ASCO 2013: PET scan illuminates breast cancer’s weaknesses (VIDEO)
June 3, 2013
| by Hiu Chung So
Trastuzumab (also known as Herceptin) and other breast cancer treatments targeting the HER2 protein have saved numerous lives, but the therapy doesn't benefit all patients equally.
After administering two doses of Herceptin (one regular, then one with a tracer agent), City of Hope researchers were able to visualize breast cancer metastases that were receptive to HER2 treatments (glowing spots in lower right diagram).
Further, because treatments are expensive — Herceptin for a year costs approximately $54,000 — and come with serious side effects, clinicians are looking for ways to identify breast cancers that are most likely to respond to the drug. The answer may lie in positron emission tomography (PET) scans, according to City of Hope research being presented at the American Society of Clinical Oncology annual meeting in Chicago. In the study, researchers administered a dose of trastuzumab to patients followed by another dose of trastuzumab modified with a tracing agent. The idea is that, although tumor and normal tissues alike will take up the normal trastuzumab, only the cancer cells will take up the tracing agent-modified trastuzumab, allowing for better visualization of the tumor. Joanne Mortimer, M.D., director of the Women’s Cancers Program at City of Hope and lead author of the study, said that, in addition to identifying tumors that were responsive to HER2 treatments, the study also found that some tumors classified as HER2-negative took in the tracer-linked trastuzumab as well. That finding implies a possible benefit for anti-HER2 treatments for this group, as well, and is worth further investigation, she said. Mortimer discussed the findings in the video above.