Positron emission tomography (PET) imaging can identify effectiveness of chemotherapy early in high-risk breast cancer patients

Jul 26 2005

The effectiveness of chemotherapy in patients with advanced breast cancer can be evaluated earlier by using 18F-FDG positron emission tomography (PET) imaging over other conventional imaging procedures, according to an article in the July issue of the Society of Nuclear Medicine's Journal of Nuclear Medicine.

PET imaging performed at baseline and after the initiation of treatment "allowed prediction of response as early as after the first cycle of chemotherapy," said Norbert Avril, M.D., chief of the division of nuclear medicine at the University of Pittsburgh Medical Center, Pittsburgh, Pa. Conventional imaging procedures, such as computed tomography (CT), magnetic resonance imaging (MRI), plain film radiography and ultrasound, do not reliably predict therapy response early in the course of treatment, explained the co-author of "Early Prediction of Response to Chemotherapy in Metastatic Breast Cancer Using Sequential 18F-FDG PET."

Metastatic breast cancer is the most advanced stage of breast cancer. Cancer cells have spread past the breast and underarm lymph nodes to other areas of the body, continuing to grow, multiply and possibly spread to other regions of the body. Chemotherapy, which uses drugs to stop the growth of cancer cells, either by killing the cells or stopping the cells from dividing, is typically used with patients. At this advanced stage of the disease, the aim of treatment is to improve survival and quality of life, since the disease is generally not curable, said Avril. It's essential to identify those individuals who don't respond to chemotherapy early "to avoid ineffective therapies and unnecessary side effects," he noted. This ability to individualize treatment gives patients and physicians options not previously available, added Avril, indicating that additional studies are needed to determine how to use 18F-FDG PET in a clinical setting.

PET is a powerful medical imaging procedure that noninvasively demonstrates the function of organs and other tissues. It is used primarily as a diagnostic tool in cardiology, neurology, oncology and many other medical specialties. To image cancer, a radiopharmaceutical such as fluorodeoxyglucose (FDG), which includes both sugar (metabolized at a higher rate by cancer cells) and a radionuclide, is injected into the patient. Because cancer cells metabolize sugar at higher rates than normal cells, the radiopharmaceutical is drawn in higher concentrations to cancerous areas. The PET scan shows where the radiopharmaceutical is by tracking the gamma ray signals given off by the radionuclides.

Avril co-wrote "Early Prediction of Response to Chemotherapy in Metastatic Breast Cancer Using Sequential 18F-FDG PET" with Joerg Dose Schwarz, M.D., Michael Bader, M.D., Gabriele Hemminger, M.D., and Fritz Janicke, M.D., department of gynecology, and Lars Jenicke, M.D., department of nuclear medicine, all at the University Hospital Hamburg-Eppendorf, Hamburg, Germany.