of normal liver. |
What types of tumors can be treated?
RF
ablation has been primarily used to treat liver tumors, either those
that originate in the liver, such as hepatocellular carcinomas, or those
that spread to the liver, such as metastatic disease. Studies are under
way to determine the potential benefits of RFA as a treatment for a
variety of cancers. In general, RFA is being tested for cancers that
cannot be removed by surgeons because of their size or location, or
because the patient is not healthy enough to have open surgery. RFA also
is used to relieve pain and suffering for patients with a variety of
cancers.
These studies include cancers of the:
Kidney: In an early study sponsored by the National Institutes of Health (NIH), 18 patients with kidney cancer were treated with RFA. The treatment successfully destroyed tumors in the majority of the patients (72 percent). After follow up of at least five months, X-rays could not detect any sign of tumor in these patients. One patient remained cancer-free two years after the treatment.
Adrenal Glands: In another NIH study of 15 patients with adrenal tumors, 10 patients (67 percent) showed no sign of active disease after treatment with RFA. The other patients had some tumor remaining that could be seen by X-rays, but in every case the treatment had killed most of the tumor.
Lung, Bone and Prostate Cancer: RFA shows promise in shrinking lung cancers that obstruct the bronchial tubes, making breathing difficult for patients. Early research also suggests the technique may be helpful for bone and prostate cancer. More studies are needed to confirm these early results.
RFA as a Treatment for Cancer Pain
Many patients have intolerable pain or other debilitating symptoms
that can be relieved by RFA shrinking the cancerous growths. The tumors
themselves may not be painful, but when they press against nerves, or
interfere with vital organs, they can cause unbearable suffering.
How effective is this form of treatment?
Since this is a relatively new procedure most of the long term data is from the treatment of liver tumors.
In
patients with tumor isolated to their liver (no tumor in the lungs,
lymph nodes, colon, etc.) improvements in survival have been
noted. About a third of tumors demonstrate local recurrence
although these areas can usually be retreated with RF ablation.
Tumors adjacent to a major blood vessel often recur locally since the
blood vessel itself draws heat away from the area during the treatment,
the so-called "heat sink phenomenon". As a result, the tumor cells next
to the blood vessel cannot get hot enough to achieve cellular death.
How is it performed?
The lesion to be treated is first localized by either CT or ultrasound. At times, both CT and ultrasound are used. A corresponding mark is made with a felt tip pen on the skin. The skin over the mark is then cleansed with a cold soap (Betadine) and a large plastic drape placed over it to maintain a sterile field. Xylocaine, a local anesthetic similar to that used by your dentist, is then infiltrated into the skin and soft tissue to numb these areas. There is a burning sensation for a few seconds. One to three tiny incisions, each measuring less than 5mm in length, are then made in the skin. The RF probe, which is similar in size to a biopsy needle, is then advanced into the lesion as guided by ultrasound, CT or both. Once in place the probe is hooked up to an electronic device and RF energy deposited for several minutes, depending upon the size of the lesion being treated. Larger lesions require longer or more treatment sessions. Since it is our goal to destroy both the tumor and a cuff of normal tissue around the tumor, we often treat each lesion more than once. After the treatments are finished the needle is slowly withdrawn. Low power RF energy is also deposited along the needle tract upon withdrawal to minimize bleeding. After the procedure a band-aid will be placed over the small incision(s). For lesions that are difficult to approach through the skin, this procedure can be performed in an open fashion in the operating room. That is, an incision is made in your upper abdomen, similar to that for a liver resection, and then the needle is inserted directly through the liver capsule into the lesion.
Is it painful?
The deposition of RF energy into the body can be quite painful.
Therefore, we offer three options for pain management. The first
is using what is called "conscious sedation", whereby medications for
pain and sedation are administered intravenously. The second
option is "monitored anesthesia care" or MAC, whereby intravenous
sedation is administered by an anesthesiologist and/or
anesthetist. With MAC the level of anesthesia is generally deeper
than it is with conscious sedation. No tube is placed in your
windpipe for MAC. The third option is a "general anesthesia",
which is also performed by an anesthesiologist and/or anesthetist and
which is even a deeper level of sedation. This option also
requires placing a tube in your windpipe. For the first 12 hours
after the procedure many patients experience only mild pain requiring an
occasional Percocet tablet. Some have a bit more pain and require
more Percocet for a longer period of time. A few patients have
also experienced nausea for which we administer Phenergan either orally
or intramuscularly.
Is it performed on an in-patient or out-patient basis?
Ideally,
we would like to perform the procedure early in the day so that there
is adequate time for the patient to be monitored and observed in the
Recovery Room. They will then be discharged from the hospital,
although we would like you to stay in town in a motel overnight.
They are then free to journey home the next morning if all goes
well. If for some reason the procedure is not performed until the
afternoon we do not have adequate resources for recovery, therefore we
admit the patient to the hospital (so-called 23 hour admission).
You will be allowed to journey home the following morning if all goes
well.
What are the risks?
Anytime a needle is placed under the skin there is almost always the risk of bleeding and infection. We will test your blood for a bleeding tendency prior to the procedure. Furthermore, bleeding complications are minimized by "coagulating" the tract with RF energy upon withdrawal of the probe. Furthermore, infectious complications are minimized by administering antibiotics intravenously during the procedure. Other less common complications include diaphragmatic injury which often manifest as right shoulder pain, a skin injury when treating superficial lesions, and a collapsed lung for those lesions that are high under the diaphragm. The latter complication may require placement of a small tube between the lung and chest wall to reinflate the lung. Injury to other structures such as the bowels or blood vessels is unlikely when US or CT are used to guide probe placement. Experience has shown that all of these complications are uncommon, occurring in approximately 5% of patients or less.
How will you feel afterwards?
As noted above, there is usually some mild-to-moderate
post-procedural pain in the region where the treatment has been
performed. This can usually be treated effectively by giving
Percocet tablets. Occasionally we administer Phenergan for nausea
and vomiting. Many of these side effects are due to the anesthesia
rather than the procedure itself. Patients with larger tumors may
experience a "post infarction syndrome" which is associated with a very
high fever, nausea at times and a generalized lousy feeling or
malaise. These symptoms, however, are not associated with
infection, are treated with Tylenol orally and usually subside within 12
to 24 hours. Very rarely patients may experience more prolonged
pain over a week or more but controlled by Percocet.
What kind of follow-up will you have?
We would like you to have a follow-up CT scan one month after the procedure. It will be important to administer intravenous contrast material during that examination. What we find during that scan will determine how often a follow-up CT will be needed thereafter. In some patients, an MRI with intravenous contrast material is an acceptable alternative. Occasionally, a PET scan is performed to help interpret the CT or MRI findings. We would prefer that you have your imaging at Duke primarily because techniques vary widely from institution to institution. Michael Morse, M.D. a medical oncologist at Duke University will also assist in following your progress after the procedure.
Can you be treated more than once?
Some lesions, particularly those that are larger, will require more than one treatment session to destroy the entire tumor. In some patients additional lesions will arise at a later date and these will also be retreated. Basically, as long as we can see the lesion with CT or US and are able to navigate the probe into the lesion, we can treat you as many times as necessary.
Vascular Access - Minimally Invasive Surgical Solutions (MISS) and Central Venous Access Catheters (CVAC)
A
CVAC is a tube that is inserted beneath your skin so there is a simple,
pain-free way for doctors or nurses to draw your blood or give you
medication or nutrients. When you have a CVAC, you are spared the
irritation and discomfort of repeated needlesticks. More than 3.4
million CVACs are placed each year, and doctors increasingly recommend
their use. There are several types of CVACs, including tunneled
catheters (Hickman or Broviac), peripherally inserted central catheters (also called PICC lines or long lines), dialysis catheters, and implantable ports.
- Chemotherapy treatments
- Infusions of antibiotics or other medications
- Nutritional supplements
- Hemodialysis