Liver and kidney cancer are among the most common types of cancer worldwide. According to the World Health Organization, liver cancer is the sixth most prevalent type, while kidney cancer ranks fourteenth. Tumor embolization is increasingly used to treat these cancers by blocking blood flow to the tumors, causing them to shrink or die.
Studies have shown that tumor embolization can improve survival rates and reduce tumor size in both liver and kidney cancers, providing an important treatment option for patients, especially those who are not candidates for surgery or are in the advanced stages of the disease.
What is tumor embolization?
Tumor embolization is a procedure that targets the blood vessels supplying the tumor to block or reduce blood flow to the cancer cells. This is achieved by reducing the tumor’s blood supply, effectively depriving the tumor of oxygen and nutrients, causing it to shrink or stop growing. Tumor embolization is often used in cases of liver and kidney cancer when surgery is not possible due to the tumor’s location, size, or the patient’s overall health.
The procedure involves inserting a catheter into an artery and guiding it to the tumor using imaging techniques such as X-rays, ultrasound, or computed tomography (CT) scans. The catheter delivers various embolic agents, including small particles, coils, or medications, directly to the blood vessels feeding the tumor.
Thermal ablation is one of the most effective forms of embolization and involves applying heat to the tumor, either through radiofrequency ablation or microwave ablation. These methods not only block blood vessels but also destroy tumor cells through heat.
Steps of tumor embolization in liver and kidney cancer
Tumor embolization is typically performed in a hospital and involves several key steps:
Preparation: The patient is positioned comfortably, and a local anesthetic is administered to numb the area where the catheter will be inserted. Depending on the patient’s condition and the complexity of the procedure, either local anesthesia or general anesthesia may be used.
Catheter Insertion: A small incision is made in the thigh, and the catheter is inserted into the blood vessels using guided imaging. The catheter is then threaded through the blood vessels toward the tumor.
Embolization and Thermal Ablation of the Tumor: Once the catheter reaches the tumor, embolic agents (such as small particles, coils, or medications) are injected to block the blood supply. If thermal ablation is used, the catheter will also deliver heat to the tumor to destroy the cancerous tissue.
Post-Procedure Monitoring: The patient is monitored for complications such as bleeding or infection. Depending on the complexity of the procedure and the patient’s condition, most patients can return home on the same day or the following day.
How does thermal ablation technology work on tumors?
Tumor embolization, a cancer treatment that involves blocking blood vessels and applying heat to target the tumor directly, uses radiofrequency ablation (RFA) or microwave ablation (MWA) to generate heat that destroys cancer cells.
Both methods cause the embolization of the cancerous tissue, which in some cases leads to the shrinkage or complete destruction of the tumor. Tumor embolization is particularly useful for tumors that are difficult to treat with traditional surgery or radiation, especially in cases of liver and kidney cancer, where the tumor’s location or the patient’s health may make surgery challenging. For example, in the case of a cancerous mass in the kidney, a radiologist performs thermal ablation on the tumors, where the patient undergoes either local or general anesthesia, depending on the case. A catheter may be inserted to drain urine from the bladder, and it is typically removed shortly after the procedure.
The doctor uses a local anesthetic to numb the area around the kidney and then conducts an ultrasound or CT scan. These scans guide the doctor to the correct area of the kidney and help monitor what is happening during the treatment. When the doctor sees the tumor on the screen, they insert one or more probes through the skin into the tumor.
The probes work by freezing or heating the tumor, with the high temperature destroying the cancer cells. The doctor also aims to destroy a small area (about 1 cm) of healthy tissue around the tumor to help ensure that no cancer cells are left to grow back.
Difference between Radiofrequency Ablation (RFA) and Microwave Ablation (MWA)
Both radiofrequency ablation (RFA) and microwave ablation (MWA) are effective techniques for treating liver and kidney tumors. The choice of method depends on the tumor’s size, location, and other clinical factors. The difference between them is:
| Microwave Wave Anaesthesia (MWA) | Radio Frequency Anesthesia (RFA) | |
| Uses microwave energy | Uses high-frequency electric currents | Heat generation |
| More efficient in generating higher temperatures | Heats up slower | Temperature |
| Faster processing | Requires longer treatment times | Speed of treatment |
| More suitable for larger tumors or tumors with complex structures | Suitable for smaller tumors (less than 3 cm) | Tumor size |
| Affects a larger volume of tissue and achieves more uniform heating | Affects a smaller, more specific area of tissue | Impact on tissues |
Advantages of tumor embolization compared to surgery
Tumor embolization, especially when using tumor thermal ablation techniques such as RFA and MWA, offers several advantages over traditional surgery:
- Less invasive: Tumor removal is performed through a small incision, as opposed to surgery that requires large incisions (often in the groin or wrist) where a catheter is inserted. This results in a lower risk of infection and a shorter recovery time.
- Shorter recovery time: Patients who undergo ablation typically recover faster than those who undergo surgery. Hospital stays are often shorter, and many patients can return to normal activities within days to a week.
- Lower risk of complications: Because the treatment of cancerous masses with coagulation is less invasive, the risk of complications such as infection and bleeding is generally lower compared to surgery. There are also fewer concerns about scarring or damage to healthy tissue.
- Has the potential for recurrence: Embolization therapy can be performed multiple times if needed, but surgery may not be a viable option for recurrent or various tumors.
- Is effective in inoperable tumors: For patients with tumors that are difficult or impossible to remove surgically due to their location or the patient’s health, Tumor embolization offers a viable alternative, especially common in cases of liver or kidney cancer with tumors near vital structures.
- A procedure that complements other treatments: Embolization can also be combined with other treatments, such as chemoembolization or radioembolization, as this can enhance the overall effectiveness of treatment, especially in advanced stages of cancer.
Effectiveness of tumor embolization compared to other treatments
Tumor embolization is highly effective, especially for tumors that are difficult to treat with conventional surgery. Although it is not a cure for all cancers, it offers significant benefits for certain types of tumors and in patients not candidates for surgery. Compared to other treatments such as surgery, radiation, and chemotherapy, Tumor embolization is less invasive and usually has a shorter recovery time. In addition, it can be combined with other treatments to enhance its effectiveness, making it an important tool in treating liver and kidney cancer.
Conditions suitable for liver and kidney cancer embolization
Tumor embolization is not right for every patient or every tumor, but it is an effective option in many scenarios:
Liver cancer (hepatocellular carcinoma)
Liver cancer is often diagnosed at an advanced stage, and surgery may not be possible for many patients. Tumor ablation is considered a preferred treatment for tumors that cannot be surgically removed due to liver cirrhosis, the large size of the tumor, or the patient’s inability to undergo surgery. Both chemoembolization and radioembolization (a form of tumor ablation using radioactive materials) are commonly used to treat liver cancer.
Kidney cancer (renal cell carcinoma)
While surgery remains the primary treatment for kidney cancer, Tumor embolization can be used when surgery is not an option, such as in patients with poor overall health or those with multiple tumors. Tumor ablation is also useful in controlling bleeding caused by advanced kidney cancer or for treating tumors that are difficult to reach surgically.
Metastatic cancers
When cancer has spread to the liver or kidneys from other parts of the body, coagulation can help shrink tumors and improve symptoms. While it is not a cure, it can provide relief and improve the quality of life for patients with metastatic disease.
Tumors that relapse after surgery
Tumor embolization in patients whose tumors have recurred after surgery can be an adjunctive and beneficial treatment. It may prevent tumor growth or provide a way to manage symptoms until other treatments become possible.
Risks and challenges in tumor embolization
Although tumor embolization offers many benefits, it is not without risks and challenges, as the procedure requires precision and involves potential complications, including:
- Infection: This infection can be controlled with antibiotics, especially at the catheter insertion site.
- Risk of bleeding: Bleeding may occur in the targeted organ or at the catheter insertion site, where imaging tools are used to prevent bleeding.
- Flu-like symptoms after embolization: Including fever, pain, nausea, and fatigue, which are typically temporary.
- Incomplete tumor destruction: While ablation can significantly shrink tumors, it may not always completely eliminate the cancer. In some cases, additional treatments like surgery, radiation, or chemotherapy may be needed.
- Risk of recurrence: Even after successful ablation, tumors can recur, making continuous monitoring essential to assessing the treatment’s success.
Common side effects of thermal ablation
Although thermal ablation is generally safe, it may cause some side effects, including:
- Pain and discomfort: Some patients may experience pain at the catheter insertion site or in the area of the treated tumor.
- Nausea and vomiting: Nausea after the procedure is common and usually subsides within a few days.
- Fatigue and fever: Many patients report feeling tired and feverish after the procedure, a condition known as post-embolization syndrome.
- Infection or bleeding: There is a risk of infection or bleeding with any procedure involving the insertion of a catheter.
Tumor relapse after thermal ablation
Tumor relapse after thermal ablation is a complication that may occur in some cases, as the cancerous tissue is destroyed using high heat. Although this treatment is effective in shrinking tumors, some tumors may continue to grow back after a period of treatment. Relapse is caused by several factors, such as cancer cells being resistant to the heat or not being covered by all the cancer cells during the sessions. This requires careful monitoring and complementary treatment to ensure the best possible results.
Tumor embolization, particularly through thermal ablation techniques such as RFA (Radiofrequency Ablation) and MWA (Microwave Ablation), provides a valuable alternative to traditional surgery for liver and kidney cancer. These procedures are minimally invasive, have a shorter recovery time, and are capable of treating inoperable tumors, making them a preferred option for many patients. However, like all medical treatments, they carry risks, and their effectiveness depends on the tumor type, size, and location. Patients and doctors can make informed decisions about incorporating tumor embolization into the initial cancer treatment plan by understanding the procedure, its benefits, and the associated risks.
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