Researchers at the University of California, San Diego are developing nonsurgical methods for identifying critical lymph nodes to help doctors determine courses of treatment for breast cancer patients. The "sentinel lymph node" is routinely biopsied or removed and dissected to determine the likelihood that the cancer has spread beyond the breast. Dr. Andrew Goodwin, a post doctoral fellow in the Department of Nanoengineering in the UC San Diego Jacobs School of Engineering recently received a Breast Cancer Postdoctoral Fellowship Award from the U.S. Department of Defense to use novel microbubbles to mark and interrogate the sentinel lymph node by means of a simple ultrasound scan.
"Since analysis of tumor stage is important for all breast cancer patients, this work would be expected to help many patients," explained Goodwin.
Cancer cells can detach from a primary tumor and enter the bloodstream by way of the lymph nodes. To determine if the cancer is spreading to other parts of the body, surgeons will biopsy or remove the lymph nodes to look for invading cells. Finding cancer cells in the lymph nodes often changes the course of treatment in an effort to kill any cancer cells that have already spread beyond the breast. Removing just the first, or sentinel, lymph node for analysis helps to reduce the likelihood of developing lymphedema, a painful, long-term swelling at the area of dissection.
The benefits of sentinel lymph node dissection for breast cancer patients were underscored by research findings recently published in The Journal of the American Medical Association: http://jama.ama-assn.org/content/305/6/569.full
However, identifying the correct lymph node to remove is not straightforward. Current methods require injection of radioactive colloids, which tend to blur at the injection site, or blue dye, which leaches into multiple nodes and can only be observed after opening up the patient. These "black box" methods provide little information about the structure of the lymph nodes at the tumor site, and both require the patient to be prepared for a surgery that may be unnecessary if the contrast administration is unsuccessful.
Ultrasound and Microbubbles