Researchers may have found a new technique to provide cancer patients with a non-invasive way to monitor how well they respond to treatment. Currently doctors assess the progress of cancer tumors using biopsies. During a biopsy, tissue samples are removed from the patient for laboratory analysis.
Researchers are studying a method in which they can look for fragments of DNA shed from tumor cells as an alternative to biopsies. This would help doctors provide custom treatment for individual patients and track the progress of treatment using a non-invasive method.
"This study offers a practical application of cancer genomics and highlights the potential of personalized cancer medicine. By understanding the point at which a cancer changes we can select the most effective treatments and minimize side effects for patients," said co-lead author professor Carlos Caldas.
Caldas and his research team conducted the study by determining the progress of 30 female breast cancer patients. The women were undergoing treatment for advanced breast cancer that was spreading, which is known as metastatic.
The research team assessed the progress of the disease by comparing the use of circulating tumor DNA against two biomarkers, the cancer antigen 15-3 (CA 15-3) and circulating tumor cells.
The results of the three sets of biomarkers were compared using CT scans to see if changes found in them matched up with changes in the cancer.
Data indicated the successful detection of tumor DNA in 97 percent of the participants. The researchers also detected circulating tumor cells in 87 percent of the women. The biomarker CA 15-3 was detected in 78 percent of the women. Out of the three biomarkers, circulating tumor DNA gave the earliest measure of treatment response in 53 percent of the women.
"Circulating tumor DNA levels showed a greater dynamic range, and greater correlation with changes in tumor burden, than did CA 15-3 or circulating tumor cells. This proof-of-concept analysis showed that circulating tumor DNA is an informative, inherently specific, and highly sensitive biomarker of metastatic breast cancer," said the researchers.
Findings of the study were published in the New England Journal of Medicine on March 13.