SIR-Spheres
Encyclopedia
SIR-Spheres microspheres is used to treat patients with unresectable liver cancer
. These are mostly patients with hepatocellular carcinoma
(HCC), metastatic colorectal cancer
(mCRC), or metastatic neuroendocrine tumours (mNET). In the US the product is only approved for the treatment of mCRC.
Therapy goals are local disease control, downstaging to resection, bridging to transplantation, and extended survival.
. The microspheres are impregnated with 90Y
, a beta radiating
isotope of yttrium
with a half-life
of 64.1 hours.
by an Interventional Radiologist the microspheres will preferably lodge in the vasculature of the tumour. The radiation will lead to damage of tumour tissue and, in the best case to a complete elimination of the tumour. Due to the half-life almost all of the radiation is delivered within 2 weeks. After 1 month almost no radioactivity will be remaining.
The procedure is also known as Selective Internal Radiation Therapy or Radioembolisation.
Liver cancer
Liver tumors or hepatic tumors are tumors or growths on or in the liver . Several distinct types of tumors can develop in the liver because the liver is made up of various cell types. These growths can be benign or malignant...
. These are mostly patients with hepatocellular carcinoma
Hepatocellular carcinoma
Hepatocellular carcinoma is the most common type of liver cancer. Most cases of HCC are secondary to either a viral hepatitide infection or cirrhosis .Compared to other cancers, HCC is quite a rare tumor in the United States...
(HCC), metastatic colorectal cancer
Colorectal cancer
Colorectal cancer, commonly known as bowel cancer, is a cancer caused by uncontrolled cell growth , in the colon, rectum, or vermiform appendix. Colorectal cancer is clinically distinct from anal cancer, which affects the anus....
(mCRC), or metastatic neuroendocrine tumours (mNET). In the US the product is only approved for the treatment of mCRC.
Therapy goals are local disease control, downstaging to resection, bridging to transplantation, and extended survival.
Description
SIR-Spheres microspheres contain resin based microspheres with an average diameter between 20 and 60 micrometreMicrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
. The microspheres are impregnated with 90Y
Isotopes of yttrium
Natural yttrium is composed of only one isotope 89Y. The most stable radioisotopes are 88Y which has a half-life of 106.65 days and 91Y with a half-life of 58.51 days. All the other isotopes have half-lives of less than a day, except 87Y, which has a half-life of 79.8 hours, and 90Y, with 64 hours...
, a beta radiating
Beta decay
In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...
isotope of yttrium
Yttrium
Yttrium is a chemical element with symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and it has often been classified as a "rare earth element". Yttrium is almost always found combined with the lanthanides in rare earth minerals and is...
with a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of 64.1 hours.
Mode of Action
Once injected into the hepatic artery via a catheterCatheter
In medicine, a catheter is a tube that can be inserted into a body cavity, duct, or vessel. Catheters thereby allow drainage, administration of fluids or gases, or access by surgical instruments. The process of inserting a catheter is catheterization...
by an Interventional Radiologist the microspheres will preferably lodge in the vasculature of the tumour. The radiation will lead to damage of tumour tissue and, in the best case to a complete elimination of the tumour. Due to the half-life almost all of the radiation is delivered within 2 weeks. After 1 month almost no radioactivity will be remaining.
The procedure is also known as Selective Internal Radiation Therapy or Radioembolisation.