NEW YORK (Reuters Health) – Nearly one-third of leukaemia patients do not respond to chemotherapy, but this is not typically discovered until they have already endured a week-long course of chemotherapy and waited even longer to see if the chemotherapy worked. A new study shows that positron emission tomography, known as PET scans, may tell doctors how well a leukaemia patient is responding after just one day of chemotherapy.

"This has very profound implications for patients," Dr. Matt Vanderhoek told Reuters Health. "Instead of making the patient go through a week of chemotherapy only to find out after the fact that their chemotherapy wasn't successful, therapy could be modified and changed on the fly."

The University of Wisconsin researcher presented the research last week at the 50th annual meeting of the American Association of Physicists in Medicine, in Houston, Texas.

Treating leukaemia typically involves killing the cancer cells where they originate in the bone marrow. Doctors traditionally take a bone marrow biopsy up to a week after the end of chemotherapy to see how well the cancer-killing drugs have worked. "The problem with the bone marrow biopsy is that it is an insensitive and weak predictor of treatment response," Vanderhoek said. "A lot of patients will be told that their treatment was successful when in fact it wasn't. As a result you have a patient who has undergone a week of chemotherapy only to find out much later on that their treatment was unsuccessful."

According to Vanderhoek and colleagues, brightness and non-uniformity in the bone marrow FLT PET scan was an indication that the patient was not responding to chemotherapy.