Overview of Percutaneous Radiofrequency Ablation of Liver Tumors
The liver can often become a spot for both original and spread-out cancer. These cancers can result in serious health issues and even death. Surgery to remove the cancer usually has a good success rate, but not all patients can go through with surgery. This may be due to the cancer being too widespread, there being an existing liver disease, or other health problems.
Advancements in technology now allow for safe and effective alternate treatments without needing surgery. One popular non-surgical method for treating liver cancer is percutaneous radiofrequency ablation (RFA). In simpler terms, this is a procedure where a doctor uses a probe that sends out radio waves to heat up and kill the cancer cells, while trying to keep the healthy tissues around it unharmed.
Anatomy and Physiology of Percutaneous Radiofrequency Ablation of Liver Tumors
Your liver gets blood from two main sources. The first is the portal vein, which is responsible for the flow of blood from the spleen and intestines. This vein provides about 80% of the blood supply to the liver. The second source is the hepatic artery, providing the remaining 20% of the blood supply. This artery typically branches from a larger artery that comes from your stomach area.
There are three main veins in the liver that help drain blood out of the organ. The right hepatic vein divides the liver into front and back parts, the left hepatic vein into inner and outer parts, and the middle hepatic vein into right and left parts. However, the portal vein does not help drain blood from the liver. Instead, it helps divide the organ into top and bottom parts.
The liver is divided into several functional sections as per a popular classification known as the Couinaud system. Each section has its own set of pathways for blood and bile flow. The classification is carried out in an order starting from the caudate lobe (segment I), continuing to the front segment of the left lobe (segment II), the back segment of the right lobe (segment III), and so forth. Understanding this segment classification is essential for healthcare professionals when preparing for treatments involving the liver.
Why do People Need Percutaneous Radiofrequency Ablation of Liver Tumors
If you have liver cancer at a very early or early stage, treatment might be necessary. “Very early” may imply that your liver functions normally (a condition often referred to as Child-Pugh A in medical terms) and you can perform daily activities without any help (what doctors often call a performance status of 0). If you are at an “early” stage, this means your liver function is slightly impaired (Child-Pugh A-B) but you can still carry out daily activities (performance status of 0).
Besides liver cancer, treatment might also be required if cancer from the colon has spread to the liver. Today, treatment may even be needed for cancer that has spread from the breast, thyroid, or other parts of the body to the liver.
Another scenario requiring treatment could be if you have a liver tumor, or hepatoma, and you are on the waiting list for a liver transplant.
The main treatment is typically for small tumors. This means a single tumor that is 5 cm or less across. Or it could be for people who have up to three tumors, each no more than 3 cm across.
Sometimes, surgery is not an option for certain types of tumors. This could be due to factors about the tumor itself, the patient being unfit for general anesthesia, or other health conditions related to older age. These tumors may keep growing or come back after treatment, so finding an effective therapy is important.
When a Person Should Avoid Percutaneous Radiofrequency Ablation of Liver Tumors
There can be absolute and relative reasons which suggest that a particular medical procedure shouldn’t be done.
Absolute reasons mean it’s totally unsafe to do the procedure. These reasons include:
– If a tumor is able to be surgically removed, or if the patient is a good candidate for a transplant, those options should be tried first. It’s because, they usually give the best results.
– If the tumor has spread to the blood vessels.
– If the tumor is located less than 1 cm from the main duct that carries bile, a fluid made by the liver and stored in the gallbladder. This is because during this procedure, the ducts are at a high risk of getting injured, leading to problems like abscess formation (pus build-up), narrowing of the bile ducts, or blockage.
– If the ducts that carry bile within the liver are dilated or widened.
– If the tumor is located externally on the organ.
– If the patient has a blood disorder that’s hard to correct.
Relative reasons mean that the procedure might still be done, but with extra caution. These include:
– If the cancer has spread to other parts of the body, but there’s a good chance of treating the spread.
– If the patient has had a surgical connection made between the bile duct and small intestine. This could potentially lead to infection, although antibiotics could help to prevent this.
– If tumors are located on the surface or just underneath the surface of the liver, especially close to the digestive tract or gallbladder. This could cause thermal injury (burns) to these organs.
– If the patient has severe cirrhosis (liver damage) or a seriously compromised liver.
In the following situations, an open surgery approach is preferred:
– Tumors that are hard to reach with electrodes.
– A single tumor that is larger than 5 cm in diameter or multiple tumors each more than 3 cm in diameter.
– More than 3 tumors but treatment can still be successful.
– Tumors immediately adjacent to liver blood vessels as this decreases the effectiveness of the procedure due to heat loss.
Equipment used for Percutaneous Radiofrequency Ablation of Liver Tumors
RFA, or Radiofrequency Ablation, is a procedure used to kill cancerous tissues by applying heat to them. This process involves using electrical currents to create a zone of damage in the tumor. An electrode, a device that conducts electricity, is inserted into the tumor. Then, several grounding pads, which help maintain a stable electrical circuit, are attached to the patient’s skin. When the electrode is activated, it generates heat, causing nearby ions (tiny charged particles) to move rapidly. This movement creates high temperatures within the tumor and surrounding tissues, ultimately causing them to be destroyed.
To perform an RFA, doctors need three main tools:
- An electrode needle probe with special features to help apply heat and monitor temperature
- An electrical generator, which is responsible for producing the electrical current
- Several grounding pads that ensure electricity can flow safely through the patient’s body
The electrode needle probe used for the process comes in two types. The first type is a solid, straight needle. The second type is a bit more complex – it’s also straight but is hollow and contains multiple bendable elements called “tynes” which can be retracted while the needle is being placed in the tumor. These tynes come with heat sensors at their tips, allowing doctors to continuously track temperature during the procedure. Once the needle is in the right spot in the tumor, the tynes are extended in a manner similar to the way the spokes of an umbrella open up.
The electrical generator is connected to the electrode via insulated wires and the aforementioned grounding pads, which are typically placed on the patient’s thighs. The generator then produces an alternating current within the Radiofrequency range of 300-500kHz, effectively doing its job in creating an environment apt for tumor destruction.
Preparing for Percutaneous Radiofrequency Ablation of Liver Tumors
Before any procedure, it’s important to make sure the patient is a good fit for what we’re planning. If someone has a liver tumor, sometimes the best way to cure it is to remove it surgically. But that’s not always the best option for everyone. Doctors, nurses, and other healthcare professionals spend time together discussing a patient’s individual case. Only after they figure what’s the best approach do they decide whether to move forward with a procedure called radiofrequency ablation (RFA). This is a minimally invasive treatment that aims to destroy cancer cells in the liver using heat.
Before they make this decision, doctors take pictures of the inside of the person’s body using tools like CT scans (a fancy kind of X-ray) or MRI scans (which uses magnets and radio waves). These images show them where the tumor is and how they might be able to reach it with the RFA needle.
Not only that, but doctors also perform a number of lab tests. These tests help them understand if a person’s liver is working properly, whether their blood clots normally, and whether there are certain chemicals in their blood that suggest they have liver cancer. If someone’s diagnosis of liver cancer isn’t clear, doctors sometimes need to take a small piece of their liver so they can look at it under a microscope.
Lastly, doctors must meet with their patients to explain what they can expect during and after the procedure, what risks may be involved, and what other treatment options they have. These conversations are a key part of the patient’s journey – they give them the chance to ask any questions they might have and understand exactly what’s going to happen.
Before we start the RFA procedure, we usually put the patient to sleep. This is better tolerated by patients as it means they won’t feel any discomfort during the treatment. Some studies even found that general anesthesia could reduce the chances of the cancer recurring in some patients.
Lastly, just how the patient is positioned during the procedure depends on a lot of things, like how we’re going to see inside the person’s body, where the tumor is, what kind of anesthesia is used, and what both the doctor and patient prefer. Ultimately, our goal is to treat the tumor effectively and ensure the patient is as comfortable as possible.
How is Percutaneous Radiofrequency Ablation of Liver Tumors performed
The following is a simple explanation of a medical procedure called Percutaneous Radiofrequency Ablation (RFA). It is generally performed by a specialist doctor known as an interventional radiologist, and on a very basic level, this procedure involves using a needle to generate heat and destroy tumor cells in the body. Let us break it down in steps for better understanding:
1. Pre-procedure planning: Before anything happens, the doctor uses pre-existing images of the patient’s body to plan the entire procedure. They identify the exact point of entry for the needle, the safest path it should take into the body, and the precise spot where it should end up.
2. Needle Insertion: After the planning stage, the needle, also referred to as a “probe,” is guided into the tumor using live images generated by an ultrasound or CT scan machine. If needed, local anesthesia may be given to numb the pain at the site of insertion. The needle then travels along the anesthetized path, right into the mass of the tumor.
3. Radiofrequency Ablation: Once the needle is in the desired position, it then delivers a series of controlled high-energy currents to heat and destroy the tumor cells. The power and length of treatment depend on the size of the tumor. The goal of the procedure is to eliminate not only the tumor but also to destroy a tiny bit of the surrounding healthy tissue for added security.
4. Large tumors: For larger-size tumors, the doctor strategizes by moving the needle around or treating different areas of the tumor consecutively. This ensures that the whole tumor, along with a small margin of the surrounding tissue, is adequately destroyed. They need to be careful not to overheat or “char” the tissue because this can actually block the treatment and stop the desired destruction of the tissue.
5. Ensuring Safety: Once the treatment part of the procedure is complete, it’s very important to carefully remove the needle to prevent any residual tumor cells from spreading. Sometimes, due to the heat produced in the treatment, tissues around blood vessels might not receive adequate heat. In these cases, readjustment of the needle might be required.
6. Post-procedure Imaging: Immediately after the procedure, imaging tests are done to check the treatment results and to look for any possible complications.
7. Follow-Up: Follow-ups are usually scheduled to occur 4 to 6 weeks after the procedure to check for any local tumor regrowth, the appearance of new tumors, or the spread of the disease to other parts of the liver. These tests can also involve various types of scans like CT, ultrasound, MRI, and PET scans.
It’s completely normal to see certain changes on the imaging test immediately after the procedure. For example, seeing fluids near the liver, some changes in the right lung, and even free fluid in the abdominal cavity (which usually clears up in several days) are common characteristics.
Success after the Radio Frequency Ablation treatment is generally indicated by the appearance of a low-density lesion, showing no contrast enhancement – about 1 to 3 months after. Unsuccessful treatments are typically identified by characteristics like thick, nodular, and asymmetrical rim enhancements or an increase in the size of the treated lesion.
Over time, the treated area might stay the same in size or may gradually shrink. Sometimes, there might be calcification along the edge of the treated area, which means the formation of a hard layer of calcium.
Ultrasounds are sometimes done to check the progress of the treatment. Though there are limitations to this method as it doesn’t give as precise results compared to a CT or MRI scan. Hence, it’s often combined with other imaging techniques to ensure a more accurate assessment.
Though Radio Frequency Ablation sounds like a complex procedure, it is fairly standard and has allowed doctors to treat tumors with precision without resorting to invasive surgery. It’s important to remember that each patient’s situation and treatment plan is unique, and any questions or concerns should be discussed with the treating doctor.
Possible Complications of Percutaneous Radiofrequency Ablation of Liver Tumors
After a procedure to treat liver tumors known as Radiofrequency Ablation (RFA), about one-third of patients may experience symptoms similar to the flu, such as low-grade fever, pain, feeling unwell, muscle aches, nausea, and vomiting. This is known as post-ablation syndrome, and it generally lasts about a week or so after the procedure.
The most common issue after RFA is internal bleeding, which can occur in the liver or abdomen. This typically happens due to injury to small blood vessels during the procedure and is often signaled by increasing abdominal pain. It’s also more common in patients with liver cancer due to potential blood clotting problems associated with an underlying liver disease, known as cirrhosis. Some bleeding might stop on its own or require blood transfusions, but severe cases may require further treatment.
Bleeding can also occur in the chest, or hemothorax, but this is less common. It usually happens due to blood vessel injury when treating tumors in the right lobe of the liver. Common symptoms include shortness of breath and chest pain. Another type of bleeding, known as hemobilia, happens within the bile ducts when both a bile duct and a liver artery/vein gets damaged. This can lead to blockage of bile, causing jaundice and liver failure.
Infections, such as abscesses or wound infections, can also occur following RFA. These can appear several weeks or even months after the procedure, with fever and abdominal pain being the most common symptoms. The risk for these infections is higher in patients with unusual biliary anatomy, which can make them more prone to infections.
Damage to the bile passage, known as the biliary tract, can result from direct heat or mechanical injury during the RFA. Complications can include direct duct injury, constriction, bile leakage, and more rarely, bile-peritoneum and bile-lung fistula.
Lastly, liver failure, though rare, is a severe complication of RFA. This is especially dangerous for patients with cirrhosis or those who have had previous liver surgery. The sudden liver failure can be due to blood vessel damage causing tissue death, or from over-ablation. It’s crucial to plan ahead carefully before the procedure to avoid causing further harm to existing liver function.
What Else Should I Know About Percutaneous Radiofrequency Ablation of Liver Tumors?
In addition to a procedure called radiofrequency ablation, where heat is used to destroy cancer cells, there are other effective methods such as microwave and cryotherapy (a treatment using extreme cold). Research suggests that there is no significant difference in survival rates, return of the cancer, or rates of complications and death in patients with liver metastases (cancer that has spread to the liver) treated with radiofrequency ablation compared to microwave ablation. This applies to both the length of survival from diagnosis and the length of survival from when the treatment was done.