What Is Tumor Ablation?

Chemical ablation is a trocar microinjection and ultrasound guided technique aimed at eliminating cancer cells.

Chemical ablation

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Chemical ablation is a trocar microinjection and ultrasound guided technique aimed at eliminating cancer cells.

Chinese name

Chemical ablation

Foreign name

chemo-ablation

Targeting illness

Eliminate cancer cells

Related technologies

Trocar microinjection, ultrasound guided technology

hospital

Fuxing Hospital, Capital Medical University

Chemical Ablation Overview of Medical Ablation, Doctor Feng Weijian, MD, Tumor Treatment Center, Fuxing Hospital, Capital Medical University

Chemo-ablation of solid tumors is percutaneously punctured tumors under image guidance and monitoring. Chemical drugs that destroy tumor proteins are injected directly into tumors, necrosis cancer cells, inactivate cancer cells, and ablate cancer tissues. A surgical approach to "removing" a tumor. As the liver is the most typical solid organ, tumor ablation therapy is mainly focused on liver tumors. In recent years, research on the application of tumor ablation therapy has attracted attention. At the Barcelona Liver Cancer Conference in 2000, percutaneous ethanol injection was used as a curative method for liver cancer. "Therapy" includes ablation therapy and embolization therapy. Ablation therapy is most commonly used for radiofrequency ablation and chemical ablation. The guidelines also specifically recommend that ablation therapy be combined with surgical resection and liver transplantation as the preferred treatment for small liver cancer.

History of chemical ablation

For a long time, people expected to inject drugs directly to kill cancer cells. In 1955, the New York Times reported that injecting ethanol into brain lesions to treat Parkinson's disease was called a "chemical knife". In 1983, Japan's first percutaneous ethanol injection was used to treat liver cancer. In 1994, Japan again reported percutaneous acetic acid injection for liver cancer. In 2002, our research team reported the first transdermal injection of dilute hydrochloric acid to treat liver cancer, and further improved CT guided puncture and microinjection technology. The era of chemical ablation for cancer treatment has arrived.

Improvement of percutaneous puncture intratumoral injection technology

Injection technology is one of the keys to chemical ablation. It is very important to accurately puncture the target under the guidance of the image, to inject the drug evenly into the tumor, and to monitor the entire treatment process with the image to grasp the injection dose and drug distribution.

Ultrasound guidance technology: The advent of ultrasound puncture guides has led to the development of ultrasound interventional technology, especially in the application of liver lesions. With its simple, fast, economic, and non-ray characteristics, it has been increasingly widely used. After the ultrasound localization, under real-time ultrasound monitoring, the puncture needle was inserted into the lesion along the puncture guide, and the medicine was slowly injected. The hyperechoic area produced by the medicine can be seen at the needle tip. Observe that the hyperechoic area gradually increases and even fills the entire tumor.

CT guidance technology: CT is a good guidance tool for non-vascular intervention. With its high density resolution, wide field of view, non-overlapping images, accurate positioning, it has obvious advantages over ultrasound guidance. The image obtained by CT can clearly show the anatomical structure of the puncture section, the location, size, shape of the lesion, the internal condition of the tumor, and the structure and spatial relationship between the lesion and surrounding tissues, especially the distribution and movement of adjacent blood vessels and nerves. The distribution of the contrast-containing drug in the lesion can be observed.

Free-handtechnique is based on the angular depth data obtained by CT scan. It is difficult for the surgeon to puncture in one step based on experience, and the needle is divided into step needles, which is greatly affected by artificial technical factors. The success of the puncture is related to the experience of the operator, the accuracy is greatly reduced, and the chance of puncture complications is more. Because there is no puncture guide, the development of CT puncture guidance lags behind ultrasound.
The application of CT-specific puncture guide stent solves the above problems. The puncture guide is fixed at the puncture point of the skin. It supports the puncture needle and displays the puncture direction of the puncture needle. The guide moves into the scanning position with the scanning bed. Angle of the needle. Use the CT scan of the metal tail and length drawn by the puncture needle as a puncture guideline to make it pass through the target point. Insert the puncture needle into the corresponding depth to hit the target point. The hit rate is close to 100%, the lesion rate for a single puncture is 98%, and the target millimeter error rate is less than 10%. The overall CT display rate of the puncture needle exceeds 95%. The accuracy of this technology reaches millimeter level, which improves accuracy and safety.

Trocar microinjection technology: Under the guidance of the CT puncture guide, a 0.8mm diameter needle is punctured to the front of the tumor, and it is used as a trocar to insert a 0.45mm diameter microinjection needle into the tumor. Micron injection needles can be bent, changing the direction of puncture, and multi-point injection of chemical ablation drugs into the tumor (Figure 1). Micron injection needles have less puncture damage and less drug reflux when the needles are ejected, which improves the treatment efficiency and reduces adverse reactions.

Figure 1: Cases of recurrence of liver cancer after surgery, Under the guidance of CT, using the characteristics of the micron injection needle can be bent, directly hit the center of the tumor, injecting chemical ablation drugs, the micron injection needle has no reflux, Complete ablation.

Chemical ablation drug

Anhydrous ethanol: Anhydrous ethanol dehydrates cancer cells, coagulates proteins and destroys tumor cells. In addition, endothelial cells in the vascular wall of tumor tissue degenerate, necrosis, and then form thrombus, leading to ischemic necrosis of the tumor. This is called percutaneous ethanol injection therapy. .
Ethanol injection is the main representative of chemical ablation therapy. It is mainly used for primary hepatocellular carcinoma with a diameter of less than 3 cm in a single lesion that cannot be operated, especially with severe liver cirrhosis or other severe heart and kidney diseases that cannot tolerate surgery.
Alcohol injection has almost curative effect in treating small liver cancer. The 1, 3, 5, and 7-year survival rates were 97.7%, 70.3%, 51.6%, and 30.6%, respectively. Common reactions include local pain, heat absorption and drunkenness. It has certain damage to liver function and transient transient aminotransferase increase.

Glacial acetic acid: Compared with ethanol, acetic acid (acetic acid) has a stronger penetrating ability, easily penetrates the fibrous spaces of cancer tissues and spreads evenly. It has the advantages of fewer injections and fewer times, so it has a stronger ability to kill cancer cells. Ability. It is mainly used for solitary primary hepatocellular carcinoma and metastatic liver cancer.
Percutaneous puncture and injection of 50% acetic acid for the treatment of liver cancer is safe and effective, the ablation effect is three times that of absolute ethanol, and its efficacy is better than that of absolute ethanol. The 1- and 2-year survival rates for small liver cancer are 100% and 92%, respectively. Acetic acid has a strong irritating odor during the treatment. The treatment of pain and recurrence is a problem that needs to be solved.

Dilute hydrochloric acid compound anti-fusion agent: Inspired by the digestion of digested food proteins, our research team found that human gastric juice has the effect of destroying cancer cells. Diluted hydrochloric acid compound anti-fusion agent, injection of 1ml can completely coagulate and necrosis 15cm3 tumors, its coagulation of cancer tissue protein is 5 times more effective than 50% glacial acetic acid, and 15 times of absolute ethanol. Experimental research shows that the compound anti-fusion agent coagulates tissue The scope is sphere, the interface is delicate, the solidified necrotic zone is clear from the normal tissue, which is obviously better than absolute ethanol and glacial acetic acid (Figure 2), which is called "chemical knife".

Figure 2 Comparison of the ablation efficacy of dilute hydrochloric acid as the main compound anti-fusion agent, 50% glacial acetic acid and absolute ethanol on muscle tissue ablation.

Percutaneous hydrochloric acid injection is suitable for isolated small liver cancer, especially for the treatment of liver cancer with an envelope diameter of less than 5 cm. Compound anti-fusion agents mainly coagulate tumor proteins, and the envelope of the tumor can prevent the spread of the drug, thereby preventing chemical ablation from damaging surrounding tissues and organs (Figure 3).

Figure 3 Top primary liver cancer, tumor 3cm (Figure 3), guided by a CT puncture guide stent, a microinjection needle was punctured into the tumor center, and 2ml of compound anti-fusion agent was injected. CT showed good drug distribution immediately, 24 hours After the drug was filled with tumor and tumor necrosis, the drug was completely absorbed after 1 week, and the liver and kidney function was well reviewed.
Studies have shown that after injecting the compound anti-fusion agent, its ablation effect gradually spreads to the surroundings and lasts about 6 hours. A plain CT scan at 24 to 72 hours after injection showed that the injection site was a high-density area of contrast medium, with a small amount of vaporized foci, and low-density changes around the lesion. There was no blood vessel release in the low-density area during intensive scanning. Pathological examination of the biopsy showed that all necrosis Tissue, PET / CT examination showed no metabolic signals in the treated area. After 3 to 6 months, the ablation area gradually decreased and even disappeared.
Solitary tumors with a diameter of 3.0cm all obtained complete necrosis after 1 or 2 treatments. For patients with a single tumor 3.0cm in diameter, the 1, 2 and 3 year survival rates were 100%, 90% and 85%, respectively. The one-year survival rate of the tumor was 87.5%.
For patients who are not suitable for surgery and intervention and local physical ablation treatment, chemical ablation treatment is mainly selected. For patients with larger masses, TACE and chemical ablation are used for "dual intervention" treatment. For blood-rich tumors, TACE is performed first. After the tumor vessels are embolized, additional chemical ablation treatment is added to the remaining lesions, which can make the lesion completely Necrosis. For tumors with poor blood supply, chemical ablation treatment is used to ablate most of the tumor, and then embolization chemotherapy is more effective. Chemical ablation can also treat metastatic liver cancer, especially single tumors, and can achieve good results (Figure 4).

Figure 4 Cases of chemical ablation treatment of massive liver cancer, giant tumor of the right posterior liver, CT-guided injection of compound defusion agent, tumor completely ablated after 1 week, tumor ablation after 1 month, part of the cavity formed, biopsy of tumor necrosis, No tumor recurrence after 8 years of tumor ablation.
Conclusion

Recently, "Malignant Liver Tumors: current and emerging therapies" edited by European scholars has a chapter on percutaneous treatment of liver cancer. The article quotes hydrochloric acid injection chemical ablation therapy, which is better than ethanol injection and acetic acid in animal experiments. It is clinically used for liver cancer and shows high ablation and fewer adverse reactions.
Liver cancer ablation technology is in the ascendant. Chemical ablation has obvious advantages in the treatment of liver cancer. Image-guided chemical ablation technology shows high-efficiency, non-toxic, non-invasive, and economic advantages. New chemical ablation agents, minimally invasive puncture injection technology, and accurate image-guided monitoring Technology is expected to bring new hope to patients with liver cancer.