An often-unpleasant means of assessing the status of a cancer is the biopsy a procedure in which a small sample of a tumor is removed for analysis, often via surgery of some type. Now a study just published in the journal Nature Communications suggests that a new type of blood test might suffice to let doctors know the status of the cancer without an invasive procedure.
Muhammed Murtaza, from Cancer Research UK Cambridge Institute, University of Cambridge, U.K., and colleagues from several institutions, followed a breast cancer patient for three years. The patient's cancer had already spread to other body areas. The investigators periodically took tumor samples and blood samples to analyze. Not all tumor cells are genetically identical, and those that have spread to other parts of the body may be more heterogeneous.
Tumor cells divide, grow, and die, and when cells die they are often shed into the blood. It is known that analyzing the DNA of such cells can provide information about the amount of tumor in a patient's body, as well as the genetic makeup of the tumor. But until now, it was unknown whether or not blood tests would also reflect the variations in the makeup of tumors that had spread or metastasized to secondary sites in the body.
In the reported study, the investigators examined eight tumor biopsies and nine blood samples that were obtained from the breast cancer patient over a period of three years as she was undergoing treatment. When they analyzed the tissues removed in the biopsies and the blood samples taken at the same time points, they found that the tumor DNA found in the blood reflected that from the biopsies. This information allowed them to understand the status of the tumors from various sites as well as the different responses those tumors had to treatments.
Although this is obviously only a very early study one the investigators called "proof of concept" the potential benefits to patients could be great. Not only would such blood tests remove the necessity for repeated surgical biopsies, they would, when perfected, allow clinicians to easily assess the efficacy of treatment(s) and perhaps alter treatments more effectively than is currently possible.
