Nuclear medicine: a possible cure to blood cancer

The latest Image of nyuclear medicine showed that nuclear medicine procedures can be used to treat non-Hodgins lymphoma

K.S.Parthasarathy


July 3, 2009


Nuclear medicine: a possible cure to blood cancer
By Dr K. S Parthasarathy
Last month, Dr. A. Lagaru from the Division of Nuclear Medicine at Stanford University Medical Centre and his colleagues won the Society of Nuclear Medicine (SNM) 2009 Image of the Year award in Toronto.
Their poster paper contained an image clearly depicting how radio-immunotherapy can successfully treat non Hodgins Lymphoma (NHL), a potentially fatal form of blood cancer. The US National Cancer Institute estimates that in 2009, 65,980 new cases of NHL will be diagnosed in the US leading to 19,500 deaths.
“Radio-immunotherapy is a form of personalised medicine that combines the cancer fighting ability of radiation therapy with the precise targeting capacity of immunotherapy” (Imaging technology, June 16,2009). It is based on the body’s natural defence system, which protects it from many diseases.
The Stanford group studied two immunotherapy agents Bexxar, which is Iodine-131 based and Zevalin, which is Yttrium-90 based. Iodine-131 and Yttrium-90 are radioactive and emit particulate radiation. The immunotherapy agents home in on the cancerous cells, which become sitting targets for the particulate radiation emitted by Iodine-131 or Yttrium-90 as the case may be. The award-winning image is two sets of before and after Positron Emission Tomography scans of two patients, one treated with Bexxar and the other with Zevalin. Both patients did not show any metabolically active cancer as early as three months after treatment as demonstrated by their PET scans.
A PET scanner uses small amounts of certain radioactive drugs. A special camera that works with a computer provides pictures of the area of the body being imaged. Cancer cells grow and multiply uncontrollably. While doing so, they consume enormous amounts of energy. Basically, this energy comes from burning glucose
Cancer cell metabolise sugar at higher rates than normal cells. Fluoro deoxyglucose (FDG) is a marker for sugar metabolism. It contains Fluorine-18, a positron emitting radionuclide, whose presence will help to trace and locate the sites where FDG molecules get accumulated. Cancerous areas draw higher amounts of FDG, an ideal marker for the disease and its spread. PET scans produce three-dimensional images of the precise location of FDG in the body
“The image of the year was chosen because it shows how molecular therapy can cure non Hodgin’s lymphoma and it provides objective evidence that the patient has been cured”, Dr Henry N, Wagner Jr, a professor of environmental sciences at Johns Hopkins University and past president of the SNM clarified. The Stanford Specialists treated 71 patients. They showed that both the immunotherapy agents are safe and effective in treating non Hodgin’s lymphoma, even in cases where the disease has spread extensively. Twenty four out of 35 patients responded to Bexxar; 28 out of 36 to Zevalin. Taken the two groups together, 27 showed complete response to the drugs. However, in 19 patients the disease progressed in spite of treatment.