Selective Internal Radiation Therapy (SIRT)
What is SIRT?
SIRT stands for Selective Internal Radiation Therapy, a well-established therapeutic procedure to treat liver cancer and metastasis to the liver. Here, tiny radiolabeled microspheres are injected into the tumor-affected liver segments via an intra-arterially placed catheter.
The microsphere application (labeled with the beta-emitter Yttrium-90) into the tumor-feeding arteries results in high radiation doses to the tumor whereas the radiation exposure of adjacent healthy liver tissue is limited.
What kinds of patients are eligible for this therapy?
SIRT is a local liver-specific therapy option. As such, it is indicated in situations with tumor spread limited to the liver, or in case of liver dominant tumor disease (in this aspect, PET/CT-imaging is usually performed to exclude relevant extra-hepatic disease and to monitor response to therapy).
The therapy is well established for liver-own tumors (e.g. hepatocellular carcinoma - HCC, cholangiocellular carcinoma - CCC) and liver metastases from e.g. colorectal cancer (CRC), neuroendocrine tumors (NET) and melanoma. However, also liver metastases from other tumor entities may be targeted, especially if they are hypervascular.
While SIRT is generally well tolerated, it is contraindicated during pregnancy and in case of limited hepatic and bone marrow function. As SIRT requires the performance of angiographic procedures, there should be no contraindications for the exposure to iodine containing contrast media (e.g. allergy or renal insufficiency). Additionally, life expectancy of eligible patients should be at least 3 months.
How can patients benefit from this therapy?
The main goal of this therapy is to induce hepatic disease stabilization resulting in improved liver function, prolonged life expectancy and improved quality of life. While SIRT cannot cure liver cancer, it can dramatically reduce the size of the tumor in certain patients. Sometimes previously not possible surgery can be performed after SIRT.