Innovative selective intra-arterial radiotherapy (SIRT) is a method of cancer treatment, during which embolization (blockage) of the blood vessels of the liver tumor with radioactive particles is performed.
SIRT procedures are used in cases of non-surgical (not suitable for operative treatment) liver tumors and liver metastases. Embolization – blockage of part or all of the radius of a blood vessel, stopping blood flow in vascular formations.
Radioembolization with Holmium-166 radioisotope.
After the radioactive material treatment, the patient’s background radioactivity is measured. If the patient has been treated with a topical approach, the radioactivity is localised to the site where it is injected. After the procedure, a larger background of radioactivity was measured, so the patient’s isolation measures are applied for a certain period of time – the patient stays in a separate ward for a day until he becomes safe for the environment and can return to the house.
SIRT application
International guidelines recommend SIRT as one of the HCC and mCRC tumorsų. It aims to increase overall survival in patients with advancedadvanced stages of HCC tumours in patients with advanced HCC who have received prior treatmentmethods have not been successful.
For early-stage HCC patients, SIRT also aims to provide access to curative treatments such as, “bridging” pre-transplant, offering tumour control to keep the patient on the transplant waiting list for a longer period of time. It can also be used to shrink patients’ tumours to allow for resection.
SIRT procedure
The radioembolisation procedure consists of 2 stages – a diagnostic stage and a treatment stage. The two steps are identical, only the amount of radioisotope injected differs. During the diagnostic phase, a small dose of a radioactive agent is injected. This stage is designed to see exactly where the product is going so that the patient can receive a safe treatment. To achieve the best possible effect, special software calculates the dose needed for each focus and patient. This leads to personalised treatment, where the tactic – the dose of the drug and the site to be treated – is personalised to the patient.
In a minimally invasive interventional procedure, holmium microspheres are deposited in the tumour tissue and the beta radiation emitted by the isotope affects the tumour biology and promotes tumour cell death. The Holmium isotope has unique properties, such as additional low-energy gamma radiation and paramagnetic radiation, which make the isotope visible in diagnostic equipment. This allows very precise planning of the procedure and calculation of the dose of radioactivity to be administered individually to maximise the success of the treatment and avoid serious side effects
SIRT course and treatment scenarios
Fast-growing liver tumours have a large number of feeding blood vessels, which is the feature that doctors try to exploit. Their job is to identify blood vessels and access them using special navigational angiography software. The treatment involves puncturing an artery in the arm or thigh, accessing the hepatic arteries with special guiding catheters, and using even thinner microcatheters (0.6-0.8 mm in diameter) to reach the arteries feeding the tumour and injecting the radioactive particles slowly with the blood stream. A precisely calculated amount of particles is “trapped” in the tumour’s microvasculature, and internal irradiation takes place – the radioactivity destroys nearby tumour cells.
Table: Different clinical scenarios for the use of SIRT in HCC that determine the usefulness of MAA analysis
SIRT procedure practices
Control angiography is performed, during which a tumor filled with contrast is observed.
Selective intra-arterial radiotherapy (SIRIT) is an extremely accurate and safe method that allows you to affect only the tumor without damaging other organs, tissues, but also the rest of the healthy part of the liver.
The drug, which is absorbed on the surface of the microspheres, has a significantly longer effect on cancerous liver tissue compared to other methods of treating liver cancer.
When microspheres enter the small blood vessels of the tumor, blood circulation is disturbed, ischemia and necrosis of tumor cells develop.
SIRT photo gallery
Radioembolisation is one of the local therapies available from 2022. included in international liver cancer treatment guides. This procedure is reimbursed in Lithuania by the Compulsory Health Insurance budget.
Products
QUIREM SPHERES
TERUMO's Holmium platform is the first SIRT: comprehensive platform for the treatment of inoperable liver tumours. Quiremspheres™: the only therapeutic SIRT microsphere used as part of a fully integrated platform
OCCLUSAFE
The occlusive balloon microcatheter from TERUMO allows redistribution of blood flow and micro-circulation, which increases the accumulation of therapeutic agents in the target lesion and reduces off-target embolization.
PROGREAT
TERUMO microcatheter with integrated wire for therapeutic embolization and angiography in peripheral blood vessels. Ease of use, bend resistance, distal flexibility
ANGIO SEAL VIP
Angio-Seal™ VIP Cruciate Vein Closure Device for closure and reduction of time to haemostasis at the site of common femoral artery puncture in patients undergoing diagnostic angiography or interventional procedures
