In minimally invasive tumour therapy, a rough distinction can be made between two types of procedure:

• Catheter-based procedures
• CT-guided insertion of probes

TACE

TACE(transarterialchemoembolisation) is a radiological, minimally invasive procedure for the palliative treatment of liver tumours.

A thin catheter, which is inserted via the inguinal artery, is advanced into the liver under fluoroscopy. This catheter is then used to inject tiny particles, known as microparticles, directly into the vessels that supply the liver tumour. On the one hand, this reduces the blood supply to the tumour, as the vessels are blocked by the particles. On the other hand, cell growth in the tumour is inhibited as the microparticles are loaded with a chemotherapeutic agent that can develop its effect directly in the tumour without spreading throughout the body as with "normal" chemotherapy.

The aim of TACE is therefore to shrink the tumour and inhibit further growth.

SIRT

Similar to TACE, SIRT(selectiveinternalradiotherapy) involves inserting a thin catheter via the inguinal artery into the liver. Microparticles loaded with a radioactive substance are injected into the vessels leading to the tumour via this catheter. The radioactive radiation emitted unfolds its effect in the tumour and leads to the destruction of the tumour cells, while the healthy tissue is largely spared due to the short range of the radiation. In contrast to radiotherapy "from the outside", i.e. conventional radiotherapy, SIRT allows a higher and more effective dose of radiation to be administered directly to the tumour.

In thermal ablation, a probe is inserted into the tumour under image control (usually CT). There, the tissue is irreversibly destroyed locally by heating (radiofrequency ablation or microwave ablation) or cooling (cryoablation), which leads to the destruction of the tumour cells.

The success of the method depends, among other things, on the size of the tumour and the blood supply to the organ. The larger the tumour and the organ perfusion, the higher the probability that not all tumour cells will be irreversibly damaged and that vital tumour tissue will remain in the peripheral areas. Tumours should therefore not be larger than 5 cm in diameter in order to be treated successfully.