(rÄâ²dÃ¤r) 1. A method of detecting distant objects and determining their position, speed, or other characteristics by causing radio waves to be reflected from them and analyzing the reflected waves. The waves can be converted into images, as for use on weather maps.
A high level of the marker may indicate a worsened prognosis in some situations. The most effective and common purpose of tumor markers is to monitor the cancer treatment. As the cancer levels go on decreasing in the body, the marker also goes down. If the marker remains stagnant or increases, it is usually an indication that the patient is not responding sufficiently to the treatment.
tumor marker. listen (TOO-mer MAR-ker) A substance found in tissue, blood, or other body fluids that may be a sign of cancer or certain benign (noncancerous) conditions. Most tumor markers are made by both normal cells and cancer cells, but they are made in larger amounts by cancer cells. A tumor marker may help to diagnose cancer, plan treatment, or find out how well treatment is working or if cancer has come back. Examples of tumor markers include CA-125 (in ovarian cancer), CA 15-3 (in breast cancer), CEA (in colon cancer), and PSA (in prostate cancer).