Selective Internal Radiotherapy (SIRT)

Overview

SIRT using resinous microspheres, is a reimbursable procedure in Switzerland. The text in the Swiss catalogue (KLV) listing such procedures states: in cases of inoperable liver tumors not amenable to chemotherapy, in which other locally ablative therapies are not possible or have not shown any effect”. This holds for all liver metastases or primary liver tumors at Zurich University Hospital mainly patients in late inoperable states and after multiple lines of chemotherapy are presented to the interdisciplinary tumor board. In such cases, first an all encompassing internal medical / oncological assessment of the patient is necessary. This assessment hinges on the performance status of the patient, the identification of the primary dominant localization of the tumor in the liver, the identification of the most recently applied chemotherapy and its potential interference with a SIR-Therapy. Important prerequisites to treat the patient with a SIR-Therapy are mainly a intact liver function, i. e. the absence of ascites as a sign of an advanced liver insufficiency, elevated bilirubin (1.5x above normal values), deranged coagulation status, elevated transaminases as well as thrombocytopenia. The indication for SIRT is summarized below.

Indication for a SIRT-Therapy

Indication

• Inoperable liver tumors, which are refractory to chemo-therapy and in which other locally ablative procedures are not possible or have not shown any benefits

Contra-Indication

• Patient has already received an external radiation therapy oft h liver (not applicable for stereotactic RT)
• Ascites of clinical liver failure
• Abnormal synthetic or excretory liver function tests (ASAT, ALAT 5x above norm, Bilirubin > 35 mumol/l)
• Hepato-pulmonic shunt of more than 20% as per Tc-99m MAA scintigraphy
• gastric refulux, pancreas or gut in Tc-99m-MAA scintigraphy
• Dominant extrahepatic disease

Procedure of the SIR therapy

After a discussion of the procedure with the patient, the preparatory procedures for a SIR-Therapy are done. This out-patient preparation concerns mainly the angiographic planning of the therapy. Only after this angiographic preparation is the patient ready for a SIR-Therapy, and the out-patient Y-90 based therapy itself can be planned and executed. Usually, the time lag between planning and therapy is around 2 weeks. After a 5 hour observation period at the hospital, the patient can normally be sent home. The follow-up occurs in close collaboration with the referring physician and mostly under his auspices.

Side effects

SIR therapy performed by experienced physicians generally has very few side effects. Mild fever, capsular pain, nausea and fatigue over few days are commonly reported. Rare but mandatory complications to be discussed are mainly migrations of the microspheres via gastric or duodenal arteries into the corresponding organs. This is very unpleasant for patients and leads to local ulceration. These rare but possible side effects are discussed with the patient during the initial consultation.