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The liver is one of the largest organs and plays a central role in metabolism. © imagebroker/Sigrid Gombert/imago
When treating liver cancer and metastases, interventional radiological oncology represents an alternative to major surgery.
Frankfurt – Surgery, chemotherapy and radiation therapy are no longer the only options in the treatment of cancer. In addition to new drug options such as immunotherapy, radiological interventional oncology also offers a number of gentle alternatives to major surgical procedures to remove or shrink tumors. The options here are particularly diverse in the treatment of primary liver cancer and liver metastases.
Thomas Vogl, Director of the Clinic for Radiology and Nuclear Medicine at the University Medical Center Frankfurt, is internationally considered a pioneer in the field of “image-guided, interventional cancer therapies”, several of which he helped develop and published clinical studies on. The somewhat unwieldy term describes therapies in which imaging procedures such as computer tomography (CT) or magnetic resonance imaging (MRI) are used to make the situation in the affected organ and the exact location of the tumors visible during treatment. These should then be destroyed using minimally invasive methods.
A targeted approach protects healthy tissue during cancer therapies
The advantage: This procedure is very precise, protects healthy tissue and is overall less stressful for patients and is therefore also suitable for people who would no longer be able to cope with a major operation. You will be given a local anesthetic and usually sedated during the procedure, but general anesthesia is usually not necessary. The procedures based on this principle include, in particular, radiofrequency ablation (RFA), microwave ablation (MWA), laser-induced thermotherapy (LITT), transarterial chemoembolization (TACE) and transarterial radioembolization (TARE). Not every method is equally suitable for every tumor in the liver, says Thomas Vogl.
A basic distinction must be made between primary liver cancer and liver metastases – although treatments can be suitable for one or the other. Primary liver cancer is a tumor that arises in the liver itself. Depending on the stage, it can be treated with partial or complete removal of the organ, the latter followed by a liver transplant. Minimally invasive methods can also be an option. A transplant achieves the best results, says Vogl.
Around 70 percent of those affected are still alive after five years. However, in many cases liver cancer is no longer operable; systemic treatments that affect the entire organism, such as chemotherapy or immunotherapy, are often used.
Liver cancer can be treated minimally invasively
Liver metastases usually occur in multiples and are tumors that have spread outside the liver. Cancers that often spread to the liver include breast, colon, lung or kidney cancer. Liver metastases can be operated on, destroyed with minimally invasive procedures, irradiated, or treated systemically.
Liver cancer
Causes Liver cancer can form spontaneously, with no apparent history. In most cases, however, the disease is preceded by long-term damage to the liver, which leads to cirrhosis and then cancer. It can result from a chronic viral infection with hepatitis C or B, from chronic alcohol abuse or even long-term non-alcoholic fatty liver disease.
frequency In Germany, around 9,800 people develop liver cancer every year. This makes liver cancer one of the rather rare types of cancer. Men are affected more often than women. However, a large study from the USA recently showed that the numbers are increasing, particularly among younger women.
Symptoms The first symptoms that liver cancer can cause are non-specific. These can include fatigue, weakness, loss of appetite, nausea, weight loss and pressure pain in the upper abdomen, and jaundice or ascites may later occur. Pam
In principle, both primary liver tumors and metastases can be treated minimally invasively under MRI or CT control. The most commonly used procedures include thermal ablation techniques, in which a probe is inserted directly into the cancerous tissue and destroyed with heat. The principle: The high temperatures denature the proteins and damage the DNA, causing the cells to die. These methods are usually suitable for tumors with a diameter of up to three or up to five centimeters, says the Frankfurt radiologist; in terms of number there should be a maximum of five.
The high temperatures required come from different sources depending on the method, explains Vogl. During radiofrequency ablation, high-frequency alternating current is intended to “cook” the tumor tissue. To do this, a probe with a needle is inserted directly into the metastasis from the outside in order to heat it up and cause it to die, explains Vogl. RFA is particularly suitable for only a few metastases.
Laser-induced thermotherapy destroys tumors in a minimally invasive way
Microwave ablation is a very similar principle – only electromagnetic waves are used instead of radio frequency. These cause the water molecules in the tissue to vibrate, creating kinetic friction and, as a result, heat. Here, too, a needle is inserted directly into the tumor from the outside.
Laser-induced thermotherapy, in turn, is somewhat older than ablation with radiofrequency and microwaves. Using a special applicator, the energy is radiated into the cancer tissue, where the laser light is absorbed and heated – resulting in the destruction of the tumor, including a seam around it.
The Frankfurt radiologist Thomas Vogl helped develop several of the procedures himself and published studies on them. University Medicine Frankfurt © University Medicine Frankfurt
TARE and TACE are minimally invasive variants of two classic forms of treatment: radiation and chemotherapy. During transarterial radioembolization, beads containing a radioactive substance that only works over a short distance are introduced via a catheter into the hepatic artery – irradiation from the inside, so to speak.
Cell toxins can also be introduced directly into the tumor
During transarterial chemoembolization, drugs – cell toxins – are introduced directly into the tumor in the same way. This locally effective chemotherapy often leads to greater destruction of the tumor than classic, systemic chemotherapy, says Thomas Vogl: “The higher the dose, the better.” In addition, during embolization, vaso-occlusive substances are transported to the liver so that the blood vessels that supply the tumor close and it dies.
An embolization procedure is therefore good for metastases with increased blood flow, explains Vogl. These methods can also be used for slightly larger tumors to initially shrink them so that they can be operated on later, says the doctor.
Study shows how cancer procedures affect survival
In a study, researchers from the Institute for Diagnostic and Interventional Radiology at Goethe University Frankfurt, led by Thomas Vogl, examined how various of these procedures affect survival. Patients lived an average of 50.8 months after treatment with radiofrequency ablation, 43 months after microwave ablation and 45.6 months after laser-induced thermotherapy.
That may not sound like much at first, but you have to know that primary liver cancer has a poor prognosis because it is usually found late and not even 20 percent of patients are still alive five years after diagnosis. When it comes to liver metastases, this always means that the cancer has already spread and is in an advanced stage. For comparison: the mean survival for surgical tumor removal was 47.3 months, and for a liver transplant (which is only possible rarely) it was 104.4 months.
Cancer therapy: Stage of the disease and state of health play a role
Which therapy is used in each individual case is always an individually tailored decision, says Thomas Vogl. The origin and number of tumors play a role, as does the stage of the disease, the general state of health – and what the patient himself or herself wants. In any case, it is important to always go to a large, specialized center with such an illness, says Vogl – specifically to a certified house that can offer all procedures available according to the current state of medicine and where doctors from various disciplines are available discuss the individual cases together at a tumor conference. (pam)
