News Release

CANCER RESEARCH HIGHLIGHTS
From the 50th AAPM Meeting in Houston, July 27 to July 31

4. SPARING LEUKEMIA PATIENTS FROM UNNECESSARY TREATMENT

Nearly a third of leukemia patients do not respond to chemotherapy, but this is not usually discovered until they have already endured a week-long chemotherapy treatment and waited a month to see whether it has worked. A new study shows that PET scans could tell how well a patient is responding after just one day of chemotherapy.

Treating leukemia primarily involves killing the cancerous cells where they originate in the bone marrow. Chemotherapy can knock out bone marrow cells, but it also kills healthy cells, causing such side effects as immunodeficiency and weight loss. Doctors traditionally take a bone marrow biopsy after the treatment to assess how well the drugs have worked. This is unfortunately rather late for those who do not respond to chemotherapy. And even for those who do, the single biopsy is not always representative of how the entire bone marrow is responding.

A PET scan can detect cancerous activity in a full-body image, but it had previously never been used to assess leukemia treatment. As an investigative study, Matt Vanderhoek (mattmv@gmail.com) of the University of Wisconsin and his colleagues imaged eight people with leukemia at different stages of their chemotherapy. They used a PET radio-tracer called FLT (fluoro-L-thymidine), which is readily taken up by cells during cell division. Since leukemia cells divide more than normal cells, they should absorb a lot of FLT and appear brighter in the bone marrow of a PET scan. However, if chemotherapy is able to kill these over-proliferative cells, then the bone marrow should appear dark.

In their sample, the researchers found that brightness and non-uniformity in bone marrow PET scans was an indication that the subject was not responding to the chemotherapy. This assessment, which apparently can be made as early as day one, could potentially spare 30 percent of people with leukemia from a treatment that is wrong for them.

Talk (TH-D-AUD C-6), "Early Assessment of Treatment Response in Hematopoietic Disease Using [18F]FLT PET Imaging " is at 1:30 p.m. on Thursday July 29, 2008 in Auditorium C. Abstract: http://www.aapm.org/meetings/amos2/pdf/35-8912-11242-598.pdf.

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HOW TO COVER THE MEETING

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ABOUT AAPM

The American Association of Physicists in Medicine (AAPM) is a scientific, educational, and professional nonprofit organization whose mission is to advance the application of physics to the diagnosis and treatment of human disease. The association encourages innovative research and development, helps disseminate scientific and technical information, fosters the education and professional development of medical physicists, and promotes the highest quality medical services for patients. In 2008, AAPM will celebrate its 50th year of serving patients, physicians, and physicists. Please visit the association's Web site at http://www.aapm.org/.

ABOUT AIP

Headquartered in College Park, MD., the American Institute of Physics is a not-for-profit membership corporation chartered in New York State in 1931 for the purpose of promoting the advancement and diffusion of the knowledge of physics and its application to human welfare.

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Media contacts:

Jason Socrates Bardi, American Institute of Physics,
301-209-3091 (office) 858-775-4080 (cell)
jbardi@aip.org

Jeff Limmer, AAPM Media Relations Subcommittee Chair
jeffl@aspirus.org