Anna D. Barker, PhD

Q: In addition to diagnosing cancer, how can doctors use  imaging to determine if treatment is working

A: New imaging technologies that measure the  extent of drug-target interactions are the latest in biomarker discoveries.  Biomarkers can also be used to predict cancer recurrence, indicate the presence  of cancer—such as prostate-specific antigen (PSA) for prostate cancer or CA-125  for ovarian cancer&mdash;or to determine which patients will respond to certain  therapies, as is the case for Herceptin (trastuzumab) in HER2-positive breast  cancer. 

The National Cancer institute, the Food and Drug Administration  and the Centers for Medicare & Medicaid Services—all part of the U.S.  Department of Health and Human Services&mdash;are collaborating on a project to  determine if dynamic, functional imaging technology can be used to measure  change in a tumor following treatment, thus making it a biomarker of therapeutic  response.

Ongoing projects include fluorodeoxyglucose- positron emission  tomography (FDG-PET) scanning of patients being treated for lung cancer or  non-Hodgkin’s lymphoma. The technique employs an imaging tool used to diagnose  cancer (PET) with a fluorescent marker (FDG) to reveal tumor growth. Cancer  cells, particularly those from aggressive tumors, consume significantly larger  amounts of FDG, a type of sugar, than surrounding normal tissue. Presence of FDG  can be detected by PET imaging in tumors as small as 1 centimeter.

FDG-PET studies could have an enormous impact on patient care by  validating a tool to identify treatment response. Doctors would be able to  compare PET scans taken before and after therapy to determine if metabolic  activity of cancer cells has increased or decreased rather than waiting for the  volume of the tumor to change, which could take weeks or months. Results from  these trials will be available on the NCI’s cancer Biomedical informatics Grid™  website at 

Anna D. Barker, PhD, is deputy director of the NCI and deputy director for Advanced Technologies and Strategic Partnerships & Gary Kelloff, MD, is special advisor to NCI's Cancer Imaging Program in the Division of Cancer Treatment and Diagnosis.

Articles

 Functional imaging more quickly determines if therapy is working. 

Anna D. Barker, PhD

Q&A: Functional Imaging

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