Taking chemotherapy directly to tumors
In addition, though, the IR team can perform a tumor-embolization procedure to also deliver chemotherapeutic drugs (mixed with an embolizing agent consisting of small spongelike particles) through the catheter into and around the tumor to more directly expose the tumor to these cancer-killing agents, and decrease the amount of drug circulated systemwide in the body. This transcatheter chemoembolization is a newer strategy that delivers a higher dose of chemotherapy to the cancerous tissue. Because further circulation to the area is blocked after the drug is delivered, the chemotherapy dwells at a higher concentration in the area of the tumor for a longer period of time. The tumor shrinks or, in some cases, dies, due to both the anti-tumor drug and the lack of blood supply. The technique produces fewer side effects, compared to standard chemotherapy, because anti-tumor drugs are trapped in and around the tumor rather than delivered to the whole body systemically.
Interventionalists most often use chemoembolization to treat cancer of the liver, although they can apply the procedure in other areas as well. Via the vessels of the liver (hepatic artery), the team injects chemotherapy into hepatic-tumor masses along with an embolizing agent.
This method of delivering cancer treatment directly to the tumor is effective in stopping or reversing tumor growth. Interventional teams use it mainly for cancers that have either started in or spread to the liver. Among these cancers are hepatoma (primary liver cancer) or liver cancers that have metastasized from colorectal cancer, pancreatic cancer, melanomas, or sarcomas. Chemoembolization is especially useful for patients who have primary hepatocellular carcinoma or tumors with rich blood circulation that are confined to the liver.
The treatment can:
• preserve liver function;
• relieve pain and other symptoms, thus contributing to quality of life;
• shrink tumors to smaller, lower-stage tumors, sometimes making a patient eligible for surgery;
• and, in some patients, especially those with hepatocellular carcinoma, improve survival.
For a chemoembolization procedure, the IR team will sedate the patient and use one or more forms of angiography to guide the procedure. Typically the team will insert the catheter into the femoral artery, through a small incision in the groin.
The IR team will usually follow up the procedure with additional angiography or other imaging to evaluate the positioning and results of the embolization. Most patients will remain for just one or two nights in the hospital after chemoembolization and will resume normal activities within a week. Pain, fever, and nausea within the first week after the procedure are normal side effects that can be addressed through medications.
The combination of chemotoxicity and blockage of blood flow is highly effective in reducing tumors. But it may take a weeks or months to fully determine whether the chemoembolization has achieved its aim of controlling symptoms, bleeding, or growth of the treated tumor. During this time, the patient will return for follow-up CT scanning, or sometimes MR imaging, to monitor this progress. Chemoembolization can be repeated to treat additional areas or to treat a recurrence of the cancer, and this type of therapy may be combined with other types of cancer treatment as well.